From patchwork Fri Apr 26 12:13:48 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Puranjay Mohan X-Patchwork-Id: 13644687 X-Patchwork-Delegate: bpf@iogearbox.net Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CA0D6145FE1; Fri, 26 Apr 2024 12:14:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714133644; cv=none; b=F99mLYfEpi/JBvBDxbyXjQZxz/HxB0u4b7wg86YgAqJmxJkvKwGN/loo9zFMte6hTE3dApEgr1WT5VAR+Qbq1YYBalsdJmmBah4GQVmI1cAYBBgpyRIao75abhc8ndzsuC6PG4+CI/+zVFYS32bs8kw9hGZtfBMc2f5Xt3Plpn4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714133644; c=relaxed/simple; bh=TbPOTBmS82ynsL8h5jbyPu2ZW+Geh2onSqdzZPRv0KM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=GWd2Koj21Dz+KF+pXLo4lowr4K9ingSNvKWvVGWHKCBKV5SB+yXYyL1s0hY6UjrK8q5XrRwHFBhY1R4ELkRZdFrwH48WA04TPqgoHkxoJQrN4QSV//ZG4kUCsryMkAnnroRfodS6UI/1jFMOa1Q2lgEulfSEo1duADaLtwfhFig= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=misLKGhS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="misLKGhS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF1E2C116B1; Fri, 26 Apr 2024 12:14:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1714133644; bh=TbPOTBmS82ynsL8h5jbyPu2ZW+Geh2onSqdzZPRv0KM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=misLKGhSz7D7/HB5koSgsOhfKKRCFUwuQxfqLAwA3MPbiSCJqYBbBSrqKb6jOh3Fv wkcr/1yw7TSMrfNKB0p8PM/0n1aDwNWjTJZ2UjFJ0on1enlEJDKC+0lMpV6bQqrkPh e+A8DyPrDkIeWOO4Cl80IpKa+INEtNApt5ARjZeNgDeOpsC0BB3SvpPaJM1dkUWYfd 0CPJmksC2w3YRvebNajBPYSZhMdC6K6vVAwHp824DjgO9QdyjuWzmHAtf+XXEOXFcq KI+Vm5+D5dvy8jY7P733NXd4qyfY9WCnKGTicPP7yFHqRpJV7PoqFC/B/6AKpspZ4I pkhHN79NlkOAQ== From: Puranjay Mohan To: Catalin Marinas , Will Deacon , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Zi Shen Lim , Xu Kuohai , Florent Revest , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Cc: puranjay12@gmail.com Subject: [PATCH bpf-next v3 1/2] arm64, bpf: add internal-only MOV instruction to resolve per-CPU addrs Date: Fri, 26 Apr 2024 12:13:48 +0000 Message-Id: <20240426121349.97651-2-puranjay@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20240426121349.97651-1-puranjay@kernel.org> References: <20240426121349.97651-1-puranjay@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Puranjay Mohan Support an instruction for resolving absolute addresses of per-CPU data from their per-CPU offsets. This instruction is internal-only and users are not allowed to use them directly. They will only be used for internal inlining optimizations for now between BPF verifier and BPF JITs. Since commit 7158627686f0 ("arm64: percpu: implement optimised pcpu access using tpidr_el1"), the per-cpu offset for the CPU is stored in the tpidr_el1/2 register of that CPU. To support this BPF instruction in the ARM64 JIT, the following ARM64 instructions are emitted: mov dst, src // Move src to dst, if src != dst mrs tmp, tpidr_el1/2 // Move per-cpu offset of the current cpu in tmp. add dst, dst, tmp // Add the per cpu offset to the dst. To measure the performance improvement provided by this change, the benchmark in [1] was used: Before: glob-arr-inc : 23.597 ± 0.012M/s arr-inc : 23.173 ± 0.019M/s hash-inc : 12.186 ± 0.028M/s After: glob-arr-inc : 23.819 ± 0.034M/s arr-inc : 23.285 ± 0.017M/s hash-inc : 12.419 ± 0.011M/s [1] https://github.com/anakryiko/linux/commit/8dec900975ef Signed-off-by: Puranjay Mohan Acked-by: Andrii Nakryiko --- arch/arm64/include/asm/insn.h | 7 +++++++ arch/arm64/lib/insn.c | 11 +++++++++++ arch/arm64/net/bpf_jit.h | 6 ++++++ arch/arm64/net/bpf_jit_comp.c | 14 ++++++++++++++ 4 files changed, 38 insertions(+) diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index db1aeacd4cd9..8de0e39b29f3 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -135,6 +135,11 @@ enum aarch64_insn_special_register { AARCH64_INSN_SPCLREG_SP_EL2 = 0xF210 }; +enum aarch64_insn_system_register { + AARCH64_INSN_SYSREG_TPIDR_EL1 = 0x4684, + AARCH64_INSN_SYSREG_TPIDR_EL2 = 0x6682, +}; + enum aarch64_insn_variant { AARCH64_INSN_VARIANT_32BIT, AARCH64_INSN_VARIANT_64BIT @@ -686,6 +691,8 @@ u32 aarch64_insn_gen_cas(enum aarch64_insn_register result, } #endif u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type); +u32 aarch64_insn_gen_mrs(enum aarch64_insn_register result, + enum aarch64_insn_system_register sysreg); s32 aarch64_get_branch_offset(u32 insn); u32 aarch64_set_branch_offset(u32 insn, s32 offset); diff --git a/arch/arm64/lib/insn.c b/arch/arm64/lib/insn.c index a635ab83fee3..b008a9b46a7f 100644 --- a/arch/arm64/lib/insn.c +++ b/arch/arm64/lib/insn.c @@ -1515,3 +1515,14 @@ u32 aarch64_insn_gen_dmb(enum aarch64_insn_mb_type type) return insn; } + +u32 aarch64_insn_gen_mrs(enum aarch64_insn_register result, + enum aarch64_insn_system_register sysreg) +{ + u32 insn = aarch64_insn_get_mrs_value(); + + insn &= ~GENMASK(19, 0); + insn |= sysreg << 5; + return aarch64_insn_encode_register(AARCH64_INSN_REGTYPE_RT, + insn, result); +} diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h index 23b1b34db088..b627ef7188c7 100644 --- a/arch/arm64/net/bpf_jit.h +++ b/arch/arm64/net/bpf_jit.h @@ -297,4 +297,10 @@ #define A64_ADR(Rd, offset) \ aarch64_insn_gen_adr(0, offset, Rd, AARCH64_INSN_ADR_TYPE_ADR) +/* MRS */ +#define A64_MRS_TPIDR_EL1(Rt) \ + aarch64_insn_gen_mrs(Rt, AARCH64_INSN_SYSREG_TPIDR_EL1) +#define A64_MRS_TPIDR_EL2(Rt) \ + aarch64_insn_gen_mrs(Rt, AARCH64_INSN_SYSREG_TPIDR_EL2) + #endif /* _BPF_JIT_H */ diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 76b91f36c729..ed8f9716d9d5 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -877,6 +877,15 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, emit(A64_ORR(1, tmp, dst, tmp), ctx); emit(A64_MOV(1, dst, tmp), ctx); break; + } else if (insn_is_mov_percpu_addr(insn)) { + if (dst != src) + emit(A64_MOV(1, dst, src), ctx); + if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN)) + emit(A64_MRS_TPIDR_EL2(tmp), ctx); + else + emit(A64_MRS_TPIDR_EL1(tmp), ctx); + emit(A64_ADD(1, dst, dst, tmp), ctx); + break; } switch (insn->off) { case 0: @@ -2527,6 +2536,11 @@ bool bpf_jit_supports_arena(void) return true; } +bool bpf_jit_supports_percpu_insn(void) +{ + return true; +} + void bpf_jit_free(struct bpf_prog *prog) { if (prog->jited) {