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x86/jump_label: Switch to jump_entry accessors

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In preparation of switching x86 to use place-relative references for
the code, target and key members of struct jump_entry, replace direct
references to the struct members with invocations of the new accessors.
This will allow us to make the switch by modifying the accessors only.

This incorporates a cleanup of __jump_label_transform() proposed by
Peter.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Link: https://lkml.kernel.org/r/20180919065144.25010-6-ard.biesheuvel@linaro.org
This commit is contained in:
Ard Biesheuvel 2018-09-18 23:51:40 -07:00 committed by Thomas Gleixner
parent b40a142b12
commit 9fc0f798ab
1 changed files with 25 additions and 37 deletions
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62
arch/x86/kernel/jump_label.c
View File

@ -42,55 +42,40 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
void *(*poker)(void *, const void *, size_t),
int init)
{
union jump_code_union code;
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;
jmp.jump = 0xe9;
jmp.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) {
/*
* Jump label is enabled for the first time.
* So we expect a default_nop...
*/
if (unlikely(memcmp((void *)entry->code, default_nop, 5)
!= 0))
bug_at((void *)entry->code, __LINE__);
expect = default_nop; line = __LINE__;
} else {
/*
* ...otherwise expect an ideal_nop. Otherwise
* something went horribly wrong.
*/
if (unlikely(memcmp((void *)entry->code, ideal_nop, 5)
!= 0))
bug_at((void *)entry->code, __LINE__);
expect = ideal_nop; line = __LINE__;
}
code.jump = 0xe9;
code.offset = entry->target -
(entry->code + JUMP_LABEL_NOP_SIZE);
code = &jmp.code;
} else {
/*
* We are disabling this jump label. If it is not what
* we think it is, then something must have gone wrong.
* If this is the first initialization call, then we
* are converting the default nop to the ideal nop.
*/
if (init) {
if (unlikely(memcmp((void *)entry->code, default_nop, 5) != 0))
bug_at((void *)entry->code, __LINE__);
expect = default_nop; line = __LINE__;
} else {
code.jump = 0xe9;
code.offset = entry->target -
(entry->code + JUMP_LABEL_NOP_SIZE);
if (unlikely(memcmp((void *)entry->code, &code, 5) != 0))
bug_at((void *)entry->code, __LINE__);
expect = &jmp.code; line = __LINE__;
}
memcpy(&code, ideal_nops[NOP_ATOMIC5], JUMP_LABEL_NOP_SIZE);
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.
*
@ -99,11 +84,14 @@ static void __ref __jump_label_transform(struct jump_entry *entry,
* always nop being the 'currently valid' instruction
*
*/
if (poker)
(*poker)((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE);
else
text_poke_bp((void *)entry->code, &code, JUMP_LABEL_NOP_SIZE,
(void *)entry->code + JUMP_LABEL_NOP_SIZE);
if (poker) {
(*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,
(void *)jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE);
}
void arch_jump_label_transform(struct jump_entry *entry,