1 2/*--------------------------------------------------------------------*/ 3/*--- Support for doing system calls. syscall-mips32-linux.S ---*/ 4/*--------------------------------------------------------------------*/ 5 6/* 7 This file is part of Valgrind, a dynamic binary instrumentation 8 framework. 9 10 Copyright (C) 2010-2015 RT-RK 11 mips-valgrind@rt-rk.com 12 13 This program is free software; you can redistribute it and/or 14 modify it under the terms of the GNU General Public License as 15 published by the Free Software Foundation; either version 2 of the 16 License, or (at your option) any later version. 17 18 This program is distributed in the hope that it will be useful, but 19 WITHOUT ANY WARRANTY; without even the implied warranty of 20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 General Public License for more details. 22 23 You should have received a copy of the GNU General Public License 24 along with this program; if not, write to the Free Software 25 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 26 02111-1307, USA. 27 28 The GNU General Public License is contained in the file COPYING. 29*/ 30 31#include "pub_core_basics_asm.h" 32 33#if defined(VGP_mips32_linux) 34 35#include "pub_core_vkiscnums_asm.h" 36#include "libvex_guest_offsets.h" 37 38 39/*----------------------------------------------------------------*/ 40/* 41 Perform a syscall for the client. This will run a syscall 42 with the client's specific per-thread signal mask. 43 44 The structure of this function is such that, if the syscall is 45 interrupted by a signal, we can determine exactly what 46 execution state we were in with respect to the execution of 47 the syscall by examining the value of IP in the signal 48 handler. This means that we can always do the appropriate 49 thing to precisely emulate the kernel's signal/syscall 50 interactions. 51 52 The syscall number is taken from the argument, even though it 53 should also be in regs->v0. The syscall result is written 54 back to regs->v0 on completion. 55 56 Returns 0 if the syscall was successfully called (even if the 57 syscall itself failed), or a nonzero error code in the lowest 58 8 bits if one of the sigprocmasks failed (there's no way to 59 determine which one failed). And there's no obvious way to 60 recover from that either, but nevertheless we want to know. 61 62 VG_(fixup_guest_state_after_syscall_interrupted) does the 63 thread state fixup in the case where we were interrupted by a 64 signal. 65 66 Prototype: 67 68 UWord ML_(do_syscall_for_client_WRK)( 69 Int syscallno, // $4 - a0 70 void* guest_state, // $5 - a1 71 const vki_sigset_t *sysmask, // $6 - a2 72 const vki_sigset_t *postmask, // $7 - a3 73 Int nsigwords) // stack 74*/ 75/* from vki_arch.h */ 76#define VKI_SIG_SETMASK 3 77 78.globl ML_(do_syscall_for_client_WRK) 79ML_(do_syscall_for_client_WRK): 80 81 subu $29, $29, 56 #set up the steck frame, 82 sw $4, 52($29) 83 sw $5, 48($29) 84 sw $6, 44($29) 85 sw $7, 40($29) 86 sw $31, 36($29) 87 sw $30, 32($29) 88 sw $16, 28($29) 89 sw $17, 24($29) 90 sw $18, 20($29) 91 sw $19, 16($29) 92 sw $20, 12($29) 93 sw $21, 8($29) 94 sw $22, 4($29) 95 sw $23, 0($29) 96 addu $30, $29, 56 97 98 99 /* Set the signal mask which should be current during the syscall. */ 100 1011: li $2, __NR_rt_sigprocmask 102 li $4, VKI_SIG_SETMASK 103 move $5, $6 /* sysmask */ 104 move $6, $7 /* postmask */ 105 lw $7, 72($29) /* nsigwords */ 106 syscall 107 nop 108 109# TODO: this should remain, keep it just for now 110 bnez $7, 7f 111 nop 112 113 lw $8, 48($29) /* t0 == ThreadState */ 114 115 lw $2, 52($29) /* v0 == syscallno */ 116 lw $4, OFFSET_mips32_r4($8) 117 lw $5, OFFSET_mips32_r5($8) 118 lw $6, OFFSET_mips32_r6($8) 119 lw $7, OFFSET_mips32_r7($8) 120 subu $29, $29, 24 #set up the steck frame, 121 lw $9, OFFSET_mips32_r29($8) 122 lw $10, 16($9) 123 sw $10, 16($29) 124 lw $10, 20($9) 125 sw $10, 20($29) 126 1272: syscall 128 1293: addu $29, $29, 24 #set up the steck frame, 130 131 lw $8, 48($29) /* t0 == ThreadState */ 132 sw $2, OFFSET_mips32_r2($8) 133 sw $3, OFFSET_mips32_r3($8) 134 sw $7, OFFSET_mips32_r7($8) 135 1364: li $2, __NR_rt_sigprocmask 137 li $4, VKI_SIG_SETMASK 138 lw $5, 40($29) 139 li $6, 0 140 lw $7, 72($29) /* nsigwords */ 141 syscall 142 nop 143 144 bnez $7, 7f 145 nop 146 147 /* Success */ 148 li $2, 0 149 1505: lw $4, 52($29) 151 lw $5, 48($29) 152 lw $6, 44($29) 153 lw $7, 40($29) 154 lw $31, 36($29) 155 lw $30, 32($29) 156 lw $16, 28($29) 157 lw $17, 24($29) 158 lw $18, 20($29) 159 lw $19, 16($29) 160 lw $20, 12($29) 161 lw $21, 8($29) 162 lw $22, 4($29) 163 lw $23, 0($29) 164 addu $29, $29, 56 #release the stack frame. 165 166 jr $31 167 nop 168 1697: /* Failure: return 0x8000 | error code */ 170 li $2, 0x8000 171 172 lw $4, 52($29) 173 lw $5, 48($29) 174 lw $6, 44($29) 175 lw $7, 40($29) 176 lw $31, 36($29) 177 lw $30, 32($29) 178 lw $16, 28($29) 179 lw $17, 24($29) 180 lw $18, 20($29) 181 lw $19, 16($29) 182 lw $20, 12($29) 183 lw $21, 8($29) 184 lw $22, 4($29) 185 lw $23, 0($29) 186 addu $29, $29, 56 #release the stack frame. 187 188 jr $31 189 nop 190 191.section .rodata 192/* export the ranges so that 193 VG_(fixup_guest_state_after_syscall_interrupted) can do the 194 right thing */ 195 196.globl ML_(blksys_setup) 197.globl ML_(blksys_restart) 198.globl ML_(blksys_complete) 199.globl ML_(blksys_committed) 200.globl ML_(blksys_finished) 201ML_(blksys_setup): .long 1b 202ML_(blksys_restart): .long 2b 203ML_(blksys_complete): .long 3b 204ML_(blksys_committed): .long 4b 205ML_(blksys_finished): .long 5b 206 207#endif // defined(VGP_mips32_linux) 208 209/* Let the linker know we don't need an executable stack */ 210MARK_STACK_NO_EXEC 211 212/*--------------------------------------------------------------------*/ 213/*--- end ---*/ 214/*--------------------------------------------------------------------*/ 215