powerpc/watchpoints: Annotate atomic context in more places

It can be easy to miss that the notifier mechanism invokes the callbacks
in an atomic context, so add some comments to that effect on the two
handlers we register here.

Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230829063457.54157-4-bgray@linux.ibm.com

diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 2854376870cf396105a3e472cf63c18a7af88492..a1318ce18d0e61b34f49869b12ae4dcfd3cc5f95 100644 (file)
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -368,6 +368,11 @@ static void handle_p10dd1_spurious_exception(struct perf_event **bp,
        }
 }
 
+/*
+ * Handle a DABR or DAWR exception.
+ *
+ * Called in atomic context.
+ */
 int hw_breakpoint_handler(struct die_args *args)
 {
        bool err = false;
@@ -495,6 +500,8 @@ NOKPROBE_SYMBOL(hw_breakpoint_handler);
 
 /*
  * Handle single-step exceptions following a DABR hit.
+ *
+ * Called in atomic context.
  */
 static int single_step_dabr_instruction(struct die_args *args)
 {
@@ -546,6 +553,8 @@ NOKPROBE_SYMBOL(single_step_dabr_instruction);
 
 /*
  * Handle debug exception notifications.
+ *
+ * Called in atomic context.
  */
 int hw_breakpoint_exceptions_notify(
                struct notifier_block *unused, unsigned long val, void *data)