[MIPS] ret_from_irq adjustment

Make sure that RA on top of interrupt stack is an address of ret_from_irq,
so that dump_stack etc. can trace info interrupted context.

Also this patch fixes except_vec_vi_handler and __smtc_ipi_vector which
seems broken.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 9 insertions, 5 deletions

diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
index e93e43e1f42d..417c08ac76eb 100644
--- a/arch/mips/kernel/entry.S
+++ b/arch/mips/kernel/entry.S
@@ -20,10 +20,7 @@
 #include <asm/mipsmtregs.h>
 #endif
 
-#ifdef CONFIG_PREEMPT
-        .macro  preempt_stop
-        .endm
-#else
+#ifndef CONFIG_PREEMPT
         .macro  preempt_stop
         local_irq_disable
         .endm
@@ -32,9 +29,16 @@
 
         .text
         .align  5
+FEXPORT(ret_from_irq)
+        LONG_S  s0, TI_REGS($28)
+#ifdef CONFIG_PREEMPT
+FEXPORT(ret_from_exception)
+#else
+        b       _ret_from_irq
 FEXPORT(ret_from_exception)
         preempt_stop
-FEXPORT(ret_from_irq)
+#endif
+FEXPORT(_ret_from_irq)
         LONG_L  t0, PT_STATUS(sp)               # returning to kernel mode?
         andi    t0, t0, KU_USER
         beqz    t0, resume_kernel