[v2,12/21] nptl: alpha: Fix Race conditions in pthread cancellation (BZ#12683)
Commit Message
This patch adds the alpha modifications required for the BZ#12683.
It basically adds the required ucontext_get_pc function
The default syscall_cancel.c should be fine for alpha and GCC 6.1
generates the following cod for syscall_cancel.os:
---
0000000000000000 <__GI___syscall_cancel_arch>:
0: 00 00 bb 27 ldah gp,0(t12)
4: 00 00 bd 23 lda gp,0(gp)
8: f0 ff de 23 lda sp,-16(sp)
c: 00 04 f1 47 mov a1,v0
10: 00 00 5e b7 stq ra,0(sp)
0000000000000014 <__syscall_cancel_arch_start>:
14: 00 00 30 a0 ldl t0,0(a0)
18: 01 00 e1 43 sextl t0,t0
1c: 01 90 20 44 and t0,0x4,t0
20: 0f 00 20 f4 bne t0,60 <__syscall_cancel_arch_end+0x20>
24: 10 04 f2 47 mov a2,a0
28: 11 04 f3 47 mov a3,a1
2c: 12 04 f4 47 mov a4,a2
30: 10 00 9e a6 ldq a4,16(sp)
34: 13 04 f5 47 mov a5,a3
38: 18 00 be a6 ldq a5,24(sp)
3c: 83 00 00 00 callsys
0000000000000040 <__syscall_cancel_arch_end>:
40: 21 05 e0 43 negq v0,t0
44: 00 00 5e a7 ldq ra,0(sp)
48: c0 04 61 46 cmovne a3,t0,v0
4c: 10 00 de 23 lda sp,16(sp)
50: 01 80 fa 6b ret
54: 00 00 fe 2f unop
58: 1f 04 ff 47 nop
5c: 00 00 fe 2f unop
60: 00 00 7d a7 ldq t12,0(gp)
64: 00 40 5b 6b jsr ra,(t12),68 <__syscall_cancel_arch_end+0x28>
68: 1f 04 ff 47 nop
6c: 00 00 fe 2f unop
---
Checked on alpha-linux-gnu, no regression found.
[BZ #12683]
* sysdeps/unix/sysv/linux/alpha/sigcontextinfo.h (ucontext_get_pc):
New function.
---
ChangeLog | 4 ++++
sysdeps/unix/sysv/linux/alpha/sigcontextinfo.h | 13 +++++++++++++
2 files changed, 17 insertions(+)
@@ -15,6 +15,11 @@
License along with the GNU C Library. If not, see
<http://www.gnu.org/licenses/>. */
+#ifndef _SIGCONTEXTINFO_H
+#define _SIGCONTEXTINFO_H
+
+#include <stdint.h>
+
#define SIGCONTEXT int _code, struct sigcontext *
#define SIGCONTEXT_EXTRA_ARGS _code,
#define GET_PC(ctx) ((void *) (ctx)->sc_pc)
@@ -22,3 +27,11 @@
#define GET_STACK(ctx) ((void *) (ctx)->sc_regs[30])
#define CALL_SIGHANDLER(handler, signo, ctx) \
(handler)((signo), SIGCONTEXT_EXTRA_ARGS (ctx))
+
+static inline uintptr_t
+ucontext_get_pc (const ucontext_t *uc)
+{
+ return uc->uc_mcontext.sc_pc;
+}
+
+#endif /* _SIGCONTEXTINFO_H */