From patchwork Wed Oct 18 18:03:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 13427678 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 73EBDC14F for ; Wed, 18 Oct 2023 18:04:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="o4Gd3PEo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E6031C433CA; Wed, 18 Oct 2023 18:04:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697652290; bh=Gr3wChi1HzP1riZzQDKuSdE7NGsTzmrRKTwTzNDyTcM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o4Gd3PEohw62jNd7jFrjuCvddr+Cpiww2vaBNqOn/Vzu2DGNLTUN5OmYmqyZXWnsa phgEwJ7VsQHSUTUcyJGld1B0jqFJ8hGKBoaIDA1+K8wtyF5Hy7gEXpthwkp3q7cyBq JCdGj+uCwNJE9xqdSLNR1fTmIzoSRX/Vrpa+wULDE3PY9pH47jJievd3NgWY1SpRfA jmLN1GA3k+u4MflQHp6PNik8uPJbZ1EtNZSJfdHLSDut/NUa2NpxAIHJe5kQ/BVi+4 N7lEEvPTo0apPJPeDP/nzeWXD4OSG7w3U9oQ1wLK/3z5jN4LgEaAUE2XUv5ijyIQxV zELoAQNZ2RsqQ== From: Song Liu To: bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@kernel.org, kernel-team@meta.com, Song Liu , Ilya Leoshkevich Subject: [PATCH v4 bpf-next 6/7] bpf: Use arch_bpf_trampoline_size Date: Wed, 18 Oct 2023 11:03:35 -0700 Message-Id: <20231018180336.1696131-7-song@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231018180336.1696131-1-song@kernel.org> References: <20231018180336.1696131-1-song@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 Instead of blindly allocating PAGE_SIZE for each trampoline, check the size of the trampoline with arch_bpf_trampoline_size(). This size is saved in bpf_tramp_image->size, and used for modmem charge/uncharge. The fallback arch_alloc_bpf_trampoline() still allocates a whole page because we need to use set_memory_* to protect the memory. struct_ops trampoline still uses a whole page for multiple trampolines. With this size check at caller (regular trampoline and struct_ops trampoline), remove arch_bpf_trampoline_size() from arch_prepare_bpf_trampoline() in archs. Signed-off-by: Song Liu Acked-by: Ilya Leoshkevich Tested-by: Ilya Leoshkevich # on s390x --- arch/arm64/net/bpf_jit_comp.c | 7 ----- arch/riscv/net/bpf_jit_comp64.c | 7 ----- include/linux/bpf.h | 1 + kernel/bpf/bpf_struct_ops.c | 7 +++++ kernel/bpf/trampoline.c | 49 +++++++++++++++++++++------------ 5 files changed, 39 insertions(+), 32 deletions(-) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index a6671253b7ed..8955da5c47cf 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -2079,13 +2079,6 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, if (nregs > 8) return -ENOTSUPP; - ret = arch_bpf_trampoline_size(m, flags, tlinks, func_addr); - if (ret < 0) - return ret; - - if (ret > ((long)image_end - (long)image)) - return -EFBIG; - jit_fill_hole(image, (unsigned int)(image_end - image)); ret = prepare_trampoline(&ctx, im, tlinks, func_addr, nregs, flags); diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 35747fafde57..58dc64dd94a8 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -1052,13 +1052,6 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, int ret; struct rv_jit_context ctx; - ret = arch_bpf_trampoline_size(im, m, flags, tlinks, func_addr); - if (ret < 0) - return ret; - - if (ret > (long)image_end - (long)image) - return -EFBIG; - ctx.ninsns = 0; /* * The bpf_int_jit_compile() uses a RW buffer (ctx.insns) to write the diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 2ed65b764aab..17bd3dbd2636 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1122,6 +1122,7 @@ enum bpf_tramp_prog_type { struct bpf_tramp_image { void *image; + int size; struct bpf_ksym ksym; struct percpu_ref pcref; void *ip_after_call; diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index e9e95879bce2..4d53c53fc5aa 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -355,6 +355,7 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, void *image, void *image_end) { u32 flags; + int size; tlinks[BPF_TRAMP_FENTRY].links[0] = link; tlinks[BPF_TRAMP_FENTRY].nr_links = 1; @@ -362,6 +363,12 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, * and it must be used alone. */ flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0; + + size = arch_bpf_trampoline_size(model, flags, tlinks, NULL); + if (size < 0) + return size; + if (size > (unsigned long)image_end - (unsigned long)image) + return -E2BIG; return arch_prepare_bpf_trampoline(NULL, image, image_end, model, flags, tlinks, NULL); } diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 285c5b7c1ea4..7c0535edab3f 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -254,8 +254,8 @@ bpf_trampoline_get_progs(const struct bpf_trampoline *tr, int *total, bool *ip_a static void bpf_tramp_image_free(struct bpf_tramp_image *im) { bpf_image_ksym_del(&im->ksym); - arch_free_bpf_trampoline(im->image, PAGE_SIZE); - bpf_jit_uncharge_modmem(PAGE_SIZE); + arch_free_bpf_trampoline(im->image, im->size); + bpf_jit_uncharge_modmem(im->size); percpu_ref_exit(&im->pcref); kfree_rcu(im, rcu); } @@ -349,7 +349,7 @@ static void bpf_tramp_image_put(struct bpf_tramp_image *im) call_rcu_tasks_trace(&im->rcu, __bpf_tramp_image_put_rcu_tasks); } -static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key) +static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key, int size) { struct bpf_tramp_image *im; struct bpf_ksym *ksym; @@ -360,12 +360,13 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key) if (!im) goto out; - err = bpf_jit_charge_modmem(PAGE_SIZE); + err = bpf_jit_charge_modmem(size); if (err) goto out_free_im; + im->size = size; err = -ENOMEM; - im->image = image = arch_alloc_bpf_trampoline(PAGE_SIZE); + im->image = image = arch_alloc_bpf_trampoline(size); if (!image) goto out_uncharge; @@ -380,9 +381,9 @@ static struct bpf_tramp_image *bpf_tramp_image_alloc(u64 key) return im; out_free_image: - arch_free_bpf_trampoline(im->image, PAGE_SIZE); + arch_free_bpf_trampoline(im->image, im->size); out_uncharge: - bpf_jit_uncharge_modmem(PAGE_SIZE); + bpf_jit_uncharge_modmem(size); out_free_im: kfree(im); out: @@ -395,7 +396,7 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut struct bpf_tramp_links *tlinks; u32 orig_flags = tr->flags; bool ip_arg = false; - int err, total; + int err, total, size; tlinks = bpf_trampoline_get_progs(tr, &total, &ip_arg); if (IS_ERR(tlinks)) @@ -408,12 +409,6 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut goto out; } - im = bpf_tramp_image_alloc(tr->key); - if (IS_ERR(im)) { - err = PTR_ERR(im); - goto out; - } - /* clear all bits except SHARE_IPMODIFY and TAIL_CALL_CTX */ tr->flags &= (BPF_TRAMP_F_SHARE_IPMODIFY | BPF_TRAMP_F_TAIL_CALL_CTX); @@ -437,13 +432,31 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut tr->flags |= BPF_TRAMP_F_ORIG_STACK; #endif - err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE, + size = arch_bpf_trampoline_size(&tr->func.model, tr->flags, + tlinks, tr->func.addr); + if (size < 0) { + err = size; + goto out; + } + + if (size > PAGE_SIZE) { + err = -E2BIG; + goto out; + } + + im = bpf_tramp_image_alloc(tr->key, size); + if (IS_ERR(im)) { + err = PTR_ERR(im); + goto out; + } + + err = arch_prepare_bpf_trampoline(im, im->image, im->image + size, &tr->func.model, tr->flags, tlinks, tr->func.addr); if (err < 0) goto out_free; - arch_protect_bpf_trampoline(im->image, PAGE_SIZE); + arch_protect_bpf_trampoline(im->image, im->size); WARN_ON(tr->cur_image && total == 0); if (tr->cur_image) @@ -463,8 +476,8 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr, bool lock_direct_mut tr->fops->func = NULL; tr->fops->trampoline = 0; - /* reset im->image memory attr for arch_prepare_bpf_trampoline */ - arch_unprotect_bpf_trampoline(im->image, PAGE_SIZE); + /* free im memory and reallocate later */ + bpf_tramp_image_free(im); goto again; } #endif