[MIPS] SMTC: Fix crash if # of TC's > # of VPE's after pt_regs irq cleanup.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/entry.S b/arch/mips/kernel/entry.S
index 417c08a..f10b6a1 100644
--- a/arch/mips/kernel/entry.S
+++ b/arch/mips/kernel/entry.S
@@ -83,7 +83,10 @@
 FEXPORT(restore_all)			# restore full frame
 #ifdef CONFIG_MIPS_MT_SMTC
 /* Detect and execute deferred IPI "interrupts" */
+	LONG_L	s0, TI_REGS($28)
+	LONG_S	sp, TI_REGS($28)
 	jal	deferred_smtc_ipi
+	LONG_S	s0, TI_REGS($28)
 /* Re-arm any temporarily masked interrupts not explicitly "acked" */
 	mfc0	v0, CP0_TCSTATUS
 	ori	v1, v0, TCSTATUS_IXMT
diff --git a/arch/mips/kernel/smtc-asm.S b/arch/mips/kernel/smtc-asm.S
index 1cb9441..921207c 100644
--- a/arch/mips/kernel/smtc-asm.S
+++ b/arch/mips/kernel/smtc-asm.S
@@ -101,7 +101,9 @@
 	lw	t0,PT_PADSLOT5(sp)
 	/* Argument from sender passed in stack pad slot 4 */
 	lw	a0,PT_PADSLOT4(sp)
-	PTR_LA	ra, _ret_from_irq
+	LONG_L	s0, TI_REGS($28)
+	LONG_S	sp, TI_REGS($28)
+	PTR_LA	ra, ret_from_irq
 	jr	t0
 
 /*
@@ -119,7 +121,10 @@
 	subu	t1,sp,PT_SIZE
 	sw	ra,PT_EPC(t1)
 	sw	a0,PT_PADSLOT4(t1)
+	LONG_L	s0, TI_REGS($28)
+	LONG_S	sp, TI_REGS($28)
 	la	t2,ipi_decode
+	LONG_S	s0, TI_REGS($28)
 	sw	t2,PT_PADSLOT5(t1)
 	/* Save pre-disable value of TCStatus */
 	sw	t0,PT_TCSTATUS(t1)