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Subject[PATCH V5 3/7] x86/jump_label: Add a __jump_label_set_jump_code() helper
Date
Move the definition of the code to be written from
__jump_label_transform() to a specialized function.

Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Chris von Recklinghausen <crecklin@redhat.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Scott Wood <swood@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
---
arch/x86/kernel/jump_label.c | 47 ++++++++++++++++++++++--------------
1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index f99bd26bd3f1..8aa65fbbd764 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c
@@ -35,24 +35,20 @@ static void bug_at(unsigned char *ip, int line)
BUG();
}

-static void __ref __jump_label_transform(struct jump_entry *entry,
- enum jump_label_type type,
- void *(*poker)(void *, const void *, size_t),
- int init)
+static void __jump_label_set_jump_code(struct jump_entry *entry,
+ enum jump_label_type type,
+ union jump_code_union *code,
+ 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;
+ const void *expect;
int line;

- jmp.jump = 0xe9;
- jmp.offset = jump_entry_target(entry) -
+ code->jump = 0xe9;
+ code->offset = jump_entry_target(entry) -
(jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);

- if (early_boot_irqs_disabled)
- poker = text_poke_early;
-
if (type == JUMP_LABEL_JMP) {
if (init) {
expect = default_nop; line = __LINE__;
@@ -60,19 +56,34 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
expect = ideal_nop; line = __LINE__;
}

- code = &jmp.code;
+ if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
+ bug_at((void *)jump_entry_code(entry), line);
+
} else {
if (init) {
expect = default_nop; line = __LINE__;
} else {
- expect = &jmp.code; line = __LINE__;
+ expect = code->code; line = __LINE__;
}

- code = ideal_nop;
+ if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
+ bug_at((void *)jump_entry_code(entry), line);
+
+ 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 code;
+
+ if (early_boot_irqs_disabled)
+ poker = text_poke_early;

- if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))
- bug_at((void *)jump_entry_code(entry), line);
+ __jump_label_set_jump_code(entry, type, &code, init);

/*
* Make text_poke_bp() a default fallback poker.
@@ -83,12 +94,12 @@ 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);
}

--
2.20.1
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