Commit 4cc6620b authored by Daniel Bristot de Oliveira's avatar Daniel Bristot de Oliveira Committed by Ingo Molnar
Browse files

x86/jump_label: Add a __jump_label_set_jump_code() helper 



Move the definition of the code to be written from
__jump_label_transform() to a specialized function. No functional
change.

Signed-off-by: default avatarDaniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris von Recklinghausen <crecklin@redhat.com>
Cc: Clark Williams <williams@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: 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: https://lkml.kernel.org/r/d2f52a0010ecd399cf9b02a65bcf5836571b9e52.1560325897.git.bristot@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e1aacb3f

arch/x86/kernel/jump_label.c

+27 −25
Original line number Diff line number Diff line
@@ -35,41 +35,43 @@ static void bug_at(unsigned char *ip, int line) 
	BUG();

}



static void __ref __jump_label_transform(struct jump_entry *entry,

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 (type == JUMP_LABEL_JMP) {

	if (init) {

		expect = default_nop; line = __LINE__;

		} else {

	} else if (type == JUMP_LABEL_JMP) {

		expect = ideal_nop; line = __LINE__;

		}



		code = &jmp.code;

	} else {

		if (init) {

			expect = default_nop; line = __LINE__;

		} else {

			expect = &jmp.code; line = __LINE__;

		}



		code = ideal_nop;

		expect = code->code; line = __LINE__;

	}



	if (memcmp((void *)jump_entry_code(entry), expect, JUMP_LABEL_NOP_SIZE))

		bug_at((void *)jump_entry_code(entry), line);



	if (type == JUMP_LABEL_NOP)

		memcpy(code, ideal_nop, JUMP_LABEL_NOP_SIZE);

}



static void __ref __jump_label_transform(struct jump_entry *entry,

					 enum jump_label_type type,

					 int init)

{

	union jump_code_union code;



	__jump_label_set_jump_code(entry, type, &code, init);



	/*

	 * As long as only a single processor is running and the code is still

	 * not marked as RO, text_poke_early() can be used; Checking that
@@ -82,12 +84,12 @@ static void __ref __jump_label_transform(struct jump_entry *entry, 
	 * always nop being the 'currently valid' instruction

	 */

	if (init || system_state == SYSTEM_BOOTING) {

		text_poke_early((void *)jump_entry_code(entry), code,

		text_poke_early((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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