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[PATCH 16/19] nptl: nios2: Fix Race conditions in pthread cancellation (BZ#12683)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Mon, 11 Dec 2017 17:07:00 -0200
- Subject: [PATCH 16/19] nptl: nios2: Fix Race conditions in pthread cancellation (BZ#12683)
- Authentication-results: sourceware.org; auth=none
- References: <1513019223-7603-1-git-send-email-adhemerval.zanella@linaro.org>
This patch adds the nios2 modifications required for the BZ#12683.
It basically adds the required ucontext_get_pc function.
The default syscall_cancel.c should be as expected for NIOS2. With
GCC 6.2.1 syscall_cancel.c generates the following code:
---
00000000 <__GI___syscall_cancel_arch>:
0: defffe04 addi sp,sp,-8
4: dd800015 stw r22,0(sp)
8: 002ce03a nextpc r22
c: 02000034 movhi r8,0
10: 42000004 addi r8,r8,0
14: dfc00115 stw ra,4(sp)
18: b22d883a add r22,r22,r8
0000001c <__syscall_cancel_arch_start>:
1c: 20c00017 ldw r3,0(r4)
20: 18c0010c andi r3,r3,4
24: 18000f1e bne r3,zero,64 <__syscall_cancel_arch_end+0x18>
28: 3015883a mov r10,r6
2c: 2805883a mov r2,r5
30: da400517 ldw r9,20(sp)
34: 380b883a mov r5,r7
38: da000417 ldw r8,16(sp)
3c: d9c00317 ldw r7,12(sp)
40: d9800217 ldw r6,8(sp)
44: 5009883a mov r4,r10
48: 003b683a trap 0
0000004c <__syscall_cancel_arch_end>:
4c: 38000126 beq r7,zero,54 <__syscall_cancel_arch_end+0x8>
50: 0085c83a sub r2,zero,r2
54: dfc00117 ldw ra,4(sp)
58: dd800017 ldw r22,0(sp)
5c: dec00204 addi sp,sp,8
60: f800283a ret
64: b0800017 ldw r2,0(r22)
68: 103ee83a callr r2
---
Checked against a build and make check run-built-tests=no for
nios2-linux-gnu.
* sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h (ucontext_get_pc):
New function.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
ChangeLog | 3 +++
sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h | 16 ++++++++++++++++
2 files changed, 19 insertions(+)
diff --git a/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h b/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
index b244478..1fba6cd 100644
--- a/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
+++ b/sysdeps/unix/sysv/linux/nios2/sigcontextinfo.h
@@ -16,6 +16,11 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
+#ifndef _SIGCONTEXTINFO_H
+#define _SIGCONTEXTINFO_H
+
+#include <stdint.h>
+
#include <sys/ucontext.h>
#include "kernel-features.h"
@@ -33,3 +38,14 @@
(act)->sa_flags |= SA_SIGINFO; \
(sigaction) (sig, act, oact); \
})
+
+static inline uintptr_t
+ucontext_get_pc (const ucontext_t *uc)
+{
+ /* rt_restore_ucontext (arch/nios/kernel/signal.c) sets this position
+ to 'ea' register which is stated as exception return address (pc)
+ at arch/nios2/include/asm/ptrace.h. */
+ return uc->uc_mcontext.regs[27];
+}
+
+#endif /* _SIGCONTEXTINFO_H */
--
2.7.4