cloudabi32_sysvec.c revision 316574
1/*- 2 * Copyright (c) 2015-2016 Nuxi, https://nuxi.nl/ 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 */ 25 26#include <sys/cdefs.h> 27__FBSDID("$FreeBSD: stable/11/sys/amd64/cloudabi32/cloudabi32_sysvec.c 316574 2017-04-06 15:10:36Z ed $"); 28 29#include <sys/param.h> 30#include <sys/imgact.h> 31#include <sys/kernel.h> 32#include <sys/proc.h> 33#include <sys/sysent.h> 34 35#include <vm/vm.h> 36#include <vm/pmap.h> 37 38#include <machine/frame.h> 39#include <machine/pcb.h> 40#include <machine/vmparam.h> 41 42#include <compat/cloudabi/cloudabi_util.h> 43 44#include <compat/cloudabi32/cloudabi32_syscall.h> 45#include <compat/cloudabi32/cloudabi32_util.h> 46 47#include <compat/ia32/ia32_signal.h> 48#include <compat/ia32/ia32_util.h> 49 50extern const char *cloudabi32_syscallnames[]; 51extern struct sysent cloudabi32_sysent[]; 52 53extern unsigned long ia32_maxssiz; 54 55static int 56cloudabi32_fixup_tcb(register_t **stack_base, struct image_params *imgp) 57{ 58 int error; 59 uint32_t args[2]; 60 61 /* Place auxiliary vector and TCB on the stack. */ 62 error = cloudabi32_fixup(stack_base, imgp); 63 if (error != 0) 64 return (error); 65 66 /* 67 * On i386, the TCB is referred to by %gs:0. Reuse the empty 68 * space normally used by the return address (args[0]) to store 69 * a single element array, containing a pointer to the TCB. %gs 70 * base will point to this. 71 * 72 * Also let the first argument of the entry point (args[1]) 73 * refer to the auxiliary vector, which is stored right after 74 * the TCB. 75 */ 76 args[0] = (uintptr_t)*stack_base; 77 args[1] = (uintptr_t)*stack_base + 78 roundup(sizeof(cloudabi32_tcb_t), sizeof(register_t)); 79 *stack_base -= howmany(sizeof(args), sizeof(register_t)); 80 return (copyout(args, *stack_base, sizeof(args))); 81} 82 83static void 84cloudabi32_proc_setregs(struct thread *td, struct image_params *imgp, 85 unsigned long stack) 86{ 87 88 ia32_setregs(td, imgp, stack); 89 (void)cpu_set_user_tls(td, (void *)stack); 90} 91 92static int 93cloudabi32_fetch_syscall_args(struct thread *td, struct syscall_args *sa) 94{ 95 struct trapframe *frame = td->td_frame; 96 int error; 97 98 /* Obtain system call number. */ 99 sa->code = frame->tf_rax; 100 if (sa->code >= CLOUDABI32_SYS_MAXSYSCALL) 101 return (ENOSYS); 102 sa->callp = &cloudabi32_sysent[sa->code]; 103 sa->narg = sa->callp->sy_narg; 104 105 /* 106 * Fetch system call arguments. 107 * 108 * The vDSO has already made sure that the arguments are 109 * eight-byte aligned. Pointers and size_t parameters are 110 * zero-extended. This makes it possible to copy in the 111 * arguments directly. As long as the call doesn't use 32-bit 112 * data structures, we can just invoke the same system call 113 * implementation used by 64-bit processes. 114 */ 115 error = copyin((void *)frame->tf_rcx, sa->args, 116 sa->narg * sizeof(sa->args[0])); 117 if (error != 0) 118 return (error); 119 120 /* Default system call return values. */ 121 td->td_retval[0] = 0; 122 td->td_retval[1] = 0; 123 return (0); 124} 125 126static void 127cloudabi32_set_syscall_retval(struct thread *td, int error) 128{ 129 struct trapframe *frame = td->td_frame; 130 131 switch (error) { 132 case 0: 133 /* 134 * System call succeeded. 135 * 136 * Simply copy out the 64-bit return values into the 137 * same buffer provided for system call arguments. The 138 * vDSO will copy them to the right spot, truncating 139 * pointers and size_t values to 32 bits. 140 */ 141 frame->tf_rax = copyout(td->td_retval, (void *)frame->tf_rcx, 142 sizeof(td->td_retval)) == 0 ? 0 : CLOUDABI_EFAULT; 143 break; 144 case ERESTART: 145 /* Restart system call. */ 146 frame->tf_rip -= frame->tf_err; 147 frame->tf_r10 = frame->tf_rcx; 148 set_pcb_flags(td->td_pcb, PCB_FULL_IRET); 149 break; 150 case EJUSTRETURN: 151 break; 152 default: 153 /* System call returned an error. */ 154 frame->tf_rax = cloudabi_convert_errno(error); 155 break; 156 } 157} 158 159static void 160cloudabi32_schedtail(struct thread *td) 161{ 162 struct trapframe *frame = td->td_frame; 163 register_t retval[2]; 164 165 /* Return values for processes returning from fork. */ 166 if ((td->td_pflags & TDP_FORKING) != 0) { 167 retval[0] = CLOUDABI_PROCESS_CHILD; 168 retval[1] = td->td_tid; 169 copyout(retval, (void *)frame->tf_rcx, sizeof(retval)); 170 } 171} 172 173int 174cloudabi32_thread_setregs(struct thread *td, 175 const cloudabi32_threadattr_t *attr, uint32_t tcb) 176{ 177 stack_t stack; 178 uint32_t args[3]; 179 void *frameptr; 180 int error; 181 182 /* Perform standard register initialization. */ 183 stack.ss_sp = TO_PTR(attr->stack); 184 stack.ss_size = attr->stack_len - sizeof(args); 185 cpu_set_upcall(td, TO_PTR(attr->entry_point), NULL, &stack); 186 187 /* 188 * Copy the arguments for the thread entry point onto the stack 189 * (args[1] and args[2]). Similar to process startup, use the 190 * otherwise unused return address (args[0]) for TLS. 191 */ 192 args[0] = tcb; 193 args[1] = td->td_tid; 194 args[2] = attr->argument; 195 frameptr = (void *)td->td_frame->tf_rsp; 196 error = copyout(args, frameptr, sizeof(args)); 197 if (error != 0) 198 return (error); 199 200 return (cpu_set_user_tls(td, frameptr)); 201} 202 203static struct sysentvec cloudabi32_elf_sysvec = { 204 .sv_size = CLOUDABI32_SYS_MAXSYSCALL, 205 .sv_table = cloudabi32_sysent, 206 .sv_fixup = cloudabi32_fixup_tcb, 207 .sv_name = "CloudABI ELF32", 208 .sv_coredump = elf32_coredump, 209 .sv_pagesize = IA32_PAGE_SIZE, 210 .sv_minuser = FREEBSD32_MINUSER, 211 .sv_maxuser = FREEBSD32_MAXUSER, 212 .sv_stackprot = VM_PROT_READ | VM_PROT_WRITE, 213 .sv_copyout_strings = cloudabi32_copyout_strings, 214 .sv_setregs = cloudabi32_proc_setregs, 215 .sv_fixlimit = ia32_fixlimit, 216 .sv_maxssiz = &ia32_maxssiz, 217 .sv_flags = SV_ABI_CLOUDABI | SV_CAPSICUM | SV_IA32 | SV_ILP32, 218 .sv_set_syscall_retval = cloudabi32_set_syscall_retval, 219 .sv_fetch_syscall_args = cloudabi32_fetch_syscall_args, 220 .sv_syscallnames = cloudabi32_syscallnames, 221 .sv_schedtail = cloudabi32_schedtail, 222}; 223 224INIT_SYSENTVEC(elf_sysvec, &cloudabi32_elf_sysvec); 225 226Elf32_Brandinfo cloudabi32_brand = { 227 .brand = ELFOSABI_CLOUDABI, 228 .machine = EM_386, 229 .sysvec = &cloudabi32_elf_sysvec, 230}; 231