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) 2005-2010 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 #if defined(VGP_ppc32_linux) 31 32 #include "pub_core_basics_asm.h" 33 #include "pub_core_vkiscnums_asm.h" 34 #include "libvex_guest_offsets.h" 35 36 37 /*----------------------------------------------------------------*/ 38 /* 39 Perform a syscall for the client. This will run a syscall 40 with the client's specific per-thread signal mask. 41 42 The structure of this function is such that, if the syscall is 43 interrupted by a signal, we can determine exactly what 44 execution state we were in with respect to the execution of 45 the syscall by examining the value of NIP in the signal 46 handler. This means that we can always do the appropriate 47 thing to precisely emulate the kernel's signal/syscall 48 interactions. 49 50 The syscall number is taken from the argument, even though it 51 should also be in regs->m_gpr[0]. The syscall result is written 52 back to regs->m_gpr[3]/m_xer/m_result on completion. 53 54 Returns 0 if the syscall was successfully called (even if the 55 syscall itself failed), or a nonzero error code in the lowest 56 8 bits if one of the sigprocmasks failed (there's no way to 57 determine which one failed). And there's no obvious way to 58 recover from that either, but nevertheless we want to know. 59 60 VG_(fixup_guest_state_after_syscall_interrupted) does the 61 thread state fixup in the case where we were interrupted by a 62 signal. 63 64 Prototype: 65 66 UWord ML_(do_syscall_for_client_WRK)( 67 Int syscallno, // r3 68 void* guest_state, // r4 69 const vki_sigset_t *sysmask, // r5 70 const vki_sigset_t *postmask, // r6 71 Int sigsetSzB) // r7 72 */ 73 /* from vki_arch.h */ 74 #define VKI_SIG_SETMASK 2 75 76 .globl ML_(do_syscall_for_client_WRK) 77 ML_(do_syscall_for_client_WRK): 78 /* make a stack frame */ 79 stwu 1,-32(1) 80 stw 31,28(1) 81 stw 30,24(1) 82 stw 29,20(1) 83 stw 28,16(1) 84 mr 31,3 /* syscall number */ 85 mr 30,4 /* guest_state */ 86 mr 29,6 /* postmask */ 87 mr 28,7 /* sigsetSzB */ 88 89 /* set the signal mask for doing the system call */ 90 /* set up for sigprocmask(SIG_SETMASK, sysmask, postmask) */ 91 1: li 0,__NR_rt_sigprocmask 92 li 3,VKI_SIG_SETMASK 93 mr 4,5 94 mr 5,6 95 mr 6,7 96 sc /* set the mask */ 97 bso 7f /* if the sigprocmask fails */ 98 99 /* load up syscall args from the threadstate */ 100 lwz 3,OFFSET_ppc32_GPR3(30) 101 lwz 4,OFFSET_ppc32_GPR4(30) 102 lwz 5,OFFSET_ppc32_GPR5(30) 103 lwz 6,OFFSET_ppc32_GPR6(30) 104 lwz 7,OFFSET_ppc32_GPR7(30) 105 lwz 8,OFFSET_ppc32_GPR8(30) 106 mr 0,31 /* syscall number */ 107 2: sc /* do the syscall */ 108 109 /* put the result back in the threadstate */ 110 3: stw 3,OFFSET_ppc32_GPR3(30) /* gst->GPR3 = sc result */ 111 /* copy cr0.so back to simulated state */ 112 mfcr 5 /* r5 = CR */ 113 rlwinm 5,5,4,31,31 /* r5 = (CR >> 28) & 1 */ 114 stb 5,OFFSET_ppc32_CR0_0(30) /* gst->CR0.SO = cr0.so */ 115 116 /* block signals again */ 117 /* set up for sigprocmask(SIG_SETMASK, postmask, NULL) */ 118 4: li 0,__NR_rt_sigprocmask 119 li 3,VKI_SIG_SETMASK 120 mr 4,29 121 li 5,0 122 mr 6,28 123 sc /* set the mask */ 124 bso 7f /* if the sigprocmask fails */ 125 /* now safe from signals */ 126 li 3,0 /* SUCCESS */ 127 128 /* pop off stack frame */ 129 5: lwz 28,16(1) 130 lwz 29,20(1) 131 lwz 30,24(1) 132 lwz 31,28(1) 133 addi 1,1,32 134 blr 135 136 /* failure: return 0x8000 | error code */ 137 7: ori 3,3,0x8000 /* FAILURE -- ensure return value is nonzero */ 138 b 5b 139 140 .section .rodata 141 /* export the ranges so that 142 VG_(fixup_guest_state_after_syscall_interrupted) can do the 143 right thing */ 144 145 .globl ML_(blksys_setup) 146 .globl ML_(blksys_restart) 147 .globl ML_(blksys_complete) 148 .globl ML_(blksys_committed) 149 .globl ML_(blksys_finished) 150 ML_(blksys_setup): .long 1b 151 ML_(blksys_restart): .long 2b 152 ML_(blksys_complete): .long 3b 153 ML_(blksys_committed): .long 4b 154 ML_(blksys_finished): .long 5b 155 156 .previous 157 158 /* Let the linker know we don't need an executable stack */ 159 .section .note.GNU-stack,"",@progbits 160 161 #endif // defined(VGP_ppc32_linux) 162 163 /*--------------------------------------------------------------------*/ 164 /*--- end ---*/ 165 /*--------------------------------------------------------------------*/ 166
