1 2 /*--------------------------------------------------------------------*/ 3 /*--- Support for doing system calls. syscall-s390x-linux.S ---*/ 4 /*--------------------------------------------------------------------*/ 5 6 /* 7 This file is part of Valgrind, a dynamic binary instrumentation 8 framework. 9 10 Copyright IBM Corp. 2010-2017 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 /* Contributed by Christian Borntraeger */ 31 32 #include "pub_core_basics_asm.h" 33 #include "pub_core_vkiscnums_asm.h" 34 #include "libvex_guest_offsets.h" 35 36 #if defined(VGA_s390x) 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, since the syscall 52 number can be encoded in the svc instruction itself. 53 The syscall result is written back to guest register r2. 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, // r2 69 void* guest_state, // r3 70 const vki_sigset_t *sysmask, // r4 71 const vki_sigset_t *postmask, // r5 72 Int nsigwords) // r6 73 */ 74 /* from vki_arch.h */ 75 #define VKI_SIG_SETMASK 2 76 77 #define SP_SAVE 16 78 #define SP_R2 SP_SAVE + 0*8 79 #define SP_R3 SP_SAVE + 1*8 80 #define SP_R4 SP_SAVE + 2*8 81 #define SP_R5 SP_SAVE + 3*8 82 #define SP_R6 SP_SAVE + 4*8 83 #define SP_R7 SP_SAVE + 5*8 84 #define SP_R8 SP_SAVE + 6*8 85 #define SP_R9 SP_SAVE + 7*8 86 87 .align 4 88 .globl ML_(do_syscall_for_client_WRK) 89 ML_(do_syscall_for_client_WRK): 90 1: /* Even though we can't take a signal until the sigprocmask completes, 91 start the range early. 92 If IA is in the range [1,2), the syscall hasn't been started yet */ 93 94 /* Set the signal mask which should be current during the syscall. */ 95 /* Save and restore all the parameters and all the registers that 96 we clobber (r6-r9) */ 97 stmg %r2,%r9, SP_R2(%r15) 98 99 lghi %r2, VKI_SIG_SETMASK /* how */ 100 lgr %r3, %r4 /* sysmask */ 101 lgr %r4, %r5 /* postmask */ 102 lgr %r5, %r6 /* nsigwords */ 103 svc __NR_rt_sigprocmask 104 cghi %r2, 0x0 105 jne 7f /* sigprocmask failed */ 106 107 /* OK, that worked. Now do the syscall proper. */ 108 lg %r9, SP_R3(%r15) /* guest state --> r9 */ 109 lg %r2, OFFSET_s390x_r2(%r9) /* guest r2 --> real r2 */ 110 lg %r3, OFFSET_s390x_r3(%r9) /* guest r3 --> real r3 */ 111 lg %r4, OFFSET_s390x_r4(%r9) /* guest r4 --> real r4 */ 112 lg %r5, OFFSET_s390x_r5(%r9) /* guest r5 --> real r5 */ 113 lg %r6, OFFSET_s390x_r6(%r9) /* guest r6 --> real r6 */ 114 lg %r7, OFFSET_s390x_r7(%r9) /* guest r7 --> real r7 */ 115 lg %r1, SP_R2(%r15) /* syscallno -> r1 */ 116 117 2: svc 0 118 119 3: 120 stg %r2, OFFSET_s390x_r2(%r9) 121 122 4: /* Re-block signals. If IA is in [4,5), then the syscall 123 is complete and we needn't worry about it. */ 124 lghi %r2, VKI_SIG_SETMASK /* how */ 125 lg %r3, SP_R5(%r15) /* postmask */ 126 lghi %r4, 0x0 /* NULL */ 127 lg %r5, SP_R6(%r15) /* nsigwords */ 128 svc __NR_rt_sigprocmask 129 cghi %r2, 0x0 130 jne 7f /* sigprocmask failed */ 131 132 5: /* Everyting ok. Return 0 and restore the call-saved 133 registers, that we have clobbered */ 134 lghi %r2, 0x0 135 lmg %r6,%r9, SP_R6(%r15) 136 br %r14 137 138 7: /* Some problem. Return 0x8000 | error and restore the call-saved 139 registers we have clobbered. */ 140 nill %r2, 0x7fff 141 oill %r2, 0x8000 142 lmg %r6,%r9, SP_R6(%r15) 143 br %r14 144 145 .section .rodata 146 /* Export the ranges so that 147 VG_(fixup_guest_state_after_syscall_interrupted) can do the 148 right thing */ 149 150 .globl ML_(blksys_setup) 151 .globl ML_(blksys_restart) 152 .globl ML_(blksys_complete) 153 .globl ML_(blksys_committed) 154 .globl ML_(blksys_finished) 155 156 /* The compiler can assume that 8 byte data elements are aligned on 8 byte */ 157 .align 8 158 ML_(blksys_setup): .quad 1b 159 ML_(blksys_restart): .quad 2b 160 ML_(blksys_complete): .quad 3b 161 ML_(blksys_committed): .quad 4b 162 ML_(blksys_finished): .quad 5b 163 .previous 164 165 #endif /* VGA_s390x */ 166 167 /* Let the linker know we don't need an executable stack */ 168 MARK_STACK_NO_EXEC 169 170 /*--------------------------------------------------------------------*/ 171 /*--- end ---*/ 172 /*--------------------------------------------------------------------*/ 173
