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(unknown [9.124.223.59]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Sat, 24 Jan 2026 07:53:05 +0000 (GMT) From: adubey@linux.ibm.com To: bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: hbathini@linux.ibm.com, sachinpb@linux.ibm.com, venkat88@linux.ibm.com, andrii@kernel.org, eddyz87@gmail.com, mykolal@fb.com, ast@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, christophe.leroy@csgroup.eu, naveen@kernel.org, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, memxor@gmail.com, iii@linux.ibm.com, shuah@kernel.org, Abhishek Dubey Subject: [PATCH v5 4/6] powerpc64/bpf: Add arch_bpf_stack_walk() for BPF JIT Date: Sat, 24 Jan 2026 13:22:21 +0530 Message-ID: <20260124075223.6033-5-adubey@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20260124075223.6033-1-adubey@linux.ibm.com> References: <20260124075223.6033-1-adubey@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=Gr1PO01C c=1 sm=1 tr=0 ts=69747a6e cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=lmbXRN_Zm_tNO3HBYvgA:9 X-Proofpoint-GUID: X_2ZuYxAxidKUGW62CFsspbQMqss3Qmk X-Proofpoint-ORIG-GUID: _Qr-1v1S46W0pKlaNUWMIFLkb5WedFBn X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTI0MDA2MCBTYWx0ZWRfX42sCkNmsDp+1 3dIc6Gqf94nZ00lqSkC023Ww1kjBYMpWPOk6s9nTx5yUXX9Nc/2sSKfp0+CS0hAyAX8fJZ66Zrz DMeHHp9ubn96lt+FL/qG3GcPEhvIvfi5x/+6uiWenTinlw/agbZqPCgMkV7W5Qui1tj3oAU/O0G CwlWd3RhqVrIVg9t6mF6Zx2Vd/dwxqtkqysNf3bacD8IpH1PsF02gnew0SFuwMKUDYbQZKZJrnN 6qZuMqzO7P9m1kP4Ef/3TN7eL+aBagxGfCkFIG6ttKN2xzm+8E3QZ/r6RHr072Hlli6wxV3ja6g vvQ5blVo83B8zA8bu+jqdfmyiFMviz1NfYF0IlccP1npIS3+JZPTr5z+QzJF3Fx3VdhK8tfm/yx /6H7mtYOMundk6hDBGkB6KaqwS8gX/wipvlum/qF7LZMhSBGXjYYq0iW09tJyEuuO334uCgrsU/ VLnorIx4teRG0Iq/jGg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.20,FMLib:17.12.100.49 definitions=2026-01-24_02,2026-01-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1015 lowpriorityscore=0 suspectscore=0 impostorscore=0 phishscore=0 malwarescore=0 adultscore=0 spamscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601240060 Content-Type: text/plain; charset="utf-8" From: Abhishek Dubey This function is used by bpf_throw() to unwind the stack until frame of exception-boundary during BPF exception handling. This function is necessary to support BPF exceptions on PowerPC. Signed-off-by: Abhishek Dubey --- arch/powerpc/net/bpf_jit_comp64.c | 41 +++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_c= omp64.c index 18da5a866447..1bba068f2c4c 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -247,6 +247,47 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen= _context *ctx) bpf_jit_build_fentry_stubs(image, ctx); } =20 +/* + * arch_bpf_stack_walk() - BPF stack walker for PowerPC + * + * Based on arch_stack_walk() from stacktrace.c. + * PowerPC uses stack frames rather than stack pointers. See [1] for + * the equivalence between frame pointers and stack pointers. + * Additional reference at [2]. + * TODO: refactor with arch_stack_walk() + * + * [1]: https://lore.kernel.org/all/20200220115141.2707-1-mpe@ellerman.id.= au/ + * [2]: https://lore.kernel.org/bpf/20260122211854.5508-5-adubey@linux.ibm= .com/ + */ + +void arch_bpf_stack_walk(bool (*consume_fn)(void *, u64, u64, u64), void *= cookie) +{ + // callback processing always in current context + unsigned long sp =3D current_stack_frame(); + + for (;;) { + unsigned long *stack =3D (unsigned long *) sp; + unsigned long ip; + + if (!validate_sp(sp, current)) + return; + + ip =3D stack[STACK_FRAME_LR_SAVE]; + if (!ip) + break; + + /* + * consume_fn common code expects stack pointer in third + * argument. There is no sp in ppc64, rather pass frame + * pointer(named sp here). + */ + if (ip && !consume_fn(cookie, ip, sp, sp)) + break; + + sp =3D stack[0]; + } +} + int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_con= text *ctx, u64 func) { unsigned long func_addr =3D func ? ppc_function_entry((void *)func) : 0; --=20 2.48.1