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-n32.S b/arch/mips/kernel/scall64-n32.S
index a3d6613..4da3faf 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -65,8 +65,9 @@
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
local_irq_disable # make sure need_resched and
@@ -106,8 +107,9 @@
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