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MIPS: Watch exception handling for HARDWARE_WATCHPOINTS. 

Here we hook up the watch exception handler so that it sends SIGTRAP when
the hardware watch registers are triggered.

Signed-off-by: David Daney <ddaney@avtrex.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2008-09-23 00:08:45 -07:00 committed by Ralf Baechle
parent 654f57bfb4
commit b67b2b7030
2 changed files with 23 additions and 5 deletions
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4
arch/mips/kernel/genex.S
View File

@ -453,7 +453,11 @@ NESTED(nmi_handler, PT_SIZE, sp)
BUILD_HANDLER tr tr sti silent /* #13 */
BUILD_HANDLER fpe fpe fpe silent /* #15 */
BUILD_HANDLER mdmx mdmx sti silent /* #22 */
#ifdef CONFIG_HARDWARE_WATCHPOINTS
BUILD_HANDLER watch watch sti silent /* #23 */
#else
BUILD_HANDLER watch watch sti verbose /* #23 */
#endif
BUILD_HANDLER mcheck mcheck cli verbose /* #24 */
BUILD_HANDLER mt mt sti silent /* #25 */
BUILD_HANDLER dsp dsp sti silent /* #26 */

24
arch/mips/kernel/traps.c
View File

@ -42,6 +42,7 @@
#include <asm/tlbdebug.h>
#include <asm/traps.h>
#include <asm/uaccess.h>
#include <asm/watch.h>
#include <asm/mmu_context.h>
#include <asm/types.h>
#include <asm/stacktrace.h>
@ -912,13 +913,26 @@ asmlinkage void do_mdmx(struct pt_regs *regs)
asmlinkage void do_watch(struct pt_regs *regs)
{
u32 cause;
/*
* We use the watch exception where available to detect stack
* overflows.
* Clear WP (bit 22) bit of cause register so we don't loop
* forever.
*/
dump_tlb_all();
show_regs(regs);
panic("Caught WATCH exception - probably caused by stack overflow.");
cause = read_c0_cause();
cause &= ~(1 << 22);
write_c0_cause(cause);
/*
* If the current thread has the watch registers loaded, save
* their values and send SIGTRAP. Otherwise another thread
* left the registers set, clear them and continue.
*/
if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
mips_read_watch_registers();
force_sig(SIGTRAP, current);
} else
mips_clear_watch_registers();
}
asmlinkage void do_mcheck(struct pt_regs *regs)