[PATCH v7 11/14] x86/jump-label: remove support for custom poker
From: Nadav Amit <hidden>
Date: 2018-12-05 08:52:15
Also in:
linux-integrity, lkml
Subsystem:
static branch/call, the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Peter Zijlstra, Josh Poimboeuf, Jason Baron, Alice Ryhl, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
There are only two types of poking: early and breakpoint based. The use of a function pointer to perform poking complicates the code and is probably inefficient due to the use of indirect branches. Cc: Andy Lutomirski <luto@kernel.org> Cc: Kees Cook <redacted> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <redacted> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Nadav Amit <redacted> --- arch/x86/kernel/jump_label.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
index ed5fe274a7d8..994c13e2867d 100644
--- a/arch/x86/kernel/jump_label.c
+++ b/arch/x86/kernel/jump_label.c@@ -39,7 +39,6 @@ static void bug_at(unsigned char *ip, int 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;
@@ -52,14 +51,6 @@ static void __ref __jump_label_transform(struct jump_entry *entry, jmp.offset = jump_entry_target(entry) - (jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE); - /* - * As long as we're UP and not yet marked RO, we can use - * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to - * SYSTEM_SCHEDULING before going either. - */ - if (system_state == SYSTEM_BOOTING) - poker = text_poke_early; - if (type == JUMP_LABEL_JMP) { if (init) { expect = default_nop; line = __LINE__;
@@ -82,16 +73,17 @@ static void __ref __jump_label_transform(struct jump_entry *entry, bug_at((void *)jump_entry_code(entry), line); /* - * Make text_poke_bp() a default fallback poker. + * As long as we're UP and not yet marked RO, we can use + * text_poke_early; SYSTEM_BOOTING guarantees both, as we switch to + * SYSTEM_SCHEDULING before going either. * * At the time the change is being done, just ignore whether we * are doing nop -> jump or jump -> nop transition, and assume * always nop being the 'currently valid' instruction - * */ - if (poker) { - (*poker)((void *)jump_entry_code(entry), code, - JUMP_LABEL_NOP_SIZE); + if (init || system_state == SYSTEM_BOOTING) { + text_poke_early((void *)jump_entry_code(entry), code, + JUMP_LABEL_NOP_SIZE); return; }
@@ -103,7 +95,7 @@ void arch_jump_label_transform(struct jump_entry *entry, enum jump_label_type type) { mutex_lock(&text_mutex); - __jump_label_transform(entry, type, NULL, 0); + __jump_label_transform(entry, type, 0); mutex_unlock(&text_mutex); }
@@ -133,7 +125,7 @@ __init_or_module void arch_jump_label_transform_static(struct jump_entry *entry, jlstate = JL_STATE_NO_UPDATE; } if (jlstate == JL_STATE_UPDATE) - __jump_label_transform(entry, type, text_poke_early, 1); + __jump_label_transform(entry, type, 1); } #endif
--
2.17.1