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[34.242.166.189]) by smtp.gmail.com with ESMTPSA id e15-20020a5d594f000000b00317df42e91dsm13921794wri.4.2023.09.12.15.46.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Sep 2023 15:46:58 -0700 (PDT) From: Puranjay Mohan To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shubham Bansal , Russell King , "James E.J. Bottomley" , Helge Deller , "Naveen N. Rao" , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Luke Nelson , Xi Wang , Paul Walmsley , Palmer Dabbelt , Albert Ou , Wang YanQing , bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, netdev@vger.kernel.org Cc: puranjay12@gmail.com Subject: [PATCH bpf-next 2/6] bpf, x86-32: Always zero extend for LDX with B/W/H Date: Tue, 12 Sep 2023 22:46:50 +0000 Message-Id: <20230912224654.6556-3-puranjay12@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230912224654.6556-1-puranjay12@gmail.com> References: <20230912224654.6556-1-puranjay12@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org 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 --- arch/x86/net/bpf_jit_comp32.c | 2 -- 1 file changed, 2 deletions(-) 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));