powerpc/watchpoints: Annotate atomic context in more places

[ Upstream commit 27646b2e02b096a6936b3e3b6ba334ae20763eab ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 1007ec36b4cb91f1039baceb4ad578f3147f8a31..fb736fdb4193f6396039394391d17175f6970c4e 100644 (file)
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -247,6 +247,11 @@ disable:
        return false;
 }
 
+/*
+ * Handle a DABR or DAWR exception.
+ *
+ * Called in atomic context.
+ */
 int hw_breakpoint_handler(struct die_args *args)
 {
        int rc = NOTIFY_STOP;
@@ -315,6 +320,8 @@ 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)
 {
@@ -355,6 +362,8 @@ 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)