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(unknown [9.39.26.73]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 22 Jan 2026 16:58:15 +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 v3 3/6] powerpc64/bpf: Avoid tailcall restore from trampoline Date: Thu, 22 Jan 2026 22:27:13 +0530 Message-ID: <20260122165716.10508-4-adubey@linux.ibm.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20260122165716.10508-1-adubey@linux.ibm.com> References: <20260122165716.10508-1-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-Proofpoint-GUID: t4OPcj_KSlIM6V7E8PUYgG2ZL_nZEP63 X-Proofpoint-ORIG-GUID: QN6Ii6DuF_E3UNSJI3OAoqT1u_KfVhsN X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTIyMDEyOSBTYWx0ZWRfX1/DDTQchqi9a i+EJLlIK2yBjorfpJeqHFxnzCnZY8EAt2B4iv12mLQ0kbFpy2fy9i/7GJLpXjZVy7Xrg26rlv4W L2Og9qohokspZ+dUpq0lIc01YdLBb/bOw4Ud7lzIxZsb/DwN2YaEjiVB1hAQ7MG/WzNp6Wq2/HK aSk+w8Vb3HEnOUJoZdLxT762vJLLTK2qs29b6oT48048cVRn21shhqvup2okBx7/ZzONsU7kl/B bCmRfWVp836UiPapmGz8JvNVq6dtUqoAoY6apD6jWoHN5h2g+34SnV5TaDdgvGaH+JZz86Z1057 /GelDXVJmyQwZqnxIufm6sx7qX1YFZIj0D2S4cOZl0oZ5Mnpg06zEOn65gAlxY0JabHpK0en9I/ m+VFE9427okVIzTSWJbDk77kLi/xoqmjEkG9+TGIHYJ2FBrghyoLgm/egmN8wVhZ9l6/ObOXDtE AtPYuiVgkn9JFEHuxGg== X-Authority-Analysis: v=2.4 cv=bopBxUai c=1 sm=1 tr=0 ts=69725736 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=HXp8xpokhkwciMovXI8A:9 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=2026-01-22_03,2026-01-22_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 bulkscore=0 adultscore=0 suspectscore=0 impostorscore=0 phishscore=0 malwarescore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601220129 Content-Type: text/plain; charset="utf-8" From: Abhishek Dubey Back propagation of tailcall count is no longer needed for powerpc64 due to use of reference, which updates the tailcall count in the tail_call_info field in the frame of the main program only. Back propagation is still required for 32-bit powerpc. Signed-off-by: Abhishek Dubey --- arch/powerpc/net/bpf_jit_comp.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_com= p.c index f3ee031edc26..9a8236d161ef 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -662,16 +662,11 @@ static void bpf_trampoline_setup_tail_call_info(u32 *= image, struct codegen_conte static void bpf_trampoline_restore_tail_call_cnt(u32 *image, struct codege= n_context *ctx, int func_frame_offset, int r4_off) { - if (IS_ENABLED(CONFIG_PPC64)) { - /* See bpf_jit_stack_tailcallcnt() */ - int tailcallcnt_offset =3D 7 * 8; - - EMIT(PPC_RAW_LL(_R3, _R1, -tailcallcnt_offset)); - EMIT(PPC_RAW_STL(_R3, _R1, func_frame_offset - tailcallcnt_offset)); - } else { - /* See bpf_jit_stack_offsetof() and BPF_PPC_TC */ - EMIT(PPC_RAW_STL(_R4, _R1, r4_off)); - } + /* + * Restore tailcall for 32-bit ppc. + * See bpf_jit_stack_offsetof() and BPF_PPC_TC + */ + EMIT(PPC_RAW_STL(_R4, _R1, r4_off)); } =20 static void bpf_trampoline_save_args(u32 *image, struct codegen_context *c= tx, int func_frame_offset, --=20 2.48.1