1 2 /*--------------------------------------------------------------------*/ 3 /*--- Support for doing system calls. syscall-ppc32-linux.S ---*/ 4 /*--------------------------------------------------------------------*/ 5 6 /* 7 This file is part of Valgrind, a dynamic binary instrumentation 8 framework. 9 10 Copyright (C) 2005-2015 Paul Mackerras (paulus (at) samba.org) 11 12 This program is free software; you can redistribute it and/or 13 modify it under the terms of the GNU General Public License as 14 published by the Free Software Foundation; either version 2 of the 15 License, or (at your option) any later version. 16 17 This program is distributed in the hope that it will be useful, but 18 WITHOUT ANY WARRANTY; without even the implied warranty of 19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 20 General Public License for more details. 21 22 You should have received a copy of the GNU General Public License 23 along with this program; if not, write to the Free Software 24 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 25 02111-1307, USA. 26 27 The GNU General Public License is contained in the file COPYING. 28 */ 29 30 #include "pub_core_basics_asm.h" 31 32 #if defined(VGP_ppc32_linux) 33 34 #include "pub_core_vkiscnums_asm.h" 35 #include "libvex_guest_offsets.h" 36 37 38 /*----------------------------------------------------------------*/ 39 /* 40 Perform a syscall for the client. This will run a syscall 41 with the client's specific per-thread signal mask. 42 43 The structure of this function is such that, if the syscall is 44 interrupted by a signal, we can determine exactly what 45 execution state we were in with respect to the execution of 46 the syscall by examining the value of NIP in the signal 47 handler. This means that we can always do the appropriate 48 thing to precisely emulate the kernel's signal/syscall 49 interactions. 50 51 The syscall number is taken from the argument, even though it 52 should also be in regs->m_gpr[0]. The syscall result is written 53 back to regs->m_gpr[3]/m_xer/m_result on completion. 54 55 Returns 0 if the syscall was successfully called (even if the 56 syscall itself failed), or a nonzero error code in the lowest 57 8 bits if one of the sigprocmasks failed (there's no way to 58 determine which one failed). And there's no obvious way to 59 recover from that either, but nevertheless we want to know. 60 61 VG_(fixup_guest_state_after_syscall_interrupted) does the 62 thread state fixup in the case where we were interrupted by a 63 signal. 64 65 Prototype: 66 67 UWord ML_(do_syscall_for_client_WRK)( 68 Int syscallno, // r3 69 void* guest_state, // r4 70 const vki_sigset_t *sysmask, // r5 71 const vki_sigset_t *postmask, // r6 72 Int sigsetSzB) // r7 73 */ 74 /* from vki_arch.h */ 75 #define VKI_SIG_SETMASK 2 76 77 .globl ML_(do_syscall_for_client_WRK) 78 ML_(do_syscall_for_client_WRK): 79 /* make a stack frame */ 80 stwu 1,-32(1) 81 stw 31,28(1) 82 stw 30,24(1) 83 stw 29,20(1) 84 stw 28,16(1) 85 mr 31,3 /* syscall number */ 86 mr 30,4 /* guest_state */ 87 mr 29,6 /* postmask */ 88 mr 28,7 /* sigsetSzB */ 89 90 /* set the signal mask for doing the system call */ 91 /* set up for sigprocmask(SIG_SETMASK, sysmask, postmask) */ 92 1: li 0,__NR_rt_sigprocmask 93 li 3,VKI_SIG_SETMASK 94 mr 4,5 95 mr 5,6 96 mr 6,7 97 sc /* set the mask */ 98 bso 7f /* if the sigprocmask fails */ 99 100 /* load up syscall args from the threadstate */ 101 lwz 3,OFFSET_ppc32_GPR3(30) 102 lwz 4,OFFSET_ppc32_GPR4(30) 103 lwz 5,OFFSET_ppc32_GPR5(30) 104 lwz 6,OFFSET_ppc32_GPR6(30) 105 lwz 7,OFFSET_ppc32_GPR7(30) 106 lwz 8,OFFSET_ppc32_GPR8(30) 107 mr 0,31 /* syscall number */ 108 2: sc /* do the syscall */ 109 110 /* put the result back in the threadstate */ 111 3: stw 3,OFFSET_ppc32_GPR3(30) /* gst->GPR3 = sc result */ 112 /* copy cr0.so back to simulated state */ 113 mfcr 5 /* r5 = CR */ 114 rlwinm 5,5,4,31,31 /* r5 = (CR >> 28) & 1 */ 115 stb 5,OFFSET_ppc32_CR0_0(30) /* gst->CR0.SO = cr0.so */ 116 117 /* block signals again */ 118 /* set up for sigprocmask(SIG_SETMASK, postmask, NULL) */ 119 4: li 0,__NR_rt_sigprocmask 120 li 3,VKI_SIG_SETMASK 121 mr 4,29 122 li 5,0 123 mr 6,28 124 sc /* set the mask */ 125 bso 7f /* if the sigprocmask fails */ 126 /* now safe from signals */ 127 li 3,0 /* SUCCESS */ 128 129 /* pop off stack frame */ 130 5: lwz 28,16(1) 131 lwz 29,20(1) 132 lwz 30,24(1) 133 lwz 31,28(1) 134 addi 1,1,32 135 blr 136 137 /* failure: return 0x8000 | error code */ 138 7: ori 3,3,0x8000 /* FAILURE -- ensure return value is nonzero */ 139 b 5b 140 141 .section .rodata 142 /* export the ranges so that 143 VG_(fixup_guest_state_after_syscall_interrupted) can do the 144 right thing */ 145 146 .globl ML_(blksys_setup) 147 .globl ML_(blksys_restart) 148 .globl ML_(blksys_complete) 149 .globl ML_(blksys_committed) 150 .globl ML_(blksys_finished) 151 ML_(blksys_setup): .long 1b 152 ML_(blksys_restart): .long 2b 153 ML_(blksys_complete): .long 3b 154 ML_(blksys_committed): .long 4b 155 ML_(blksys_finished): .long 5b 156 157 #endif // defined(VGP_ppc32_linux) 158 159 /* Let the linker know we don't need an executable stack */ 160 MARK_STACK_NO_EXEC 161 162 /*--------------------------------------------------------------------*/ 163 /*--- end ---*/ 164 /*--------------------------------------------------------------------*/ 165
