| Message ID | 1519679016-12241-8-git-send-email-adhemerval.zanella@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | nptl: Fix Race conditions in pthread cancellation (BZ#12683) | expand |
Adhemerval Zanella <adhemerval.zanella@linaro.org> writes: > This patches adds the powerpc64 modification required for the BZ#12683. > It basically adds the required __pthread_get_pc function and a arch > specific syscall_cancel implementation. > > The powerpc requires an arch-specific syscall_cancel because > INTERNAL_SYSCALL_NCS adds a mfcr just after the sc instruction to get > the CR0.SO bit information from kernel (which signals the error > return status). So for cancelled syscalls with side effects, > __pthread_get_pc will point to mcfr and thus invalidating the checks > on sigcancel_handler. > > Checked on powerpc64le-linux-gnu and powerpc-linux-gnu. > > [BZ #12683] > * sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S: New file. > * sysdeps/unix/sysv/linux/powerpc/sysdep-cancel.h > (__pthread_get_pc): New function. This entry is outdated. Both the file name and the function name need to be updated. > diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S > new file mode 100644 > index 0000000..2e56c72 > --- /dev/null > +++ b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S > @@ -0,0 +1,64 @@ > +/* Cancellable syscall wrapper. Linux/powerpc version. > + Copyright (C) 2017 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <http://www.gnu.org/licenses/>. */ > + > +#include <sysdep.h> > + > +/* long int [r3] __syscall_cancel_arch (int *cancelhandling [r3], > + long int nr [r4], > + long int arg1 [r5], > + long int arg2 [r6], > + long int arg3 [r7], > + long int arg4 [r8], > + long int arg5 [r9], > + long int arg6 [r10]) */ > + > +ENTRY (__syscall_cancel_arch) > + > + .globl __syscall_cancel_arch_start > + .type __syscall_cancel_arch_start,@function > +__syscall_cancel_arch_start: > + > + /* if (*cancelhandling & CANCELED_BITMASK) > + __syscall_do_cancel() */ > + lwz r0,0(r3) > + rldicl. r0,r0,62,63 > + beq 1f > + b __syscall_do_cancel Should this be a Branch & Link? -- Tulio Magno
On 07/05/2018 16:25, Tulio Magno Quites Machado Filho wrote: > Adhemerval Zanella <adhemerval.zanella@linaro.org> writes: > >> This patches adds the powerpc64 modification required for the BZ#12683. >> It basically adds the required __pthread_get_pc function and a arch >> specific syscall_cancel implementation. >> >> The powerpc requires an arch-specific syscall_cancel because >> INTERNAL_SYSCALL_NCS adds a mfcr just after the sc instruction to get >> the CR0.SO bit information from kernel (which signals the error >> return status). So for cancelled syscalls with side effects, >> __pthread_get_pc will point to mcfr and thus invalidating the checks >> on sigcancel_handler. >> >> Checked on powerpc64le-linux-gnu and powerpc-linux-gnu. >> >> [BZ #12683] >> * sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S: New file. >> * sysdeps/unix/sysv/linux/powerpc/sysdep-cancel.h >> (__pthread_get_pc): New function. > > This entry is outdated. Both the file name and the function name need to be > updated. Ack. > >> diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S >> new file mode 100644 >> index 0000000..2e56c72 >> --- /dev/null >> +++ b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S >> @@ -0,0 +1,64 @@ >> +/* Cancellable syscall wrapper. Linux/powerpc version. >> + Copyright (C) 2017 Free Software Foundation, Inc. >> + This file is part of the GNU C Library. >> + >> + The GNU C Library is free software; you can redistribute it and/or >> + modify it under the terms of the GNU Lesser General Public >> + License as published by the Free Software Foundation; either >> + version 2.1 of the License, or (at your option) any later version. >> + >> + The GNU C Library 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 >> + Lesser General Public License for more details. >> + >> + You should have received a copy of the GNU Lesser General Public >> + License along with the GNU C Library; if not, see >> + <http://www.gnu.org/licenses/>. */ >> + >> +#include <sysdep.h> >> + >> +/* long int [r3] __syscall_cancel_arch (int *cancelhandling [r3], >> + long int nr [r4], >> + long int arg1 [r5], >> + long int arg2 [r6], >> + long int arg3 [r7], >> + long int arg4 [r8], >> + long int arg5 [r9], >> + long int arg6 [r10]) */ >> + >> +ENTRY (__syscall_cancel_arch) >> + >> + .globl __syscall_cancel_arch_start >> + .type __syscall_cancel_arch_start,@function >> +__syscall_cancel_arch_start: >> + >> + /* if (*cancelhandling & CANCELED_BITMASK) >> + __syscall_do_cancel() */ >> + lwz r0,0(r3) >> + rldicl. r0,r0,62,63 >> + beq 1f >> + b __syscall_do_cancel > > Should this be a Branch & Link? > Right, I think ABI really mandates branch & link even for no-return calls. I will change it.
diff --git a/sysdeps/unix/sysv/linux/powerpc/sigcontextinfo.h b/sysdeps/unix/sysv/linux/powerpc/sigcontextinfo.h index 72381e3..3be71f7 100644 --- a/sysdeps/unix/sysv/linux/powerpc/sigcontextinfo.h +++ b/sysdeps/unix/sysv/linux/powerpc/sigcontextinfo.h @@ -15,7 +15,11 @@ License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ +#ifndef _SIGCONTEXTINFO_H +#define _SIGCONTEXTINFO_H + #include <signal.h> +#include <stdint.h> #define SIGCONTEXT struct sigcontext * #define SIGCONTEXT_EXTRA_ARGS @@ -24,3 +28,15 @@ #define GET_STACK(ctx) ((void *)((ctx)->regs->gpr[1])) #define CALL_SIGHANDLER(handler, signo, ctx) \ (handler)((signo), SIGCONTEXT_EXTRA_ARGS (ctx)) + +static inline uintptr_t +ucontext_get_pc (const ucontext_t *uc) +{ +#ifdef __powerpc64__ + return uc->uc_mcontext.gp_regs[PT_NIP]; +#else + return uc->uc_mcontext.uc_regs->gregs[PT_NIP]; +#endif +} + +#endif /* _SIGCONTEXTINFO_H */ diff --git a/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S new file mode 100644 index 0000000..2e56c72 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/syscall_cancel.S @@ -0,0 +1,64 @@ +/* Cancellable syscall wrapper. Linux/powerpc version. + Copyright (C) 2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <sysdep.h> + +/* long int [r3] __syscall_cancel_arch (int *cancelhandling [r3], + long int nr [r4], + long int arg1 [r5], + long int arg2 [r6], + long int arg3 [r7], + long int arg4 [r8], + long int arg5 [r9], + long int arg6 [r10]) */ + +ENTRY (__syscall_cancel_arch) + + .globl __syscall_cancel_arch_start + .type __syscall_cancel_arch_start,@function +__syscall_cancel_arch_start: + + /* if (*cancelhandling & CANCELED_BITMASK) + __syscall_do_cancel() */ + lwz r0,0(r3) + rldicl. r0,r0,62,63 + beq 1f + b __syscall_do_cancel + nop +1: + ABORT_TRANSACTION + /* Issue a 6 argument syscall, the nr [r4] being the syscall + number. */ + mr r0,r4 + mr r3,r5 + mr r4,r6 + mr r5,r7 + mr r6,r8 + mr r7,r9 + mr r8,r10 + sc + + .globl __syscall_cancel_arch_end + .type __syscall_cancel_arch_end,@function +__syscall_cancel_arch_end: + + bnslr+ + neg r3,r3 + blr +END (__syscall_cancel_arch) +libc_hidden_def (__syscall_cancel_arch)