[2/2] powerpc: Change hardware breakpoint to allow longer ranges

Submitted by Michael Neuling on Jan. 25, 2013, 1:02 a.m.

Details

Message ID 1359075779-27492-2-git-send-email-mikey@neuling.org
State Accepted, archived
Commit 4ae7ebe9522a9e3626e28b4d268dae712738573d
Headers show

Commit Message

Michael Neuling Jan. 25, 2013, 1:02 a.m.
Change the hardware breakpoint code so that we can support wider ranged
breakpoints.

This means both ptrace and perf hardware breakpoints can use upto 512 byte long
breakpoints when using the DAWR and only 8 byte when using the DABR.

Signed-off-by: Michael Neuling <mikey@neuling.org>
---
 arch/powerpc/include/asm/hw_breakpoint.h |    2 --
 arch/powerpc/kernel/hw_breakpoint.c      |   12 ++++++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

Patch hide | download patch | download mbox

diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index 96437e5..eb0f4ac 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -57,8 +57,6 @@  struct pmu;
 struct perf_sample_data;
 
 #define HW_BREAKPOINT_ALIGN 0x7
-/* Maximum permissible length of any HW Breakpoint */
-#define HW_BREAKPOINT_LEN 0x8
 
 extern int hw_breakpoint_slots(int type);
 extern int arch_bp_generic_fields(int type, int *gen_bp_type);
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 2a3e8dd..a949bdf 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -142,7 +142,7 @@  int arch_bp_generic_fields(int type, int *gen_bp_type)
  */
 int arch_validate_hwbkpt_settings(struct perf_event *bp)
 {
-	int ret = -EINVAL;
+	int ret = -EINVAL, length_max;
 	struct arch_hw_breakpoint *info = counter_arch_bp(bp);
 
 	if (!bp)
@@ -171,8 +171,16 @@  int arch_validate_hwbkpt_settings(struct perf_event *bp)
 	 * HW_BREAKPOINT_ALIGN by rounding off to the lower address, the
 	 * 'symbolsize' should satisfy the check below.
 	 */
+	length_max = 8; /* DABR */
+	if (cpu_has_feature(CPU_FTR_DAWR)) {
+		length_max = 512 ; /* 64 doublewords */
+		/* DAWR region can't cross 512 boundary */
+		if ((bp->attr.bp_addr >> 10) != 
+		    ((bp->attr.bp_addr + bp->attr.bp_len) >> 10))
+			return -EINVAL;
+	}
 	if (info->len >
-	    (HW_BREAKPOINT_LEN - (info->address & HW_BREAKPOINT_ALIGN)))
+	    (length_max - (info->address & HW_BREAKPOINT_ALIGN)))
 		return -EINVAL;
 	return 0;
 }