diff mbox series

[bpf-next,2/6] bpf, x86-32: Always zero extend for LDX with B/W/H

Message ID 20230912224654.6556-3-puranjay12@gmail.com (mailing list archive)
State New, archived
Headers show
Series bpf: verifier: stop emitting zext for LDX | expand

Commit Message

Puranjay Mohan Sept. 12, 2023, 10:46 p.m. UTC 
The JITs should not depend on the verifier for zero extending the upper
32 bits of the destination register when loading a byte, half-word, or
word.

A following patch will make the verifier stop patching zext instructions
after LDX.

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
---
 arch/x86/net/bpf_jit_comp32.c | 2 --
 1 file changed, 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index 429a89c5468b..aef9183ff107 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c
@@ -2050,8 +2050,6 @@  static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
 			case BPF_B:
 			case BPF_H:
 			case BPF_W:
-				if (bpf_prog->aux->verifier_zext)
-					break;
 				if (dstk) {
 					EMIT3(0xC7, add_1reg(0x40, IA32_EBP),
 					      STACK_VAR(dst_hi));