From patchwork Thu Jan 27 18:09:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 537567 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 479A5C433EF for ; Thu, 27 Jan 2022 18:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239535AbiA0SLe (ORCPT ); Thu, 27 Jan 2022 13:11:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239257AbiA0SKw (ORCPT ); Thu, 27 Jan 2022 13:10:52 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EF0EC0613EF; Thu, 27 Jan 2022 10:10:51 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F1D6CB820C4; Thu, 27 Jan 2022 18:10:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21A9BC36AF9; Thu, 27 Jan 2022 18:10:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643307048; bh=+dh3RZOUBJys2eS26CJjaYdbREwEpfqi92Y7FfQ0FQM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Nh+2/YDHLaxyM13ysYtRycCKQw2lCj/QKoy2yrh1fFJTQ/x2i5lfWwHQqH8nNHMhj FOKEiTB2kW29GhPL+PpgYzIaDVFdhXt3ZqoUqpMan/X3Il+xkJs46q17Grtbw4U0Db cbR1XLj5WgcUleMl7ZzPoIht43f36ktGXCQNzQ0s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ard Biesheuvel , Russell King , Daniel Borkmann , Alan Maguire , Tom Saeger Subject: [PATCH 5.15 12/12] arm64/bpf: Remove 128MB limit for BPF JIT programs Date: Thu, 27 Jan 2022 19:09:36 +0100 Message-Id: <20220127180259.497850764@linuxfoundation.org> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20220127180259.078563735@linuxfoundation.org> References: <20220127180259.078563735@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Russell King commit b89ddf4cca43f1269093942cf5c4e457fd45c335 upstream. Commit 91fc957c9b1d ("arm64/bpf: don't allocate BPF JIT programs in module memory") restricts BPF JIT program allocation to a 128MB region to ensure BPF programs are still in branching range of each other. However this restriction should not apply to the aarch64 JIT, since BPF_JMP | BPF_CALL are implemented as a 64-bit move into a register and then a BLR instruction - which has the effect of being able to call anything without proximity limitation. The practical reason to relax this restriction on JIT memory is that 128MB of JIT memory can be quickly exhausted, especially where PAGE_SIZE is 64KB - one page is needed per program. In cases where seccomp filters are applied to multiple VMs on VM launch - such filters are classic BPF but converted to BPF - this can severely limit the number of VMs that can be launched. In a world where we support BPF JIT always on, turning off the JIT isn't always an option either. Fixes: 91fc957c9b1d ("arm64/bpf: don't allocate BPF JIT programs in module memory") Suggested-by: Ard Biesheuvel Signed-off-by: Russell King Signed-off-by: Daniel Borkmann Tested-by: Alan Maguire Link: https://lore.kernel.org/bpf/1636131046-5982-2-git-send-email-alan.maguire@oracle.com Reviewed-by: Tom Saeger Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/extable.h | 9 --------- arch/arm64/include/asm/memory.h | 5 +---- arch/arm64/kernel/traps.c | 2 +- arch/arm64/mm/extable.c | 13 +++++++++---- arch/arm64/mm/ptdump.c | 2 -- arch/arm64/net/bpf_jit_comp.c | 7 ++----- 6 files changed, 13 insertions(+), 25 deletions(-) --- a/arch/arm64/include/asm/extable.h +++ b/arch/arm64/include/asm/extable.h @@ -22,15 +22,6 @@ struct exception_table_entry #define ARCH_HAS_RELATIVE_EXTABLE -static inline bool in_bpf_jit(struct pt_regs *regs) -{ - if (!IS_ENABLED(CONFIG_BPF_JIT)) - return false; - - return regs->pc >= BPF_JIT_REGION_START && - regs->pc < BPF_JIT_REGION_END; -} - #ifdef CONFIG_BPF_JIT int arm64_bpf_fixup_exception(const struct exception_table_entry *ex, struct pt_regs *regs); --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -44,11 +44,8 @@ #define _PAGE_OFFSET(va) (-(UL(1) << (va))) #define PAGE_OFFSET (_PAGE_OFFSET(VA_BITS)) #define KIMAGE_VADDR (MODULES_END) -#define BPF_JIT_REGION_START (_PAGE_END(VA_BITS_MIN)) -#define BPF_JIT_REGION_SIZE (SZ_128M) -#define BPF_JIT_REGION_END (BPF_JIT_REGION_START + BPF_JIT_REGION_SIZE) #define MODULES_END (MODULES_VADDR + MODULES_VSIZE) -#define MODULES_VADDR (BPF_JIT_REGION_END) +#define MODULES_VADDR (_PAGE_END(VA_BITS_MIN)) #define MODULES_VSIZE (SZ_128M) #define VMEMMAP_START (-(UL(1) << (VA_BITS - VMEMMAP_SHIFT))) #define VMEMMAP_END (VMEMMAP_START + VMEMMAP_SIZE) --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -988,7 +988,7 @@ static struct break_hook bug_break_hook static int reserved_fault_handler(struct pt_regs *regs, unsigned int esr) { pr_err("%s generated an invalid instruction at %pS!\n", - in_bpf_jit(regs) ? "BPF JIT" : "Kernel text patching", + "Kernel text patching", (void *)instruction_pointer(regs)); /* We cannot handle this */ --- a/arch/arm64/mm/extable.c +++ b/arch/arm64/mm/extable.c @@ -9,14 +9,19 @@ int fixup_exception(struct pt_regs *regs) { const struct exception_table_entry *fixup; + unsigned long addr; - fixup = search_exception_tables(instruction_pointer(regs)); - if (!fixup) - return 0; + addr = instruction_pointer(regs); - if (in_bpf_jit(regs)) + /* Search the BPF tables first, these are formatted differently */ + fixup = search_bpf_extables(addr); + if (fixup) return arm64_bpf_fixup_exception(fixup, regs); + fixup = search_exception_tables(addr); + if (!fixup) + return 0; + regs->pc = (unsigned long)&fixup->fixup + fixup->fixup; return 1; } --- a/arch/arm64/mm/ptdump.c +++ b/arch/arm64/mm/ptdump.c @@ -41,8 +41,6 @@ static struct addr_marker address_marker { 0 /* KASAN_SHADOW_START */, "Kasan shadow start" }, { KASAN_SHADOW_END, "Kasan shadow end" }, #endif - { BPF_JIT_REGION_START, "BPF start" }, - { BPF_JIT_REGION_END, "BPF end" }, { MODULES_VADDR, "Modules start" }, { MODULES_END, "Modules end" }, { VMALLOC_START, "vmalloc() area" }, --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -1138,15 +1138,12 @@ out: u64 bpf_jit_alloc_exec_limit(void) { - return BPF_JIT_REGION_SIZE; + return VMALLOC_END - VMALLOC_START; } void *bpf_jit_alloc_exec(unsigned long size) { - return __vmalloc_node_range(size, PAGE_SIZE, BPF_JIT_REGION_START, - BPF_JIT_REGION_END, GFP_KERNEL, - PAGE_KERNEL, 0, NUMA_NO_NODE, - __builtin_return_address(0)); + return vmalloc(size); } void bpf_jit_free_exec(void *addr)