hw-breakpoints: Use overflow handler instead of the event callback
struct perf_event::event callback was called when a breakpoint
triggers. But this is a rather opaque callback, pretty
tied-only to the breakpoint API and not really integrated into perf
as it triggers even when we don't overflow.
We prefer to use overflow_handler() as it fits into the perf events
rules, being called only when we overflow.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index d42f65a..05d5fec 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -362,8 +362,7 @@
return ret;
}
- if (bp->callback)
- ret = arch_store_info(bp);
+ ret = arch_store_info(bp);
if (ret < 0)
return ret;
@@ -519,7 +518,7 @@
break;
}
- (bp->callback)(bp, args->regs);
+ perf_bp_event(bp, args->regs);
rcu_read_unlock();
}
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index dbb3955..b361d28 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -555,7 +555,9 @@
return ret;
}
-static void ptrace_triggered(struct perf_event *bp, void *data)
+static void ptrace_triggered(struct perf_event *bp, int nmi,
+ struct perf_sample_data *data,
+ struct pt_regs *regs)
{
int i;
struct thread_struct *thread = &(current->thread);
@@ -599,7 +601,7 @@
{
int err;
int gen_len, gen_type;
- DEFINE_BREAKPOINT_ATTR(attr);
+ struct perf_event_attr attr;
/*
* We shoud have at least an inactive breakpoint at this
@@ -721,9 +723,10 @@
{
struct perf_event *bp;
struct thread_struct *t = &tsk->thread;
- DEFINE_BREAKPOINT_ATTR(attr);
+ struct perf_event_attr attr;
if (!t->ptrace_bps[nr]) {
+ hw_breakpoint_init(&attr);
/*
* Put stub len and type to register (reserve) an inactive but
* correct bp