[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>

3 files changed, 15 insertions, 16 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
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 50ed77297728..5baca16993d0 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -133,9 +133,8 @@ NESTED(handle_int, PT_SIZE, sp)
 
         LONG_L  s0, TI_REGS($28)
         LONG_S  sp, TI_REGS($28)
-        jal     plat_irq_dispatch
-        LONG_S  s0, TI_REGS($28)
-        j       ret_from_irq
+        PTR_LA  ra, ret_from_irq
+        j       plat_irq_dispatch
         END(handle_int)
 
         __INIT
@@ -224,9 +223,8 @@ NESTED(except_vec_vi_handler, 0, sp)
 
         LONG_L  s0, TI_REGS($28)
         LONG_S  sp, TI_REGS($28)
-        jalr    v0
-        LONG_S  s0, TI_REGS($28)
         PTR_LA  ra, ret_from_irq
+        jr      v0
         END(except_vec_vi_handler)
 
 /*
diff --git a/arch/mips/kernel/smtc-asm.S b/arch/mips/kernel/smtc-asm.S
index 76cb31d57482..1cb9441f1474 100644
--- a/arch/mips/kernel/smtc-asm.S
+++ b/arch/mips/kernel/smtc-asm.S
@@ -97,15 +97,12 @@ FEXPORT(__smtc_ipi_vector)
         SAVE_ALL
         CLI
         TRACE_IRQS_OFF
-        move    a0,sp
         /* Function to be invoked passed stack pad slot 5 */
         lw      t0,PT_PADSLOT5(sp)
         /* Argument from sender passed in stack pad slot 4 */
-        lw      a1,PT_PADSLOT4(sp)
-        jalr    t0
-        nop
-        j       ret_from_irq
-        nop
+        lw      a0,PT_PADSLOT4(sp)
+        PTR_LA  ra, _ret_from_irq
+        jr      t0
 
 /*
  * Called from idle loop to provoke processing of queued IPIs