From patchwork Tue Oct 10 20:20:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Leoshkevich X-Patchwork-Id: 13416056 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 1B334208D9 for ; Tue, 10 Oct 2023 20:35:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="dgTCCo39" Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B69BF91 for ; Tue, 10 Oct 2023 13:35:35 -0700 (PDT) Received: from pps.filterd (m0353722.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 39AKU3IA025190; Tue, 10 Oct 2023 20:35:23 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=G/mfDxEp03rPYb6uh3oLP2Pn4fyAG4lWQ5YC8+LNxLo=; b=dgTCCo395fACM6h7T6klkICtuQ9wHQ+MFKPXG2Iu8Kd6oPk/x1wsEXylZtJvVxdkCjgh tHWqdCIXeWucabnekLvmkSKKbEBjeUIl3rom+cfC21Vtj+NBWY+8m0b/GtBmug106xnu ZvHOn1DeLVNGFnN4zNmGZ1U7c4VqaFMbeW4anJEiwZa5QSrEw77F2gXekogEiyEKGd0s ZGwpCsAZnoy57mt/05Jeg6fxb7bZP/cX6XCWjkKXJddQEWx6pe5MP0DVKjrOdaJ0vYdM xmaHkjuKP7IDQ1Ie9psA3mklZ643C2jAQDimd+UFB+a+y/WSDu7sbN8BWnc4s91e+iAH oQ== Received: from ppma22.wdc07v.mail.ibm.com (5c.69.3da9.ip4.static.sl-reverse.com [169.61.105.92]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3tndq1g85k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 10 Oct 2023 20:35:22 +0000 Received: from pps.filterd (ppma22.wdc07v.mail.ibm.com [127.0.0.1]) by ppma22.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 39AJ8teg028188; Tue, 10 Oct 2023 20:35:22 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3tkj1y34x2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 10 Oct 2023 20:35:21 +0000 Received: from smtpav06.fra02v.mail.ibm.com (smtpav06.fra02v.mail.ibm.com [10.20.54.105]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 39AKZI4T43319716 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 10 Oct 2023 20:35:18 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2FCB42004B; Tue, 10 Oct 2023 20:35:18 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 86FA62004E; Tue, 10 Oct 2023 20:35:17 +0000 (GMT) Received: from heavy.boeblingen.de.ibm.com (unknown [9.171.0.76]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 10 Oct 2023 20:35:17 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Song Liu , Ilya Leoshkevich Subject: [PATCH bpf 2/2] s390/bpf: Fix unwinding past the trampoline Date: Tue, 10 Oct 2023 22:20:10 +0200 Message-ID: <20231010203512.385819-3-iii@linux.ibm.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231010203512.385819-1-iii@linux.ibm.com> References: <20231010203512.385819-1-iii@linux.ibm.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: yu7UX69sPGUvQy7AcbpOatKFODqtF7Re X-Proofpoint-GUID: yu7UX69sPGUvQy7AcbpOatKFODqtF7Re X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-10_16,2023-10-10_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 bulkscore=0 impostorscore=0 adultscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=999 malwarescore=0 clxscore=1015 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310100159 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net When functions called by the trampoline panic, the backtrace that is printed stops at the trampoline, because the trampoline does not store its caller's frame address (backchain) on stack; it also stores the return address at a wrong location. Store both the same way as is already done for the regular eBPF programs. Fixes: 528eb2cb87bc ("s390/bpf: Implement arch_prepare_bpf_trampoline()") Signed-off-by: Ilya Leoshkevich --- arch/s390/net/bpf_jit_comp.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 8955bc80270a..082b913f214e 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -2205,6 +2205,7 @@ struct bpf_tramp_jit { * func_addr's original caller */ int stack_size; /* Trampoline stack size */ + int backchain_off; /* Offset of backchain */ int stack_args_off; /* Offset of stack arguments for calling * func_addr, has to be at the top */ @@ -2225,9 +2226,10 @@ struct bpf_tramp_jit { * for __bpf_prog_enter() return value and * func_addr respectively */ - int r14_off; /* Offset of saved %r14 */ int run_ctx_off; /* Offset of struct bpf_tramp_run_ctx */ int tccnt_off; /* Offset of saved tailcall counter */ + int r14_off; /* Offset of saved %r14, has to be at the + * bottom */ int do_fexit; /* do_fexit: label */ }; @@ -2386,8 +2388,12 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, * Calculate the stack layout. */ - /* Reserve STACK_FRAME_OVERHEAD bytes for the callees. */ + /* + * Allocate STACK_FRAME_OVERHEAD bytes for the callees. As the s390x + * ABI requires, put our backchain at the end of the allocated memory. + */ tjit->stack_size = STACK_FRAME_OVERHEAD; + tjit->backchain_off = tjit->stack_size - sizeof(u64); tjit->stack_args_off = alloc_stack(tjit, nr_stack_args * sizeof(u64)); tjit->reg_args_off = alloc_stack(tjit, nr_reg_args * sizeof(u64)); tjit->ip_off = alloc_stack(tjit, sizeof(u64)); @@ -2395,10 +2401,10 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, tjit->bpf_args_off = alloc_stack(tjit, nr_bpf_args * sizeof(u64)); tjit->retval_off = alloc_stack(tjit, sizeof(u64)); tjit->r7_r8_off = alloc_stack(tjit, 2 * sizeof(u64)); - tjit->r14_off = alloc_stack(tjit, sizeof(u64)); tjit->run_ctx_off = alloc_stack(tjit, sizeof(struct bpf_tramp_run_ctx)); tjit->tccnt_off = alloc_stack(tjit, sizeof(u64)); + tjit->r14_off = alloc_stack(tjit, sizeof(u64) * 2); /* * In accordance with the s390x ABI, the caller has allocated * STACK_FRAME_OVERHEAD bytes for us. 8 of them contain the caller's @@ -2407,8 +2413,13 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, tjit->stack_size -= STACK_FRAME_OVERHEAD - sizeof(u64); tjit->orig_stack_args_off = tjit->stack_size + STACK_FRAME_OVERHEAD; + /* lgr %r1,%r15 */ + EMIT4(0xb9040000, REG_1, REG_15); /* aghi %r15,-stack_size */ EMIT4_IMM(0xa70b0000, REG_15, -tjit->stack_size); + /* stg %r1,backchain_off(%r15) */ + EMIT6_DISP_LH(0xe3000000, 0x0024, REG_1, REG_0, REG_15, + tjit->backchain_off); /* mvc tccnt_off(4,%r15),stack_size+STK_OFF_TCCNT(%r15) */ _EMIT6(0xd203f000 | tjit->tccnt_off, 0xf000 | (tjit->stack_size + STK_OFF_TCCNT));