ARC: Remove explicit passing around of ECR

With ECR now part of pt_regs

* No need to propagate from lowest asm handlers as arg
* No need to save it in tsk->thread.cause_code
* Avoid bit chopping to access the bit-fields

More code consolidation, cleanup

Signed-off-by: Vineet Gupta <[e-mail]>

arch/arc/include/asm/bug.h

···
 void show_regs(struct pt_regs *regs);
 void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs);
 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
-			    unsigned long address, unsigned long cause_reg);
-void die(const char *str, struct pt_regs *regs, unsigned long address,
-	 unsigned long cause_reg);
+			    unsigned long address);
+void die(const char *str, struct pt_regs *regs, unsigned long address);
 
 #define BUG()	do {				\
 	dump_stack();					\

arch/arc/include/asm/kgdb.h

···
 	__asm__ __volatile__ ("trap_s	0x4\n");
 }
 
-extern void kgdb_trap(struct pt_regs *regs, int param);
+extern void kgdb_trap(struct pt_regs *regs);
 
 enum arc700_linux_regnums {
 	_R0		= 0,
···
 };
 
 #else
-#define kgdb_trap(regs, param)
+#define kgdb_trap(regs)
 #endif
 
 #endif	/* __ARC_KGDB_H__ */

arch/arc/include/asm/kprobes.h

···
 
 int kprobe_fault_handler(struct pt_regs *regs, unsigned long cause);
 void kretprobe_trampoline(void);
-void trap_is_kprobe(unsigned long cause, unsigned long address,
-			   struct pt_regs *regs);
+void trap_is_kprobe(unsigned long address, struct pt_regs *regs);
 #else
-static void trap_is_kprobe(unsigned long cause, unsigned long address,
-			   struct pt_regs *regs)
+static void trap_is_kprobe(unsigned long address, struct pt_regs *regs)
 {
 }
 #endif

arch/arc/include/asm/processor.h

···
 	unsigned long ksp;	/* kernel mode stack pointer */
 	unsigned long callee_reg;	/* pointer to callee regs */
 	unsigned long fault_address;	/* dbls as brkpt holder as well */
-	unsigned long cause_code;	/* Exception Cause Code (ECR) */
 #ifdef CONFIG_ARC_FPU_SAVE_RESTORE
 	struct arc_fpu fpu;
 #endif

arch/arc/include/asm/unaligned.h

···
 
 #ifdef CONFIG_ARC_MISALIGN_ACCESS
 int misaligned_fixup(unsigned long address, struct pt_regs *regs,
-		     unsigned long cause, struct callee_regs *cregs);
+		     struct callee_regs *cregs);
 #else
 static inline int
 misaligned_fixup(unsigned long address, struct pt_regs *regs,
-		 unsigned long cause, struct callee_regs *cregs)
+		 struct callee_regs *cregs)
 {
 	return 0;
 }

arch/arc/kernel/entry.S

···
 	SWITCH_TO_KERNEL_STK
 	SAVE_ALL_SYS
 
-	lr  r0, [ecr]
-	lr  r1, [efa]
-
-	mov r2, sp
+	lr  r0, [efa]
+	mov r1, sp
 
 	FAKE_RET_FROM_EXCPN r9
 
···
 	SWITCH_TO_KERNEL_STK
 	SAVE_ALL_SYS
 
-	lr  r0, [ecr]
-	lr  r1, [efa]
-	mov r2, sp
+	lr  r0, [efa]
+	mov r1, sp
 	bl  do_memory_error
 	b   ret_from_exception
 ARC_EXIT mem_service
···
 	SWITCH_TO_KERNEL_STK
 	SAVE_ALL_SYS
 
-	lr  r0, [ecr]
-	lr  r1, [efa]
-	mov r2, sp
+	lr  r2, [ecr]
+	lr  r0, [efa]
+	mov r1, sp
 
-	lsr  	r3, r0, 8
+	lsr  	r3, r2, 8
 	bmsk 	r3, r3, 7
 	brne    r3, ECR_C_MCHK_DUP_TLB, 1f
 
···
 
 	;========== (6b) Non aligned access ============
 4:
-	mov r0, r2              ; cause code
-	mov r2, sp              ; pt_regs
+	mov r0, r1
+	mov r1, sp              ; pt_regs
 
 #ifdef  CONFIG_ARC_MISALIGN_ACCESS
 	SAVE_CALLEE_SAVED_USER
-	mov r3, sp              ; callee_regs
+	mov r2, sp              ; callee_regs
 
 	bl  do_misaligned_access
 
···
 	SWITCH_TO_KERNEL_STK
 	SAVE_ALL_SYS
 
-	lr  r0, [ecr]
-	lr  r1, [efa]
-	mov r2, sp
+	lr  r0, [efa]
+	mov r1, sp
 
 	FAKE_RET_FROM_EXCPN r9
 
···
 	SWITCH_TO_KERNEL_STK
 	SAVE_ALL_SYS
 
-	lr  r0, [ecr]
-	lr  r1, [efa]
-	mov r2, sp
+	lr  r0, [efa]
+	mov r1, sp
 	bl  do_extension_fault
 	b   ret_from_exception
 ARC_EXIT EV_Extension
···
 trap_with_param:
 
 	; stop_pc info by gdb needs this info
-	mov r0, r12
-	lr  r1, [efa]
-	mov r2, sp
+	lr  r0, [efa]
+	mov r1, sp
 
 	; Now that we have read EFA, its safe to do "fake" rtie
 	;   and get out of CPU exception mode

arch/arc/kernel/kgdb.c

···
 	return 0;
 }
 
-void kgdb_trap(struct pt_regs *regs, int param)
+void kgdb_trap(struct pt_regs *regs)
 {
 	/* trap_s 3 is used for breakpoints that overwrite existing
 	 * instructions, while trap_s 4 is used for compiled breakpoints.

arch/arc/kernel/kprobes.c

···
 	return 0;
 }
 
-void trap_is_kprobe(unsigned long cause, unsigned long address,
-		    struct pt_regs *regs)
+void trap_is_kprobe(unsigned long address, struct pt_regs *regs)
 {
-	notify_die(DIE_TRAP, "kprobe_trap", regs, address, cause, SIGTRAP);
+	notify_die(DIE_TRAP, "kprobe_trap", regs, address, 0, SIGTRAP);
 }

arch/arc/kernel/traps.c

···
 	return;
 }
 
-void die(const char *str, struct pt_regs *regs, unsigned long address,
-	 unsigned long cause_reg)
+void die(const char *str, struct pt_regs *regs, unsigned long address)
 {
-	show_kernel_fault_diag(str, regs, address, cause_reg);
+	show_kernel_fault_diag(str, regs, address);
 
 	/* DEAD END */
 	__asm__("flag 1");
···
  *  -for user faults enqueues requested signal
  *  -for kernel, chk if due to copy_(to|from)_user, otherwise die()
  */
-static noinline int handle_exception(unsigned long cause, char *str,
-				     struct pt_regs *regs, siginfo_t *info)
+static noinline int
+handle_exception(const char *str, struct pt_regs *regs, siginfo_t *info)
 {
 	if (user_mode(regs)) {
 		struct task_struct *tsk = current;
 
 		tsk->thread.fault_address = (__force unsigned int)info->si_addr;
-		tsk->thread.cause_code = cause;
 
 		force_sig_info(info->si_signo, info, tsk);
 
···
 		if (fixup_exception(regs))
 			return 0;
 
-		die(str, regs, (unsigned long)info->si_addr, cause);
+		die(str, regs, (unsigned long)info->si_addr);
 	}
 
 	return 1;
 }
 
 #define DO_ERROR_INFO(signr, str, name, sicode) \
-int name(unsigned long cause, unsigned long address, struct pt_regs *regs) \
+int name(unsigned long address, struct pt_regs *regs) \
 {						\
 	siginfo_t info = {			\
 		.si_signo = signr,		\
···
 		.si_code  = sicode,		\
 		.si_addr = (void __user *)address,	\
 	};					\
-	return handle_exception(cause, str, regs, &info);\
+	return handle_exception(str, regs, &info);\
 }
 
 /*
···
 /*
  * Entry Point for Misaligned Data access Exception, for emulating in software
  */
-int do_misaligned_access(unsigned long cause, unsigned long address,
-			 struct pt_regs *regs, struct callee_regs *cregs)
+int do_misaligned_access(unsigned long address, struct pt_regs *regs,
+			 struct callee_regs *cregs)
 {
-	if (misaligned_fixup(address, regs, cause, cregs) != 0)
-		return do_misaligned_error(cause, address, regs);
+	if (misaligned_fixup(address, regs, cregs) != 0)
+		return do_misaligned_error(address, regs);
 
 	return 0;
 }
···
  * Entry point for miscll errors such as Nested Exceptions
  *  -Duplicate TLB entry is handled seperately though
  */
-void do_machine_check_fault(unsigned long cause, unsigned long address,
-			    struct pt_regs *regs)
+void do_machine_check_fault(unsigned long address, struct pt_regs *regs)
 {
-	die("Machine Check Exception", regs, address, cause);
+	die("Machine Check Exception", regs, address);
 }
 
 
···
  *  -1 used for software breakpointing (gdb)
  *  -2 used by kprobes
  */
-void do_non_swi_trap(unsigned long cause, unsigned long address,
-			struct pt_regs *regs)
+void do_non_swi_trap(unsigned long address, struct pt_regs *regs)
 {
-	unsigned int param = cause & 0xff;
+	unsigned int param = regs->ecr_param;
 
 	switch (param) {
 	case 1:
-		trap_is_brkpt(cause, address, regs);
+		trap_is_brkpt(address, regs);
 		break;
 
 	case 2:
-		trap_is_kprobe(param, address, regs);
+		trap_is_kprobe(address, regs);
 		break;
 
 	case 3:
 	case 4:
-		kgdb_trap(regs, param);
+		kgdb_trap(regs);
 		break;
 
 	default:
···
  *  -For a corner case, ARC kprobes implementation resorts to using
  *   this exception, hence the check
  */
-void do_insterror_or_kprobe(unsigned long cause,
-				       unsigned long address,
-				       struct pt_regs *regs)
+void do_insterror_or_kprobe(unsigned long address, struct pt_regs *regs)
 {
+	int rc;
+
 	/* Check if this exception is caused by kprobes */
-	if (notify_die(DIE_IERR, "kprobe_ierr", regs, address,
-		       cause, SIGILL) == NOTIFY_STOP)
+	rc = notify_die(DIE_IERR, "kprobe_ierr", regs, address, 0, SIGILL);
+	if (rc == NOTIFY_STOP)
 		return;
 
-	insterror_is_error(cause, address, regs);
+	insterror_is_error(address, regs);
 }

arch/arc/kernel/troubleshoot.c

···
 }
 
 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
-			    unsigned long address, unsigned long cause_reg)
+			    unsigned long address)
 {
 	current->thread.fault_address = address;
-	current->thread.cause_code = cause_reg;
 
 	/* Caller and Callee regs */
 	show_regs(regs);

arch/arc/kernel/unaligned.c

···
  * Returns 0 if successfully handled, 1 if some error happened
  */
 int misaligned_fixup(unsigned long address, struct pt_regs *regs,
-		     unsigned long cause, struct callee_regs *cregs)
+		     struct callee_regs *cregs)
 {
 	struct disasm_state state;
 	char buf[TASK_COMM_LEN];

arch/arc/mm/fault.c

···
 	return 1;
 }
 
-void do_page_fault(struct pt_regs *regs, unsigned long address,
-		   unsigned long cause_code)
+void do_page_fault(struct pt_regs *regs, unsigned long address)
 {
 	struct vm_area_struct *vma = NULL;
 	struct task_struct *tsk = current;
 	struct mm_struct *mm = tsk->mm;
 	siginfo_t info;
 	int fault, ret;
-	int write = cause_code & (1 << ECR_C_BIT_DTLB_ST_MISS);  /* ST/EX */
+	int write = regs->ecr_cause & ECR_C_PROTV_STORE;  /* ST/EX */
 	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
 				(write ? FAULT_FLAG_WRITE : 0);
 
···
 
 	/* Handle protection violation, execute on heap or stack */
 
-	if (cause_code == ((ECR_V_PROTV << 16) | ECR_C_PROTV_INST_FETCH))
+	if ((regs->ecr_vec == ECR_V_PROTV) &&
+	    (regs->ecr_cause == ECR_C_PROTV_INST_FETCH))
 		goto bad_area;
 
 	if (write) {
···
 	/* User mode accesses just cause a SIGSEGV */
 	if (user_mode(regs)) {
 		tsk->thread.fault_address = address;
-		tsk->thread.cause_code = cause_code;
 		info.si_signo = SIGSEGV;
 		info.si_errno = 0;
 		/* info.si_code has been set above */
···
 	if (fixup_exception(regs))
 		return;
 
-	die("Oops", regs, address, cause_code);
+	die("Oops", regs, address);
 
 out_of_memory:
 	if (is_global_init(tsk)) {
···
 		goto no_context;
 
 	tsk->thread.fault_address = address;
-	tsk->thread.cause_code = cause_code;
 	info.si_signo = SIGBUS;
 	info.si_errno = 0;
 	info.si_code = BUS_ADRERR;

arch/arc/mm/tlbex.S

···
 	; ------- setup args for Linux Page fault Hanlder ---------
 	mov_s r0, sp
 	lr  r1, [efa]
-	lr  r2, [ecr]
 
 	; We don't want exceptions to be disabled while the fault is handled.
 	; Now that we have saved the context we return from exception hence