[PATCH V2 1/4] perf: Add hardware breakpoint address mask

[Jacob Shin]

Some architectures (for us, AMD Family 16h) allow for "don't care" bit
mask to further qualify a hardware breakpoint address, in order to
trap on range of addresses. Update perf uapi to add bp_addr_mask field.

Signed-off-by: Jacob Shin <jacob.s...@amd.com>
---
 include/uapi/linux/perf_event.h |    5 ++++-
 kernel/events/hw_breakpoint.c   |    9 +++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index fb104e5..e22e1d1 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -286,7 +286,10 @@ struct perf_event_attr {
                __u64           config1; /* extension of config */
        };
        union {
-               __u64           bp_len;
+               struct {
+                       __u32           bp_len;
+                       __u32           bp_addr_mask;
+               };
                __u64           config2; /* extension of config1 */
        };
        __u64   branch_sample_type; /* enum perf_branch_sample_type */
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index a64f8ae..c454880 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -385,6 +385,11 @@ int dbg_release_bp_slot(struct perf_event *bp)
        return 0;
 }
 
+__weak int arch_validate_hwbkpt_addr_mask(struct perf_event *bp)
+{
+       return bp->attr.bp_addr_mask == 0;
+}
+
 static int validate_hw_breakpoint(struct perf_event *bp)
 {
        int ret;
@@ -393,6 +398,10 @@ static int validate_hw_breakpoint(struct perf_event *bp)
        if (ret)
                return ret;
 
+       ret = arch_validate_hwbkpt_addr_mask(bp);
+       if (ret)
+               return ret;
+
        if (arch_check_bp_in_kernelspace(bp)) {
                if (bp->attr.exclude_kernel)
                        return -EINVAL;
-- 
1.7.9.5


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