| Message ID | 20230912224654.6556-7-puranjay12@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf: verifier: stop emitting zext for LDX | expand |
| 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-0 | success | Logs for ShellCheck |
| bpf/vmtest-bpf-next-VM_Test-5 | success | Logs for set-matrix |
| bpf/vmtest-bpf-next-VM_Test-2 | pending | Logs for build for s390x with gcc |
| 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: 1352 this patch: 1352 |
| netdev/cc_maintainers | success | CCed 16 of 16 maintainers |
| netdev/build_clang | success | Errors and warnings before: 1364 this patch: 1364 |
| 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: 1375 this patch: 1375 |
| netdev/checkpatch | warning | WARNING: line length of 92 exceeds 80 columns |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index dbba2b806017..02a1ac1a1327 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -3028,9 +3028,7 @@ static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn, return false; if (class == BPF_LDX) { - if (t != SRC_OP) - return BPF_SIZE(code) == BPF_DW; - /* LDX source must be ptr. */ + /* LDX source must be a ptr. and LDX destination is always zero-extended. */ return true; }
All 64-bit JITs utilize a single instruction to load + zero-extend a byte, word, or a half-word. The optimisation of emitting zext for LDX is not useful for most of the JITs. All the JITs that relied on the verifier for zero extension of LDX desitination registers have been modified to always zero extend the destination. Now the verifier can safely mark LDX destination as 64-bit and stop emitting zero-extension instructions for it. Signed-off-by: Puranjay Mohan <puranjay12@gmail.com> --- kernel/bpf/verifier.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)