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Subject[PATCH] csky: Fixup CONFIG_DEBUG_RSEQ
Date
From: Guo Ren <guoren@linux.alibaba.com>

Put the rseq_syscall check point at the prologue of the syscall
will break the a0 ... a7. This will casue system call bug when
DEBUG_RSEQ is enabled.

So move it to the epilogue of syscall, but before syscall_trace.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
---
arch/csky/kernel/entry.S | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index 9595e86..f138003 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -128,15 +128,11 @@ tlbop_end 1
ENTRY(csky_systemcall)
SAVE_ALL TRAP0_SIZE
zero_fp
-#ifdef CONFIG_RSEQ_DEBUG
- mov a0, sp
- jbsr rseq_syscall
-#endif
psrset ee, ie

lrw r9, __NR_syscalls
cmphs syscallid, r9 /* Check nr of syscall */
- bt ret_from_exception
+ bt 1f

lrw r9, sys_call_table
ixw r9, syscallid
@@ -162,6 +158,11 @@ ENTRY(csky_systemcall)
jsr syscallid
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */
+1:
+#ifdef CONFIG_DEBUG_RSEQ
+ mov a0, sp
+ jbsr rseq_syscall
+#endif
jmpi ret_from_exception

csky_syscall_trace:
@@ -187,6 +188,10 @@ csky_syscall_trace:
#endif
stw a0, (sp, LSAVE_A0) /* Save return value */

+#ifdef CONFIG_DEBUG_RSEQ
+ mov a0, sp
+ jbsr rseq_syscall
+#endif
mov a0, sp /* right now, sp --> pt_regs */
jbsr syscall_trace_exit
br ret_from_exception
--
2.7.4
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