/*--------------------------------------------------------------------*/ /*--- Support for doing system calls. syscall-s390x-linux.S ---*/ /*--------------------------------------------------------------------*/ /* This file is part of Valgrind, a dynamic binary instrumentation framework. Copyright IBM Corp. 2010-2015 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. The GNU General Public License is contained in the file COPYING. */ /* Contributed by Christian Borntraeger */ #include "pub_core_basics_asm.h" #include "pub_core_vkiscnums_asm.h" #include "libvex_guest_offsets.h" #if defined(VGA_s390x) /*----------------------------------------------------------------*/ /* Perform a syscall for the client. This will run a syscall with the client's specific per-thread signal mask. The structure of this function is such that, if the syscall is interrupted by a signal, we can determine exactly what execution state we were in with respect to the execution of the syscall by examining the value of NIP in the signal handler. This means that we can always do the appropriate thing to precisely emulate the kernel's signal/syscall interactions. The syscall number is taken from the argument, since the syscall number can be encoded in the svc instruction itself. The syscall result is written back to guest register r2. Returns 0 if the syscall was successfully called (even if the syscall itself failed), or a nonzero error code in the lowest 8 bits if one of the sigprocmasks failed (there's no way to determine which one failed). And there's no obvious way to recover from that either, but nevertheless we want to know. VG_(fixup_guest_state_after_syscall_interrupted) does the thread state fixup in the case where we were interrupted by a signal. Prototype: UWord ML_(do_syscall_for_client_WRK)( Int syscallno, // r2 void* guest_state, // r3 const vki_sigset_t *sysmask, // r4 const vki_sigset_t *postmask, // r5 Int nsigwords) // r6 */ /* from vki_arch.h */ #define VKI_SIG_SETMASK 2 #define SP_SAVE 16 #define SP_R2 SP_SAVE + 0*8 #define SP_R3 SP_SAVE + 1*8 #define SP_R4 SP_SAVE + 2*8 #define SP_R5 SP_SAVE + 3*8 #define SP_R6 SP_SAVE + 4*8 #define SP_R7 SP_SAVE + 5*8 #define SP_R8 SP_SAVE + 6*8 #define SP_R9 SP_SAVE + 7*8 .align 4 .globl ML_(do_syscall_for_client_WRK) ML_(do_syscall_for_client_WRK): 1: /* Even though we can't take a signal until the sigprocmask completes, start the range early. If IA is in the range [1,2), the syscall hasn't been started yet */ /* Set the signal mask which should be current during the syscall. */ /* Save and restore all the parameters and all the registers that we clobber (r6-r9) */ stmg %r2,%r9, SP_R2(%r15) lghi %r2, VKI_SIG_SETMASK /* how */ lgr %r3, %r4 /* sysmask */ lgr %r4, %r5 /* postmask */ lgr %r5, %r6 /* nsigwords */ svc __NR_rt_sigprocmask cghi %r2, 0x0 jne 7f /* sigprocmask failed */ /* OK, that worked. Now do the syscall proper. */ lg %r9, SP_R3(%r15) /* guest state --> r9 */ lg %r2, OFFSET_s390x_r2(%r9) /* guest r2 --> real r2 */ lg %r3, OFFSET_s390x_r3(%r9) /* guest r3 --> real r3 */ lg %r4, OFFSET_s390x_r4(%r9) /* guest r4 --> real r4 */ lg %r5, OFFSET_s390x_r5(%r9) /* guest r5 --> real r5 */ lg %r6, OFFSET_s390x_r6(%r9) /* guest r6 --> real r6 */ lg %r7, OFFSET_s390x_r7(%r9) /* guest r7 --> real r7 */ lg %r1, SP_R2(%r15) /* syscallno -> r1 */ 2: svc 0 3: stg %r2, OFFSET_s390x_r2(%r9) 4: /* Re-block signals. If IA is in [4,5), then the syscall is complete and we needn't worry about it. */ lghi %r2, VKI_SIG_SETMASK /* how */ lg %r3, SP_R5(%r15) /* postmask */ lghi %r4, 0x0 /* NULL */ lg %r5, SP_R6(%r15) /* nsigwords */ svc __NR_rt_sigprocmask cghi %r2, 0x0 jne 7f /* sigprocmask failed */ 5: /* Everyting ok. Return 0 and restore the call-saved registers, that we have clobbered */ lghi %r2, 0x0 lmg %r6,%r9, SP_R6(%r15) br %r14 7: /* Some problem. Return 0x8000 | error and restore the call-saved registers we have clobbered. */ nill %r2, 0x7fff oill %r2, 0x8000 lmg %r6,%r9, SP_R6(%r15) br %r14 .section .rodata /* Export the ranges so that VG_(fixup_guest_state_after_syscall_interrupted) can do the right thing */ .globl ML_(blksys_setup) .globl ML_(blksys_restart) .globl ML_(blksys_complete) .globl ML_(blksys_committed) .globl ML_(blksys_finished) /* The compiler can assume that 8 byte data elements are aligned on 8 byte */ .align 8 ML_(blksys_setup): .quad 1b ML_(blksys_restart): .quad 2b ML_(blksys_complete): .quad 3b ML_(blksys_committed): .quad 4b ML_(blksys_finished): .quad 5b .previous #endif /* VGA_s390x */ /* Let the linker know we don't need an executable stack */ MARK_STACK_NO_EXEC /*--------------------------------------------------------------------*/ /*--- end ---*/ /*--------------------------------------------------------------------*/