sh: Fix bogus regs pointer in do_IRQ().

SH-3 and SH-4 were trampling the register, and SH-2 wasn't even
setting it in the first place. This ended up with some rather
broken behaviour in the sysrq show_regs().
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/cpu/sh2/entry.S

@@ -165,6 +165,7 @@ ENTRY(exception_handler)
 
 interrupt_entry:
 	mov	r9,r4
+	mov	r15,r5
 	mov.l	6f,r9
 	mov.l	7f,r8
 	jmp	@r8

arch/sh/kernel/cpu/sh3/entry.S

@@ -514,13 +514,16 @@ skip_save:
 
 interrupt_exception:
 	mov.l	1f, r9
+	mov.l	2f, r4
+	mov.l	@r4, r4
 	jmp	@r9
-	 nop
+	 mov	r15, r5
 	rts
 	 nop
 
 	.align 2
 1:	.long	do_IRQ
+2:	.long	INTEVT
 
 	.align	2
 ENTRY(exception_none)

arch/sh/kernel/irq.c

@@ -11,7 +11,6 @@
 #include <linux/module.h>
 #include <linux/kernel_stat.h>
 #include <linux/seq_file.h>
-#include <linux/io.h>
 #include <linux/irq.h>
 #include <asm/processor.h>
 #include <asm/uaccess.h>
@@ -82,13 +81,9 @@ static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 #endif
 
-asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
-		      unsigned long r6, unsigned long r7,
-		      struct pt_regs __regs)
+asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
-	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	struct pt_regs *old_regs = set_irq_regs(regs);
-	int irq;
 #ifdef CONFIG_4KSTACKS
 	union irq_ctx *curctx, *irqctx;
 #endif
@@ -111,13 +106,7 @@ asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
 	}
 #endif
 
-#ifdef CONFIG_CPU_HAS_INTEVT
-	irq = evt2irq(ctrl_inl(INTEVT));
-#else
-	irq = r4;
-#endif
-
-	irq = irq_demux(irq);
+	irq = irq_demux(evt2irq(irq));
 
 #ifdef CONFIG_4KSTACKS
 	curctx = (union irq_ctx *)current_thread_info();

include/asm-sh/irq.h

@@ -94,8 +94,13 @@
 /*
  * Convert back and forth between INTEVT and IRQ values.
  */
+#ifdef CONFIG_CPU_HAS_INTEVT
 #define evt2irq(evt)		(((evt) >> 5) - 16)
 #define irq2evt(irq)		(((irq) + 16) << 5)
+#else
+#define evt2irq(evt)		(evt)
+#define irq2evt(irq)		(irq)
+#endif
 
 /*
  * Simple Mask Register Support