MIPS: Sanitize restart logics
Put the original syscall number into ->regs[0] when we leave syscall
with error. Use it in restart logics. Everything else will have
it 0 since we pass through SAVE_SOME on all the ways in. Note that
in places like bad_stack and inllegal_syscall we leave it 0 - it's not
restartable.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1698/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 813689e..7ce0a36 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -93,8 +93,9 @@
sd t0, PT_R7(sp) # set error flag
beqz t0, 1f
+ ld t1, PT_R2(sp) # syscall number
dnegu v0 # error
- sd v0, PT_R0(sp) # flag for syscall restarting
+ sd t1, PT_R0(sp) # save it for syscall restarting
1: sd v0, PT_R2(sp) # result
o32_syscall_exit:
@@ -142,8 +143,9 @@
sd t0, PT_R7(sp) # set error flag
beqz t0, 1f
+ ld t1, PT_R2(sp) # syscall number
dnegu v0 # error
- sd v0, PT_R0(sp) # set flag for syscall restarting
+ sd t1, PT_R0(sp) # save it for syscall restarting
1: sd v0, PT_R2(sp) # result
j syscall_exit
@@ -155,7 +157,6 @@
*/
bad_stack:
dnegu v0 # error
- sd v0, PT_R0(sp)
sd v0, PT_R2(sp)
li t0, 1 # set error flag
sd t0, PT_R7(sp)