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>
This commit is contained in:
Al Viro 2016-12-25 14:12:18 -05:00
parent d597580d37
commit 9a7513cfa2
5 changed files with 18 additions and 46 deletions

View File

@ -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

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@ -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 */

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@ -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"

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@ -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() */
}

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@ -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