kernel misc: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove the sentinel from ctl_table arrays. Reduce by one the values used
to compare the size of the adjusted arrays.

Signed-off-by: Joel Granados <j.granados@samsung.com>

kexec: copy only happens before uchunk goes to zero

When loading segments, ubytes is <= mbytes. When ubytes is exhausted,
there could be remaining mbytes. Then in the while loop, the buf pointer
advancing with mchunk will causing meaningless reading even though it
doesn't harm.

So let's change to make sure that all of the copying and the rest only
happens before uchunk goes to zero.

Link: https://lkml.kernel.org/r/20240222092119.5602-1-gaoshanliukou@163.com
Signed-off-by: yang.zhang <yang.zhang@hexintek.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

crash: split crash dumping code out from kexec_core.c

Currently, KEXEC_CORE select CRASH_CORE automatically because crash codes
need be built in to avoid compiling error when building kexec code even
though the crash dumping functionality is not enabled. E.g
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_KEXEC=y
CONFIG_KEXEC_FILE=y
---------------------

After splitting out crashkernel reservation code and vmcoreinfo exporting
code, there's only crash related code left in kernel/crash_core.c. Now
move crash related codes from kexec_core.c to crash_core.c and only build it
in when CONFIG_CRASH_DUMP=y.

And also wrap up crash codes inside CONFIG_CRASH_DUMP ifdeffery scope,
or replace inappropriate CONFIG_KEXEC_CORE ifdef with CONFIG_CRASH_DUMP
ifdef in generic kernel files.

With these changes, crash_core codes are abstracted from kexec codes and
can be disabled at all if only kexec reboot feature is wanted.

Link: https://lkml.kernel.org/r/20240124051254.67105-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Klara Modin <klarasmodin@gmail.com>
Cc: Michael Kelley <mhklinux@outlook.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: do syscore_shutdown() in kernel_kexec

syscore_shutdown() runs driver and module callbacks to get the system into
a state where it can be correctly shut down. In commit 6f389a8f1dd2 ("PM
/ reboot: call syscore_shutdown() after disable_nonboot_cpus()")
syscore_shutdown() was removed from kernel_restart_prepare() and hence got
(incorrectly?) removed from the kexec flow. This was innocuous until
commit 6735150b6997 ("KVM: Use syscore_ops instead of reboot_notifier to
hook restart/shutdown") changed the way that KVM registered its shutdown
callbacks, switching from reboot notifiers to syscore_ops.shutdown. As
syscore_shutdown() is missing from kexec, KVM's shutdown hook is not run
and virtualisation is left enabled on the boot CPU which results in triple
faults when switching to the new kernel on Intel x86 VT-x with VMXE
enabled.

Fix this by adding syscore_shutdown() to the kexec sequence. In terms of
where to add it, it is being added after migrating the kexec task to the
boot CPU, but before APs are shut down. It is not totally clear if this
is the best place: in commit 6f389a8f1dd2 ("PM / reboot: call
syscore_shutdown() after disable_nonboot_cpus()") it is stated that
"syscore_ops operations should be carried with one CPU on-line and
interrupts disabled." APs are only offlined later in machine_shutdown(),
so this syscore_shutdown() is being run while APs are still online. This
seems to be the correct place as it matches where syscore_shutdown() is
run in the reboot and halt flows - they also run it before APs are shut
down. The assumption is that the commit message in commit 6f389a8f1dd2
("PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()") is
no longer valid.

KVM has been discussed here as it is what broke loudly by not having
syscore_shutdown() in kexec, but this change impacts more than just KVM;
all drivers/modules which register a syscore_ops.shutdown callback will
now be invoked in the kexec flow. Looking at some of them like x86 MCE it
is probably more correct to also shut these down during kexec.
Maintainers of all drivers which use syscore_ops.shutdown are added on CC
for visibility. They are:

arch/powerpc/platforms/cell/spu_base.c .shutdown = spu_shutdown,
arch/x86/kernel/cpu/mce/core.c .shutdown = mce_syscore_shutdown,
arch/x86/kernel/i8259.c .shutdown = i8259A_shutdown,
drivers/irqchip/irq-i8259.c .shutdown = i8259A_shutdown,
drivers/irqchip/irq-sun6i-r.c .shutdown = sun6i_r_intc_shutdown,
drivers/leds/trigger/ledtrig-cpu.c .shutdown = ledtrig_cpu_syscore_shutdown,
drivers/power/reset/sc27xx-poweroff.c .shutdown = sc27xx_poweroff_shutdown,
kernel/irq/generic-chip.c .shutdown = irq_gc_shutdown,
virt/kvm/kvm_main.c .shutdown = kvm_shutdown,

This has been tested by doing a kexec on x86_64 and aarch64.

Link: https://lkml.kernel.org/r/20231213064004.2419447-1-jgowans@amazon.com
Fixes: 6735150b6997 ("KVM: Use syscore_ops instead of reboot_notifier to hook restart/shutdown")
Signed-off-by: James Gowans <jgowans@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Samuel Holland <samuel@sholland.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Alexander Graf <graf@amazon.de>
Cc: Jan H. Schoenherr <jschoenh@amazon.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec_core: fix the assignment to kimage->control_page

image->control_page represents the starting address for allocating the
next control page, while hole_end represents the address of the last valid
byte of the currently allocated control page.

This bug actually does not affect the correctness of allocating control
pages, because image->control_page is currently only used in
kimage_alloc_crash_control_pages(), and this function, when allocating
control pages, will first align image->control_page up to the nearest
`(1 << order) << PAGE_SHIFT` boundary, then use this value as the
starting address of the next control page. This ensures that the newly
allocated control page will use the correct starting address and not
overlap with previously allocated control pages.

Although it does not affect the correctness of the final result, it is
better for us to set image->control_page to the correct value, in case
it might be used elsewhere in the future, potentially causing errors.

Therefore, after successfully allocating a control page,
image->control_page should be updated to `hole_end + 1`, rather than
hole_end.

Link: https://lkml.kernel.org/r/20231221042308.11076-1-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: modify the meaning of the end parameter in kimage_is_destination_range()

The end parameter received by kimage_is_destination_range() should be the
last valid byte address of the target memory segment plus 1. However, in
the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions,
the corresponding value passed to kimage_is_destination_range() is the
last valid byte address of the target memory segment, which is 1 less.

There are two ways to fix this bug. We can either correct the logic of
the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions,
or we can fix kimage_is_destination_range() by making the end parameter
represent the last valid byte address of the target memory segment. Here,
we choose the second approach.

Due to the modification to kimage_is_destination_range(), we also need to
adjust its callers, such as kimage_alloc_normal_control_pages() and
kimage_alloc_page().

Link: https://lkml.kernel.org/r/20231217033528.303333-2-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: use ALIGN macro instead of open-coding it

Use ALIGN macro instead of open-coding it to improve code readability.

Link: https://lkml.kernel.org/r/20231212142706.25149-1-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec_file: add kexec_file flag to control debug printing

Patch series "kexec_file: print out debugging message if required", v4.

Currently, specifying '-d' on kexec command will print a lot of debugging
informationabout kexec/kdump loading with kexec_load interface.

However, kexec_file_load prints nothing even though '-d' is specified.
It's very inconvenient to debug or analyze the kexec/kdump loading when
something wrong happened with kexec/kdump itself or develper want to check
the kexec/kdump loading.

In this patchset, a kexec_file flag is KEXEC_FILE_DEBUG added and checked
in code. If it's passed in, debugging message of kexec_file code will be
printed out and can be seen from console and dmesg. Otherwise, the
debugging message is printed like beofre when pr_debug() is taken.

Note:
****
=====
1) The code in kexec-tools utility also need be changed to support
passing KEXEC_FILE_DEBUG to kernel when 'kexec -s -d' is specified.
The patch link is here:
=========
[PATCH] kexec_file: add kexec_file flag to support debug printing
http://lists.infradead.org/pipermail/kexec/2023-November/028505.html

2) s390 also has kexec_file code, while I am not sure what debugging
information is necessary. So leave it to s390 developer.

Test:
****
====
Testing was done in v1 on x86_64 and arm64. For v4, tested on x86_64
again. And on x86_64, the printed messages look like below:
--------------------------------------------------------------
kexec measurement buffer for the loaded kernel at 0x207fffe000.
Loaded purgatory at 0x207fff9000
Loaded boot_param, command line and misc at 0x207fff3000 bufsz=0x1180 memsz=0x1180
Loaded 64bit kernel at 0x207c000000 bufsz=0xc88200 memsz=0x3c4a000
Loaded initrd at 0x2079e79000 bufsz=0x2186280 memsz=0x2186280
Final command line is: root=/dev/mapper/fedora_intel--knightslanding--lb--02-root ro
rd.lvm.lv=fedora_intel-knightslanding-lb-02/root console=ttyS0,115200N81 crashkernel=256M
E820 memmap:
0000000000000000-000000000009a3ff (1)
000000000009a400-000000000009ffff (2)
00000000000e0000-00000000000fffff (2)
0000000000100000-000000006ff83fff (1)
000000006ff84000-000000007ac50fff (2)
......
000000207fff6150-000000207fff615f (128)
000000207fff6160-000000207fff714f (1)
000000207fff7150-000000207fff715f (128)
000000207fff7160-000000207fff814f (1)
000000207fff8150-000000207fff815f (128)
000000207fff8160-000000207fffffff (1)
nr_segments = 5
segment[0]: buf=0x000000004e5ece74 bufsz=0x211 mem=0x207fffe000 memsz=0x1000
segment[1]: buf=0x000000009e871498 bufsz=0x4000 mem=0x207fff9000 memsz=0x5000
segment[2]: buf=0x00000000d879f1fe bufsz=0x1180 mem=0x207fff3000 memsz=0x2000
segment[3]: buf=0x000000001101cd86 bufsz=0xc88200 mem=0x207c000000 memsz=0x3c4a000
segment[4]: buf=0x00000000c6e38ac7 bufsz=0x2186280 mem=0x2079e79000 memsz=0x2187000
kexec_file_load: type:0, start:0x207fff91a0 head:0x109e004002 flags:0x8
---------------------------------------------------------------------------


This patch (of 7):

When specifying 'kexec -c -d', kexec_load interface will print loading
information, e.g the regions where kernel/initrd/purgatory/cmdline are
put, the memmap passed to 2nd kernel taken as system RAM ranges, and
printing all contents of struct kexec_segment, etc. These are very
helpful for analyzing or positioning what's happening when kexec/kdump
itself failed. The debugging printing for kexec_load interface is made in
user space utility kexec-tools.

Whereas, with kexec_file_load interface, 'kexec -s -d' print nothing.
Because kexec_file code is mostly implemented in kernel space, and the
debugging printing functionality is missed. It's not convenient when
debugging kexec/kdump loading and jumping with kexec_file_load interface.

Now add KEXEC_FILE_DEBUG to kexec_file flag to control the debugging
message printing. And add global variable kexec_file_dbg_print and macro
kexec_dprintk() to facilitate the printing.

This is a preparation, later kexec_dprintk() will be used to replace the
existing pr_debug(). Once 'kexec -s -d' is specified, it will print out
kexec/kdump loading information. If '-d' is not specified, it regresses
to pr_debug().

Link: https://lkml.kernel.org/r/20231213055747.61826-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20231213055747.61826-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Conor Dooley <conor@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: use atomic_try_cmpxchg in crash_kexec

Use atomic_try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
crash_kexec(). x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after cmpxchg.

No functional change intended.

Link: https://lkml.kernel.org/r/20231114161228.108516-1-ubizjak@gmail.com
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

crash_core: move crashk_*res definition into crash_core.c

Both crashk_res and crashk_low_res are used to mark the reserved
crashkernel regions in iomem_resource tree. And later the generic
crashkernel resrvation will be added into crash_core.c. So move
crashk_res and crashk_low_res definition into crash_core.c to avoid
compiling error if CONFIG_CRASH_CORE=on while CONFIG_KEXEC_CORE is unset.

Meanwhile include <asm/crash_core.h> in <linux/crash_core.h> if generic
reservation is needed. In that case, <asm/crash_core.h> need be added by
ARCH. In asm/crash_core.h, ARCH can provide its own macro definitions to
override macros in <linux/crash_core.h> if needed. Wrap the including
into CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION ifdeffery scope to
avoid compiling error in other ARCH-es which don't take the generic
reservation way yet.

Link: https://lkml.kernel.org/r/20230914033142.676708-6-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Jiahao <chenjiahao16@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

crash: add generic infrastructure for crash hotplug support

To support crash hotplug, a mechanism is needed to update the crash
elfcorehdr upon CPU or memory changes (eg. hot un/plug or off/ onlining).
The crash elfcorehdr describes the CPUs and memory to be written into the
vmcore.

To track CPU changes, callbacks are registered with the cpuhp mechanism
via cpuhp_setup_state_nocalls(CPUHP_BP_PREPARE_DYN). The crash hotplug
elfcorehdr update has no explicit ordering requirement (relative to other
cpuhp states), so meets the criteria for utilizing CPUHP_BP_PREPARE_DYN.
CPUHP_BP_PREPARE_DYN is a dynamic state and avoids the need to introduce a
new state for crash hotplug. Also, CPUHP_BP_PREPARE_DYN is the last state
in the PREPARE group, just prior to the STARTING group, which is very
close to the CPU starting up in a plug/online situation, or stopping in a
unplug/ offline situation. This minimizes the window of time during an
actual plug/online or unplug/offline situation in which the elfcorehdr
would be inaccurate. Note that for a CPU being unplugged or offlined, the
CPU will still be present in the list of CPUs generated by
crash_prepare_elf64_headers(). However, there is no need to explicitly
omit the CPU, see justification in 'crash: change
crash_prepare_elf64_headers() to for_each_possible_cpu()'.

To track memory changes, a notifier is registered to capture the memblock
MEM_ONLINE and MEM_OFFLINE events via register_memory_notifier().

The CPU callbacks and memory notifiers invoke crash_handle_hotplug_event()
which performs needed tasks and then dispatches the event to the
architecture specific arch_crash_handle_hotplug_event() to update the
elfcorehdr with the current state of CPUs and memory. During the process,
the kexec_lock is held.

Link: https://lkml.kernel.org/r/20230814214446.6659-3-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Akhil Raj <lf32.dev@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

crash: move a few code bits to setup support of crash hotplug

Patch series "crash: Kernel handling of CPU and memory hot un/plug", v28.

Once the kdump service is loaded, if changes to CPUs or memory occur,
either by hot un/plug or off/onlining, the crash elfcorehdr must also be
updated.

The elfcorehdr describes to kdump the CPUs and memory in the system, and
any inaccuracies can result in a vmcore with missing CPU context or memory
regions.

The current solution utilizes udev to initiate an unload-then-reload of
the kdump image (eg. kernel, initrd, boot_params, purgatory and
elfcorehdr) by the userspace kexec utility. In the original post I
outlined the significant performance problems related to offloading this
activity to userspace.

This patchset introduces a generic crash handler that registers with the
CPU and memory notifiers. Upon CPU or memory changes, from either hot
un/plug or off/onlining, this generic handler is invoked and performs
important housekeeping, for example obtaining the appropriate lock, and
then invokes an architecture specific handler to do the appropriate
elfcorehdr update.

Note the description in patch 'crash: change crash_prepare_elf64_headers()
to for_each_possible_cpu()' and 'x86/crash: optimize CPU changes' that
enables further optimizations related to CPU plug/unplug/online/offline
performance of elfcorehdr updates.

In the case of x86_64, the arch specific handler generates a new
elfcorehdr, and overwrites the old one in memory; thus no involvement with
userspace needed.

To realize the benefits/test this patchset, one must make a couple
of minor changes to userspace:

- Prevent udev from updating kdump crash kernel on hot un/plug changes.
Add the following as the first lines to the RHEL udev rule file
/usr/lib/udev/rules.d/98-kexec.rules:

# The kernel updates the crash elfcorehdr for CPU and memory changes
SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"
SUBSYSTEM=="memory", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"

With this changeset applied, the two rules evaluate to false for
CPU and memory change events and thus skip the userspace
unload-then-reload of kdump.

- Change to the kexec_file_load for loading the kdump kernel:
Eg. on RHEL: in /usr/bin/kdumpctl, change to:
standard_kexec_args="-p -d -s"
which adds the -s to select kexec_file_load() syscall.

This kernel patchset also supports kexec_load() with a modified kexec
userspace utility. A working changeset to the kexec userspace utility is
posted to the kexec-tools mailing list here:

http://lists.infradead.org/pipermail/kexec/2023-May/027049.html

To use the kexec-tools patch, apply, build and install kexec-tools, then
change the kdumpctl's standard_kexec_args to replace the -s with
--hotplug. The removal of -s reverts to the kexec_load syscall and the
addition of --hotplug invokes the changes put forth in the kexec-tools
patch.


This patch (of 8):

The crash hotplug support leans on the work for the kexec_file_load()
syscall. To also support the kexec_load() syscall, a few bits of code
need to be move outside of CONFIG_KEXEC_FILE. As such, these bits are
moved out of kexec_file.c and into a common location crash_core.c.

In addition, struct crash_mem and crash_notes were moved to new locales so
that PROC_KCORE, which sets CRASH_CORE alone, builds correctly.

No functionality change intended.

Link: https://lkml.kernel.org/r/20230814214446.6659-1-eric.devolder@oracle.com
Link: https://lkml.kernel.org/r/20230814214446.6659-2-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Akhil Raj <lf32.dev@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: enable kexec_crash_size to support two crash kernel regions

The crashk_low_res should be considered by /sys/kernel/kexec_crash_size
to support two crash kernel regions shrinking if existing.

While doing it, crashk_low_res will only be shrunk when the entire
crashk_res is empty; and if the crashk_res is empty and crahk_low_res
is not, change crashk_low_res to be crashk_res.

[bhe@redhat.com: redo changelog]
Link: https://lkml.kernel.org/r/20230527123439.772-7-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: add helper __crash_shrink_memory()

No functional change, in preparation for the next patch so that it is
easier to review.

[akpm@linux-foundation.org: make __crash_shrink_memory() static]
Link: https://lore.kernel.org/oe-kbuild-all/202305280717.Pw06aLkz-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230527123439.772-6-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: improve the readability of crash_shrink_memory()

The major adjustments are:
1. end = start + new_size.
The 'end' here is not an accurate representation, because it is not the
new end of crashk_res, but the start of ram_res, difference 1. So
eliminate it and replace it with ram_res->start.
2. Use 'ram_res->start' and 'ram_res->end' as arguments to
crash_free_reserved_phys_range() to indicate that the memory covered by
'ram_res' is released from the crashk. And keep it close to
insert_resource().
3. Replace 'if (start == end)' with 'if (!new_size)', clear indication that
all crashk memory will be shrunken.

No functional change.

Link: https://lkml.kernel.org/r/20230527123439.772-5-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: clear crashk_res if all its memory has been released

If the resource of crashk_res has been released, it is better to clear
crashk_res.start and crashk_res.end. Because 'end = start - 1' is not
reasonable, and in some places the test is based on crashk_res.end, not
resource_size(&crashk_res).

Link: https://lkml.kernel.org/r/20230527123439.772-4-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: delete a useless check in crash_shrink_memory()

The check '(crashk_res.parent != NULL)' is added by commit e05bd3367bd3
("kexec: fix Oops in crash_shrink_memory()"), but it's stale now. Because
if 'crashk_res' is not reserved, it will be zero in size and will be
intercepted by the above 'if (new_size >= old_size)'.

Ago:
if (new_size >= end - start + 1)

Now:
old_size = (end == 0) ? 0 : end - start + 1;
if (new_size >= old_size)

Link: https://lkml.kernel.org/r/20230527123439.772-3-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: fix a memory leak in crash_shrink_memory()

Patch series "kexec: enable kexec_crash_size to support two crash kernel
regions".

When crashkernel=X fails to reserve region under 4G, it will fall back to
reserve region above 4G and a region of the default size will also be
reserved under 4G. Unfortunately, /sys/kernel/kexec_crash_size only
supports one crash kernel region now, the user cannot sense the low memory
reserved by reading /sys/kernel/kexec_crash_size. Also, low memory cannot
be freed by writing this file.

For example:
resource_size(crashk_res) = 512M
resource_size(crashk_low_res) = 256M

The result of 'cat /sys/kernel/kexec_crash_size' is 512M, but it should be
768M. When we execute 'echo 0 > /sys/kernel/kexec_crash_size', the size
of crashk_res becomes 0 and resource_size(crashk_low_res) is still 256 MB,
which is incorrect.

Since crashk_res manages the memory with high address and crashk_low_res
manages the memory with low address, crashk_low_res is shrunken only when
all crashk_res is shrunken. And because when there is only one crash
kernel region, crashk_res is always used. Therefore, if all crashk_res is
shrunken and crashk_low_res still exists, swap them.


This patch (of 6):

If the value of parameter 'new_size' is in the semi-open and semi-closed
interval (crashk_res.end - KEXEC_CRASH_MEM_ALIGN + 1, crashk_res.end], the
calculation result of ram_res is:

ram_res->start = crashk_res.end + 1
ram_res->end = crashk_res.end

The operation of insert_resource() fails, and ram_res is not added to
iomem_resource. As a result, the memory of the control block ram_res is
leaked.

In fact, on all architectures, the start address and size of crashk_res
are already aligned by KEXEC_CRASH_MEM_ALIGN. Therefore, we do not need
to round up crashk_res.start again. Instead, we should round up
'new_size' in advance.

Link: https://lkml.kernel.org/r/20230527123439.772-1-thunder.leizhen@huawei.com
Link: https://lkml.kernel.org/r/20230527123439.772-2-thunder.leizhen@huawei.com
Fixes: 6480e5a09237 ("kdump: add missing RAM resource in crash_shrink_memory()")
Fixes: 06a7f711246b ("kexec: premit reduction of the reserved memory size")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Cong Wang <amwang@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: introduce sysctl parameters kexec_load_limit_*

kexec allows replacing the current kernel with a different one. This is
usually a source of concerns for sysadmins that want to harden a system.

Linux already provides a way to disable loading new kexec kernel via
kexec_load_disabled, but that control is very coard, it is all or nothing
and does not make distinction between a panic kexec and a normal kexec.

This patch introduces new sysctl parameters, with finer tuning to specify
how many times a kexec kernel can be loaded. The sysadmin can set
different limits for kexec panic and kexec reboot kernels. The value can
be modified at runtime via sysctl, but only with a stricter value.

With these new parameters on place, a system with loadpin and verity
enabled, using the following kernel parameters:
sysctl.kexec_load_limit_reboot=0 sysct.kexec_load_limit_panic=1 can have a
good warranty that if initrd tries to load a panic kernel, a malitious
user will have small chances to replace that kernel with a different one,
even if they can trigger timeouts on the disk where the panic kernel
lives.

Link: https://lkml.kernel.org/r/20221114-disable-kexec-reset-v6-3-6a8531a09b9a@chromium.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: factor out kexec_load_permitted

Both syscalls (kexec and kexec_file) do the same check, let's factor it
out.

Link: https://lkml.kernel.org/r/20221114-disable-kexec-reset-v6-2-6a8531a09b9a@chromium.org
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

bpf: Add __bpf_kfunc tag to all kfuncs

Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com

kexec: remove the unneeded result variable

Return the value kimage_add_entry() directly instead of storing it in
another redundant variable.

Link: https://lkml.kernel.org/r/20220929042936.22012-3-bhe@redhat.com
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chen Lifu <chenlifu@huawei.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Jianglei Nie <niejianglei2021@163.com>
Cc: Li Chen <lchen@ambarella.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: replace kmap() with kmap_local_page()

kmap() is being deprecated in favor of kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.

Since its use in kexec_core.c is safe everywhere, it should be preferred.

Therefore, replace kmap() with kmap_local_page() in kexec_core.c.

Tested on a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Link: https://lkml.kernel.org/r/20220821182519.9483-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

panic, kexec: make __crash_kexec() NMI safe

Attempting to get a crash dump out of a debug PREEMPT_RT kernel via an NMI
panic() doesn't work. The cause of that lies in the PREEMPT_RT definition
of mutex_trylock():

if (IS_ENABLED(CONFIG_DEBUG_RT_MUTEXES) && WARN_ON_ONCE(!in_task()))
return 0;

This prevents an nmi_panic() from executing the main body of
__crash_kexec() which does the actual kexec into the kdump kernel. The
warning and return are explained by:

6ce47fd961fa ("rtmutex: Warn if trylock is called from hard/softirq context")
[...]
The reasons for this are:

1) There is a potential deadlock in the slowpath

2) Another cpu which blocks on the rtmutex will boost the task
which allegedly locked the rtmutex, but that cannot work
because the hard/softirq context borrows the task context.

Furthermore, grabbing the lock isn't NMI safe, so do away with kexec_mutex
and replace it with an atomic variable. This is somewhat overzealous as
*some* callsites could keep using a mutex (e.g. the sysfs-facing ones
like crash_shrink_memory()), but this has the benefit of involving a
single unified lock and preventing any future NMI-related surprises.

Tested by triggering NMI panics via:

$ echo 1 > /proc/sys/kernel/panic_on_unrecovered_nmi
$ echo 1 > /proc/sys/kernel/unknown_nmi_panic
$ echo 1 > /proc/sys/kernel/panic

$ ipmitool power diag

Link: https://lkml.kernel.org/r/20220630223258.4144112-3-vschneid@redhat.com
Fixes: 6ce47fd961fa ("rtmutex: Warn if trylock is called from hard/softirq context")
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baoquan He <bhe@redhat.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: turn all kexec_mutex acquisitions into trylocks

Patch series "kexec, panic: Making crash_kexec() NMI safe", v4.


This patch (of 2):

Most acquistions of kexec_mutex are done via mutex_trylock() - those were
a direct "translation" from:

8c5a1cf0ad3a ("kexec: use a mutex for locking rather than xchg()")

there have however been two additions since then that use mutex_lock():
crash_get_memory_size() and crash_shrink_memory().

A later commit will replace said mutex with an atomic variable, and
locking operations will become atomic_cmpxchg(). Rather than having those
mutex_lock() become while (atomic_cmpxchg(&lock, 0, 1)), turn them into
trylocks that can return -EBUSY on acquisition failure.

This does halve the printable size of the crash kernel, but that's still
neighbouring 2G for 32bit kernels which should be ample enough.

Link: https://lkml.kernel.org/r/20220630223258.4144112-1-vschneid@redhat.com
Link: https://lkml.kernel.org/r/20220630223258.4144112-2-vschneid@redhat.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Juri Lelli <jlelli@redhat.com>
Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kexec: drop weak attribute from functions

Drop __weak attribute from functions in kexec_core.c:
- machine_kexec_post_load()
- arch_kexec_protect_crashkres()
- arch_kexec_unprotect_crashkres()
- crash_free_reserved_phys_range()

Link: https://lkml.kernel.org/r/c0f6219e03cb399d166d518ab505095218a902dd.1656659357.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

kexec: remove redundant assignments

Get rid of redundant assignments which end up in values not being read
either because they are overwritten or the function ends.

Reported by clang-tidy [deadcode.DeadStores]

Link: https://lkml.kernel.org/r/20220326180948.192154-1-michalorzel.eng@gmail.com
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Michal Orzel <michalorzel.eng@gmail.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/kexec_core: move kexec_core sysctls into its own file

This move the kernel/kexec_core.c respective sysctls to its own file.

kernel/sysctl.c has grown to an insane mess, We move sysctls to places
where features actually belong to improve the readability and reduce
merge conflicts. At the same time, the proc-sysctl maintainers can easily
care about the core logic other than the sysctl knobs added for some feature.

We already moved all filesystem sysctls out. This patch is part of the effort
to move kexec related sysctls out.

Signed-off-by: yingelin <yingelin@huawei.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

ELF: Remove elf_core_copy_kernel_regs()

x86-32 was the last architecture that implemented separate user and
kernel registers.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220325153953.162643-3-brgerst@gmail.com

exit: Move oops specific logic from do_exit into make_task_dead

The beginning of do_exit has become cluttered and difficult to read as
it is filled with checks to handle things that can only happen when
the kernel is operating improperly.

Now that we have a dedicated function for cleaning up a task when the
kernel is operating improperly move the checks there.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

printk: remove safe buffers

With @logbuf_lock removed, the high level printk functions for
storing messages are lockless. Messages can be stored from any
context, so there is no need for the NMI and safe buffers anymore.
Remove the NMI and safe buffers.

Although the safe buffers are removed, the NMI and safe context
tracking is still in place. In these contexts, store the message
immediately but still use irq_work to defer the console printing.

Since printk recursion tracking is in place, safe context tracking
for most of printk is not needed. Remove it. Only safe context
tracking relating to the console and console_owner locks is left
in place. This is because the console and console_owner locks are
needed for the actual printing.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20210715193359.25946-4-john.ogness@linutronix.de

kernel.h: split out panic and oops helpers

kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.

There are several purposes of doing this:
- dropping dependency in bug.h
- dropping a loop by moving out panic_notifier.h
- unload kernel.h from something which has its own domain

At the same time convert users tree-wide to use new headers, although for
the time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.

[akpm@linux-foundation.org: thread_info.h needs limits.h]
[andriy.shevchenko@linux.intel.com: ia64 fix]
Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com

Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: dump kmessage before machine_kexec

kmsg_dump(KMSG_DUMP_SHUTDOWN) is called before machine_restart(),
machine_halt(), and machine_power_off(). The only one that is missing
is machine_kexec().

The dmesg output that it contains can be used to study the shutdown
performance of both kernel and systemd during kexec reboot.

Here is example of dmesg data collected after kexec:

root@dplat-cp22:~# cat /sys/fs/pstore/dmesg-ramoops-0 | tail
...
[ 70.914592] psci: CPU3 killed (polled 0 ms)
[ 70.915705] CPU4: shutdown
[ 70.916643] psci: CPU4 killed (polled 4 ms)
[ 70.917715] CPU5: shutdown
[ 70.918725] psci: CPU5 killed (polled 0 ms)
[ 70.919704] CPU6: shutdown
[ 70.920726] psci: CPU6 killed (polled 4 ms)
[ 70.921642] CPU7: shutdown
[ 70.922650] psci: CPU7 killed (polled 0 ms)

Link: https://lkml.kernel.org/r/20210319192326.146000-2-pasha.tatashin@soleen.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Cc: James Morris <jmorris@namei.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Anton Vorontsov <anton@enomsg.org>
Cc: Colin Cross <ccross@android.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: Add kexec reboot string

The purpose is to notify the kernel module for fast reboot.

Upstream a patch from the SONiC network operating system [1].

[1]: https://github.com/Azure/sonic-linux-kernel/pull/46

Link: https://lkml.kernel.org/r/20210304124626.13927-1-pmenzel@molgen.mpg.de
Signed-off-by: Joe LeVeque <jolevequ@microsoft.com>
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Guohan Lu <lguohan@gmail.com>
Cc: Joe LeVeque <jolevequ@microsoft.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

elf_prstatus: collect the common part (everything before pr_reg) into a struct

Preparations to doing i386 compat elf_prstatus sanely - rather than duplicating
the beginning of compat_elf_prstatus, take these fields into a separate
structure (compat_elf_prstatus_common), so that it could be reused. Due to
the incestous relationship between binfmt_elf.c and compat_binfmt_elf.c we
need the same shape change done to native struct elf_prstatus, gathering the
fields prior to pr_reg into a new structure (struct elf_prstatus_common).

Fortunately, offset of pr_reg is always a multiple of 16 with no padding
right before it, so it's possible to turn all the stuff prior to it into
a single member without disturbing the layout.

[build fix from Geert Uytterhoeven folded in]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel: kexec: remove the lock operation of system_transition_mutex

Function kernel_kexec() is called with lock system_transition_mutex
held in reboot system call. While inside kernel_kexec(), it will
acquire system_transition_mutex agin. This will lead to dead lock.

The dead lock should be easily triggered, it hasn't caused any
failure report just because the feature 'kexec jump' is almost not
used by anyone as far as I know. An inquiry can be made about who
is using 'kexec jump' and where it's used. Before that, let's simply
remove the lock operation inside CONFIG_KEXEC_JUMP ifdeffery scope.

Fixes: 55f2503c3b69 ("PM / reboot: Eliminate race between reboot and suspend")
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Pingfan Liu <kernelfans@gmail.com>
Cc: 4.19+ <stable@vger.kernel.org> # 4.19+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

crypto: sha - split sha.h into sha1.h and sha2.h

Currently <crypto/sha.h> contains declarations for both SHA-1 and SHA-2,
and <crypto/sha3.h> contains declarations for SHA-3.

This organization is inconsistent, but more importantly SHA-1 is no
longer considered to be cryptographically secure. So to the extent
possible, SHA-1 shouldn't be grouped together with any of the other SHA
versions, and usage of it should be phased out.

Therefore, split <crypto/sha.h> into two headers <crypto/sha1.h> and
<crypto/sha2.h>, and make everyone explicitly specify whether they want
the declarations for SHA-1, SHA-2, or both.

This avoids making the SHA-1 declarations visible to files that don't
want anything to do with SHA-1. It also prepares for potentially moving
sha1.h into a new insecure/ or dangerous/ directory.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

kernel/: fix repeated words in comments

Fix multiple occurrences of duplicated words in kernel/.

Fix one typo/spello on the same line as a duplicate word. Change one
instance of "the the" to "that the". Otherwise just drop one of the
repeated words.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

objtool: Rename frame.h -> objtool.h

Header frame.h is getting more code annotations to help objtool analyze
object files.

Rename the file to objtool.h.

[ jpoimboe: add objtool.h to MAINTAINERS ]

Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>

kexec: add machine_kexec_post_load()

It is the same as machine_kexec_prepare(), but is called after segments are
loaded. This way, can do processing work with already loaded relocation
segments. One such example is arm64: it has to have segments loaded in
order to create a page table, but it cannot do it during kexec time,
because at that time allocations won't be possible anymore.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>

kexec: quiet down kexec reboot

Here is a regular kexec command sequence and output:
=====
$ kexec --reuse-cmdline -i --load Image
$ kexec -e
[ 161.342002] kexec_core: Starting new kernel

Welcome to Buildroot
buildroot login:
=====

Even when "quiet" kernel parameter is specified, "kexec_core: Starting
new kernel" is printed.

This message has KERN_EMERG level, but there is no emergency, it is a
normal kexec operation, so quiet it down to appropriate KERN_NOTICE.

Machines that have slow console baud rate benefit from less output.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>

kexec: bail out upon SIGKILL when allocating memory.

syzbot found that a thread can stall for minutes inside kexec_load() after
that thread was killed by SIGKILL [1]. It turned out that the reproducer
was trying to allocate 2408MB of memory using kimage_alloc_page() from
kimage_load_normal_segment(). Let's check for SIGKILL before doing memory
allocation.

[1] https://syzkaller.appspot.com/bug?id=a0e3436829698d5824231251fad9d8e998f94f5e

Link: http://lkml.kernel.org/r/993c9185-d324-2640-d061-bed2dd18b1f7@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+8ab2d0f39fb79fe6ca40@syzkaller.appspotmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230

Based on 2 normalized pattern(s):

this source code is licensed under the gnu general public license
version 2 see the file copying for more details

this source code is licensed under general public license version 2
see

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 52 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190602204653.449021192@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

power/suspend: Add function to disable secondaries for suspend

This adds a function to disable secondary CPUs for suspend that are
not necessarily non-zero / non-boot CPUs. Platforms will be able to
use this to suspend using non-zero CPUs.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lkml.kernel.org/r/20190411033448.20842-3-npiggin@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

mm: convert totalram_pages and totalhigh_pages variables to atomic

totalram_pages and totalhigh_pages are made static inline function.

Main motivation was that managed_page_count_lock handling was complicating
things. It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: reference totalram_pages and managed_pages once per function

Patch series "mm: convert totalram_pages, totalhigh_pages and managed
pages to atomic", v5.

This series converts totalram_pages, totalhigh_pages and
zone->managed_pages to atomic variables.

totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear.

Main motivation was that managed_page_count_lock handling was complicating
things. It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 It seemes better
to remove the lock and convert variables to atomic. With the change,
preventing poteintial store-to-read tearing comes as a bonus.

This patch (of 4):

This is in preparation to a later patch which converts totalram_pages and
zone->managed_pages to atomic variables. Please note that re-reading the
value might lead to a different value and as such it could lead to
unexpected behavior. There are no known bugs as a result of the current
code but it is better to prevent from them in principle.

Link: http://lkml.kernel.org/r/1542090790-21750-2-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: Allocate decrypted control pages for kdump if SME is enabled

When SME is enabled in the first kernel, it needs to allocate decrypted
pages for kdump because when the kdump kernel boots, these pages need to
be accessed decrypted in the initial boot stage, before SME is enabled.

[ bp: clean up text. ]

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180930031033.22110-3-lijiang@redhat.com

kexec: yield to scheduler when loading kimage segments

Without yielding while loading kimage segments, a large initrd will
block all other work on the CPU performing the load until it is
completed. For example loading an initrd of 200MB on a low power single
core system will lock up the system for a few seconds.

To increase system responsiveness to other tasks at that time, call
cond_resched() in both the crash kernel and normal kernel segment
loading loops.

I did run into a practical problem. Hardware watchdogs on embedded
systems can have short timers on the order of seconds. If the system is
locked up for a few seconds with only a single core available, the
watchdog may not be pet in a timely fashion. If this happens, the
hardware watchdog will fire and reset the system.

This really only becomes a problem when you are working with a single
core, a decently sized initrd, and have a constrained hardware watchdog.

Link: http://lkml.kernel.org/r/1528738546-3328-1-git-send-email-jmf@amazon.com
Signed-off-by: Jarrett Farnitano <jmf@amazon.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x86/mm, kexec: Allow kexec to be used with SME

Provide support so that kexec can be used to boot a kernel when SME is
enabled.

Support is needed to allocate pages for kexec without encryption. This
is needed in order to be able to reboot in the kernel in the same manner
as originally booted.

Additionally, when shutting down all of the CPUs we need to be sure to
flush the caches and then halt. This is needed when booting from a state
where SME was not active into a state where SME is active (or vice-versa).
Without these steps, it is possible for cache lines to exist for the same
physical location but tagged both with and without the encryption bit. This
can cause random memory corruption when caches are flushed depending on
which cacheline is written last.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: <kexec@lists.infradead.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Toshimitsu Kani <toshi.kani@hpe.com>
Cc: kasan-dev@googlegroups.com
Cc: kvm@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/b95ff075db3e7cd545313f2fb609a49619a09625.1500319216.git.thomas.lendacky@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kdump: protect vmcoreinfo data under the crash memory

Currently vmcoreinfo data is updated at boot time subsys_initcall(), it
has the risk of being modified by some wrong code during system is
running.

As a result, vmcore dumped may contain the wrong vmcoreinfo. Later on,
when using "crash", "makedumpfile", etc utility to parse this vmcore, we
probably will get "Segmentation fault" or other unexpected errors.

E.g. 1) wrong code overwrites vmcoreinfo_data; 2) further crashes the
system; 3) trigger kdump, then we obviously will fail to recognize the
crash context correctly due to the corrupted vmcoreinfo.

Now except for vmcoreinfo, all the crash data is well
protected(including the cpu note which is fully updated in the crash
path, thus its correctness is guaranteed). Given that vmcoreinfo data
is a large chunk prepared for kdump, we better protect it as well.

To solve this, we relocate and copy vmcoreinfo_data to the crash memory
when kdump is loading via kexec syscalls. Because the whole crash
memory will be protected by existing arch_kexec_protect_crashkres()
mechanism, we naturally protect vmcoreinfo_data from write(even read)
access under kernel direct mapping after kdump is loaded.

Since kdump is usually loaded at the very early stage after boot, we can
trust the correctness of the vmcoreinfo data copied.

On the other hand, we still need to operate the vmcoreinfo safe copy
when crash happens to generate vmcoreinfo_note again, we rely on vmap()
to map out a new kernel virtual address and update to use this new one
instead in the following crash_save_vmcoreinfo().

BTW, we do not touch vmcoreinfo_note, because it will be fully updated
using the protected vmcoreinfo_data after crash which is surely correct
just like the cpu crash note.

Link: http://lkml.kernel.org/r/1493281021-20737-3-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

objtool, x86: Add several functions and files to the objtool whitelist

In preparation for an objtool rewrite which will have broader checks,
whitelist functions and files which cause problems because they do
unusual things with the stack.

These whitelists serve as a TODO list for which functions and files
don't yet have undwarf unwinder coverage. Eventually most of the
whitelists can be removed in favor of manual CFI hint annotations or
objtool improvements.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/7f934a5d707a574bda33ea282e9478e627fb1829.1498659915.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

ia64: reuse append_elf_note() and final_note() functions

Get rid of multiple definitions of append_elf_note() & final_note()
functions. Reuse these functions compiled under CONFIG_CRASH_CORE Also,
define Elf_Word and use it instead of generic u32 or the more specific
Elf64_Word.

Link: http://lkml.kernel.org/r/149035342324.6881.11667840929850361402.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

crash: move crashkernel parsing and vmcore related code under CONFIG_CRASH_CORE

Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and
reuse crashkernel parameter for fadump", v4.

Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

This patchset removes dependency with CONFIG_KEXEC for crashkernel
parameter and vmcoreinfo related code as it can be reused without kexec
support. Also, crashkernel parameter is reused instead of
fadump_reserve_mem to reserve memory for fadump.

The first patch moves crashkernel parameter parsing and vmcoreinfo
related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE. The
second patch reuses the definitions of append_elf_note() & final_note()
functions under CONFIG_CRASH_CORE in IA64 arch code. The third patch
removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump)
in powerpc. The next patch reuses crashkernel parameter for reserving
memory for fadump, instead of the fadump_reserve_mem parameter. This
has the advantage of using all syntaxes crashkernel parameter supports,
for fadump as well. The last patch updates fadump kernel documentation
about use of crashkernel parameter.

This patch (of 5):

Traditionally, kdump is used to save vmcore in case of a crash. Some
architectures like powerpc can save vmcore using architecture specific
support instead of kexec/kdump mechanism. Such architecture specific
support also needs to reserve memory, to be used by dump capture kernel.
crashkernel parameter can be a reused, for memory reservation, by such
architecture specific infrastructure.

But currently, code related to vmcoreinfo and parsing of crashkernel
parameter is built under CONFIG_KEXEC_CORE. This patch introduces
CONFIG_CRASH_CORE and moves the above mentioned code under this config,
allowing code reuse without dependency on CONFIG_KEXEC. There is no
functional change with this patch.

Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.com
Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk: rename nmi.c and exported api

A preparation patch for printk_safe work. No functional change.
- rename nmi.c to print_safe.c
- add `printk_safe' prefix to some (which used both by printk-safe
and printk-nmi) of the exported functions.

Link: http://lkml.kernel.org/r/20161227141611.940-3-sergey.senozhatsky@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Calvin Owens <calvinowens@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

kexec: Switch to __pa_symbol

__pa_symbol is the correct api to get the physical address of kernel
symbols. Switch to it to allow for better debug checking.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

kexec: add cond_resched into kimage_alloc_crash_control_pages

A soft lookup will occur when I run trinity in syscall kexec_load. the
corresponding stack information is as follows.

BUG: soft lockup - CPU#6 stuck for 22s! [trinity-c6:13859]
Kernel panic - not syncing: softlockup: hung tasks
CPU: 6 PID: 13859 Comm: trinity-c6 Tainted: G O L ----V------- 3.10.0-327.28.3.35.zhongjiang.x86_64 #1
Hardware name: Huawei Technologies Co., Ltd. Tecal BH622 V2/BC01SRSA0, BIOS RMIBV386 06/30/2014
Call Trace:
<IRQ> dump_stack+0x19/0x1b
panic+0xd8/0x214
watchdog_timer_fn+0x1cc/0x1e0
__hrtimer_run_queues+0xd2/0x260
hrtimer_interrupt+0xb0/0x1e0
? call_softirq+0x1c/0x30
local_apic_timer_interrupt+0x37/0x60
smp_apic_timer_interrupt+0x3f/0x60
apic_timer_interrupt+0x6d/0x80
<EOI> ? kimage_alloc_control_pages+0x80/0x270
? kmem_cache_alloc_trace+0x1ce/0x1f0
? do_kimage_alloc_init+0x1f/0x90
kimage_alloc_init+0x12a/0x180
SyS_kexec_load+0x20a/0x260
system_call_fastpath+0x16/0x1b

the first time allocation of control pages may take too much time
because crash_res.end can be set to a higher value. we need to add
cond_resched to avoid the issue.

The patch have been tested and above issue is not appear.

Link: http://lkml.kernel.org/r/1481164674-42775-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: export the value of phys_base instead of symbol address

Currently in x86_64, the symbol address of phys_base is exported to
vmcoreinfo. Dave Anderson complained this is really useless for his
Crash implementation. Because in user-space utility Crash and
Makedumpfile which exported vmcore information is mainly used for, value
of phys_base is needed to covert virtual address of exported kernel
symbol to physical address. Especially init_level4_pgt, if we want to
access and go over the page table to look up a PA corresponding to VA,
firstly we need calculate

page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + phys_base;

Now in Crash and Makedumpfile, we have to analyze the vmcore elf program
header to get value of phys_base. As Dave said, it would be preferable
if it were readily availabl in vmcoreinfo rather than depending upon the
PT_LOAD semantics.

Hence in this patch change to export the value of phys_base instead of
its virtual address.

And people also complained that KERNEL_IMAGE_SIZE exporting is x86_64
only, should be moved into arch dependent function
arch_crash_save_vmcoreinfo. Do the moving in this patch.

Link: http://lkml.kernel.org/r/1478568596-30060-2-git-send-email-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Eugene Surovegin <surovegin@google.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Cc: Dave Anderson <anderson@redhat.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Revert "kexec: Export kexec_in_progress to modules"

This reverts commit 97dcaa0fcfd24daa9a36c212c1ad1d5a97759212. Based on
the review discussion with Eric, we will come up with a different fix
for the bcm_sf2 driver which does not make it rely on the
kexec_in_progress value.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kexec: Export kexec_in_progress to modules

The bcm_sf2 driver uses kexec_in_progress to know whether it can power
down an integrated PHY during shutdown, and can be built as a module.
Other modules may be using this in the future, so export it.

Fixes: 2399d6143f85 ("net: dsa: bcm_sf2: Prevent GPHY shutdown for kexec'd kernels")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

kexec: add restriction on kexec_load() segment sizes

I hit the following issue when run trinity in my system. The kernel is
3.4 version, but mainline has the same issue.

The root cause is that the segment size is too large so the kerenl
spends too long trying to allocate a page. Other cases will block until
the test case quits. Also, OOM conditions will occur.

Call Trace:
__alloc_pages_nodemask+0x14c/0x8f0
alloc_pages_current+0xaf/0x120
kimage_alloc_pages+0x10/0x60
kimage_alloc_control_pages+0x5d/0x270
machine_kexec_prepare+0xe5/0x6c0
? kimage_free_page_list+0x52/0x70
sys_kexec_load+0x141/0x600
? vfs_write+0x100/0x180
system_call_fastpath+0x16/0x1b

The patch changes sanity_check_segment_list() to verify that the usage by
all segments does not exceed half of memory.

[akpm@linux-foundation.org: fix for kexec-return-error-number-directly.patch, update comment]
Link: http://lkml.kernel.org/r/1469625474-53904-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: add a kexec_crash_loaded() function

Provide a wrapper function to be used by kernel code to check whether a
crash kernel is loaded. It returns the same value that can be seen in
/sys/kernel/kexec_crash_loaded by userspace programs.

I'm exporting the function, because it will be used by Xen, and it is
possible to compile Xen modules separately to enable the use of PV
drivers with unmodified bare-metal kernels.

Link: http://lkml.kernel.org/r/20160713121955.14969.69080.stgit@hananiah.suse.cz
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: allow architectures to override boot mapping

kexec physical addresses are the boot-time view of the system. For
certain ARM systems (such as Keystone 2), the boot view of the system
does not match the kernel's view of the system: the boot view uses a
special alias in the lower 4GB of the physical address space.

To cater for these kinds of setups, we need to translate between the
boot view physical addresses and the normal kernel view physical
addresses. This patch extracts the current transation points into
linux/kexec.h, and allows an architecture to override the functions.

Due to the translations required, we unfortunately end up with six
translation functions, which are reduced down to four that the
architecture can override.

[akpm@linux-foundation.org: kexec.h needs asm/io.h for phys_to_virt()]
Link: http://lkml.kernel.org/r/E1b8koP-0004HZ-Vf@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kdump: arrange for paddr_vmcoreinfo_note() to return phys_addr_t

On PAE systems (eg, ARM LPAE) the vmcore note may be located above 4GB
physical on 32-bit architectures, so we need a wider type than "unsigned
long" here. Arrange for paddr_vmcoreinfo_note() to return a
phys_addr_t, thereby allowing it to be located above 4GB.

This makes no difference for kexec-tools, as they already assume a
64-bit type when reading from this file.

Link: http://lkml.kernel.org/r/E1b8koK-0004HS-K9@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: ensure user memory sizes do not wrap

Ensure that user memory sizes do not wrap around when validating the
user input, which can lead to the following input validation working
incorrectly.

[akpm@linux-foundation.org: fix it for kexec-return-error-number-directly.patch]
Link: http://lkml.kernel.org/r/E1b8koF-0004HM-5x@rmk-PC.armlinux.org.uk
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Pratyush Anand <panand@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Keerthy <j-keerthy@ti.com>
Cc: Vitaly Andrianov <vitalya@ti.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: return error number directly

This is a cleanup patch to make kexec more clear to return error number
directly. The variable result is useless, because there is no other
function's return value assignes to it. So remove it.

Link: http://lkml.kernel.org/r/1464179273-57668-1-git-send-email-mnghuan@gmail.com
Signed-off-by: Minfei Huang <mnghuan@gmail.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

s390/kexec: consolidate crash_map/unmap_reserved_pages() and arch_kexec_protect(unprotect)_crashkres()

Commit 3f625002581b ("kexec: introduce a protection mechanism for the
crashkernel reserved memory") is a similar mechanism for protecting the
crash kernel reserved memory to previous crash_map/unmap_reserved_pages()
implementation, the new one is more generic in name and cleaner in code
(besides, some arch may not be allowed to unmap the pgtable).

Therefore, this patch consolidates them, and uses the new
arch_kexec_protect(unprotect)_crashkres() to replace former
crash_map/unmap_reserved_pages() which by now has been only used by
S390.

The consolidation work needs the crash memory to be mapped initially,
this is done in machine_kdump_pm_init() which is after
reserve_crashkernel(). Once kdump kernel is loaded, the new
arch_kexec_protect_crashkres() implemented for S390 will actually
unmap the pgtable like before.

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Minfei Huang <mhuang@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: introduce a protection mechanism for the crashkernel reserved memory

For the cases that some kernel (module) path stamps the crash reserved
memory(already mapped by the kernel) where has been loaded the second
kernel data, the kdump kernel will probably fail to boot when panic
happens (or even not happens) leaving the culprit at large, this is
unacceptable.

The patch introduces a mechanism for detecting such cases:

1) After each crash kexec loading, it simply marks the reserved memory
regions readonly since we no longer access it after that. When someone
stamps the region, the first kernel will panic and trigger the kdump.
The weak arch_kexec_protect_crashkres() is introduced to do the actual
protection.

2) To allow multiple loading, once 1) was done we also need to remark
the reserved memory to readwrite each time a system call related to
kdump is made. The weak arch_kexec_unprotect_crashkres() is introduced
to do the actual protection.

The architecture can make its specific implementation by overriding
arch_kexec_protect_crashkres() and arch_kexec_unprotect_crashkres().

Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Minfei Huang <mhuang@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

printk/nmi: flush NMI messages on the system panic

In NMI context, printk() messages are stored into per-CPU buffers to
avoid a possible deadlock. They are normally flushed to the main ring
buffer via an IRQ work. But the work is never called when the system
calls panic() in the very same NMI handler.

This patch tries to flush NMI buffers before the crash dump is
generated. In this case it does not risk a double release and bails out
when the logbuf_lock is already taken. The aim is to get the messages
into the main ring buffer when possible. It makes them better
accessible in the vmcore.

Then the patch tries to flush the buffers second time when other CPUs
are down. It might be more aggressive and reset logbuf_lock. The aim
is to get the messages available for the consequent kmsg_dump() and
console_flush_on_panic() calls.

The patch causes vprintk_emit() to be called even in NMI context again.
But it is done via printk_deferred() so that the console handling is
skipped. Consoles use internal locks and we could not prevent a
deadlock easily. They are explicitly called later when the crash dump
is not generated, see console_flush_on_panic().

Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm: rename _count, field of the struct page, to _refcount

Many developers already know that field for reference count of the
struct page is _count and atomic type. They would try to handle it
directly and this could break the purpose of page reference count
tracepoint. To prevent direct _count modification, this patch rename it
to _refcount and add warning message on the code. After that, developer
who need to handle reference count will find that field should not be
accessed directly.

[akpm@linux-foundation.org: fix comments, per Vlastimil]
[akpm@linux-foundation.org: Documentation/vm/transhuge.txt too]
[sfr@canb.auug.org.au: sync ethernet driver changes]
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Manish Chopra <manish.chopra@qlogic.com>
Cc: Yuval Mintz <yuval.mintz@qlogic.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: export OFFSET(page.compound_head) to find out compound tail page

PageAnon() always look at head page to check PAGE_MAPPING_ANON and tail
page's page->mapping has just a poisoned data since commit 1c290f642101
("mm: sanitize page->mapping for tail pages").

If makedumpfile checks page->mapping of a compound tail page to
distinguish anonymous page as usual, it must fail in newer kernel. So
it's necessary to export OFFSET(page.compound_head) to avoid checking
compound tail pages.

The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.5.x and later. This means that extra disk space would
be consumed. It's a problem, but not critical.

Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: update VMCOREINFO for compound_order/dtor

makedumpfile refers page.lru.next to get the order of compound pages for
page filtering.

However, now the order is stored in page.compound_order, hence
VMCOREINFO should be updated to export the offset of
page.compound_order.

The fact is, page.compound_order was introduced already in kernel 4.0,
but the offset of it was the same as page.lru.next until kernel 4.3, so
this was not actual problem.

The above can be said also for page.lru.prev and page.compound_dtor,
it's necessary to detect hugetlbfs pages. Further, the content was
changed from direct address to the ID which means dtor.

The problem is that unnecessary hugepages won't be removed from a dump
file in kernels 4.4.x and later. This means that extra disk space would
be consumed. It's a problem, but not critical.

Signed-off-by: Atsushi Kumagai <ats-kumagai@wm.jp.nec.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: Set IORESOURCE_SYSTEM_RAM for System RAM

Set proper ioresource flags and types for crash kernel
reservation areas.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Minfei Huang <mnfhuang@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: kexec@lists.infradead.org
Cc: linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>
Link: http://lkml.kernel.org/r/1453841853-11383-8-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/kexec_core.c: use list_for_each_entry_safe in kimage_free_page_list

Use list_for_each_entry_safe() instead of list_for_each_safe() to
simplify the code.

Signed-off-by: Geliang Tang <geliangtang@163.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: Fix race between panic() and crash_kexec()

Currently, panic() and crash_kexec() can be called at the same time.
For example (x86 case):

CPU 0:
oops_end()
crash_kexec()
mutex_trylock() // acquired
nmi_shootdown_cpus() // stop other CPUs

CPU 1:
panic()
crash_kexec()
mutex_trylock() // failed to acquire
smp_send_stop() // stop other CPUs
infinite loop

If CPU 1 calls smp_send_stop() before nmi_shootdown_cpus(), kdump
fails.

In another case:

CPU 0:
oops_end()
crash_kexec()
mutex_trylock() // acquired
<NMI>
io_check_error()
panic()
crash_kexec()
mutex_trylock() // failed to acquire
infinite loop

Clearly, this is an undesirable result.

To fix this problem, this patch changes crash_kexec() to exclude others
by using the panic_cpu atomic.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: kexec@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Minfei Huang <mnfhuang@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/20151210014630.25437.94161.stgit@softrs
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kexec: use file name as the output message prefix

kexec output message misses the prefix "kexec", when Dave Young split the
kexec code. Now, we use file name as the output message prefix.

Currently, the format of output message:
[ 140.290795] SYSC_kexec_load: hello, world
[ 140.291534] kexec: sanity_check_segment_list: hello, world

Ideally, the format of output message:
[ 30.791503] kexec: SYSC_kexec_load, Hello, world
[ 79.182752] kexec_core: sanity_check_segment_list, Hello, world

Remove the custom prefix "kexec" in output message.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Acked-by: Dave Young <dyoung@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec/crash: Say which char is the unrecognized

It is helpful when the crashkernel cmdline parsing routines
actually say which character is the unrecognized one. Make them
do so.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Joerg Roedel <jroedel@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Baoquan He <bhe@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Chao <chaowang@redhat.com>
Cc: jerry_hoemann@hp.com
Link: http://lkml.kernel.org/r/1445246268-26285-8-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kexec: export KERNEL_IMAGE_SIZE to vmcoreinfo

In x86_64, since v2.6.26 the KERNEL_IMAGE_SIZE is changed to 512M, and
accordingly the MODULES_VADDR is changed to 0xffffffffa0000000. However,
in v3.12 Kees Cook introduced kaslr to randomise the location of kernel.
And the kernel text mapping addr space is enlarged from 512M to 1G. That
means now KERNEL_IMAGE_SIZE is variable, its value is 512M when kaslr
support is not compiled in and 1G when kaslr support is compiled in.
Accordingly the MODULES_VADDR is changed too to be:

#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)

So when kaslr is compiled in and enabled, the kernel text mapping addr
space and modules vaddr space need be adjusted. Otherwise makedumpfile
will collapse since the addr for some symbols is not correct.

Hence KERNEL_IMAGE_SIZE need be exported to vmcoreinfo and got in
makedumpfile to help calculate MODULES_VADDR.

Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: align crash_notes allocation to make it be inside one physical page

People reported that crash_notes in /proc/vmcore were corrupted and this
cause crash kdump failure. With code debugging and log we got the root
cause. This is because percpu variable crash_notes are allocated in 2
vmalloc pages. Currently percpu is based on vmalloc by default. Vmalloc
can't guarantee 2 continuous vmalloc pages are also on 2 continuous
physical pages. So when 1st kernel exports the starting address and size
of crash_notes through sysfs like below:

/sys/devices/system/cpu/cpux/crash_notes
/sys/devices/system/cpu/cpux/crash_notes_size

kdump kernel use them to get the content of crash_notes. However the 2nd
part may not be in the next neighbouring physical page as we expected if
crash_notes are allocated accross 2 vmalloc pages. That's why
nhdr_ptr->n_namesz or nhdr_ptr->n_descsz could be very huge in
update_note_header_size_elf64() and cause note header merging failure or
some warnings.

In this patch change to call __alloc_percpu() to passed in the align value
by rounding crash_notes_size up to the nearest power of two. This makes
sure the crash_notes is allocated inside one physical page since
sizeof(note_buf_t) in all ARCHS is smaller than PAGE_SIZE. Meanwhile add
a BUILD_BUG_ON to break compile if size is bigger than PAGE_SIZE since
crash_notes definitely will be in 2 pages. That need be avoided, and need
be reported if it's unavoidable.

[akpm@linux-foundation.org: use correct comment layout]
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Lisa Mitchell <lisa.mitchell@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: remove unnecessary test in kimage_alloc_crash_control_pages()

Transforming PFN(Page Frame Number) to struct page is never failure, so we
can simplify the code logic to do the image->control_page assignment
directly in the loop, and remove the unnecessary conditional judgement.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kexec: split kexec_load syscall from kexec core code

There are two kexec load syscalls, kexec_load another and kexec_file_load.
kexec_file_load has been splited as kernel/kexec_file.c. In this patch I
split kexec_load syscall code to kernel/kexec.c.

And add a new kconfig option KEXEC_CORE, so we can disable kexec_load and
use kexec_file_load only, or vice verse.

The original requirement is from Ted Ts'o, he want kexec kernel signature
being checked with CONFIG_KEXEC_VERIFY_SIG enabled. But kexec-tools use
kexec_load syscall can bypass the checking.

Vivek Goyal proposed to create a common kconfig option so user can compile
in only one syscall for loading kexec kernel. KEXEC/KEXEC_FILE selects
KEXEC_CORE so that old config files still work.

Because there's general code need CONFIG_KEXEC_CORE, so I updated all the
architecture Kconfig with a new option KEXEC_CORE, and let KEXEC selects
KEXEC_CORE in arch Kconfig. Also updated general kernel code with to
kexec_load syscall.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Petr Tesarik <ptesarik@suse.cz>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>