Commit b67b2b70 authored by David Daney's avatar David Daney Committed by Ralf Baechle
Browse files

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: default avatarDavid Daney <ddaney@avtrex.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 654f57bf

arch/mips/kernel/genex.S

+4 −0
Original line number Diff line number Diff line
@@ -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 */

arch/mips/kernel/traps.c

+19 −5
Original line number Diff line number Diff line
@@ -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)