From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793829652; b=j0fD9VxIAOBdkrFUAv02BuO9p4bnGKLsIPajb8W4x19Ub9IyhHqCKXzGED8NN3bSPPcW 2npqvh7alPbZK3NDPIIfmJyezJWeu8pTItGzk9C7vSehenCuNIQlHAobpTwjScxz6jITN p/3keD2KQJ0eIjPS7gfT6vQReiXSCT8NrfidbFGFeF7xyC74AglyCeQ5kYE4CimgGIlMb D5C4TL6q+q0zqe8XrLGOKuTvUn5eJbLjllZqtMMan4uE26a6qbzYBOj33PE2oBUASV8ps GfTfqnsBXjChufCy2kZEEzqwFw1o2pQX+fZyt15mvvIJcbCxn/ikGLkR+iIERqY+rog== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793829652; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=2kB6VfYetYYo2afpxDIrbi+HuCduDUgnTqzzKDsNi9A=; b=F4xtTthgV+qc6jwICMJAbw0FyYK7tCecIteVvBmT+HvN8BP7VOWs6qEmEXRyNyrDQ/IL t1jkkbMeB3HQHA9eO/aBYP7zB35DGMJU1KqMeAYi7lCJnEoTVhS+TdKMDuD58VbDPHBno LmAVYqRQIfg0xFdzF6r446hdkLr+mJAIXB4qIp3ZrgJMRV2Kf0IgUmAw2krzK0TsZVj3N +Ad1w1nKKuYxrjeoxsvfEO7ZV3ZNOuNbjqsL4aTGj33axSCKmhRfKWj9uZF2ZG1bvf3dH t8pAhYwI4Me2oI89AOGE/eMbl8KW49+xrpOzAfTsTYszcH8YPu9U1p2T65D5SPp69OQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=m7wkOn9U; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 30393606AC15; Wed, 4 Nov 2026 22:00:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=m7wkOn9U Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBD131F00A17; Wed, 4 Nov 2026 22:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793829652; bh=2kB6VfYetYYo2afpxDIrbi+HuCduDUgnTqzzKDsNi9A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=m7wkOn9UdOsWsvASRphKggLGlSh1FmARqMPon8piowe7Wnr/L9bH43OvX192ppWSw LNepx/9DiJ0rTceWP+7maxkQloSqSo94w6kyKmRrDgcxvfKK7z93e0exLpMErSvztd pRjbKHO6GZdzdUZnf3v4j5UAGUdfXMOMcSyqJgBk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuan-Wei Chiu , Pu Lehui , Kumar Kartikeya Dwivedi , Sasha Levin Subject: [PATCH 6.18 0221/1005] riscv, bpf: Add support for BPF_MOVSX in RV32 JIT Date: Wed, 4 Nov 2026 15:59:14 -0500 Message-ID: <20261104211050.009405594@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuan-Wei Chiu [ Upstream commit c6a08afdfe3a81b1a54e921921e9481dd6c78f8a ] The current rv32 bpf jit compiler incorrectly treats BPF_MOVSX as a standard zero-extended move operation. The bpf instruction set allows sign-extension moves by reusing the BPF_MOV opcode with the instruction offset set to 8, 16, or 32. Update the bpf_jit_emit_insn() function to check the offset field for both ALU and ALU64 MOV operations. If the offset is non-zero, emit the correct slli and srai instructions to perform the sign extension. Before this patch: [ 19.549705] test_bpf: #82 ALU_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times) [ 19.551354] test_bpf: #83 ALU_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times) [ 19.552576] test_bpf: #84 ALU64_MOVSX | BPF_B jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times) [ 19.553542] test_bpf: #85 ALU64_MOVSX | BPF_H jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times) [ 19.554807] test_bpf: #86 ALU64_MOVSX | BPF_W jited:1 ret 2 != 1 (0x2 != 0x1)FAIL (1 times) After this patch: [ 17.931172] test_bpf: #82 ALU_MOVSX | BPF_B jited:1 125 PASS [ 17.932198] test_bpf: #83 ALU_MOVSX | BPF_H jited:1 124 PASS [ 17.933039] test_bpf: #84 ALU64_MOVSX | BPF_B jited:1 124 PASS [ 17.933918] test_bpf: #85 ALU64_MOVSX | BPF_H jited:1 124 PASS [ 17.934751] test_bpf: #86 ALU64_MOVSX | BPF_W jited:1 122 PASS Signed-off-by: Kuan-Wei Chiu Reviewed-by: Pu Lehui Link: https://lore.kernel.org/bpf/20260714002451.4091139-3-visitorckw@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Sasha Levin --- arch/riscv/net/bpf_jit_comp32.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/arch/riscv/net/bpf_jit_comp32.c b/arch/riscv/net/bpf_jit_comp32.c index 89153946a4e46..39e2b0b907dc3 100644 --- a/arch/riscv/net/bpf_jit_comp32.c +++ b/arch/riscv/net/bpf_jit_comp32.c @@ -972,6 +972,24 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, switch (code) { case BPF_ALU64 | BPF_MOV | BPF_X: + if (insn->off != 0) { + const s8 *rd = bpf_get_reg64(dst, tmp1, ctx); + const s8 *rs = bpf_get_reg64(src, tmp2, ctx); + + if (insn->off == 8) { + emit(rv_slli(lo(rd), lo(rs), 24), ctx); + emit(rv_srai(lo(rd), lo(rd), 24), ctx); + } else if (insn->off == 16) { + emit(rv_slli(lo(rd), lo(rs), 16), ctx); + emit(rv_srai(lo(rd), lo(rd), 16), ctx); + } else { + emit(rv_addi(lo(rd), lo(rs), 0), ctx); + } + emit(rv_srai(hi(rd), lo(rd), 31), ctx); + bpf_put_reg64(dst, rd, ctx); + break; + } + fallthrough; case BPF_ALU64 | BPF_ADD | BPF_X: case BPF_ALU64 | BPF_ADD | BPF_K: @@ -1022,6 +1040,20 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, emit_zext64(dst, ctx); break; } + if (insn->off != 0) { + const s8 *rd = bpf_get_reg32(dst, tmp1, ctx); + const s8 *rs = bpf_get_reg32(src, tmp2, ctx); + + if (insn->off == 8) { + emit(rv_slli(lo(rd), lo(rs), 24), ctx); + emit(rv_srai(lo(rd), lo(rd), 24), ctx); + } else if (insn->off == 16) { + emit(rv_slli(lo(rd), lo(rs), 16), ctx); + emit(rv_srai(lo(rd), lo(rd), 16), ctx); + } + bpf_put_reg32(dst, rd, ctx); + break; + } fallthrough; case BPF_ALU | BPF_ADD | BPF_X: -- 2.53.0