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Subject[tip:x86/alternatives] x86/jump_label: Add __jump_label_set_jump_code() helper
Commit-ID:  369670e583390ce7324ba3db988de09a7fceca93
Gitweb: https://git.kernel.org/tip/369670e583390ce7324ba3db988de09a7fceca93
Author: Daniel Bristot de Oliveira <bristot@redhat.com>
AuthorDate: Fri, 21 Dec 2018 11:27:29 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 19 Apr 2019 19:37:34 +0200

x86/jump_label: Add __jump_label_set_jump_code() helper

Move the definition of the code to be written from
__jump_label_transform() to a specialized function. No change in the
method, code relocation only.

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/eb97675f0d139aa6f78874db3abc81fcdba7a80f.1545228276.git.bristot@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/jump_label.c | 38 ++++++++++++++++++++++----------------
1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index e443c43478eb..2ef687db5a87 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -73,30 +73,36 @@ static inline void __jump_label_trans_check_disable(struct jump_entry *entry,
bug_at((void *)jump_entry_code(entry), line);
}

+static void __jump_label_set_jump_code(struct jump_entry *entry,
+ enum jump_label_type type,
+ union jump_code_union *code,
+ int init)
+{
+ const unsigned char *ideal_nop = ideal_nops[NOP_ATOMIC5];
+
+ code->jump = 0xe9;
+ code->offset = jump_entry_target(entry) -
+ (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
+
+ if (type == JUMP_LABEL_JMP) {
+ __jump_label_trans_check_enable(entry, type, ideal_nop, init);
+ } else {
+ __jump_label_trans_check_disable(entry, type, code, init);
+ memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE);
+ }
+}

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 *ideal_nop = ideal_nops[NOP_ATOMIC5];
- const void *code;
-
- jmp.jump = 0xe9;
- jmp.offset = jump_entry_target(entry) -
- (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
+ union jump_code_union code;

if (early_boot_irqs_disabled)
poker = text_poke_early;

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

/*
* Make text_poke_bp() a default fallback poker.
@@ -107,12 +113,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
*
*/
if (poker) {
- (*poker)((void *)jump_entry_code(entry), code,
+ (*poker)((void *)jump_entry_code(entry), &code,
JUMP_LABEL_NOP_SIZE);
return;
}

- text_poke_bp((void *)jump_entry_code(entry), code, JUMP_LABEL_NOP_SIZE,
+ text_poke_bp((void *)jump_entry_code(entry), &code, JUMP_LABEL_NOP_SIZE,
(void *)jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
}

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