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Tue, 18 Aug 2026 04:44:28 +0000 (GMT) Received: from li-1cb9f04c-2ae1-11b2-a85c-a8a0a83790a8.ibm.com.com (unknown [9.39.17.69]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 18 Aug 2026 04:44:28 +0000 (GMT) From: Saket Kumar Bhaskar To: bpf@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: hbathini@linux.ibm.com, maddy@linux.ibm.com, ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net, shuah@kernel.org, linux-kselftest@vger.kernel.org, stable@vger.kernel.org, venkat88@linux.ibm.com, yeswanth@linux.ibm.com, skb99@linux.ibm.com Subject: [PATCH v12 4/8] powerpc64/bpf: fix compare instruction emitted for tailcall Date: Tue, 18 Aug 2026 10:13:37 +0530 Message-ID: <25eadeff8698eae0fb2ce9e6bc323d3e0876fcd8.1787027080.git.skb99@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE4MDAzMSBTYWx0ZWRfXw1c2d0kIR1/d C4PWggmXXs17jiZ0XvRJf2a1DUBg9c8JvCRGJpkekGeHuVEOzRGsnGDWOnAkcx3AmhQvDsLc7jy EJXacWlf4bjXYvY3mg8f21s3c+vErdDm/3Mfw4GcIbxJNjKRRMLXTwD7hoCNIzhX17GhdYbJtXY aVz1NcQQKJ+umOnHvFw1MyaEdEfU8yCtm2CjfgRf2kFC1tkjxqGDwboeiaiG7TXTKRYaQ/TmypL 9BKxwrNqJYz3LW7NaKOowdYHGJWm9PMvOyQdKEJ12VSws4GBNtrsPuClY+QcsT4hWlj2bRIEavx 5uDjQqdfwMRfY0UnFGvGKoN2b3NHMtBh0o3J0m8COtLvBP4uSnDGQD4Tqx6F056gecUTBnmPLYI go0WwdrPT7N5r8gcuF8bELtOfN2sGrTjRtrI4gkOj/stfTgEjLGXgIq3l7gbFLqKOIRaMjrGgOt gQ5fo9xwSRsOqkdafIQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwODE4MDAzMSBTYWx0ZWRfXxwmFnb1hozqf JRitTtpIYAwPjARMhRg1Cu+UQZpbqln81LpQI5JgdUGkkdKtlZRwenV1dsCNffPbayaQvHF0245 xESyf5yzo6ZnkHvJmYg8XINJjPC6z+U= X-Authority-Analysis: v=2.4 cv=JKkLdcKb c=1 sm=1 tr=0 ts=6a83e337 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=_ChPpPKTfPU_lHkPiKQA:9 X-Proofpoint-ORIG-GUID: aLsGWgYVyTDJaMb8XlUSjLx5-YowwcQl X-Proofpoint-GUID: aLsGWgYVyTDJaMb8XlUSjLx5-YowwcQl X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-17_04,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1015 adultscore=0 impostorscore=0 spamscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608180031 From: Abhishek Dubey The tail_call_info field can contain either a scalar counter value or a 64-bit pointer to the counter, using a 32-bit compare (cmplwi) only checks the lower 32 bits, which can lead to incorrect comparisions when location of counter is near 4GB boundary. Use instruction cmpldi/cmplwi for accurate comparision in corresponding cases. Reported-by: sashiko-bot@kernel.org Closes: https://lore.kernel.org/bpf/20260517191450.85AE6C2BCB8@smtp.kernel.org/ Fixes: 2ed2d8f6fb38 ("powerpc64/bpf: Support tailcalls with subprogs") Signed-off-by: Abhishek Dubey Signed-off-by: Saket Kumar Bhaskar Tested-by: Yeswanth Krishna Tellakula Acked-by: Hari Bathini --- arch/powerpc/net/bpf_jit.h | 6 ++++++ arch/powerpc/net/bpf_jit_comp.c | 2 +- arch/powerpc/net/bpf_jit_comp64.c | 8 ++++---- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/net/bpf_jit.h b/arch/powerpc/net/bpf_jit.h index 44fa414dc5a7..4da8bde92e1e 100644 --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -195,6 +195,12 @@ struct codegen_context { #define bpf_to_ppc(r) (ctx->b2p[r]) +#ifdef CONFIG_PPC64 +#define PPC_RAW_CMPLLI(a, i) PPC_RAW_CMPLDI(a, i) +#else +#define PPC_RAW_CMPLLI(a, i) PPC_RAW_CMPLWI(a, i) +#endif + #ifdef CONFIG_PPC32 #define BPF_FIXUP_LEN 3 /* Three instructions => 12 bytes */ #else diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 870cbffdbb93..38acef44c097 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -786,7 +786,7 @@ static void bpf_trampoline_setup_tail_call_info(u32 *image, struct codegen_conte * Setting the tail_call_info in trampoline's frame * depending on if previous frame had value or reference. */ - EMIT(PPC_RAW_CMPLWI(_R3, MAX_TAIL_CALL_CNT)); + EMIT(PPC_RAW_CMPLLI(_R3, MAX_TAIL_CALL_CNT)); PPC_BCC_CONST_SHORT(COND_GT, 8); EMIT(PPC_RAW_ADDI(_R3, _R4, -BPF_PPC_TAILCALL)); diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 951eb10ca1f6..e80312171aa7 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -276,7 +276,7 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx) */ EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_2), _R1, 0)); EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_1), bpf_to_ppc(TMP_REG_2), -(BPF_PPC_TAILCALL))); - EMIT(PPC_RAW_CMPLWI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); + EMIT(PPC_RAW_CMPLDI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); PPC_BCC_CONST_SHORT(COND_GT, 8); EMIT(PPC_RAW_ADDI(bpf_to_ppc(TMP_REG_1), bpf_to_ppc(TMP_REG_2), -(BPF_PPC_TAILCALL))); @@ -662,7 +662,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o PPC_BCC_SHORT(COND_GE, out); EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_1), _R1, bpf_jit_stack_tailcallinfo_offset(ctx))); - EMIT(PPC_RAW_CMPLWI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); + EMIT(PPC_RAW_CMPLDI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); PPC_BCC_CONST_SHORT(COND_LE, 8); /* dereference TMP_REG_1 */ @@ -672,7 +672,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o * if (tail_call_info == MAX_TAIL_CALL_CNT) * goto out; */ - EMIT(PPC_RAW_CMPLWI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); + EMIT(PPC_RAW_CMPLDI(bpf_to_ppc(TMP_REG_1), MAX_TAIL_CALL_CNT)); PPC_BCC_SHORT(COND_EQ, out); /* @@ -707,7 +707,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o * tail_call_info. */ EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_2), _R1, bpf_jit_stack_tailcallinfo_offset(ctx))); - EMIT(PPC_RAW_CMPLWI(bpf_to_ppc(TMP_REG_2), MAX_TAIL_CALL_CNT)); + EMIT(PPC_RAW_CMPLDI(bpf_to_ppc(TMP_REG_2), MAX_TAIL_CALL_CNT)); PPC_BCC_CONST_SHORT(COND_GT, 8); /* First get address of tail_call_info */ -- 2.55.0