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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=jc0VYpbbwwHp06Vd4b4APbV9LFmrdZq9B0FcghhcNas=; b=X/Hl1VY83Zb4RouQ1U8J8zALOIsAhcidCMXDKYGXywgCDGavDjUJ68fd05zv9BxVy1 Rpip98NEoxCfV93c1ke6c784gFIo4bSdDjVyqTpKgfXG3+QvRWhfslS8bkzmMwxgBMZE nbw1Ph5mGySbvGW1Amr0L6jPue3QFsgejfBOWHxlHNDfKFcioTy/XcsXn6Hu1nnc/Jk/ eYQyhua9KLYoc2XcIW2C1wxw1eokhY0ljyYW0KExEUqvph+cNBkcV745guHmKf5vhz4s zPBBblxKVX7wmCb9CjjMmUlENL0tSJJNVGVNNlt3RMR5zPekcGLeDeoW/dpffMVLTFde LztQ== X-Gm-Message-State: AOAM533eHXip3+K8xtb52/wheB783AdKnmg33x9HYfRV2zI331QYsLTy EeLbsodg1MbeN+PQ8NxgYl/M8vkkGw== X-Google-Smtp-Source: ABdhPJxNUkuLAO9y2rbZdFgphW1Q+h54SGmHVNnG677jxAI1ltghY7irm/us6h8t84X9VnswP6n3DNuunA== X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) (user=elver job=sendgmr) by 2002:a05:6214:17ca:: with SMTP id cu10mr18279241qvb.6.1599486076914; Mon, 07 Sep 2020 06:41:16 -0700 (PDT) Date: Mon, 7 Sep 2020 15:40:48 +0200 In-Reply-To: <20200907134055.2878499-1-elver@google.com> Message-Id: <20200907134055.2878499-4-elver@google.com> Mime-Version: 1.0 References: <20200907134055.2878499-1-elver@google.com> X-Mailer: git-send-email 2.28.0.526.ge36021eeef-goog Subject: [PATCH RFC 03/10] arm64, kfence: enable KFENCE for ARM64 From: Marco Elver To: elver@google.com, glider@google.com, akpm@linux-foundation.org, catalin.marinas@arm.com, cl@linux.com, rientjes@google.com, iamjoonsoo.kim@lge.com, mark.rutland@arm.com, penberg@kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200907_094120_937713_1D13A366 X-CRM114-Status: GOOD ( 22.83 ) X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:84a listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-doc@vger.kernel.org, peterz@infradead.org, dave.hansen@linux.intel.com, linux-mm@kvack.org, edumazet@google.com, hpa@zytor.com, will@kernel.org, corbet@lwn.net, x86@kernel.org, kasan-dev@googlegroups.com, mingo@redhat.com, linux-arm-kernel@lists.infradead.org, aryabinin@virtuozzo.com, keescook@chromium.org, paulmck@kernel.org, jannh@google.com, andreyknvl@google.com, cai@lca.pw, luto@kernel.org, tglx@linutronix.de, dvyukov@google.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, bp@alien8.de Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Add architecture specific implementation details for KFENCE and enable KFENCE for the arm64 architecture. In particular, this implements the required interface in . Currently, the arm64 version does not yet use a statically allocated memory pool, at the cost of a pointer load for each is_kfence_address(). Co-developed-by: Alexander Potapenko Signed-off-by: Alexander Potapenko Signed-off-by: Marco Elver --- For ARM64, we would like to solicit feedback on what the best option is to obtain a constant address for __kfence_pool. One option is to declare a memory range in the memory layout to be dedicated to KFENCE (like is done for KASAN), however, it is unclear if this is the best available option. We would like to avoid touching the memory layout. --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/kfence.h | 39 +++++++++++++++++++++++++++++++++ arch/arm64/mm/fault.c | 4 ++++ 3 files changed, 44 insertions(+) create mode 100644 arch/arm64/include/asm/kfence.h diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d232837cbee..1acc6b2877c3 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -132,6 +132,7 @@ config ARM64 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48) select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN + select HAVE_ARCH_KFENCE if (!ARM64_16K_PAGES && !ARM64_64K_PAGES) select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h new file mode 100644 index 000000000000..608dde80e5ca --- /dev/null +++ b/arch/arm64/include/asm/kfence.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __ASM_KFENCE_H +#define __ASM_KFENCE_H + +#include +#include +#include + +#include + +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync" + +/* + * FIXME: Support HAVE_ARCH_KFENCE_STATIC_POOL: Use the statically allocated + * __kfence_pool, to avoid the extra pointer load for is_kfence_address(). By + * default, however, we do not have struct pages for static allocations. + */ + +static inline bool arch_kfence_initialize_pool(void) +{ + const unsigned int num_pages = ilog2(roundup_pow_of_two(KFENCE_POOL_SIZE / PAGE_SIZE)); + struct page *pages = alloc_pages(GFP_KERNEL, num_pages); + + if (!pages) + return false; + + __kfence_pool = page_address(pages); + return true; +} + +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + set_memory_valid(addr, 1, !protect); + + return true; +} + +#endif /* __ASM_KFENCE_H */ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index f07333e86c2f..d5b72ecbeeea 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -310,6 +311,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr, "Ignoring spurious kernel translation fault at virtual address %016lx\n", addr)) return; + if (kfence_handle_page_fault(addr)) + return; + if (is_el1_permission_fault(addr, esr, regs)) { if (esr & ESR_ELx_WNR) msg = "write to read-only memory";