frv: switch to use of fixup_exception()

Massage frv search_exception_table() to
	a) taking pt_regs pointer as explicit argument
	b) updating ->pc on success
Simplifies callers a bit and allows to convert to generic extable.h,
while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

arch/frv/include/asm/Kbuild

@@ -1,6 +1,7 @@
 
 generic-y += clkdev.h
 generic-y += exec.h
+generic-y += extable.h
 generic-y += irq_work.h
 generic-y += mcs_spinlock.h
 generic-y += mm-arch-hooks.h

arch/frv/include/asm/uaccess.h

@@ -18,6 +18,7 @@
 #include <linux/mm.h>
 #include <asm/segment.h>
 #include <asm/sections.h>
+#include <asm/extable.h>
 
 #define __ptr(x) ((unsigned long __force *)(x))
 
@@ -59,26 +60,6 @@ static inline int ___range_ok(unsigned long addr, unsigned long size)
 #define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
 #define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
 
-/*
- * The exception table consists of pairs of addresses: the first is the
- * address of an instruction that is allowed to fault, and the second is
- * the address at which the program should continue.  No registers are
- * modified, so it is entirely up to the continuation code to figure out
- * what to do.
- *
- * All the routines below use bits of fixup code that are out of line
- * with the main instruction path.  This means when everything is well,
- * we don't even have to jump over them.  Further, they do not intrude
- * on our cache or tlb entries.
- */
-struct exception_table_entry
-{
-	unsigned long insn, fixup;
-};
-
-/* Returns 0 if exception not found and fixup otherwise.  */
-extern unsigned long search_exception_table(unsigned long);
-
 
 /*
  * These are the main single-value transfer routines.  They automatically
@@ -314,6 +295,4 @@ extern long strnlen_user(const char __user *src, long count);
 
 #define strlen_user(str) strnlen_user(str, 32767)
 
-extern unsigned long search_exception_table(unsigned long addr);
-
 #endif /* _ASM_UACCESS_H */

arch/frv/kernel/traps.c

@@ -360,13 +360,8 @@ asmlinkage void memory_access_exception(unsigned long esr0,
 	siginfo_t info;
 
 #ifdef CONFIG_MMU
-	unsigned long fixup;
-
-	fixup = search_exception_table(__frame->pc);
-	if (fixup) {
-		__frame->pc = fixup;
+	if (fixup_exception(__frame))
 		return;
-	}
 #endif
 
 	die_if_kernel("-- Memory Access Exception --\n"

arch/frv/mm/extable.c

@@ -10,40 +10,39 @@ extern const void __memset_end, __memset_user_error_lr, __memset_user_error_hand
 extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
 extern spinlock_t modlist_lock;
 
-
-/*****************************************************************************/
-/*
- * see if there's a fixup handler available to deal with a kernel fault
- */
-unsigned long search_exception_table(unsigned long pc)
+int fixup_exception(struct pt_regs *regs)
 {
 	const struct exception_table_entry *extab;
+	unsigned long pc = regs->pc;
 
 	/* determine if the fault lay during a memcpy_user or a memset_user */
-	if (__frame->lr == (unsigned long) &__memset_user_error_lr &&
+	if (regs->lr == (unsigned long) &__memset_user_error_lr &&
 	    (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
 	    ) {
 		/* the fault occurred in a protected memset
 		 * - we search for the return address (in LR) instead of the program counter
 		 * - it was probably during a clear_user()
 		 */
-		return (unsigned long) &__memset_user_error_handler;
+		regs->pc = (unsigned long) &__memset_user_error_handler;
+		return 1;
 	}
 
-	if (__frame->lr == (unsigned long) &__memcpy_user_error_lr &&
+	if (regs->lr == (unsigned long) &__memcpy_user_error_lr &&
 	    (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
 	    ) {
 		/* the fault occurred in a protected memset
 		 * - we search for the return address (in LR) instead of the program counter
 		 * - it was probably during a copy_to/from_user()
 		 */
-		return (unsigned long) &__memcpy_user_error_handler;
+		regs->pc = (unsigned long) &__memcpy_user_error_handler;
+		return 1;
 	}
 
 	extab = search_exception_tables(pc);
-	if (extab)
-		return extab->fixup;
+	if (extab) {
+		regs->pc = extab->fixup;
+		return 1;
+	}
 
 	return 0;
-
-} /* end search_exception_table() */
+}

arch/frv/mm/fault.c

@@ -33,7 +33,7 @@ asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear
 {
 	struct vm_area_struct *vma;
 	struct mm_struct *mm;
-	unsigned long _pme, lrai, lrad, fixup;
+	unsigned long _pme, lrai, lrad;
 	unsigned long flags = 0;
 	siginfo_t info;
 	pgd_t *pge;
@@ -201,10 +201,8 @@ asmlinkage void do_page_fault(int datammu, unsigned long esr0, unsigned long ear
 
  no_context:
 	/* are we prepared to handle this kernel fault? */
-	if ((fixup = search_exception_table(__frame->pc)) != 0) {
-		__frame->pc = fixup;
+	if (fixup_exception(__frame))
 		return;
-	}
 
 /*
  * Oops. The kernel tried to access some bad page. We'll have to