From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EFEFD285CBA; Wed, 20 May 2026 18:30:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301812; cv=none; b=AYwz1sgOaPzcnl/3Z9FgVQgrGST24s1l4kWtfH8nmV5klVf70o4YhXiwAkWu/WgWW0nldXBdMKqTLzAcdhOYj4MTD5FOFkV+PRPLz4APPiHGLvy5D85gKfqybO/tiF7luQrIWY9tlA6JYwAGLWM1Jw9IEdQRn998x/9meGBcQG4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779301812; c=relaxed/simple; bh=GwGkcMhx7QWh/FDCsSI7XYAxZMZrYR7VWN+v4BaARIQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kuTVnAgw7LX4GwUlCuZ90g8uglUP9c6CmooRV4VZylTjhmpP4Cp8HQU2J0Wuabjqs59kZTQ/K4jrOUk+cozTfmfvrMn9V6GFn+2zel/HZxQINHu9qWYRycf+qsE8dYcKn0R0VDhaIC81g7xvXaNwU4QKYCZUYmHz7aMxNghw+Vg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pXahF4TN; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pXahF4TN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 623B91F000E9; Wed, 20 May 2026 18:30:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779301810; bh=ctuFBVsgEaebp4f9ulwHVWKofrQkdMw2/Y2GA0qyb1o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pXahF4TNXCV2ahbuEJOHKSILD3n5NZkbSqNkJ8Ivfjs72GdIlmCABZ2Kp82RBla8d JKzg/dclcZesSxutWfMTutoby52vlaWJf/5UCCDnoyqzHv67TOqpMMWmNh0bDpCdmS 7tJ0bldibk9O9qiIY5HhhI/4cREpoMekhTaeaIiM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Hari Bathini , Ilya Leoshkevich , Ihor Solodrai , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.6 029/508] s390/bpf: Zero-extend bpf prog return values and kfunc arguments Date: Wed, 20 May 2026 18:17:32 +0200 Message-ID: <20260520162059.221531408@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162058.573354582@linuxfoundation.org> References: <20260520162058.573354582@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ilya Leoshkevich [ Upstream commit 202e42e4aa890172366354b233c42c73107a3f59 ] s390x ABI requires callers to zero-extend unsigned arguments and sign-extend signed arguments, and callees to zero-extend unsigned return values and sign-extend signed return values. s390 BPF JIT currently implements only sign extension. Fix this omission and implement zero extension too. Fixes: 528eb2cb87bc ("s390/bpf: Implement arch_prepare_bpf_trampoline()") Reported-by: Hari Bathini Closes: https://lore.kernel.org/bpf/20260312080113.843408-1-hbathini@linux.ibm.com/ Signed-off-by: Ilya Leoshkevich Tested-by: Ihor Solodrai Link: https://lore.kernel.org/r/20260313174807.581826-1-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- arch/s390/net/bpf_jit_comp.c | 39 ++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 5a64d34a37482..491789420d7c0 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -759,25 +759,34 @@ static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp, } /* - * Sign-extend the register if necessary + * Sign- or zero-extend the register if necessary */ -static int sign_extend(struct bpf_jit *jit, int r, u8 size, u8 flags) +static int sign_zero_extend(struct bpf_jit *jit, int r, u8 size, u8 flags) { - if (!(flags & BTF_FMODEL_SIGNED_ARG)) - return 0; - switch (size) { case 1: - /* lgbr %r,%r */ - EMIT4(0xb9060000, r, r); + if (flags & BTF_FMODEL_SIGNED_ARG) + /* lgbr %r,%r */ + EMIT4(0xb9060000, r, r); + else + /* llgcr %r,%r */ + EMIT4(0xb9840000, r, r); return 0; case 2: - /* lghr %r,%r */ - EMIT4(0xb9070000, r, r); + if (flags & BTF_FMODEL_SIGNED_ARG) + /* lghr %r,%r */ + EMIT4(0xb9070000, r, r); + else + /* llghr %r,%r */ + EMIT4(0xb9850000, r, r); return 0; case 4: - /* lgfr %r,%r */ - EMIT4(0xb9140000, r, r); + if (flags & BTF_FMODEL_SIGNED_ARG) + /* lgfr %r,%r */ + EMIT4(0xb9140000, r, r); + else + /* llgfr %r,%r */ + EMIT4(0xb9160000, r, r); return 0; case 8: return 0; @@ -1452,9 +1461,9 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, return -1; for (j = 0; j < m->nr_args; j++) { - if (sign_extend(jit, BPF_REG_1 + j, - m->arg_size[j], - m->arg_flags[j])) + if (sign_zero_extend(jit, BPF_REG_1 + j, + m->arg_size[j], + m->arg_flags[j])) return -1; } } @@ -2186,7 +2195,7 @@ static int invoke_bpf_prog(struct bpf_tramp_jit *tjit, call_r1(jit); /* stg %r2,retval_off(%r15) */ if (save_ret) { - if (sign_extend(jit, REG_2, m->ret_size, m->ret_flags)) + if (sign_zero_extend(jit, REG_2, m->ret_size, m->ret_flags)) return -1; EMIT6_DISP_LH(0xe3000000, 0x0024, REG_2, REG_0, REG_15, tjit->retval_off); -- 2.53.0