[PATCH v4 12/21] nptl: sparc: Fix Race conditions in pthread cancellation [BZ#12683]
Adhemerval Zanella
adhemerval.zanella@linaro.org
Fri Apr 3 20:31:52 GMT 2020
This patch adds the sparc modifications required for the BZ#12683 fix.
Different than other architectures, SPARC passes the sigcontext_t
struct pointer as third argument in the signal handler set with
SA_SIGINFO (some info at [1]) for 64 bits and the pt_regs in 32 bits.
>From Linux code:
* arch/sparc/kernel/signal_64.c
428 /* 3. signal handler back-trampoline and parameters */
429 regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
430 regs->u_regs[UREG_I0] = ksig->sig;
431 regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
432
433 /* The sigcontext is passed in this way because of how it
434 * is defined in GLIBC's /usr/include/bits/sigcontext.h
435 * for sparc64. It includes the 128 bytes of siginfo_t.
436 */
437 regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
* arch/sparc/kernel/signal_32.c:
392 regs->u_regs[UREG_FP] = (unsigned long) sf;
393 regs->u_regs[UREG_I0] = ksig->sig;
394 regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
395 regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
396
397 regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
398 regs->npc = (regs->pc + 4);
So it requires an arch-specific ucontext_add_cancel.
Also on sparc interrupted pause syscall returns with a PC indicating a
side-effect and this deviates from other architectures. The sparc64
pause fall back to ppool syscall.
Checked on sparc64-linux-gnu and sparcv9-linux-gnu.
[1] https://www.spinics.net/lists/sparclinux/msg05037.html
---
sysdeps/sparc/nptl/tcb-offsets.sym | 3 +
.../sysv/linux/sparc/cancellation-sigmask.h | 39 ++++++++++
.../sysv/linux/sparc/sparc32/syscall_cancel.S | 71 ++++++++++++++++++
sysdeps/unix/sysv/linux/sparc/sparc64/pause.c | 25 +++++++
.../sysv/linux/sparc/sparc64/syscall_cancel.S | 74 +++++++++++++++++++
5 files changed, 212 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
create mode 100644 sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
diff --git a/sysdeps/sparc/nptl/tcb-offsets.sym b/sysdeps/sparc/nptl/tcb-offsets.sym
index f75d02065e..8112290d88 100644
--- a/sysdeps/sparc/nptl/tcb-offsets.sym
+++ b/sysdeps/sparc/nptl/tcb-offsets.sym
@@ -4,3 +4,6 @@
MULTIPLE_THREADS_OFFSET offsetof (tcbhead_t, multiple_threads)
POINTER_GUARD offsetof (tcbhead_t, pointer_guard)
TID offsetof (struct pthread, tid)
+
+-- Not strictly offsets, used on syscall_cancel.S
+TCB_CANCELED_BITMASK CANCELED_BITMASK
diff --git a/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h b/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
new file mode 100644
index 0000000000..8086228828
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/cancellation-sigmask.h
@@ -0,0 +1,39 @@
+/* Architecture specific bits for cancellation handling.
+ Copyright (C) 2020 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/>. */
+
+#ifndef _NPTL_CANCELLATION_SIGMASK_H
+#define _NPTL_CANCELLATION_SIGMASK_H 1
+
+/* Add the SIGCANCEL signal on sigmask set at the ucontext CTX obtained from
+ the sigaction handler. */
+static void
+ucontext_block_sigcancel (void *ctx)
+{
+ sigset_t *set;
+#ifdef __arch64__
+ struct pt_regs *regs = (struct pt_regs*) ((siginfo_t *)(ctx) + 1);
+ __siginfo_fpu_t *f = (__siginfo_fpu_t *)(regs + 1);
+ set = (sigset_t *) ((stack_t *)(f + 1) + 1);
+#else
+ struct pt_regs32 *ptregs = (struct pt_regs32 *) (ctx);
+ set = (sigset_t *) (ptregs + 1);
+#endif
+ __sigaddset (set, SIGCANCEL);
+}
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S b/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
new file mode 100644
index 0000000000..2393bf9be0
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/syscall_cancel.S
@@ -0,0 +1,71 @@
+/* Cancellable syscall wrapper. Linux/sparc32 version.
+ Copyright (C) 2020 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 __syscall_cancel_arch (int *cancelhandling,
+ long int nr,
+ long int arg1,
+ long int arg2,
+ long int arg3,
+ long int arg4,
+ long int arg5,
+ long int arg6) */
+
+ENTRY (__syscall_cancel_arch)
+ save %sp, -96, %sp
+
+ cfi_window_save
+ cfi_register (%o7, %i7)
+ cfi_def_cfa_register (%fp)
+
+ .globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+ /* if (*cancelhandling & CANCELED_BITMASK)
+ __syscall_do_cancel() */
+ ld [%i0], %g2
+ andcc %g2, TCB_CANCELED_BITMASK, %g0
+ bne,pn %icc, 2f
+ /* Issue a 6 argument syscall. */
+ mov %i1, %g1
+ mov %i2, %o0
+ mov %i3, %o1
+ mov %i4, %o2
+ mov %i5, %o3
+ ld [%fp+92], %o4
+ ld [%fp+96], %o5
+ ta 0x10
+
+ .globl __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+ bcc 1f
+ nop
+ sub %g0, %o0, %o0
+1:
+ mov %o0, %i0
+ return %i7+8
+ nop
+
+2:
+ call __syscall_do_cancel, 0
+ nop
+ nop
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
new file mode 100644
index 0000000000..4fae573091
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/pause.c
@@ -0,0 +1,25 @@
+/* Linux pause syscall implementation. Linux/sparc64.
+ Copyright (C) 2020 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 <sys/syscall.h>
+
+/* On sparc interrupted pause syscall returns with a PC indicating a
+ side-effect and this deviates from other architectures. Fall back to
+ ppool implementation. */
+#undef __NR_pause
+#include <sysdeps/unix/sysv/linux/pause.c>
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S b/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
new file mode 100644
index 0000000000..f9ecb4a851
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/syscall_cancel.S
@@ -0,0 +1,74 @@
+/* Cancellable syscall wrapper. Linux/sparc64 version.
+ Copyright (C) 2020 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>
+
+ .register %g2, #scratch
+
+/* long int __syscall_cancel_arch (int *cancelhandling,
+ long int nr,
+ long int arg1,
+ long int arg2,
+ long int arg3,
+ long int arg4,
+ long int arg5,
+ long int arg6) */
+
+ENTRY (__syscall_cancel_arch)
+ save %sp, -176, %sp
+
+ cfi_window_save
+ cfi_register (%o7, %i7)
+ cfi_def_cfa_register (%fp)
+
+ .globl __syscall_cancel_arch_start
+__syscall_cancel_arch_start:
+
+ /* if (*cancelhandling & CANCELED_BITMASK)
+ __syscall_do_cancel() */
+ lduw [%i0], %g2
+ andcc %g2, TCB_CANCELED_BITMASK, %g0
+ bne,pn %xcc, 2f
+ /* Issue a 6 argument syscall. */
+ mov %i1, %g1
+ mov %i2, %o0
+ mov %i3, %o1
+ mov %i4, %o2
+ mov %i5, %o3
+ ldx [%fp + STACK_BIAS + 176], %o4
+ ldx [%fp + STACK_BIAS + 184], %o5
+ ta 0x6d
+
+ .global __syscall_cancel_arch_end
+__syscall_cancel_arch_end:
+
+ bcc,pt %xcc, 1f
+ nop
+ sub %g0, %o0, %o0
+1:
+ mov %o0, %i0
+ return %i7+8
+ nop
+
+2:
+ call __syscall_do_cancel, 0
+ nop
+ nop
+
+END (__syscall_cancel_arch)
+libc_hidden_def (__syscall_cancel_arch)
--
2.17.1
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