x86: regparm calling convention for exceptions and interrupts.

This clarifies more of the x86 caller/callee stack ownership
issues by making the exception and interrupt handler assembler
interfaces use register calling conventions.

System calls still use the stack.

Tested with "crashme" on UP/SMP.

arch/i386/kernel/cpu/mcheck/p4.c

@@ -70,10 +70,10 @@ static void intel_thermal_interrupt(struct pt_regs *regs)
 /* Thermal interrupt handler for this CPU setup */
 static void (*vendor_thermal_interrupt)(struct pt_regs *regs) = unexpected_thermal_interrupt;
 
-asmlinkage void smp_thermal_interrupt(struct pt_regs regs)
+fastcall void smp_thermal_interrupt(struct pt_regs *regs)
 {
 	irq_enter();
-	vendor_thermal_interrupt(&regs);
+	vendor_thermal_interrupt(regs);
 	irq_exit();
 }
 

arch/i386/kernel/entry.S

@@ -131,7 +131,7 @@ VM_MASK		= 0x00020000
 	movl $(__USER_DS), %edx; \
 	movl %edx, %ds; \
 	movl %edx, %es; \
-	pushl $11;	\
+	movl $11,%eax;	\
 	call do_exit;	\
 .previous;		\
 .section __ex_table,"a";\
@@ -291,8 +291,8 @@ work_notifysig:				# deal with pending signals and
 
 	ALIGN
 work_notifysig_v86:
-	pushl %ecx
-	call save_v86_state
+	pushl %ecx			# save ti_flags for do_notify_resume
+	call save_v86_state		# %eax contains pt_regs pointer
 	popl %ecx
 	movl %eax, %esp
 	xorl %edx, %edx
@@ -359,6 +359,7 @@ vector=vector+1
 	ALIGN
 common_interrupt:
 	SAVE_ALL
+	movl %esp,%eax
 	call do_IRQ
 	jmp ret_from_intr
 
@@ -366,7 +367,8 @@ common_interrupt:
 ENTRY(name)				\
 	pushl $nr-256;			\
 	SAVE_ALL			\
-	call smp_/**/name;	\
+	movl %esp,%eax;			\
+	call smp_/**/name;		\
 	jmp ret_from_intr;
 
 /* The include is where all of the SMP etc. interrupts come from */
@@ -389,18 +391,15 @@ error_code:
 	pushl %ebx
 	cld
 	movl %es, %ecx
-	movl ORIG_EAX(%esp), %esi	# get the error code
 	movl ES(%esp), %edi		# get the function address
+	movl ORIG_EAX(%esp), %edx	# get the error code
 	movl %eax, ORIG_EAX(%esp)
 	movl %ecx, ES(%esp)
-	movl %esp, %edx
-	pushl %esi			# push the error code
-	pushl %edx			# push the pt_regs pointer
-	movl $(__USER_DS), %edx
-	movl %edx, %ds
-	movl %edx, %es
+	movl $(__USER_DS), %ecx
+	movl %ecx, %ds
+	movl %ecx, %es
+	movl %esp,%eax			# pt_regs pointer
 	call *%edi
-	addl $8, %esp
 	jmp ret_from_exception
 
 ENTRY(coprocessor_error)
@@ -457,11 +456,9 @@ ENTRY(debug)
 debug_stack_correct:
 	pushl $-1			# mark this as an int
 	SAVE_ALL
-	movl %esp,%edx
-  	pushl $0
-	pushl %edx
+	xorl %edx,%edx			# error code 0
+	movl %esp,%eax			# pt_regs pointer
 	call do_debug
-	addl $8,%esp
 	testl %eax,%eax
 	jnz restore_all
 	jmp ret_from_exception
@@ -491,11 +488,9 @@ ENTRY(nmi)
 nmi_stack_correct:
 	pushl %eax
 	SAVE_ALL
-	movl %esp, %edx
-	pushl $0
-	pushl %edx
+	xorl %edx,%edx		# zero error code
+	movl %esp,%eax		# pt_regs pointer
 	call do_nmi
-	addl $8, %esp
 	RESTORE_ALL
 
 nmi_stack_fixup:
@@ -515,11 +510,9 @@ nmi_debug_stack_fixup:
 ENTRY(int3)
 	pushl $-1			# mark this as an int
 	SAVE_ALL
-	movl %esp,%edx
-	pushl $0
-	pushl %edx
+	xorl %edx,%edx		# zero error code
+	movl %esp,%eax		# pt_regs pointer
 	call do_int3
-	addl $8,%esp
 	testl %eax,%eax
 	jnz restore_all
 	jmp ret_from_exception

arch/i386/kernel/irq.c

@@ -45,10 +45,10 @@ static union irq_ctx *softirq_ctx[NR_CPUS];
  * SMP cross-CPU interrupts have their own specific
  * handlers).
  */
-asmlinkage unsigned int do_IRQ(struct pt_regs regs)
+fastcall unsigned int do_IRQ(struct pt_regs *regs)
 {	
 	/* high bits used in ret_from_ code */
-	int irq = regs.orig_eax & 0xff;
+	int irq = regs->orig_eax & 0xff;
 #ifdef CONFIG_4KSTACKS
 	union irq_ctx *curctx, *irqctx;
 	u32 *isp;
@@ -82,24 +82,24 @@ asmlinkage unsigned int do_IRQ(struct pt_regs regs)
 	 * current stack (which is the irq stack already after all)
 	 */
 	if (curctx != irqctx) {
+		int arg1, arg2, ebx;
+
 		/* build the stack frame on the IRQ stack */
 		isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
 		irqctx->tinfo.task = curctx->tinfo.task;
 		irqctx->tinfo.previous_esp = current_stack_pointer();
 
-		*--isp = (u32) &regs;
-		*--isp = (u32) irq;
-
 		asm volatile(
 			"       xchgl   %%ebx,%%esp      \n"
 			"       call    __do_IRQ         \n"
-			"       xchgl   %%ebx,%%esp      \n"
-			: : "b"(isp)
-			: "memory", "cc", "eax", "edx", "ecx"
+			"       movl   %%ebx,%%esp      \n"
+			: "=a" (arg1), "=d" (arg2), "=b" (ebx)
+			:  "0" (irq),   "1" (regs),  "2" (isp)
+			: "memory", "cc", "ecx"
 		);
 	} else
 #endif
-		__do_IRQ(irq, &regs);
+		__do_IRQ(irq, regs);
 
 	irq_exit();
 

arch/i386/kernel/traps.c

@@ -404,7 +404,7 @@ static inline void do_trap(int trapnr, int signr, char *str, int vm86,
 }
 
 #define DO_ERROR(trapnr, signr, str, name) \
-asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
 { \
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
@@ -413,7 +413,7 @@ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 }
 
 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
-asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
 { \
 	siginfo_t info; \
 	info.si_signo = signr; \
@@ -427,7 +427,7 @@ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 }
 
 #define DO_VM86_ERROR(trapnr, signr, str, name) \
-asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
 { \
 	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) \
 						== NOTIFY_STOP) \
@@ -436,7 +436,7 @@ asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 }
 
 #define DO_VM86_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
-asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
+fastcall void do_##name(struct pt_regs * regs, long error_code) \
 { \
 	siginfo_t info; \
 	info.si_signo = signr; \
@@ -462,7 +462,7 @@ DO_ERROR(11, SIGBUS,  "segment not present", segment_not_present)
 DO_ERROR(12, SIGBUS,  "stack segment", stack_segment)
 DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
 
-asmlinkage void do_general_protection(struct pt_regs * regs, long error_code)
+fastcall void do_general_protection(struct pt_regs * regs, long error_code)
 {
 	int cpu = get_cpu();
 	struct tss_struct *tss = &per_cpu(init_tss, cpu);
@@ -622,7 +622,7 @@ static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
  
 static nmi_callback_t nmi_callback = dummy_nmi_callback;
  
-asmlinkage void do_nmi(struct pt_regs * regs, long error_code)
+fastcall void do_nmi(struct pt_regs * regs, long error_code)
 {
 	int cpu;
 
@@ -648,7 +648,7 @@ void unset_nmi_callback(void)
 }
 
 #ifdef CONFIG_KPROBES
-asmlinkage int do_int3(struct pt_regs *regs, long error_code)
+fastcall int do_int3(struct pt_regs *regs, long error_code)
 {
 	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 			== NOTIFY_STOP)
@@ -683,7 +683,7 @@ asmlinkage int do_int3(struct pt_regs *regs, long error_code)
  * find every occurrence of the TF bit that could be saved away even
  * by user code)
  */
-asmlinkage void do_debug(struct pt_regs * regs, long error_code)
+fastcall void do_debug(struct pt_regs * regs, long error_code)
 {
 	unsigned int condition;
 	struct task_struct *tsk = current;
@@ -822,7 +822,7 @@ void math_error(void __user *eip)
 	force_sig_info(SIGFPE, &info, task);
 }
 
-asmlinkage void do_coprocessor_error(struct pt_regs * regs, long error_code)
+fastcall void do_coprocessor_error(struct pt_regs * regs, long error_code)
 {
 	ignore_fpu_irq = 1;
 	math_error((void __user *)regs->eip);
@@ -876,7 +876,7 @@ void simd_math_error(void __user *eip)
 	force_sig_info(SIGFPE, &info, task);
 }
 
-asmlinkage void do_simd_coprocessor_error(struct pt_regs * regs,
+fastcall void do_simd_coprocessor_error(struct pt_regs * regs,
 					  long error_code)
 {
 	if (cpu_has_xmm) {
@@ -900,7 +900,7 @@ asmlinkage void do_simd_coprocessor_error(struct pt_regs * regs,
 	}
 }
 
-asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs,
+fastcall void do_spurious_interrupt_bug(struct pt_regs * regs,
 					  long error_code)
 {
 #if 0

arch/i386/mm/fault.c

@@ -201,7 +201,7 @@ static inline int is_prefetch(struct pt_regs *regs, unsigned long addr,
 	return 0;
 } 
 
-asmlinkage void do_invalid_op(struct pt_regs *, unsigned long);
+fastcall void do_invalid_op(struct pt_regs *, unsigned long);
 
 /*
  * This routine handles page faults.  It determines the address,
@@ -213,7 +213,7 @@ asmlinkage void do_invalid_op(struct pt_regs *, unsigned long);
  *	bit 1 == 0 means read, 1 means write
  *	bit 2 == 0 means kernel, 1 means user-mode
  */
-asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
+fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code)
 {
 	struct task_struct *tsk;
 	struct mm_struct *mm;

include/asm-i386/hw_irq.h

@@ -32,16 +32,16 @@ extern u8 irq_vector[NR_IRQ_VECTORS];
 extern void (*interrupt[NR_IRQS])(void);
 
 #ifdef CONFIG_SMP
-asmlinkage void reschedule_interrupt(void);
-asmlinkage void invalidate_interrupt(void);
-asmlinkage void call_function_interrupt(void);
+fastcall void reschedule_interrupt(void);
+fastcall void invalidate_interrupt(void);
+fastcall void call_function_interrupt(void);
 #endif
 
 #ifdef CONFIG_X86_LOCAL_APIC
-asmlinkage void apic_timer_interrupt(void);
-asmlinkage void error_interrupt(void);
-asmlinkage void spurious_interrupt(void);
-asmlinkage void thermal_interrupt(struct pt_regs);
+fastcall void apic_timer_interrupt(void);
+fastcall void error_interrupt(void);
+fastcall void spurious_interrupt(void);
+fastcall void thermal_interrupt(struct pt_regs *);
 #define platform_legacy_irq(irq)	((irq) < 16)
 #endif
 

include/linux/irq.h

@@ -79,9 +79,9 @@ extern cpumask_t irq_affinity[NR_IRQS];
 extern int no_irq_affinity;
 extern int noirqdebug_setup(char *str);
 
-extern asmlinkage int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
+extern fastcall int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
 				       struct irqaction *action);
-extern asmlinkage unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs);
+extern fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs);
 extern void note_interrupt(unsigned int irq, irq_desc_t *desc, int action_ret);
 extern void report_bad_irq(unsigned int irq, irq_desc_t *desc, int action_ret);
 extern int can_request_irq(unsigned int irq, unsigned long irqflags);

include/linux/kernel.h

@@ -69,7 +69,7 @@ extern struct notifier_block *panic_notifier_list;
 extern long (*panic_blink)(long time);
 NORET_TYPE void panic(const char * fmt, ...)
 	__attribute__ ((NORET_AND format (printf, 1, 2)));
-asmlinkage NORET_TYPE void do_exit(long error_code)
+fastcall NORET_TYPE void do_exit(long error_code)
 	ATTRIB_NORET;
 NORET_TYPE void complete_and_exit(struct completion *, long)
 	ATTRIB_NORET;

kernel/exit.c

@@ -780,7 +780,7 @@ static void exit_notify(struct task_struct *tsk)
 	tsk->flags |= PF_DEAD;
 }
 
-asmlinkage NORET_TYPE void do_exit(long code)
+fastcall NORET_TYPE void do_exit(long code)
 {
 	struct task_struct *tsk = current;
 	int group_dead;

kernel/irq/handle.c

@@ -86,7 +86,7 @@ void irq_exit(void)
 /*
  * Have got an event to handle:
  */
-asmlinkage int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
+fastcall int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
 				struct irqaction *action)
 {
 	int ret, retval = 0, status = 0;
@@ -114,7 +114,7 @@ asmlinkage int handle_IRQ_event(unsigned int irq, struct pt_regs *regs,
  * SMP cross-CPU interrupts have their own specific
  * handlers).
  */
-asmlinkage unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
+fastcall unsigned int __do_IRQ(unsigned int irq, struct pt_regs *regs)
 {
 	irq_desc_t *desc = irq_desc + irq;
 	struct irqaction * action;