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 Handled Elsewhere
Headers show
Series bpf: verifier: stop emitting zext for LDX | expand

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Context Check Description
conchuod/cover_letter success Series has a cover letter
conchuod/tree_selection success Guessed tree name to be for-next at HEAD 0bb80ecc33a8
conchuod/fixes_present success Fixes tag not required for -next series
conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 5 and now 5
conchuod/verify_signedoff success Signed-off-by tag matches author and committer
conchuod/kdoc success Errors and warnings before: 0 this patch: 0
conchuod/build_rv64_clang_allmodconfig success Errors and warnings before: 9 this patch: 9
conchuod/module_param success Was 0 now: 0
conchuod/build_rv64_gcc_allmodconfig success Errors and warnings before: 9 this patch: 9
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 25 this patch: 25
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
conchuod/build_rv64_nommu_k210_defconfig success Build OK
conchuod/verify_fixes success No Fixes tag
conchuod/build_rv64_nommu_virt_defconfig success Build OK

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));