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 Changes Requested
Delegated to: BPF
Headers show
Series bpf: verifier: stop emitting zext for LDX | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR pending PR summary
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-1 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-next-VM_Test-2 pending Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-5 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-0 success Logs for ShellCheck
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1342 this patch: 1342
netdev/cc_maintainers warning 8 maintainers not CCed: bp@alien8.de tglx@linutronix.de davem@davemloft.net mingo@redhat.com dsahern@kernel.org x86@kernel.org hpa@zytor.com dave.hansen@linux.intel.com
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

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));