[tip: objtool/core] jump_label: Free jump_entry::key bit1 for build use

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     5af0ea293d78c8b8f0b87ae2b13f7ac584057bc3
Gitweb:        https://git.kernel.org/tip/5af0ea293d78c8b8f0b87ae2b13f7ac584057bc3
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Thu, 06 May 2021 21:34:00 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Wed, 12 May 2021 14:54:55 +02:00

jump_label: Free jump_entry::key bit1 for build use

Have jump_label_init() set jump_entry::key bit1 to either 0 ot 1
unconditionally. This makes it available for build-time games.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210506194157.906893264@xxxxxxxxxxxxx
---
 include/linux/jump_label.h |  7 +++++--
 kernel/jump_label.c        | 10 ++++++----
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 8c45f58..48b9b2a 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -171,9 +171,12 @@ static inline bool jump_entry_is_init(const struct jump_entry *entry)
 	return (unsigned long)entry->key & 2UL;
 }
 
-static inline void jump_entry_set_init(struct jump_entry *entry)
+static inline void jump_entry_set_init(struct jump_entry *entry, bool set)
 {
-	entry->key |= 2;
+	if (set)
+		entry->key |= 2;
+	else
+		entry->key &= ~2;
 }
 
 static inline int jump_entry_size(struct jump_entry *entry)
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 521cafc..bdb0681 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -483,13 +483,14 @@ void __init jump_label_init(void)
 
 	for (iter = iter_start; iter < iter_stop; iter++) {
 		struct static_key *iterk;
+		bool in_init;
 
 		/* rewrite NOPs */
 		if (jump_label_type(iter) == JUMP_LABEL_NOP)
 			arch_jump_label_transform_static(iter, JUMP_LABEL_NOP);
 
-		if (init_section_contains((void *)jump_entry_code(iter), 1))
-			jump_entry_set_init(iter);
+		in_init = init_section_contains((void *)jump_entry_code(iter), 1);
+		jump_entry_set_init(iter, in_init);
 
 		iterk = jump_entry_key(iter);
 		if (iterk == key)
@@ -634,9 +635,10 @@ static int jump_label_add_module(struct module *mod)
 
 	for (iter = iter_start; iter < iter_stop; iter++) {
 		struct static_key *iterk;
+		bool in_init;
 
-		if (within_module_init(jump_entry_code(iter), mod))
-			jump_entry_set_init(iter);
+		in_init = within_module_init(jump_entry_code(iter), mod);
+		jump_entry_set_init(iter, in_init);
 
 		iterk = jump_entry_key(iter);
 		if (iterk == key)