Commit fd0c153d authored by Al Viro's avatar Al Viro Committed by Dinh Nguyen

nios2: add force_successful_syscall_return()

If we use the ancient SysV syscall ABI, we'd better have tell the
kernel how to claim that a negative return value is a success.
Use ->orig_r2 for that - it's inaccessible via ptrace, so it's
a fair game for changes and it's normally[*] non-negative on return
from syscall.  Set to -1; syscall is not going to be restart-worthy
by definition, so we won't interfere with that use either.

[*] the only exception is rt_sigreturn(), where we skip the entire
messing with r1/r2 anyway.

Fixes: 82ed08dd ("nios2: Exception handling")
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarDinh Nguyen <dinguyen@kernel.org>
parent 411a76b7
...@@ -74,6 +74,8 @@ extern void show_regs(struct pt_regs *); ...@@ -74,6 +74,8 @@ extern void show_regs(struct pt_regs *);
((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE)\ ((struct pt_regs *)((unsigned long)current_thread_info() + THREAD_SIZE)\
- 1) - 1)
#define force_successful_syscall_return() (current_pt_regs()->orig_r2 = -1)
int do_syscall_trace_enter(void); int do_syscall_trace_enter(void);
void do_syscall_trace_exit(void); void do_syscall_trace_exit(void);
#endif /* __ASSEMBLY__ */ #endif /* __ASSEMBLY__ */
......
...@@ -213,6 +213,9 @@ local_restart: ...@@ -213,6 +213,9 @@ local_restart:
translate_rc_and_ret: translate_rc_and_ret:
movi r1, 0 movi r1, 0
bge r2, zero, 3f bge r2, zero, 3f
ldw r1, PT_ORIG_R2(sp)
addi r1, r1, 1
beq r1, zero, 3f
sub r2, zero, r2 sub r2, zero, r2
movi r1, 1 movi r1, 1
3: 3:
...@@ -276,6 +279,9 @@ traced_system_call: ...@@ -276,6 +279,9 @@ traced_system_call:
translate_rc_and_ret2: translate_rc_and_ret2:
movi r1, 0 movi r1, 0
bge r2, zero, 4f bge r2, zero, 4f
ldw r1, PT_ORIG_R2(sp)
addi r1, r1, 1
beq r1, zero, 4f
sub r2, zero, r2 sub r2, zero, r2
movi r1, 1 movi r1, 1
4: 4:
......
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