arch like ARM64 expects 'step_needed = 1' in order to use default single step handler. Therefore, modify register_wide_hw_breakpoint() implementation,so that we can set this field in struct hw_perf_event to be used later by arch specific code.
Other arch will not have any affect as they do not use it so far. Signed-off-by: Pratyush Anand <[email protected]> --- arch/x86/kernel/kgdb.c | 2 +- include/linux/hw_breakpoint.h | 4 ++-- kernel/events/hw_breakpoint.c | 4 +++- samples/hw_breakpoint/data_breakpoint.c | 3 ++- 4 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 8e36f249646e..19b24c50a952 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -674,7 +674,7 @@ void kgdb_arch_late(void) for (i = 0; i < HBP_NUM; i++) { if (breakinfo[i].pev) continue; - breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL); + breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL, NULL, 0); if (IS_ERR((void * __force)breakinfo[i].pev)) { printk(KERN_ERR "kgdb: Could not allocate hw" "breakpoints\nDisabling the kernel debugger\n"); diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h index b9ac9629bf74..8cbc8ded6d50 100644 --- a/include/linux/hw_breakpoint.h +++ b/include/linux/hw_breakpoint.h @@ -71,7 +71,7 @@ register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr, extern struct perf_event * __percpu * register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, - void *context); + void *context, int step); extern int register_perf_hw_breakpoint(struct perf_event *bp); extern int __register_perf_hw_breakpoint(struct perf_event *bp); @@ -110,7 +110,7 @@ register_wide_hw_breakpoint_cpu(struct perf_event_attr *attr, static inline struct perf_event * __percpu * register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, - void *context) { return NULL; } + void *context, int step) { return NULL; } static inline int register_perf_hw_breakpoint(struct perf_event *bp) { return -ENOSYS; } static inline int diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index 3f8cb1e14588..0dcb175276b2 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -492,13 +492,14 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); * register_wide_hw_breakpoint - register a wide breakpoint in the kernel * @attr: breakpoint attributes * @triggered: callback to trigger when we hit the breakpoint + * @step: tells if framework can use default arch step handler * * @return a set of per_cpu pointers to perf events */ struct perf_event * __percpu * register_wide_hw_breakpoint(struct perf_event_attr *attr, perf_overflow_handler_t triggered, - void *context) + void *context, int step) { struct perf_event * __percpu *cpu_events, *bp; long err = 0; @@ -512,6 +513,7 @@ register_wide_hw_breakpoint(struct perf_event_attr *attr, for_each_online_cpu(cpu) { bp = perf_event_create_kernel_counter(attr, cpu, NULL, triggered, context); + bp->hw.step_needed = step; if (IS_ERR(bp)) { err = PTR_ERR(bp); break; diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c index ef7f32291852..f64e59f9fbc6 100644 --- a/samples/hw_breakpoint/data_breakpoint.c +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -60,7 +60,8 @@ static int __init hw_break_module_init(void) attr.bp_len = HW_BREAKPOINT_LEN_4; attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; - sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, NULL); + sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler, + NULL, 1); if (IS_ERR((void __force *)sample_hbp)) { ret = PTR_ERR((void __force *)sample_hbp); goto fail; -- 2.9.4
