From patchwork Thu May 2 17:32:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 13651937 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 A7B7728FC; Thu, 2 May 2024 17:32:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714671176; cv=none; b=KZpgOINhvIQ5cq0LtE3yjQ3FluysqfcGZtK/blqlbPfPZbf5ksDLMftbSLwNjipjPvmZtP53+ujP8z1CdhNylWkL5vBTqv5XWCMpsbyKQdJBpxS61RR14TYFvnIDc75nBnYAwvoW00phk6aVldG3ppAbcxzLpAxBPYtA2nz7K00= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714671176; c=relaxed/simple; bh=LaCvykQvdmUOuzSwHmR3Avj+B1lxgk4vwyJwgGxaceo=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=rLUF6hQlX/iKdjM+PKXdV3+t566PWuEsVz1JKBPX4XJGpVQilnALJZ6pKiEKWEUwqTOsxJ62oUh9FH9z6wSAuZvZVGB8NFrZyVEktf6lFGRwVwKuz7TPoN+fOPAQkqif+pq6TWV5Cl5v+LFQT6itwoveQEJ75/BLt653VJXpqy8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com; spf=pass smtp.mailfrom=linux.ibm.com; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b=GBt2AHgZ; arc=none smtp.client-ip=148.163.156.1 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="GBt2AHgZ" Received: from pps.filterd (m0353729.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 442HRCti021266; Thu, 2 May 2024 17:32:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=JIL5lk6UNm+SMBzpIAyATQq6e3XKM7ByRDdvdp+Nd6U=; b=GBt2AHgZy2ljW+aV4fCT/SgKow/iYqbWiusf4yRCqk/Z4b4nlO8dYhquVDp2Kds8FLqn CI76xWPfVSd1WjGyzfNoXMejjii3/iZKJiFIqeFoZTbtzbSFKRbDiQ/ck90jIzGmZcKa gCliM7lhw6sIPDVCDCXuvTD/h81CIb4AeJay//Mm3A7OUvqgcB+FXvux/SWixZ1iBACe W0laFeQTPR5RaLdUh6jvHZMBBSyB8+bfHatBk4qsHEEQB4bc983z8FunJmWHc6A6l7k+ TeaOTLUoESXpR9NHXNdE7hlvvqDKEyHjLVQSa8nM2O5WfsWneNGpV77Hssfc2qkkU3fm Sw== 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 3xvf87r0eb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 May 2024 17:32:14 +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 442EsJdi027556; Thu, 2 May 2024 17:32:13 GMT Received: from smtprelay03.fra02v.mail.ibm.com ([9.218.2.224]) by ppma22.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3xsc30sc95-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 02 May 2024 17:32:13 +0000 Received: from smtpav07.fra02v.mail.ibm.com (smtpav07.fra02v.mail.ibm.com [10.20.54.106]) by smtprelay03.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 442HW9wO30605740 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 2 May 2024 17:32:11 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A65BF20065; Thu, 2 May 2024 17:32:09 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E144F2004D; Thu, 2 May 2024 17:32:06 +0000 (GMT) Received: from li-bd3f974c-2712-11b2-a85c-df1cec4d728e.ibm.com.com (unknown [9.43.113.195]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 2 May 2024 17:32:06 +0000 (GMT) From: Hari Bathini To: linuxppc-dev , bpf@vger.kernel.org Cc: Song Liu , Daniel Borkmann , Alexei Starovoitov , Andrii Nakryiko , "Naveen N. Rao" , Christophe Leroy , Martin KaFai Lau , stable@vger.kernel.org Subject: [PATCH v4 1/2] powerpc64/bpf: fix tail calls for PCREL addressing Date: Thu, 2 May 2024 23:02:04 +0530 Message-ID: <20240502173205.142794-1-hbathini@linux.ibm.com> X-Mailer: git-send-email 2.44.0 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: jYrSV768ZNXbY9FSJdfTlD6fTHVxz4kW X-Proofpoint-GUID: jYrSV768ZNXbY9FSJdfTlD6fTHVxz4kW X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1011,Hydra:6.0.650,FMLib:17.11.176.26 definitions=2024-05-02_09,2024-05-02_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 clxscore=1011 impostorscore=0 spamscore=0 bulkscore=0 mlxscore=0 adultscore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2404010000 definitions=main-2405020115 X-Patchwork-Delegate: bpf@iogearbox.net With PCREL addressing, there is no kernel TOC. So, it is not setup in prologue when PCREL addressing is used. But the number of instructions to skip on a tail call was not adjusted accordingly. That resulted in not so obvious failures while using tailcalls. 'tailcalls' selftest crashed the system with the below call trace: bpf_test_run+0xe8/0x3cc (unreliable) bpf_prog_test_run_skb+0x348/0x778 __sys_bpf+0xb04/0x2b00 sys_bpf+0x28/0x38 system_call_exception+0x168/0x340 system_call_vectored_common+0x15c/0x2ec Also, as bpf programs are always module addresses and a bpf helper in general is a core kernel text address, using PC relative addressing often fails with "out of range of pcrel address" error. Switch to using kernel base for relative addressing to handle this better. Fixes: 7e3a68be42e1 ("powerpc/64: vmlinux support building with PCREL addresing") Cc: stable@vger.kernel.org Signed-off-by: Hari Bathini Reviewed-by: Naveen N Rao --- * Changes in v4: - Fix out of range errors by switching to kernelbase instead of PC for relative addressing. * Changes in v3: - New patch to fix tailcall issues with PCREL addressing. arch/powerpc/net/bpf_jit_comp64.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 79f23974a320..4de08e35e284 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -202,7 +202,8 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) EMIT(PPC_RAW_BLR()); } -static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u64 func) +static int +bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func) { unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0; long reladdr; @@ -211,19 +212,20 @@ static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u return -EINVAL; if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { - reladdr = func_addr - CTX_NIA(ctx); + reladdr = func_addr - local_paca->kernelbase; if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) { - pr_err("eBPF: address of %ps out of range of pcrel address.\n", - (void *)func); + pr_err("eBPF: address of %ps out of range of 34-bit relative address.\n", + (void *)func); return -ERANGE; } - /* pla r12,addr */ - EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(1) | IMM_H18(reladdr)); - EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | IMM_L(reladdr)); - EMIT(PPC_RAW_MTCTR(_R12)); - EMIT(PPC_RAW_BCTR()); - + EMIT(PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase))); + /* Align for subsequent prefix instruction */ + if (!IS_ALIGNED((unsigned long)fimage + CTX_NIA(ctx), 8)) + EMIT(PPC_RAW_NOP()); + /* paddi r12,r12,addr */ + EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(0) | IMM_H18(reladdr)); + EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12) | IMM_L(reladdr)); } else { reladdr = func_addr - kernel_toc_addr(); if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { @@ -233,9 +235,9 @@ static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u EMIT(PPC_RAW_ADDIS(_R12, _R2, PPC_HA(reladdr))); EMIT(PPC_RAW_ADDI(_R12, _R12, PPC_LO(reladdr))); - EMIT(PPC_RAW_MTCTR(_R12)); - EMIT(PPC_RAW_BCTRL()); } + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); return 0; } @@ -285,7 +287,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o int b2p_index = bpf_to_ppc(BPF_REG_3); int bpf_tailcall_prologue_size = 8; - if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) + if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL) && IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2)) bpf_tailcall_prologue_size += 4; /* skip past the toc load */ /* @@ -993,7 +995,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code return ret; if (func_addr_fixed) - ret = bpf_jit_emit_func_call_hlp(image, ctx, func_addr); + ret = bpf_jit_emit_func_call_hlp(image, fimage, ctx, func_addr); else ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr); From patchwork Thu May 2 17:32:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hari Bathini X-Patchwork-Id: 13651938 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (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 A7BCD16FF3D for ; Thu, 2 May 2024 17:32:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.163.156.1 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714671176; cv=none; b=V28mxD/TPvW577lAbnTcfQqJHHAE0t/z2egDYtyGhLn/K6/24nrZmxvi9lhb9n9ywyefP0fFbQ9fW6MSLCl9FHC0PmGbcGmWeRKGeMM/WBSkC146lWRZXh4J9Qn4KR7acfMcoBKzm3O9KeCRrmKwIDqMlQl7pGbGTgTT0orVFXI= ARC-Message-Signature: i=1; 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Rao" , Christophe Leroy , Martin KaFai Lau Subject: [PATCH v4 2/2] powerpc/bpf: enable kfunc call Date: Thu, 2 May 2024 23:02:05 +0530 Message-ID: <20240502173205.142794-2-hbathini@linux.ibm.com> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240502173205.142794-1-hbathini@linux.ibm.com> References: <20240502173205.142794-1-hbathini@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-GUID: Agu0v6p1xyuZw_1Xp9VVo3N1RZK4b-SM X-Proofpoint-ORIG-GUID: Agu0v6p1xyuZw_1Xp9VVo3N1RZK4b-SM X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1011,Hydra:6.0.650,FMLib:17.11.176.26 definitions=2024-05-02_09,2024-05-02_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 bulkscore=0 phishscore=0 priorityscore=1501 mlxscore=0 spamscore=0 impostorscore=0 clxscore=1015 mlxlogscore=999 adultscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2404010000 definitions=main-2405020115 X-Patchwork-Delegate: bpf@iogearbox.net Currently, bpf jit code on powerpc assumes all the bpf functions and helpers to be part of core kernel text. This is false for kfunc case, as function addresses may not be part of core kernel text area. So, add support for addresses that are not within core kernel text area too, to enable kfunc support. Emit instructions based on whether the function address is within core kernel text address or not, to retain optimized instruction sequence where possible. In case of PCREL, as a bpf function that is not within core kernel text area is likely to go out of range with relative addressing on kernel base, use PC relative addressing. If that goes out of range, load the full address with PPC_LI64(). With addresses that are not within core kernel text area supported, override bpf_jit_supports_kfunc_call() to enable kfunc support. Also, override bpf_jit_supports_far_kfunc_call() to enable 64-bit pointers, as an address offset can be more than 32-bit long on PPC64. Signed-off-by: Hari Bathini Reviewed-by: Naveen N Rao --- * Changes in v4: - Use either kernelbase or PC for relative addressing. Also, fallback to PPC_LI64(), if both are out of range. - Update r2 with kernel TOC for elfv1 too as elfv1 also uses the optimization sequence, that expects r2 to be kernel TOC, when function address is within core kernel text. * Changes in v3: - Retained optimized instruction sequence when function address is a core kernel address as suggested by Naveen. - Used unoptimized instruction sequence for PCREL addressing to avoid out of range errors for core kernel function addresses. - Folded patch that adds support for kfunc calls with patch that enables/advertises this support as suggested by Naveen. arch/powerpc/net/bpf_jit_comp.c | 10 +++++ arch/powerpc/net/bpf_jit_comp64.c | 61 ++++++++++++++++++++++++++----- 2 files changed, 61 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 0f9a21783329..984655419da5 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -359,3 +359,13 @@ void bpf_jit_free(struct bpf_prog *fp) bpf_prog_unlock_free(fp); } + +bool bpf_jit_supports_kfunc_call(void) +{ + return true; +} + +bool bpf_jit_supports_far_kfunc_call(void) +{ + return IS_ENABLED(CONFIG_PPC64); +} diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 4de08e35e284..8afc14a4a125 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -208,17 +208,13 @@ bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0; long reladdr; - if (WARN_ON_ONCE(!core_kernel_text(func_addr))) + if (WARN_ON_ONCE(!kernel_text_address(func_addr))) return -EINVAL; - if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) { - reladdr = func_addr - local_paca->kernelbase; +#ifdef CONFIG_PPC_KERNEL_PCREL + reladdr = func_addr - local_paca->kernelbase; - if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) { - pr_err("eBPF: address of %ps out of range of 34-bit relative address.\n", - (void *)func); - return -ERANGE; - } + if (reladdr < (long)SZ_8G && reladdr >= -(long)SZ_8G) { EMIT(PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase))); /* Align for subsequent prefix instruction */ if (!IS_ALIGNED((unsigned long)fimage + CTX_NIA(ctx), 8)) @@ -227,6 +223,26 @@ bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(0) | IMM_H18(reladdr)); EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12) | IMM_L(reladdr)); } else { + unsigned long pc = (unsigned long)fimage + CTX_NIA(ctx); + bool alignment_needed = !IS_ALIGNED(pc, 8); + + reladdr = func_addr - (alignment_needed ? pc + 4 : pc); + + if (reladdr < (long)SZ_8G && reladdr >= -(long)SZ_8G) { + if (alignment_needed) + EMIT(PPC_RAW_NOP()); + /* pla r12,addr */ + EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(1) | IMM_H18(reladdr)); + EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | IMM_L(reladdr)); + } else { + /* We can clobber r12 */ + PPC_LI64(_R12, func); + } + } + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); +#else + if (core_kernel_text(func_addr)) { reladdr = func_addr - kernel_toc_addr(); if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { pr_err("eBPF: address of %ps out of range of kernel_toc.\n", (void *)func); @@ -235,9 +251,34 @@ bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, EMIT(PPC_RAW_ADDIS(_R12, _R2, PPC_HA(reladdr))); EMIT(PPC_RAW_ADDI(_R12, _R12, PPC_LO(reladdr))); + EMIT(PPC_RAW_MTCTR(_R12)); + EMIT(PPC_RAW_BCTRL()); + } else { + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1)) { + /* func points to the function descriptor */ + PPC_LI64(bpf_to_ppc(TMP_REG_2), func); + /* Load actual entry point from function descriptor */ + EMIT(PPC_RAW_LD(bpf_to_ppc(TMP_REG_1), bpf_to_ppc(TMP_REG_2), 0)); + /* ... and move it to CTR */ + EMIT(PPC_RAW_MTCTR(bpf_to_ppc(TMP_REG_1))); + /* + * Load TOC from function descriptor at offset 8. + * We can clobber r2 since we get called through a + * function pointer (so caller will save/restore r2). + */ + EMIT(PPC_RAW_LD(_R2, bpf_to_ppc(TMP_REG_2), 8)); + } else { + PPC_LI64(_R12, func); + EMIT(PPC_RAW_MTCTR(_R12)); + } + EMIT(PPC_RAW_BCTRL()); + /* + * Load r2 with kernel TOC as kernel TOC is used if function address falls + * within core kernel text. + */ + EMIT(PPC_RAW_LD(_R2, _R13, offsetof(struct paca_struct, kernel_toc))); } - EMIT(PPC_RAW_MTCTR(_R12)); - EMIT(PPC_RAW_BCTRL()); +#endif return 0; }