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Subject[tip:x86/alternatives] x86/jump_label: Move checking code away from __jump_label_transform()
Commit-ID:  ddbefdc167f3d492036e6b0babd11a350c3bd3e3
Gitweb: https://git.kernel.org/tip/ddbefdc167f3d492036e6b0babd11a350c3bd3e3
Author: Daniel Bristot de Oliveira <bristot@redhat.com>
AuthorDate: Fri, 21 Dec 2018 11:27:28 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 19 Apr 2019 19:37:34 +0200

x86/jump_label: Move checking code away from __jump_label_transform()

Move the check of the current code, before updating an entry, to specialized
functions. No changes in the method, only code relocation.

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/296d5a75c4aee4a957ee7923127c0604903f9daa.1545228276.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/jump_label.c | 60 +++++++++++++++++++++++++++++++-------------
1 file changed, 42 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index f99bd26bd3f1..e443c43478eb 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -35,16 +35,53 @@ static void bug_at(unsigned char *ip, int line)
BUG();
}

+static inline void __jump_label_trans_check_enable(struct jump_entry *entry,
+ enum jump_label_type type,
+ const unsigned char *ideal_nop,
+ int init)
+{
+ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
+ const void *expect;
+ int line;
+
+ if (init) {
+ expect = default_nop; line = __LINE__;
+ } else {
+ expect = ideal_nop; line = __LINE__;
+ }
+
+ if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
+ bug_at((void *)jump_entry_code(entry), line);
+}
+
+static inline void __jump_label_trans_check_disable(struct jump_entry *entry,
+ enum jump_label_type type,
+ union jump_code_union *jmp,
+ int init)
+{
+ const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
+ const void *expect;
+ int line;
+
+ if (init) {
+ expect = default_nop; line = __LINE__;
+ } else {
+ expect = jmp->code; line = __LINE__;
+ }
+
+ if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
+ bug_at((void *)jump_entry_code(entry), line);
+}
+
+
static void __ref __jump_label_transform(struct jump_entry *entry,
enum jump_label_type type,
void *(*poker)(void *, const void *, size_t),
int init)
{
union jump_code_union jmp;
- const unsigned char default_nop[] = { STATIC_KEY_INIT_NOP };
const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
- const void *expect, *code;
- int line;
+ const void *code;

jmp.jump = 0xe9;
jmp.offset = jump_entry_target(entry) -
@@ -54,26 +91,13 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
poker = text_poke_early;

if (type == JUMP_LABEL_JMP) {
- if (init) {
- expect = default_nop; line = __LINE__;
- } else {
- expect = ideal_nop; line = __LINE__;
- }
-
+ __jump_label_trans_check_enable(entry, type, ideal_nop, init);
code = &jmp.code;
} else {
- if (init) {
- expect = default_nop; line = __LINE__;
- } else {
- expect = &jmp.code; line = __LINE__;
- }
-
+ __jump_label_trans_check_disable(entry, type, &jmp, init);
code = ideal_nop;
}

- if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
- bug_at((void *)jump_entry_code(entry), line);
-
/*
* Make text_poke_bp() a default fallback poker.
*
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