sewardj | f0c1250 | 2014-01-12 12:54:00 +0000 | [diff] [blame] | 1 | |
| 2 | /*--------------------------------------------------------------------*/ |
| 3 | /*--- Support for doing system calls. syscall-arm64-linux.S ---*/ |
| 4 | /*--------------------------------------------------------------------*/ |
| 5 | |
| 6 | /* |
| 7 | This file is part of Valgrind, a dynamic binary instrumentation |
| 8 | framework. |
| 9 | |
| 10 | Copyright (C) 2013-2013 OpenWorks |
| 11 | info@open-works.net |
| 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 | #if defined(VGP_arm64_linux) |
| 32 | |
| 33 | #include "pub_core_basics_asm.h" |
| 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 IP 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 guest_state->guest_X8. The syscall result |
| 53 | is written back to guest_state->guest_X0 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, // x0 |
| 69 | void* guest_state, // x1 |
| 70 | const vki_sigset_t *sysmask, // x2 |
| 71 | const vki_sigset_t *postmask, // x3 |
| 72 | Int nsigwords) // x4 |
| 73 | */ |
| 74 | /* from vki-arm64-linux.h */ |
| 75 | #define VKI_SIG_SETMASK 2 |
| 76 | |
| 77 | .globl ML_(do_syscall_for_client_WRK) |
| 78 | ML_(do_syscall_for_client_WRK): |
| 79 | |
| 80 | /* Stash callee-saves and our args on the stack */ |
| 81 | stp x29, x30, [sp, #-16]! |
| 82 | stp x27, x28, [sp, #-16]! |
| 83 | stp x25, x26, [sp, #-16]! |
| 84 | stp x23, x24, [sp, #-16]! |
| 85 | stp x21, x22, [sp, #-16]! |
| 86 | stp x19, x20, [sp, #-16]! |
| 87 | stp x4, x5, [sp, #-16]! |
| 88 | stp x2, x3, [sp, #-16]! |
| 89 | stp x0, x1, [sp, #-16]! |
| 90 | |
| 91 | 1: |
| 92 | |
| 93 | mov x8, #__NR_rt_sigprocmask |
| 94 | mov x0, #VKI_SIG_SETMASK |
| 95 | mov x1, x2 /* sysmask */ |
| 96 | mov x2, x3 /* postmask */ |
| 97 | mov x3, x4 /* nsigwords */ |
| 98 | svc 0x00000000 |
| 99 | |
| 100 | |
| 101 | ldr x5, [sp, #8] /* saved x1 == guest_state */ |
| 102 | |
| 103 | ldr x8, [sp, #0] /* saved x0 == syscall# */ |
| 104 | ldr x0, [x5, #OFFSET_arm64_X0] |
| 105 | ldr x1, [x5, #OFFSET_arm64_X1] |
| 106 | ldr x2, [x5, #OFFSET_arm64_X2] |
| 107 | ldr x3, [x5, #OFFSET_arm64_X3] |
| 108 | ldr x4, [x5, #OFFSET_arm64_X4] |
| 109 | ldr x5, [x5, #OFFSET_arm64_X5] |
| 110 | |
| 111 | 2: svc 0x00000000 |
| 112 | 3: |
| 113 | ldr x5, [sp, #8] /* saved x1 == guest_state */ |
| 114 | str x0, [x5, #OFFSET_arm64_X0] |
| 115 | |
| 116 | 4: |
| 117 | mov x8, #__NR_rt_sigprocmask |
| 118 | mov x0, #VKI_SIG_SETMASK |
| 119 | ldr x1, [sp, #24] /* saved x3 == postmask */ |
| 120 | mov x2, #0 |
| 121 | ldr x3, [sp, #32] /* saved x4 == nsigwords */ |
| 122 | svc 0x00000000 |
| 123 | |
| 124 | cmp x0, #0 |
| 125 | blt 7f |
| 126 | |
| 127 | 5: /* Success: return zero */ |
| 128 | mov x0, #0 |
| 129 | ldp xzr, x1, [sp], #16 |
| 130 | ldp x2, x3, [sp], #16 |
| 131 | ldp x4, x5, [sp], #16 |
| 132 | ldp x19, x20, [sp], #16 |
| 133 | ldp x21, x22, [sp], #16 |
| 134 | ldp x23, x24, [sp], #16 |
| 135 | ldp x25, x26, [sp], #16 |
| 136 | ldp x27, x28, [sp], #16 |
| 137 | ldp x29, x30, [sp], #16 |
| 138 | ret |
| 139 | |
| 140 | 7: /* Failure: return 0x8000 | error code */ |
| 141 | orr x0, x0, #0x8000 |
| 142 | ldp xzr, x1, [sp], #16 |
| 143 | ldp x2, x3, [sp], #16 |
| 144 | ldp x4, x5, [sp], #16 |
| 145 | ldp x19, x20, [sp], #16 |
| 146 | ldp x21, x22, [sp], #16 |
| 147 | ldp x23, x24, [sp], #16 |
| 148 | ldp x25, x26, [sp], #16 |
| 149 | ldp x27, x28, [sp], #16 |
| 150 | ldp x29, x30, [sp], #16 |
| 151 | ret |
| 152 | |
| 153 | |
| 154 | |
| 155 | .section .rodata |
| 156 | /* export the ranges so that |
| 157 | VG_(fixup_guest_state_after_syscall_interrupted) can do the |
| 158 | right thing */ |
| 159 | |
| 160 | .globl ML_(blksys_setup) |
| 161 | .globl ML_(blksys_restart) |
| 162 | .globl ML_(blksys_complete) |
| 163 | .globl ML_(blksys_committed) |
| 164 | .globl ML_(blksys_finished) |
| 165 | ML_(blksys_setup): .quad 1b |
| 166 | ML_(blksys_restart): .quad 2b |
| 167 | ML_(blksys_complete): .quad 3b |
| 168 | ML_(blksys_committed): .quad 4b |
| 169 | ML_(blksys_finished): .quad 5b |
| 170 | |
| 171 | /* Let the linker know we don't need an executable stack */ |
| 172 | .section .note.GNU-stack,"",%progbits |
| 173 | |
| 174 | .previous |
| 175 | |
| 176 | #endif // defined(VGP_arm_linux) |
| 177 | |
| 178 | /*--------------------------------------------------------------------*/ |
| 179 | /*--- end ---*/ |
| 180 | /*--------------------------------------------------------------------*/ |