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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=5z/J5FmpUih5AunXUZcBxXMftgMmrnQQb5zqsYk89+U=; b=SeBSK9/tv4XnGZ90jzFEtrT3txiB9S5jUlLKCL98iedcZT9DXLrbkeFbOOye3ILoML Oe7hvii4h9S1RWHL4CA3V+SM2hE2S89E/xHVyIUqiwNkfKks3tGTwcH3PizaFSS+/P0m gR+roWBmzRzAh8mT6dDUTAsxmAgvzy9Wpyu6/qWPKjtfQuJ1qoC1kxNhAFRsQe2fYElq LaoQcdNxvrFsqMpz/v8PJnKZ581QHvx8nhDGoaLaaYWXouKBM6qWMOrFKRce6Gijzpp1 1b1KbHFdcNDvE5D+N0DuBJ1+dywd2cVcI2jzA11+1v7rZE0l03zqcE0LIKBnX89kom// Y8sw== X-Gm-Message-State: AOAM530tL6tuutOx2QrOtYDRhAnVSShO2bzJ1wL77ZVptcoNpq4rfWjl QCiUx5d8ZGQeym82BXPHzv4DFds6mg== X-Google-Smtp-Source: ABdhPJxhActcecvve95wvtZfEwTJHuDIR+XsqED/73NlG4rCv/rWU9g+NLwhYgxlkuyB59M81PWVbgm4Nw== X-Received: from elver.muc.corp.google.com ([2a00:79e0:15:13:f693:9fff:fef4:2449]) (user=elver job=sendgmr) by 2002:a7b:c14f:: with SMTP id z15mr9137wmi.1.1599486074403; Mon, 07 Sep 2020 06:41:14 -0700 (PDT) Date: Mon, 7 Sep 2020 15:40:47 +0200 In-Reply-To: <20200907134055.2878499-1-elver@google.com> Message-Id: <20200907134055.2878499-3-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 02/10] x86, kfence: enable KFENCE for x86 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_094117_941001_679F90CE X-CRM114-Status: GOOD ( 19.83 ) 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 [2a00:1450:4864:20:0:0:0:44a 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 From: Alexander Potapenko Add architecture specific implementation details for KFENCE and enable KFENCE for the x86 architecture. In particular, this implements the required interface in for setting up the pool and providing helper functions for protecting and unprotecting pages. For x86, we need to ensure that the pool uses 4K pages, which is done using the set_memory_4k() helper function. Co-developed-by: Marco Elver Signed-off-by: Marco Elver Signed-off-by: Alexander Potapenko --- arch/x86/Kconfig | 2 ++ arch/x86/include/asm/kfence.h | 60 +++++++++++++++++++++++++++++++++++ arch/x86/mm/fault.c | 4 +++ 3 files changed, 66 insertions(+) create mode 100644 arch/x86/include/asm/kfence.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 7101ac64bb20..e22dc722698c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -144,6 +144,8 @@ config X86 select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if X86_64 select HAVE_ARCH_KASAN_VMALLOC if X86_64 + select HAVE_ARCH_KFENCE + select HAVE_ARCH_KFENCE_STATIC_POOL select HAVE_ARCH_KGDB select HAVE_ARCH_MMAP_RND_BITS if MMU select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT diff --git a/arch/x86/include/asm/kfence.h b/arch/x86/include/asm/kfence.h new file mode 100644 index 000000000000..cf09e377faf9 --- /dev/null +++ b/arch/x86/include/asm/kfence.h @@ -0,0 +1,60 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_X86_KFENCE_H +#define _ASM_X86_KFENCE_H + +#include +#include + +#include +#include +#include +#include + +/* The alignment should be at least a 4K page. */ +#define KFENCE_POOL_ALIGNMENT PAGE_SIZE + +/* + * The page fault handler entry function, up to which the stack trace is + * truncated in reports. + */ +#define KFENCE_SKIP_ARCH_FAULT_HANDLER "asm_exc_page_fault" + +/* Force 4K pages for __kfence_pool. */ +static inline bool arch_kfence_initialize_pool(void) +{ + unsigned long addr; + + for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); + addr += PAGE_SIZE) { + unsigned int level; + + if (!lookup_address(addr, &level)) + return false; + + if (level != PG_LEVEL_4K) + set_memory_4k(addr, 1); + } + + return true; +} + +/* Protect the given page and flush TLBs. */ +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + unsigned int level; + pte_t *pte = lookup_address(addr, &level); + + if (!pte || level != PG_LEVEL_4K) + return false; + + if (protect) + set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); + else + set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); + + flush_tlb_one_kernel(addr); + return true; +} + +#endif /* _ASM_X86_KFENCE_H */ diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 6e3e8a124903..423e15ad5eb6 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -9,6 +9,7 @@ #include /* oops_begin/end, ... */ #include /* search_exception_tables */ #include /* max_low_pfn */ +#include /* kfence_handle_page_fault */ #include /* NOKPROBE_SYMBOL, ... */ #include /* kmmio_handler, ... */ #include /* perf_sw_event */ @@ -701,6 +702,9 @@ no_context(struct pt_regs *regs, unsigned long error_code, } #endif + if (kfence_handle_page_fault(address)) + return; + /* * 32-bit: *