IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

44 files changed, 178 insertions, 156 deletions

diff --git a/arch/frv/kernel/dma.c b/arch/frv/kernel/dma.c
index f5de6cf7df4..156184e17e5 100644
--- a/arch/frv/kernel/dma.c
+++ b/arch/frv/kernel/dma.c
@@ -121,15 +121,14 @@ unsigned long frv_dma_inprogress;
 /*
  * DMA irq handler - determine channel involved, grab status and call real handler
  */
-static irqreturn_t dma_irq_handler(int irq, void *_channel, struct pt_regs *regs)
+static irqreturn_t dma_irq_handler(int irq, void *_channel)
 {
 	struct frv_dma_channel *channel = _channel;
 
 	frv_clear_dma_inprogress(channel - frv_dma_channels);
 	return channel->handler(channel - frv_dma_channels,
 				__get_DMAC(channel->ioaddr, CSTR),
-				channel->data,
-				regs);
+				channel->data);
 
 } /* end dma_irq_handler() */
 
diff --git a/arch/frv/kernel/irq-mb93091.c b/arch/frv/kernel/irq-mb93091.c
index 369bc0a7443..ad753c1e9b8 100644
--- a/arch/frv/kernel/irq-mb93091.c
+++ b/arch/frv/kernel/irq-mb93091.c
@@ -80,7 +80,7 @@ static struct irq_chip frv_fpga_pic = {
 /*
  * FPGA PIC interrupt handler
  */
-static irqreturn_t fpga_interrupt(int irq, void *_mask, struct pt_regs *regs)
+static irqreturn_t fpga_interrupt(int irq, void *_mask)
 {
 	uint16_t imr, mask = (unsigned long) _mask;
 
@@ -95,7 +95,7 @@ static irqreturn_t fpga_interrupt(int irq, void *_mask, struct pt_regs *regs)
 		irq = 31 - irq;
 		mask &= ~(1 << irq);
 
-		generic_handle_irq(IRQ_BASE_FPGA + irq, regs);
+		generic_handle_irq(IRQ_BASE_FPGA + irq);
 	}
 
 	return IRQ_HANDLED;
diff --git a/arch/frv/kernel/irq-mb93093.c b/arch/frv/kernel/irq-mb93093.c
index a43a2215895..e0983f6926e 100644
--- a/arch/frv/kernel/irq-mb93093.c
+++ b/arch/frv/kernel/irq-mb93093.c
@@ -79,7 +79,7 @@ static struct irq_chip frv_fpga_pic = {
 /*
  * FPGA PIC interrupt handler
  */
-static irqreturn_t fpga_interrupt(int irq, void *_mask, struct pt_regs *regs)
+static irqreturn_t fpga_interrupt(int irq, void *_mask)
 {
 	uint16_t imr, mask = (unsigned long) _mask;
 
@@ -94,7 +94,7 @@ static irqreturn_t fpga_interrupt(int irq, void *_mask, struct pt_regs *regs)
 		irq = 31 - irq;
 		mask &= ~(1 << irq);
 
-		generic_irq_handle(IRQ_BASE_FPGA + irq, regs);
+		generic_irq_handle(IRQ_BASE_FPGA + irq);
 	}
 
 	return IRQ_HANDLED;
diff --git a/arch/frv/kernel/irq-mb93493.c b/arch/frv/kernel/irq-mb93493.c
index 39c0188a349..c157eeff871 100644
--- a/arch/frv/kernel/irq-mb93493.c
+++ b/arch/frv/kernel/irq-mb93493.c
@@ -90,7 +90,7 @@ static struct irq_chip frv_mb93493_pic = {
 /*
  * MB93493 PIC interrupt handler
  */
-static irqreturn_t mb93493_interrupt(int irq, void *_piqsr, struct pt_regs *regs)
+static irqreturn_t mb93493_interrupt(int irq, void *_piqsr)
 {
 	volatile void *piqsr = _piqsr;
 	uint32_t iqsr;
@@ -106,7 +106,7 @@ static irqreturn_t mb93493_interrupt(int irq, void *_piqsr, struct pt_regs *regs
 		irq = 31 - irq;
 		iqsr &= ~(1 << irq);
 
-		generic_handle_irq(IRQ_BASE_MB93493 + irq, regs);
+		generic_handle_irq(IRQ_BASE_MB93493 + irq);
 	}
 
 	return IRQ_HANDLED;
diff --git a/arch/frv/kernel/irq.c b/arch/frv/kernel/irq.c
index 5ac041c7c0a..87f360a4ea2 100644
--- a/arch/frv/kernel/irq.c
+++ b/arch/frv/kernel/irq.c
@@ -143,7 +143,7 @@ static struct irq_chip frv_cpu_pic = {
 asmlinkage void do_IRQ(void)
 {
 	irq_enter();
-	generic_handle_irq(__get_IRL(), __frame);
+	generic_handle_irq(__get_IRL());
 	irq_exit();
 }
 
diff --git a/arch/frv/kernel/time.c b/arch/frv/kernel/time.c
index 44a9aebc4f5..ed588d73d7d 100644
--- a/arch/frv/kernel/time.c
+++ b/arch/frv/kernel/time.c
@@ -40,7 +40,7 @@ unsigned long __nongprelbss __dsu_clock_speed_HZ;
 unsigned long __nongprelbss __serial_clock_speed_HZ;
 unsigned long __delay_loops_MHz;
 
-static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs *regs);
+static irqreturn_t timer_interrupt(int irq, void *dummy);
 
 static struct irqaction timer_irq  = {
 	timer_interrupt, IRQF_DISABLED, CPU_MASK_NONE, "timer", NULL, NULL
@@ -55,7 +55,7 @@ static inline int set_rtc_mmss(unsigned long nowtime)
  * timer_interrupt() needs to keep up the real-time clock,
  * as well as call the "do_timer()" routine every clocktick
  */
-static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
+static irqreturn_t timer_interrupt(int irq, void *dummy)
 {
 	/* last time the cmos clock got updated */
 	static long last_rtc_update = 0;
@@ -70,8 +70,8 @@ static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
 	write_seqlock(&xtime_lock);
 
 	do_timer(1);
-	update_process_times(user_mode(regs));
-	profile_tick(CPU_PROFILING, regs);
+	update_process_times(user_mode(get_irq_regs()));
+	profile_tick(CPU_PROFILING);
 
 	/*
 	 * If we have an externally synchronized Linux clock, then update
diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index 90faae5c5d3..7d500da0e63 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -1193,11 +1193,11 @@ EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
  * value into /proc/profile.
  */
 
-inline void smp_local_timer_interrupt(struct pt_regs * regs)
+inline void smp_local_timer_interrupt(void)
 {
-	profile_tick(CPU_PROFILING, regs);
+	profile_tick(CPU_PROFILING);
 #ifdef CONFIG_SMP
-	update_process_times(user_mode_vm(regs));
+	update_process_times(user_mode_vm(irq_regs));
 #endif
 
 	/*
@@ -1223,6 +1223,7 @@ inline void smp_local_timer_interrupt(struct pt_regs * regs)
 
 fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	int cpu = smp_processor_id();
 
 	/*
@@ -1241,12 +1242,13 @@ fastcall void smp_apic_timer_interrupt(struct pt_regs *regs)
 	 * interrupt lock, which is the WrongThing (tm) to do.
 	 */
 	irq_enter();
-	smp_local_timer_interrupt(regs);
+	smp_local_timer_interrupt();
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 #ifndef CONFIG_SMP
-static void up_apic_timer_interrupt_call(struct pt_regs *regs)
+static void up_apic_timer_interrupt_call(void)
 {
 	int cpu = smp_processor_id();
 
@@ -1255,11 +1257,11 @@ static void up_apic_timer_interrupt_call(struct pt_regs *regs)
 	 */
 	per_cpu(irq_stat, cpu).apic_timer_irqs++;
 
-	smp_local_timer_interrupt(regs);
+	smp_local_timer_interrupt();
 }
 #endif
 
-void smp_send_timer_broadcast_ipi(struct pt_regs *regs)
+void smp_send_timer_broadcast_ipi(void)
 {
 	cpumask_t mask;
 
@@ -1272,7 +1274,7 @@ void smp_send_timer_broadcast_ipi(struct pt_regs *regs)
 		 * We can directly call the apic timer interrupt handler
 		 * in UP case. Minus all irq related functions
 		 */
-		up_apic_timer_interrupt_call(regs);
+		up_apic_timer_interrupt_call();
 #endif
 	}
 }
diff --git a/arch/i386/kernel/i8259.c b/arch/i386/kernel/i8259.c
index d07ed31f11e..d53eafb6daa 100644
--- a/arch/i386/kernel/i8259.c
+++ b/arch/i386/kernel/i8259.c
@@ -335,13 +335,13 @@ void init_8259A(int auto_eoi)
  */
  
 
-static irqreturn_t math_error_irq(int cpl, void *dev_id, struct pt_regs *regs)
+static irqreturn_t math_error_irq(int cpl, void *dev_id)
 {
 	extern void math_error(void __user *);
 	outb(0,0xF0);
 	if (ignore_fpu_irq || !boot_cpu_data.hard_math)
 		return IRQ_NONE;
-	math_error((void __user *)regs->eip);
+	math_error((void __user *)get_irq_regs()->eip);
 	return IRQ_HANDLED;
 }
 
diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
index 3dd2e180151..8cfc7dbec7b 100644
--- a/arch/i386/kernel/irq.c
+++ b/arch/i386/kernel/irq.c
@@ -53,6 +53,7 @@ static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  */
 fastcall unsigned int do_IRQ(struct pt_regs *regs)
 {	
+	struct pt_regs *old_regs;
 	/* high bit used in ret_from_ code */
 	int irq = ~regs->orig_eax;
 	struct irq_desc *desc = irq_desc + irq;
@@ -67,6 +68,7 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs)
 		BUG();
 	}
 
+	old_regs = set_irq_regs(regs);
 	irq_enter();
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 	/* Debugging check for stack overflow: is there less than 1KB free? */
@@ -95,7 +97,7 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (curctx != irqctx) {
-		int arg1, arg2, arg3, ebx;
+		int arg1, arg2, ebx;
 
 		/* build the stack frame on the IRQ stack */
 		isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
@@ -114,17 +116,17 @@ fastcall unsigned int do_IRQ(struct pt_regs *regs)
 			"       xchgl  %%ebx,%%esp      \n"
 			"       call   *%%edi           \n"
 			"       movl   %%ebx,%%esp      \n"
-			: "=a" (arg1), "=d" (arg2), "=c" (arg3), "=b" (ebx)
-			:  "0" (irq),   "1" (desc),  "2" (regs),  "3" (isp),
+			: "=a" (arg1), "=d" (arg2), "=b" (ebx)
+			:  "0" (irq),   "1" (desc),  "2" (isp),
 			   "D" (desc->handle_irq)
 			: "memory", "cc"
 		);
 	} else
 #endif
-		desc->handle_irq(irq, desc, regs);
+		desc->handle_irq(irq, desc);
 
 	irq_exit();
-
+	set_irq_regs(old_regs);
 	return 1;
 }
 
diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
index 1b080ab8a49..31e5c6573aa 100644
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -321,6 +321,7 @@ static inline void leave_mm (unsigned long cpu)
 
 fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	unsigned long cpu;
 
 	cpu = get_cpu();
@@ -351,6 +352,7 @@ fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
 	smp_mb__after_clear_bit();
 out:
 	put_cpu_no_resched();
+	set_irq_regs(old_regs);
 }
 
 static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
@@ -605,11 +607,14 @@ void smp_send_stop(void)
  */
 fastcall void smp_reschedule_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	ack_APIC_irq();
+	set_irq_regs(old_regs);
 }
 
 fastcall void smp_call_function_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	void (*func) (void *info) = call_data->func;
 	void *info = call_data->info;
 	int wait = call_data->wait;
@@ -632,6 +637,7 @@ fastcall void smp_call_function_interrupt(struct pt_regs *regs)
 		mb();
 		atomic_inc(&call_data->finished);
 	}
+	set_irq_regs(old_regs);
 }
 
 /*
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 58a2d558241..3f221f5eb47 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -161,7 +161,7 @@ EXPORT_SYMBOL(profile_pc);
  * Time Stamp Counter value at the time of the timer interrupt, so that
  * we later on can estimate the time of day more exactly.
  */
-irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+irqreturn_t timer_interrupt(int irq, void *dev_id)
 {
 	/*
 	 * Here we are in the timer irq handler. We just have irqs locally
@@ -188,7 +188,7 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	}
 #endif
 
-	do_timer_interrupt_hook(regs);
+	do_timer_interrupt_hook();
 
 
 	if (MCA_bus) {
@@ -209,7 +209,7 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 
 #ifdef CONFIG_X86_LOCAL_APIC
 	if (using_apic_timer)
-		smp_send_timer_broadcast_ipi(regs);
+		smp_send_timer_broadcast_ipi();
 #endif
 
 	return IRQ_HANDLED;
diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index 6bf14a4e995..1a2a979cf6a 100644
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -441,7 +441,7 @@ int hpet_rtc_dropped_irq(void)
 	return 1;
 }
 
-irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
 {
 	struct rtc_time curr_time;
 	unsigned long rtc_int_flag = 0;
@@ -480,7 +480,7 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	}
 	if (call_rtc_interrupt) {
 		rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
-		rtc_interrupt(rtc_int_flag, dev_id, regs);
+		rtc_interrupt(rtc_int_flag, dev_id);
 	}
 	return IRQ_HANDLED;
 }
diff --git a/arch/i386/kernel/vm86.c b/arch/i386/kernel/vm86.c
index 8355d8d87d1..cbcd61d6120 100644
--- a/arch/i386/kernel/vm86.c
+++ b/arch/i386/kernel/vm86.c
@@ -714,7 +714,7 @@ static int irqbits;
 	| (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO)  | (1 << SIGURG) \
 	| (1 << SIGUNUSED) )
 	
-static irqreturn_t irq_handler(int intno, void *dev_id, struct pt_regs * regs)
+static irqreturn_t irq_handler(int intno, void *dev_id)
 {
 	int irq_bit;
 	unsigned long flags;
diff --git a/arch/i386/mach-visws/visws_apic.c b/arch/i386/mach-visws/visws_apic.c
index 5929f884d79..07097ed4889 100644
--- a/arch/i386/mach-visws/visws_apic.c
+++ b/arch/i386/mach-visws/visws_apic.c
@@ -191,7 +191,7 @@ static struct hw_interrupt_type piix4_virtual_irq_type = {
  * enable_irq gets the right irq. This 'master' irq is never directly
  * manipulated by any driver.
  */
-static irqreturn_t piix4_master_intr(int irq, void *dev_id, struct pt_regs * regs)
+static irqreturn_t piix4_master_intr(int irq, void *dev_id)
 {
 	int realirq;
 	irq_desc_t *desc;
@@ -244,7 +244,7 @@ static irqreturn_t piix4_master_intr(int irq, void *dev_id, struct pt_regs * reg
 	kstat_cpu(smp_processor_id()).irqs[realirq]++;
 
 	if (likely(desc->action != NULL))
-		handle_IRQ_event(realirq, regs, desc->action);
+		handle_IRQ_event(realirq, desc->action);
 
 	if (!(desc->status & IRQ_DISABLED))
 		enable_8259A_irq(realirq);
diff --git a/arch/i386/mach-voyager/voyager_basic.c b/arch/i386/mach-voyager/voyager_basic.c
index 80b7f2fc4f4..c639d30d8bd 100644
--- a/arch/i386/mach-voyager/voyager_basic.c
+++ b/arch/i386/mach-voyager/voyager_basic.c
@@ -87,7 +87,7 @@ voyager_detect(struct voyager_bios_info *bios)
 }
 
 void
-voyager_system_interrupt(int cpl, void *dev_id, struct pt_regs *regs)
+voyager_system_interrupt(int cpl, void *dev_id)
 {
 	printk("Voyager: detected system interrupt\n");
 }
diff --git a/arch/i386/mach-voyager/voyager_smp.c b/arch/i386/mach-voyager/voyager_smp.c
index 856c73fcb7e..d42422fc4af 100644
--- a/arch/i386/mach-voyager/voyager_smp.c
+++ b/arch/i386/mach-voyager/voyager_smp.c
@@ -126,10 +126,10 @@ send_QIC_CPI(__u32 cpuset, __u8 cpi)
 }
 
 static inline void
-wrapper_smp_local_timer_interrupt(struct pt_regs *regs)
+wrapper_smp_local_timer_interrupt(void)
 {
 	irq_enter();
-	smp_local_timer_interrupt(regs);
+	smp_local_timer_interrupt();
 	irq_exit();
 }
 
@@ -786,7 +786,7 @@ fastcall void
 smp_vic_sys_interrupt(struct pt_regs *regs)
 {
 	ack_CPI(VIC_SYS_INT);
-	printk("Voyager SYSTEM INTERRUPT\n");
+	printk("Voyager SYSTEM INTERRUPT\n");	
 }
 
 /* Handle a voyager CMN_INT; These interrupts occur either because of
@@ -1135,7 +1135,9 @@ EXPORT_SYMBOL(smp_call_function);
 fastcall void 
 smp_apic_timer_interrupt(struct pt_regs *regs)
 {
-	wrapper_smp_local_timer_interrupt(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	wrapper_smp_local_timer_interrupt();
+	set_irq_regs(old_regs);
 }
 
 /* All of the QUAD interrupt GATES */
@@ -1143,7 +1145,9 @@ fastcall void
 smp_qic_timer_interrupt(struct pt_regs *regs)
 {
 	ack_QIC_CPI(QIC_TIMER_CPI);
-	wrapper_smp_local_timer_interrupt(regs);
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	wrapper_smp_local_timer_interrupt(void);
+	set_irq_regs(old_regs);
 }
 
 fastcall void
@@ -1177,6 +1181,7 @@ smp_qic_call_function_interrupt(struct pt_regs *regs)
 fastcall void
 smp_vic_cpi_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	__u8 cpu = smp_processor_id();
 
 	if(is_cpu_quad())
@@ -1185,7 +1190,7 @@ smp_vic_cpi_interrupt(struct pt_regs *regs)
 		ack_VIC_CPI(VIC_CPI_LEVEL0);
 
 	if(test_and_clear_bit(VIC_TIMER_CPI, &vic_cpi_mailbox[cpu]))
-		wrapper_smp_local_timer_interrupt(regs);
+		wrapper_smp_local_timer_interrupt();
 	if(test_and_clear_bit(VIC_INVALIDATE_CPI, &vic_cpi_mailbox[cpu]))
 		smp_invalidate_interrupt();
 	if(test_and_clear_bit(VIC_RESCHEDULE_CPI, &vic_cpi_mailbox[cpu]))
@@ -1194,6 +1199,7 @@ smp_vic_cpi_interrupt(struct pt_regs *regs)
 		smp_enable_irq_interrupt();
 	if(test_and_clear_bit(VIC_CALL_FUNCTION_CPI, &vic_cpi_mailbox[cpu]))
 		smp_call_function_interrupt();
+	set_irq_regs(old_regs);
 }
 
 static void
@@ -1266,8 +1272,10 @@ smp_send_stop(void)
 void
 smp_vic_timer_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	send_CPI_allbutself(VIC_TIMER_CPI);
-	smp_local_timer_interrupt(regs);
+	smp_local_timer_interrupt();
+	set_irq_regs(old_regs);
 }
 
 /* local (per CPU) timer interrupt.  It does both profiling and
@@ -1279,12 +1287,12 @@ smp_vic_timer_interrupt(struct pt_regs *regs)
  * value into /proc/profile.
  */
 void
-smp_local_timer_interrupt(struct pt_regs * regs)
+smp_local_timer_interrupt(void)
 {
 	int cpu = smp_processor_id();
 	long weight;
 
-	profile_tick(CPU_PROFILING, regs);
+	profile_tick(CPU_PROFILING);
 	if (--per_cpu(prof_counter, cpu) <= 0) {
 		/*
 		 * The multiplier may have changed since the last time we got
@@ -1302,7 +1310,7 @@ smp_local_timer_interrupt(struct pt_regs * regs)
 						per_cpu(prof_counter, cpu);
 		}
 
-		update_process_times(user_mode_vm(regs));
+		update_process_times(user_mode_vm(irq_regs));
 	}
 
 	if( ((1<<cpu) & voyager_extended_vic_processors) == 0)
diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c
index ab2d19c3661..7fd3ef9e064 100644
--- a/arch/ia64/kernel/irq_ia64.c
+++ b/arch/ia64/kernel/irq_ia64.c
@@ -138,6 +138,7 @@ void destroy_irq(unsigned int irq)
 void
 ia64_handle_irq (ia64_vector vector, struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	unsigned long saved_tpr;
 
 #if IRQ_DEBUG
@@ -183,7 +184,7 @@ ia64_handle_irq (ia64_vector vector, struct pt_regs *regs)
 			ia64_setreg(_IA64_REG_CR_TPR, vector);
 			ia64_srlz_d();
 
-			__do_IRQ(local_vector_to_irq(vector), regs);
+			__do_IRQ(local_vector_to_irq(vector));
 
 			/*
 			 * Disable interrupts and send EOI:
@@ -200,6 +201,7 @@ ia64_handle_irq (ia64_vector vector, struct pt_regs *regs)
 	 * come through until ia64_eoi() has been done.
 	 */
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
diff --git a/arch/ia64/kernel/machvec.c b/arch/ia64/kernel/machvec.c
index d4a546aa504..9620822270a 100644
--- a/arch/ia64/kernel/machvec.c
+++ b/arch/ia64/kernel/machvec.c
@@ -60,7 +60,7 @@ machvec_setup (char **arg)
 EXPORT_SYMBOL(machvec_setup);
 
 void
-machvec_timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
+machvec_timer_interrupt (int irq, void *dev_id)
 {
 }
 EXPORT_SYMBOL(machvec_timer_interrupt);
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 66323018325..7cfa63a98cb 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -499,7 +499,7 @@ int cpe_vector = -1;
 int ia64_cpe_irq = -1;
 
 static irqreturn_t
-ia64_mca_cpe_int_handler (int cpe_irq, void *arg, struct pt_regs *ptregs)
+ia64_mca_cpe_int_handler (int cpe_irq, void *arg)
 {
 	static unsigned long	cpe_history[CPE_HISTORY_LENGTH];
 	static int		index;
@@ -744,7 +744,7 @@ ia64_mca_wakeup_all(void)
  *  Outputs :   None
  */
 static irqreturn_t
-ia64_mca_rendez_int_handler(int rendez_irq, void *arg, struct pt_regs *regs)
+ia64_mca_rendez_int_handler(int rendez_irq, void *arg)
 {
 	unsigned long flags;
 	int cpu = smp_processor_id();
@@ -753,8 +753,8 @@ ia64_mca_rendez_int_handler(int rendez_irq, void *arg, struct pt_regs *regs)
 
 	/* Mask all interrupts */
 	local_irq_save(flags);
-	if (notify_die(DIE_MCA_RENDZVOUS_ENTER, "MCA", regs, (long)&nd, 0, 0)
-			== NOTIFY_STOP)
+	if (notify_die(DIE_MCA_RENDZVOUS_ENTER, "MCA", get_irq_regs(),
+		       (long)&nd, 0, 0) == NOTIFY_STOP)
 		ia64_mca_spin(__FUNCTION__);
 
 	ia64_mc_info.imi_rendez_checkin[cpu] = IA64_MCA_RENDEZ_CHECKIN_DONE;
@@ -763,16 +763,16 @@ ia64_mca_rendez_int_handler(int rendez_irq, void *arg, struct pt_regs *regs)
 	 */
 	ia64_sal_mc_rendez();
 
-	if (notify_die(DIE_MCA_RENDZVOUS_PROCESS, "MCA", regs, (long)&nd, 0, 0)
-			== NOTIFY_STOP)
+	if (notify_die(DIE_MCA_RENDZVOUS_PROCESS, "MCA", get_irq_regs(),
+		       (long)&nd, 0, 0) == NOTIFY_STOP)
 		ia64_mca_spin(__FUNCTION__);
 
 	/* Wait for the monarch cpu to exit. */
 	while (monarch_cpu != -1)
 	       cpu_relax();	/* spin until monarch leaves */
 
-	if (notify_die(DIE_MCA_RENDZVOUS_LEAVE, "MCA", regs, (long)&nd, 0, 0)
-			== NOTIFY_STOP)
+	if (notify_die(DIE_MCA_RENDZVOUS_LEAVE, "MCA", get_irq_regs(),
+		       (long)&nd, 0, 0) == NOTIFY_STOP)
 		ia64_mca_spin(__FUNCTION__);
 
 	/* Enable all interrupts */
@@ -791,12 +791,11 @@ ia64_mca_rendez_int_handler(int rendez_irq, void *arg, struct pt_regs *regs)
  *
  *  Inputs  :   wakeup_irq  (Wakeup-interrupt bit)
  *	arg		(Interrupt handler specific argument)
- *	ptregs		(Exception frame at the time of the interrupt)
  *  Outputs :   None
  *
  */
 static irqreturn_t
-ia64_mca_wakeup_int_handler(int wakeup_irq, void *arg, struct pt_regs *ptregs)
+ia64_mca_wakeup_int_handler(int wakeup_irq, void *arg)
 {
 	return IRQ_HANDLED;
 }
@@ -1261,13 +1260,12 @@ static DECLARE_WORK(cmc_enable_work, ia64_mca_cmc_vector_enable_keventd, NULL);
  * Inputs
  *      interrupt number
  *      client data arg ptr
- *      saved registers ptr
  *
  * Outputs
  *	None
  */
 static irqreturn_t
-ia64_mca_cmc_int_handler(int cmc_irq, void *arg, struct pt_regs *ptregs)
+ia64_mca_cmc_int_handler(int cmc_irq, void *arg)
 {
 	static unsigned long	cmc_history[CMC_HISTORY_LENGTH];
 	static int		index;
@@ -1336,12 +1334,11 @@ out:
  * Inputs
  *	interrupt number
  *	client data arg ptr
- *	saved registers ptr
  * Outputs
  * 	handled
  */
 static irqreturn_t
-ia64_mca_cmc_int_caller(int cmc_irq, void *arg, struct pt_regs *ptregs)
+ia64_mca_cmc_int_caller(int cmc_irq, void *arg)
 {
 	static int start_count = -1;
 	unsigned int cpuid;
@@ -1352,7 +1349,7 @@ ia64_mca_cmc_int_caller(int cmc_irq, void *arg, struct pt_regs *ptregs)
 	if (start_count == -1)
 		start_count = IA64_LOG_COUNT(SAL_INFO_TYPE_CMC);
 
-	ia64_mca_cmc_int_handler(cmc_irq, arg, ptregs);
+	ia64_mca_cmc_int_handler(cmc_irq, arg);
 
 	for (++cpuid ; cpuid < NR_CPUS && !cpu_online(cpuid) ; cpuid++);
 
@@ -1403,14 +1400,13 @@ ia64_mca_cmc_poll (unsigned long dummy)
  * Inputs
  *	interrupt number
  *	client data arg ptr
- *	saved registers ptr
  * Outputs
  * 	handled
  */
 #ifdef CONFIG_ACPI
 
 static irqreturn_t
-ia64_mca_cpe_int_caller(int cpe_irq, void *arg, struct pt_regs *ptregs)
+ia64_mca_cpe_int_caller(int cpe_irq, void *arg)
 {
 	static int start_count = -1;
 	static int poll_time = MIN_CPE_POLL_INTERVAL;
@@ -1422,7 +1418,7 @@ ia64_mca_cpe_int_caller(int cpe_irq, void *arg, struct pt_regs *ptregs)
 	if (start_count == -1)
 		start_count = IA64_LOG_COUNT(SAL_INFO_TYPE_CPE);
 
-	ia64_mca_cpe_int_handler(cpe_irq, arg, ptregs);
+	ia64_mca_cpe_int_handler(cpe_irq, arg);
 
 	for (++cpuid ; cpuid < NR_CPUS && !cpu_online(cpuid) ; cpuid++);
 
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 62e07f906e0..41169a9bc30 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -45,7 +45,7 @@ static struct time_interpolator itc_interpolator = {
 };
 
 static irqreturn_t
-timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
+timer_interrupt (int irq, void *dev_id)
 {
 	unsigned long new_itm;
 
@@ -53,7 +53,7 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
 		return IRQ_HANDLED;
 	}
 
-	platform_timer_interrupt(irq, dev_id, regs);
+	platform_timer_interrupt(irq, dev_id);
 
 	new_itm = local_cpu_data->itm_next;
 
@@ -61,10 +61,10 @@ timer_interrupt (int irq, void *dev_id, struct pt_regs *regs)
 		printk(KERN_ERR "Oops: timer tick before it's due (itc=%lx,itm=%lx)\n",
 		       ia64_get_itc(), new_itm);
 
-	profile_tick(CPU_PROFILING, regs);
+	profile_tick(CPU_PROFILING);
 
 	while (1) {
-		update_process_times(user_mode(regs));
+		update_process_times(user_mode(get_irq_regs()));
 
 		new_itm += local_cpu_data->itm_delta;
 
diff --git a/arch/ia64/sn/pci/tioca_provider.c b/arch/ia64/sn/pci/tioca_provider.c
index c36b0f5affb..8a2cb4e691f 100644
--- a/arch/ia64/sn/pci/tioca_provider.c
+++ b/arch/ia64/sn/pci/tioca_provider.c
@@ -550,13 +550,12 @@ tioca_dma_map(struct pci_dev *pdev, u64 paddr, size_t byte_count, int dma_flags)
  * tioca_error_intr_handler - SGI TIO CA error interrupt handler
  * @irq: unused
  * @arg: pointer to tioca_common struct for the given CA
- * @pt: unused
  *
  * Handle a CA error interrupt.  Simply a wrapper around a SAL call which
  * defers processing to the SGI prom.
  */
 static irqreturn_t
-tioca_error_intr_handler(int irq, void *arg, struct pt_regs *pt)
+tioca_error_intr_handler(int irq, void *arg)
 {
 	struct tioca_common *soft = arg;
 	struct ia64_sal_retval ret_stuff;
diff --git a/arch/ia64/sn/pci/tioce_provider.c b/arch/ia64/sn/pci/tioce_provider.c
index af7171adcd2..0e81f68aaf8 100644
--- a/arch/ia64/sn/pci/tioce_provider.c
+++ b/arch/ia64/sn/pci/tioce_provider.c
@@ -666,12 +666,11 @@ tioce_dma_consistent(struct pci_dev *pdev, u64 paddr, size_t byte_count, int dma
  * tioce_error_intr_handler - SGI TIO CE error interrupt handler
  * @irq: unused
  * @arg: pointer to tioce_common struct for the given CE
- * @pt: unused
  *
  * Handle a CE error interrupt.  Simply a wrapper around a SAL call which
  * defers processing to the SGI prom.
  */ static irqreturn_t
-tioce_error_intr_handler(int irq, void *arg, struct pt_regs *pt)
+tioce_error_intr_handler(int irq, void *arg)
 {
 	struct tioce_common *soft = arg;
 	struct ia64_sal_retval ret_stuff;
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index d955aaefbb8..a00b0e7ab9b 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -55,13 +55,15 @@ unsigned long irq_hwmask[NR_IRQS];
  */
 asmlinkage unsigned int do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	irq_enter();
 
 	__DO_IRQ_SMTC_HOOK();
-	__do_IRQ(irq, regs);
+	__do_IRQ(irq);
 
 	irq_exit();
 
+	set_irq_regs(old_regs);
 	return 1;
 }
 
diff --git a/arch/mips/kernel/time.c b/arch/mips/kernel/time.c
index a8340802f2d..d349eb9e4ff 100644
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -322,18 +322,18 @@ static long last_rtc_update;
  * a broadcasted inter-processor interrupt which itself is triggered
  * by the global timer interrupt.
  */
-void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+void local_timer_interrupt(int irq, void *dev_id)
 {
 	if (current->pid)
-		profile_tick(CPU_PROFILING, regs);
-	update_process_times(user_mode(regs));
+		profile_tick(CPU_PROFILING);
+	update_process_times(user_mode(get_irq_regs()));
 }
 
 /*
  * High-level timer interrupt service routines.  This function
  * is set as irqaction->handler and is invoked through do_IRQ.
  */
-irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+irqreturn_t timer_interrupt(int irq, void *dev_id)
 {
 	unsigned long j;
 	unsigned int count;
@@ -419,23 +419,24 @@ irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	 * In SMP mode, local_timer_interrupt() is invoked by appropriate
 	 * low-level local timer interrupt handler.
 	 */
-	local_timer_interrupt(irq, dev_id, regs);
+	local_timer_interrupt(irq, dev_id);
 
 	return IRQ_HANDLED;
 }
 
-int null_perf_irq(struct pt_regs *regs)
+int null_perf_irq(void)
 {
 	return 0;
 }
 
-int (*perf_irq)(struct pt_regs *regs) = null_perf_irq;
+int (*perf_irq)(void) = null_perf_irq;
 
 EXPORT_SYMBOL(null_perf_irq);
 EXPORT_SYMBOL(perf_irq);
 
 asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	int r2 = cpu_has_mips_r2;
 
 	irq_enter();
@@ -448,27 +449,30 @@ asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs)
 	 * performance counter interrupt handler anyway.
 	 */
 	if (!r2 || (read_c0_cause() & (1 << 26)))
-		if (perf_irq(regs))
+		if (perf_irq())
 			goto out;
 
 	/* we keep interrupt disabled all the time */
 	if (!r2 || (read_c0_cause() & (1 << 30)))
-		timer_interrupt(irq, NULL, regs);
+		timer_interrupt(irq, NULL);
 
 out:
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	irq_enter();
 	if (smp_processor_id() != 0)
 		kstat_this_cpu.irqs[irq]++;
 
 	/* we keep interrupt disabled all the time */
-	local_timer_interrupt(irq, NULL, regs);
+	local_timer_interrupt(irq, NULL);
 
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 /*
diff --git a/arch/mips/sgi-ip22/ip22-reset.c b/arch/mips/sgi-ip22/ip22-reset.c
index 7a941ecff3b..66df5ac8f08 100644
--- a/arch/mips/sgi-ip22/ip22-reset.c
+++ b/arch/mips/sgi-ip22/ip22-reset.c
@@ -169,7 +169,7 @@ static inline void volume_down_button(unsigned long data)
 	}
 }
 
-static irqreturn_t panel_int(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t panel_int(int irq, void *dev_id)
 {
 	unsigned int buttons;
 
diff --git a/arch/mips/sgi-ip22/ip22-time.c b/arch/mips/sgi-ip22/ip22-time.c
index 0e061890f79..3462b0d98de 100644
--- a/arch/mips/sgi-ip22/ip22-time.c
+++ b/arch/mips/sgi-ip22/ip22-time.c
@@ -191,12 +191,14 @@ void indy_8254timer_irq(struct pt_regs *regs)
 
 void indy_r4k_timer_interrupt(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	int irq = SGI_TIMER_IRQ;
 
 	irq_enter();
 	kstat_this_cpu.irqs[irq]++;
-	timer_interrupt(irq, NULL, regs);
+	timer_interrupt(irq, NULL);
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 void __init plat_timer_setup(struct irqaction *irq)
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index c3f58f2f9f5..5deaab3090b 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -187,6 +187,7 @@ void fixup_irqs(cpumask_t map)
 
 void do_IRQ(struct pt_regs *regs)
 {
+	struct pt_regs *old_regs = set_irq_regs(regs);
 	unsigned int irq;
 #ifdef CONFIG_IRQSTACKS
 	struct thread_info *curtp, *irqtp;
@@ -230,18 +231,19 @@ void do_IRQ(struct pt_regs *regs)
 				handler = &__do_IRQ;
 			irqtp->task = curtp->task;
 			irqtp->flags = 0;
-			call_handle_irq(irq, desc, regs, irqtp, handler);
+			call_handle_irq(irq, desc, irqtp, handler);
 			irqtp->task = NULL;
 			if (irqtp->flags)
 				set_bits(irqtp->flags, &curtp->flags);
 		} else
 #endif
-			generic_handle_irq(irq, regs);
+			generic_handle_irq(irq);
 	} else if (irq != NO_IRQ_IGNORE)
 		/* That's not SMP safe ... but who cares ? */
 		ppc_spurious_interrupts++;
 
         irq_exit();
+	set_irq_regs(old_regs);
 
 #ifdef CONFIG_PPC_ISERIES
 	if (get_lppaca()->int_dword.fields.decr_int) {
diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index 41521b30c3c..c70e20708a1 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -52,12 +52,12 @@ _GLOBAL(call_do_softirq)
 	blr
 
 _GLOBAL(call_handle_irq)
-	ld	r8,0(r7)
+	ld	r8,0(r6)
 	mflr	r0
 	std	r0,16(r1)
 	mtctr	r8
-	stdu	r1,THREAD_SIZE-112(r6)
-	mr	r1,r6
+	stdu	r1,THREAD_SIZE-112(r5)
+	mr	r1,r5
 	bctrl
 	ld	r1,0(r1)
 	ld	r0,16(r1)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 6a9bc9ce54e..35c6309bdb7 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -115,7 +115,7 @@ void __devinit smp_generic_kick_cpu(int nr)
 }
 #endif
 
-void smp_message_recv(int msg, struct pt_regs *regs)
+void smp_message_recv(int msg)
 {
 	switch(msg) {
 	case PPC_MSG_CALL_FUNCTION:
@@ -127,11 +127,11 @@ void smp_message_recv(int msg, struct pt_regs *regs)
 		break;
 	case PPC_MSG_DEBUGGER_BREAK:
 		if (crash_ipi_function_ptr) {
-			crash_ipi_function_ptr(regs);
+			crash_ipi_function_ptr(get_irq_regs());
 			break;
 		}
 #ifdef CONFIG_DEBUGGER
-		debugger_ipi(regs);
+		debugger_ipi(get_irq_regs());
 		break;
 #endif /* CONFIG_DEBUGGER */
 		/* FALLTHROUGH */
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 85b9244a098..d210d0a5006 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -51,6 +51,7 @@
 #include <linux/rtc.h>
 #include <linux/jiffies.h>
 #include <linux/posix-timers.h>
+#include <linux/irq.h>
 
 #include <asm/io.h>
 #include <asm/processor.h>
@@ -643,6 +644,7 @@ static void iSeries_tb_recal(void)
  */
 void timer_interrupt(struct pt_regs * regs)
 {
+	struct pt_regs *old_regs;
 	int next_dec;
 	int cpu = smp_processor_id();
 	unsigned long ticks;
@@ -653,9 +655,10 @@ void timer_interrupt(struct pt_regs * regs)
 		do_IRQ(regs);
 #endif
 
+	old_regs = set_irq_regs(regs);
 	irq_enter();
 
-	profile_tick(CPU_PROFILING, regs);
+	profile_tick(CPU_PROFILING);
 	calculate_steal_time();
 
 #ifdef CONFIG_PPC_ISERIES
@@ -715,6 +718,7 @@ void timer_interrupt(struct pt_regs * regs)
 #endif
 
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 void wakeup_decrementer(void)
diff --git a/arch/powerpc/platforms/cell/interrupt.c b/arch/powerpc/platforms/cell/interrupt.c
index 8533f13a5ed..434fb934dd2 100644
--- a/arch/powerpc/platforms/cell/interrupt.c
+++ b/arch/powerpc/platforms/cell/interrupt.c
@@ -190,11 +190,11 @@ struct irq_host *iic_get_irq_host(int node)
 EXPORT_SYMBOL_GPL(iic_get_irq_host);
 
 
-static irqreturn_t iic_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t iic_ipi_action(int irq, void *dev_id)
 {
 	int ipi = (int)(long)dev_id;
 
-	smp_message_recv(ipi, regs);
+	smp_message_recv(ipi);
 
 	return IRQ_HANDLED;
 }
diff --git a/arch/powerpc/platforms/cell/spider-pic.c b/arch/powerpc/platforms/cell/spider-pic.c
index b0e95d594c5..21a9ebd4978 100644
--- a/arch/powerpc/platforms/cell/spider-pic.c
+++ b/arch/powerpc/platforms/cell/spider-pic.c
@@ -213,8 +213,7 @@ static struct irq_host_ops spider_host_ops = {
 	.xlate = spider_host_xlate,
 };
 
-static void spider_irq_cascade(unsigned int irq, struct irq_desc *desc,
-			       struct pt_regs *regs)
+static void spider_irq_cascade(unsigned int irq, struct irq_desc *desc)
 {
 	struct spider_pic *pic = desc->handler_data;
 	unsigned int cs, virq;
@@ -225,7 +224,7 @@ static void spider_irq_cascade(unsigned int irq, struct irq_desc *desc,
 	else
 		virq = irq_linear_revmap(pic->host, cs);
 	if (virq != NO_IRQ)
-		generic_handle_irq(virq, regs);
+		generic_handle_irq(virq);
 	desc->chip->eoi(irq);
 }
 
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c
index c2c7cf75dd5..bfc4829162f 100644
--- a/arch/powerpc/platforms/powermac/low_i2c.c
+++ b/arch/powerpc/platforms/powermac/low_i2c.c
@@ -342,7 +342,7 @@ static void kw_i2c_handle_interrupt(struct pmac_i2c_host_kw *host, u8 isr)
 }
 
 /* Interrupt handler */
-static irqreturn_t kw_i2c_irq(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t kw_i2c_irq(int irq, void *dev_id)
 {
 	struct pmac_i2c_host_kw *host = dev_id;
 	unsigned long flags;
diff --git a/arch/powerpc/platforms/powermac/pfunc_base.c b/arch/powerpc/platforms/powermac/pfunc_base.c
index ee3b223ab17..5c6c15c5f9a 100644
--- a/arch/powerpc/platforms/powermac/pfunc_base.c
+++ b/arch/powerpc/platforms/powermac/pfunc_base.c
@@ -15,7 +15,7 @@
 #define DBG(fmt...)
 #endif
 
-static irqreturn_t macio_gpio_irq(int irq, void *data, struct pt_regs *regs)
+static irqreturn_t macio_gpio_irq(int irq, void *data)
 {
 	pmf_do_irq(data);
 
diff --git a/arch/powerpc/platforms/powermac/pic.c b/arch/powerpc/platforms/powermac/pic.c
index 39f7ddb554e..e93a115961a 100644
--- a/arch/powerpc/platforms/powermac/pic.c
+++ b/arch/powerpc/platforms/powermac/pic.c
@@ -440,14 +440,13 @@ static void __init pmac_pic_probe_oldstyle(void)
 }
 #endif /* CONFIG_PPC32 */
 
-static void pmac_u3_cascade(unsigned int irq, struct irq_desc *desc,
-			    struct pt_regs *regs)
+static void pmac_u3_cascade(unsigned int irq, struct irq_desc *desc)
 {
 	struct mpic *mpic = desc->handler_data;
 
-	unsigned int cascade_irq = mpic_get_one_irq(mpic, regs);
+	unsigned int cascade_irq = mpic_get_one_irq(mpic, get_irq_regs());
 	if (cascade_irq != NO_IRQ)
-		generic_handle_irq(cascade_irq, regs);
+		generic_handle_irq(cascade_irq);
 	desc->chip->eoi(irq);
 }
 
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 311ed1993fc..b1d3d161249 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -65,16 +65,14 @@ static int ras_check_exception_token;
 #define EPOW_SENSOR_INDEX	0
 #define RAS_VECTOR_OFFSET	0x500
 
-static irqreturn_t ras_epow_interrupt(int irq, void *dev_id,
-					struct pt_regs * regs);
-static irqreturn_t ras_error_interrupt(int irq, void *dev_id,
-					struct pt_regs * regs);
+static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
+static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
 
 /* #define DEBUG */
 
 
 static void request_ras_irqs(struct device_node *np,
-			irqreturn_t (*handler)(int, void *, struct pt_regs *),
+			irq_handler_t handler,
 			const char *name)
 {
 	int i, index, count = 0;
@@ -166,8 +164,7 @@ __initcall(init_ras_IRQ);
  * to examine the type of power failure and take appropriate action where
  * the time horizon permits something useful to be done.
  */
-static irqreturn_t
-ras_epow_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
 {
 	int status = 0xdeadbeef;
 	int state = 0;
@@ -210,8 +207,7 @@ ras_epow_interrupt(int irq, void *dev_id, struct pt_regs * regs)
  * For nonrecoverable errors, an error is logged and we stop all processing
  * as quickly as possible in order to prevent propagation of the failure.
  */
-static irqreturn_t
-ras_error_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
 {
 	struct rtas_error_log *rtas_elog;
 	int status = 0xdeadbeef;
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index f82b13e531a..ad9aec2c6fe 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -121,12 +121,11 @@ static void __init fwnmi_init(void)
 		fwnmi_active = 1;
 }
 
-void pseries_8259_cascade(unsigned int irq, struct irq_desc *desc,
-			  struct pt_regs *regs)
+void pseries_8259_cascade(unsigned int irq, struct irq_desc *desc)
 {
-	unsigned int cascade_irq = i8259_irq(regs);
+	unsigned int cascade_irq = i8259_irq(get_irq_regs());
 	if (cascade_irq != NO_IRQ)
-		generic_handle_irq(cascade_irq, regs);
+		generic_handle_irq(cascade_irq);
 	desc->chip->eoi(irq);
 }
 
diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c
index 253972e5479..f6bd2f28515 100644
--- a/arch/powerpc/platforms/pseries/xics.c
+++ b/arch/powerpc/platforms/pseries/xics.c
@@ -324,7 +324,7 @@ static unsigned int xics_get_irq_lpar(struct pt_regs *regs)
 
 #ifdef CONFIG_SMP
 
-static irqreturn_t xics_ipi_dispatch(int cpu, struct pt_regs *regs)
+static irqreturn_t xics_ipi_dispatch(int cpu)
 {
 	WARN_ON(cpu_is_offline(cpu));
 
@@ -332,47 +332,47 @@ static irqreturn_t xics_ipi_dispatch(int cpu, struct pt_regs *regs)
 		if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
 				       &xics_ipi_message[cpu].value)) {
 			mb();
-			smp_message_recv(PPC_MSG_CALL_FUNCTION, regs);
+			smp_message_recv(PPC_MSG_CALL_FUNCTION);
 		}
 		if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
 				       &xics_ipi_message[cpu].value)) {
 			mb();
-			smp_message_recv(PPC_MSG_RESCHEDULE, regs);
+			smp_message_recv(PPC_MSG_RESCHEDULE);
 		}
 #if 0
 		if (test_and_clear_bit(PPC_MSG_MIGRATE_TASK,
 				       &xics_ipi_message[cpu].value)) {
 			mb();
-			smp_message_recv(PPC_MSG_MIGRATE_TASK, regs);
+			smp_message_recv(PPC_MSG_MIGRATE_TASK);
 		}
 #endif
 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
 		if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
 				       &xics_ipi_message[cpu].value)) {
 			mb();
-			smp_message_recv(PPC_MSG_DEBUGGER_BREAK, regs);
+			smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
 		}
 #endif
 	}
 	return IRQ_HANDLED;
 }
 
-static irqreturn_t xics_ipi_action_direct(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t xics_ipi_action_direct(int irq, void *dev_id)
 {
 	int cpu = smp_processor_id();
 
 	direct_qirr_info(cpu, 0xff);
 
-	return xics_ipi_dispatch(cpu, regs);
+	return xics_ipi_dispatch(cpu);
 }
 
-static irqreturn_t xics_ipi_action_lpar(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t xics_ipi_action_lpar(int irq, void *dev_id)
 {
 	int cpu = smp_processor_id();
 
 	lpar_qirr_info(cpu, 0xff);
 
-	return xics_ipi_dispatch(cpu, regs);
+	return xics_ipi_dispatch(cpu);
 }
 
 void xics_cause_IPI(int cpu)
diff --git a/arch/powerpc/platforms/pseries/xics.h b/arch/powerpc/platforms/pseries/xics.h
index 6ee1055b0ff..db0ec3ba3ae 100644
--- a/arch/powerpc/platforms/pseries/xics.h
+++ b/arch/powerpc/platforms/pseries/xics.h
@@ -31,7 +31,6 @@ struct xics_ipi_struct {
 extern struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
 
 struct irq_desc;
-extern void pseries_8259_cascade(unsigned int irq, struct irq_desc *desc,
-				 struct pt_regs *regs);
+extern void pseries_8259_cascade(unsigned int irq, struct irq_desc *desc);
 
 #endif /* _POWERPC_KERNEL_XICS_H */
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 3ee03a9a98f..195215560fd 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -489,9 +489,9 @@ static inline void mpic_eoi(struct mpic *mpic)
 }
 
 #ifdef CONFIG_SMP
-static irqreturn_t mpic_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t mpic_ipi_action(int irq, void *dev_id)
 {
-	smp_message_recv(mpic_irq_to_hw(irq) - MPIC_VEC_IPI_0, regs);
+	smp_message_recv(mpic_irq_to_hw(irq) - MPIC_VEC_IPI_0);
 	return IRQ_HANDLED;
 }
 #endif /* CONFIG_SMP */
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 708236f3474..5a854f36383 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/sysrq.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 
 #include <asm/ptrace.h>
 #include <asm/string.h>
@@ -2577,12 +2578,11 @@ void xmon_init(int enable)
 }
 
 #ifdef CONFIG_MAGIC_SYSRQ
-static void sysrq_handle_xmon(int key, struct pt_regs *pt_regs,
-			      struct tty_struct *tty) 
+static void sysrq_handle_xmon(int key, struct tty_struct *tty) 
 {
 	/* ensure xmon is enabled */
 	xmon_init(1);
-	debugger(pt_regs);
+	debugger(get_irq_regs());
 }
 
 static struct sysrq_key_op sysrq_xmon_op = 
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index 6472e321cad..af4a1c71a80 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -885,14 +885,14 @@ void setup_APIC_extened_lvt(unsigned char lvt_off, unsigned char vector,
  * value into /proc/profile.
  */
 
-void smp_local_timer_interrupt(struct pt_regs *regs)
+void smp_local_timer_interrupt(void)
 {
-	profile_tick(CPU_PROFILING, regs);
+	profile_tick(CPU_PROFILING);
 #ifdef CONFIG_SMP
-	update_process_times(user_mode(regs));
+	update_process_times(user_mode(get_irq_regs()));
 #endif
 	if (apic_runs_main_timer > 1 && smp_processor_id() == boot_cpu_id)
-		main_timer_handler(regs);
+		main_timer_handler();
 	/*
 	 * We take the 'long' return path, and there every subsystem
 	 * grabs the appropriate locks (kernel lock/ irq lock).
@@ -913,7 +913,7 @@ void smp_local_timer_interrupt(struct pt_regs *regs)
  * [ if a single-CPU system runs an SMP kernel then we call the local
  *   interrupt as well. Thus we cannot inline the local irq ... ]
  */
-void smp_apic_timer_interrupt(struct pt_regs *regs)
+void smp_apic_timer_interrupt(void)
 {
 	/*
 	 * the NMI deadlock-detector uses this.
@@ -932,7 +932,7 @@ void smp_apic_timer_interrupt(struct pt_regs *regs)
 	 */
 	exit_idle();
 	irq_enter();
-	smp_local_timer_interrupt(regs);
+	smp_local_timer_interrupt();
 	irq_exit();
 }
 
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index 506f27c85ca..b8a407fcd5d 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -103,7 +103,9 @@ skip:
  * handlers).
  */
 asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
-{	
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
 	/* high bit used in ret_from_ code  */
 	unsigned vector = ~regs->orig_rax;
 	unsigned irq;
@@ -121,9 +123,10 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 	stack_overflow_check(regs);
 #endif
-	generic_handle_irq(irq, regs);
+	generic_handle_irq(irq);
 	irq_exit();
 
+	set_irq_regs(old_regs);
 	return 1;
 }
 
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 557e92af7be..1ba5a442ac3 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -302,20 +302,20 @@ unsigned long long monotonic_clock(void)
 }
 EXPORT_SYMBOL(monotonic_clock);
 
-static noinline void handle_lost_ticks(int lost, struct pt_regs *regs)
+static noinline void handle_lost_ticks(int lost)
 {
 	static long lost_count;
 	static int warned;
 	if (report_lost_ticks) {
 		printk(KERN_WARNING "time.c: Lost %d timer tick(s)! ", lost);
-		print_symbol("rip %s)\n", regs->rip);
+		print_symbol("rip %s)\n", get_irq_regs()->rip);
 	}
 
 	if (lost_count == 1000 && !warned) {
 		printk(KERN_WARNING "warning: many lost ticks.\n"
 		       KERN_WARNING "Your time source seems to be instable or "
 		   		"some driver is hogging interupts\n");
-		print_symbol("rip %s\n", regs->rip);
+		print_symbol("rip %s\n", get_irq_regs()->rip);
 		if (vxtime.mode == VXTIME_TSC && vxtime.hpet_address) {
 			printk(KERN_WARNING "Falling back to HPET\n");
 			if (hpet_use_timer)
@@ -339,7 +339,7 @@ static noinline void handle_lost_ticks(int lost, struct pt_regs *regs)
 #endif
 }
 
-void main_timer_handler(struct pt_regs *regs)
+void main_timer_handler(void)
 {
 	static unsigned long rtc_update = 0;
 	unsigned long tsc;
@@ -411,7 +411,7 @@ void main_timer_handler(struct pt_regs *regs)
 	}
 
 	if (lost > 0)
-		handle_lost_ticks(lost, regs);
+		handle_lost_ticks(lost);
 	else
 		lost = 0;
 
@@ -421,7 +421,7 @@ void main_timer_handler(struct pt_regs *regs)
 
 	do_timer(lost + 1);
 #ifndef CONFIG_SMP
-	update_process_times(user_mode(regs));
+	update_process_times(user_mode(get_irq_regs()));
 #endif
 
 /*
@@ -431,7 +431,7 @@ void main_timer_handler(struct pt_regs *regs)
  */
 
 	if (!using_apic_timer)
-		smp_local_timer_interrupt(regs);
+		smp_local_timer_interrupt();
 
 /*
  * If we have an externally synchronized Linux clock, then update CMOS clock
@@ -450,11 +450,11 @@ void main_timer_handler(struct pt_regs *regs)
 	write_sequnlock(&xtime_lock);
 }
 
-static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+static irqreturn_t timer_interrupt(int irq, void *dev_id)
 {
 	if (apic_runs_main_timer > 1)
 		return IRQ_HANDLED;
-	main_timer_handler(regs);
+	main_timer_handler();
 	if (using_apic_timer)
 		smp_send_timer_broadcast_ipi();
 	return IRQ_HANDLED;
@@ -1337,7 +1337,7 @@ irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 	}
 	if (call_rtc_interrupt) {
 		rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
-		rtc_interrupt(rtc_int_flag, dev_id, regs);
+		rtc_interrupt(rtc_int_flag, dev_id);
 	}
 	return IRQ_HANDLED;
 }