[RFC PATCH 2/6] jump_label: Add the jump_label_can_update_check() helper

From: Daniel Bristot de Oliveira
Date: Mon Oct 08 2018 - 08:53:36 EST


Move the check of if a jump_entry is valid to a function.

Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Cc: Zhou Chengming <zhouchengming1@xxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Chris von Recklinghausen <crecklin@xxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Scott Wood <swood@xxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Clark Williams <williams@xxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
kernel/jump_label.c | 29 ++++++++++++++++++-----------
1 file changed, 18 insertions(+), 11 deletions(-)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index e853916a3b46..940ba7819c87 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -361,22 +361,29 @@ static enum jump_label_type jump_label_type(struct jump_entry *entry)
return enabled ^ branch;
}

+bool jump_label_can_update_check(struct jump_entry *entry)
+{
+ /*
+ * An entry->code of 0 indicates an entry which has been
+ * disabled because it was in an init text area.
+ */
+ if (entry->code) {
+ if (kernel_text_address(entry->code))
+ return 1;
+ else
+ WARN_ONCE(1, "can't patch jump_label at %pS",
+ (void *)(unsigned long)entry->code);
+ }
+ return 0;
+}
+
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop)
{
for_each_label_entry(key, entry, stop) {
- /*
- * An entry->code of 0 indicates an entry which has been
- * disabled because it was in an init text area.
- */
- if (entry->code) {
- if (kernel_text_address(entry->code))
- arch_jump_label_transform(entry, jump_label_type(entry));
- else
- WARN_ONCE(1, "can't patch jump_label at %pS",
- (void *)(unsigned long)entry->code);
- }
+ if (jump_label_can_update_check(entry))
+ arch_jump_label_transform(entry, jump_label_type(entry));
}
}

--
2.17.1