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Subject[tip:x86/alternatives] jump_label: Add the jump_label_can_update_check() helper
Commit-ID:  41bef31d0abe29b5888b33b526cacc8a30795318
Gitweb: https://git.kernel.org/tip/41bef31d0abe29b5888b33b526cacc8a30795318
Author: Daniel Bristot de Oliveira <bristot@redhat.com>
AuthorDate: Fri, 21 Dec 2018 11:27:27 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 19 Apr 2019 19:37:34 +0200

jump_label: Add the jump_label_can_update_check() helper

Move the check of if a jump_entry is valid to a specific function. No
functional change.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris von Recklinghausen <crecklin@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Scott Wood <swood@redhat.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1e758cd3b2206be96091a57a17b26585e94792b6.1545228276.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/jump_label.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 288d630da22d..456c0d7cbb5b 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -374,22 +374,32 @@ 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, bool init)
+{
+ /*
+ * An entry->code of 0 indicates an entry which has been
+ * disabled because it was in an init text area.
+ */
+ if (init || !jump_entry_is_init(entry)) {
+ if (!kernel_text_address(jump_entry_code(entry))) {
+ WARN_ONCE(1, "can't patch jump_label at %pS",
+ (void *)jump_entry_code(entry));
+ return 0;
+ }
+ return 1;
+ }
+ return 0;
+}
+
static void __jump_label_update(struct static_key *key,
struct jump_entry *entry,
struct jump_entry *stop,
bool init)
{
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 (init || !jump_entry_is_init(entry)) {
- if (kernel_text_address(jump_entry_code(entry)))
- arch_jump_label_transform(entry, jump_label_type(entry));
- else
- WARN_ONCE(1, "can't patch jump_label at %pS",
- (void *)jump_entry_code(entry));
+ if (jump_label_can_update_check(entry, init)) {
+ arch_jump_label_transform(entry,
+ jump_label_type(entry));
}
}
}
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