diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2025-02-24 13:37:08 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-02-26 12:24:09 +0100 |
| commit | 06926c6cdb955bf24521d4e13af95b4d062d02d0 (patch) | |
| tree | ba8f9d9d2c26983f3b3968d8e7ff22776e3057cd /arch/x86/net/bpf_jit_comp.c | |
| parent | x86/traps: Allow custom fixups in handle_bug() (diff) | |
| download | linux-06926c6cdb955bf24521d4e13af95b4d062d02d0.tar.gz linux-06926c6cdb955bf24521d4e13af95b4d062d02d0.zip | |
x86/ibt: Optimize the FineIBT instruction sequence
Scott notes that non-taken branches are faster. Abuse overlapping code
that traps instead of explicit UD2 instructions.
And LEA does not modify flags and will have less dependencies.
Suggested-by: Scott Constable <scott.d.constable@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250224124200.371942555@infradead.org
Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index f36508b67278..ce033e63bc27 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -417,9 +417,8 @@ static void emit_fineibt(u8 **pprog, u32 hash) EMIT_ENDBR(); EMIT3_off32(0x41, 0x81, 0xea, hash); /* subl $hash, %r10d */ - EMIT2(0x74, 0x07); /* jz.d8 +7 */ - EMIT2(0x0f, 0x0b); /* ud2 */ - EMIT1(0x90); /* nop */ + EMIT2(0x75, 0xf9); /* jne.d8 .-7 */ + EMIT3(0x0f, 0x1f, 0x00); /* nop3 */ EMIT_ENDBR_POISON(); *pprog = prog; |