1/* 2 * Copyright (c) 2002 Jonathan Mini <mini@freebsd.org>. 3 * Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Neither the name of the author nor the names of its contributors 12 * may be used to endorse or promote products derived from this software 13 * without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30#include <machine/asm.h> 31__FBSDID("$FreeBSD$"); 32 33/* 34 * Where do we define these? 35 */ 36#define MC_SIZE 640 /* sizeof mcontext_t */ 37#define UC_MC_OFFSET 16 /* offset to mcontext from ucontext */ 38#define UC_MC_LEN_OFFSET 96 /* offset to mc_len from mcontext */ 39#define MC_LEN_OFFSET 80 /* offset to mc_len from mcontext */ 40#define MC_FP_REGS_OFFSET 96 /* offset to FP regs from mcontext */ 41#define MC_FP_CW_OFFSET 96 /* offset to FP control word */ 42#define MC_OWNEDFP_OFFSET 88 /* offset to mc_ownedfp from mcontext */ 43#define KM_STACK_SP_OFFSET 36 /* offset to km_stack.ss_sp */ 44#define KM_STACK_SIZE_OFFSET 40 /* offset to km_stack.ss_sp */ 45#define KM_FUNC_OFFSET 32 /* offset to km_func */ 46 47/* 48 * int uts_to_thread(struct kse_thr_mailbox *tdp, 49 * struct kse_thr_mailbox **curthreadp); 50 * 51 * Does not return on success, returns -1 otherwise. 52 */ 53ENTRY(uts_to_thread) 54 movl 4(%esp), %edx /* get address of kse_thr_mailbox */ 55 /* .. ucontext_t is at offset 0 */ 56 cmpl $0, %edx /* check for null pointer */ 57 jne 1f 58 movl $-1, %eax 59 jmp 5f 601: cmpl $MC_SIZE, UC_MC_LEN_OFFSET(%edx) /* is context valid? */ 61 je 2f 62 movl $-1, %eax /* bzzzt, invalid context */ 63 jmp 5f 642: movl 8(%esp), %ecx /* get address of curthreadp */ 65 movl %edx, %ebx /* save the pointer for later */ 66 /* 67 * From here on, we don't touch the old stack. 68 */ 69 addl $UC_MC_OFFSET, %edx /* add offset to mcontext */ 70 movl 4(%edx), %gs 71 movl 8(%edx), %fs 72 movl 12(%edx), %es 73 movl 16(%edx), %ds 74 movl 76(%edx), %ss 75 movl 20(%edx), %edi 76 movl 24(%edx), %esi 77 movl 28(%edx), %ebp 78 movl 72(%edx), %esp /* switch to context defined stack */ 79 subl $4, %esp /* leave space for the return address */ 80 movl 60(%edx), %eax /* put return address at top of stack */ 81 movl %eax, (%esp) 82 cmpl $0, MC_OWNEDFP_OFFSET(%edx) /* are FP regs valid? */ 83 jz 3f 84 frstor MC_FP_REGS_OFFSET(%edx) /* restore FP regs */ 85 jmp 4f 863: fninit 87 fldcw MC_FP_CW_OFFSET(%edx) 884: movl 48(%edx), %eax /* restore ax, bx, cx, dx */ 89 pushl 68(%edx) /* flags on stack */ 90 pushl 36(%edx) /* %ebx on stack */ 91 pushl 44(%edx) /* %ecx on stack */ 92 movl 40(%edx), %edx /* %edx */ 93 /* 94 * all registers are now moved out of mailbox, 95 * it's safe to set current thread pointer 96 */ 97 movl %ebx,(%ecx) 98 popl %ecx /* %ecx off stack */ 99 pop %ebx /* %ebx off stack */ 100 popf /* flags off stack */ 1015: ret /* %eip off stack */ 102END(uts_to_thread) 103 104/* 105 * int thread_to_uts(struct kse_thr_mailbox *tm, struct kse_mailbox *km); 106 * 107 * Does not return on success, returns -1 otherwise. 108 */ 109ENTRY(thread_to_uts) 110 movl 4(%esp), %eax /* get address of context */ 111 cmpl $0, %eax /* check for null pointer */ 112 jne 1f 113 movl $-1, %eax 114 jmp 2f 1151: pushl %edx /* save value of edx */ 116 movl %eax, %edx /* get address of context */ 117 addl $UC_MC_OFFSET, %edx /* add offset to mcontext */ 118 movl %gs, 4(%edx) 119 movl %fs, 8(%edx) 120 movl %es, 12(%edx) 121 movl %ds, 16(%edx) 122 movl %edi, 20(%edx) 123 movl %esi, 24(%edx) 124 movl %ebp, 28(%edx) 125 movl %ebx, 36(%edx) 126 movl $0, 48(%edx) /* store successful return in eax */ 127 popl %eax /* get saved value of edx */ 128 movl %eax, 40(%edx) /* save edx */ 129 movl %ecx, 44(%edx) 130 movl (%esp), %eax /* get return address */ 131 movl %eax, 60(%edx) /* save return address */ 132 movl %ss, 76(%edx) 133 /* 134 * Don't save floating point registers here. 135 * 136 * This is an explicit call to get the current context, so 137 * the caller is done with the floating point registers. 138 * Contexts formed by involuntary switches, such as signal delivery, 139 * have floating point registers saved by the kernel. 140 */ 141 fnstcw MC_FP_CW_OFFSET(%edx) 142 movl $0, MC_OWNEDFP_OFFSET(%edx) /* no FP */ 143 pushfl /* get eflags */ 144 popl %eax 145 movl %eax, 68(%edx) /* store eflags */ 146 movl %esp, %eax /* setcontext pushes the return */ 147 addl $4, %eax /* address onto the top of the */ 148 movl %eax, 72(%edx) /* stack; account for this */ 149 movl $MC_SIZE, MC_LEN_OFFSET(%edx) /* context is now valid */ 150 movl 8(%esp), %edx /* get address of mailbox */ 151 movl KM_STACK_SP_OFFSET(%edx), %eax /* get bottom of stack */ 152 addl KM_STACK_SIZE_OFFSET(%edx), %eax /* add length */ 153 movl %eax, %esp /* switch to the uts's stack */ 154 pushl %edx /* push the address of the mailbox */ 155 pushl KM_FUNC_OFFSET(%edx) /* .. the uts can return to itself */ 156 pushl KM_FUNC_OFFSET(%edx) /* push the address of the uts func */ 1572: ret 158END(thread_to_uts) 159 160