Commit 9a7513cf authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d597580d

arch/frv/include/asm/Kbuild

+1 −0
Original line number Diff line number Diff line 


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

+1 −22
Original line number Diff line number Diff line
@@ -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

+1 −6
Original line number Diff line number Diff line
@@ -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

+13 −14
Original line number Diff line number Diff line
@@ -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

+2 −4
Original line number Diff line number Diff line
@@ -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