From patchwork Tue Mar 28 06:51:24 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: AKASHI Takahiro X-Patchwork-Id: 9648219 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id DF413601E9 for ; Tue, 28 Mar 2017 06:49:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CFB182839B for ; Tue, 28 Mar 2017 06:49:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C42F8283C9; Tue, 28 Mar 2017 06:49:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 20E9B2839B for ; Tue, 28 Mar 2017 06:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=kXusGhOhcUF3rg8Q2c8oH2qezgjZbC5Cf0r+T7GOjgI=; b=aY2P1+jrd3MAOwOWRUKJaVckE1 i7R3/GddYjyMw5ZTyik/5Koo48obfGkPH62ak4OOZHPGJ26QXNvginrVVPGsRl6o0CJKbVBgKLV2x ttPaG9zcZDnNseLvx/De9oei+ORjNCrn1vRNQl0KvDir7gfKhR11jfkQoGIPg+0lhneFdJPrbhzxX Iob8hwxKbJyYLJZA0dfD8aYxN2d+f7c2Yu71Ye2cJPDUmkjsduBhMmLVcb0PpQRjMg6iPRKikM0g5 pR8znqnpSNJ7jM2hPzqQgGYE+WNQy2fhAlA8xxQzf4WtkaePjbB7ER720OVOhBg9L9+xH/aOMiE6c SIcUKi9w==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cskwv-0003S8-GD; Tue, 28 Mar 2017 06:49:49 +0000 Received: from mail-pg0-x233.google.com ([2607:f8b0:400e:c05::233]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cskwN-0002lc-8D for linux-arm-kernel@lists.infradead.org; Tue, 28 Mar 2017 06:49:22 +0000 Received: by mail-pg0-x233.google.com with SMTP id 81so49046408pgh.2 for ; Mon, 27 Mar 2017 23:48:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Q7IH6/xTf1GePlnJ/3j5K7imhtOtvixDiswbo8LtUq4=; b=OQy4YTkqja41iGemsWYMY2VeBXJPcm0HDPMViXWeOhUfA3TJ1KEZYxsc/Lbj7Dib2U bBcuFtKj3Xw3JOZenZdYbpMSAnS7OVCj87IM+lsxajes7kdTkfLQHi/tP8suyqiy5Ieu 70FdUg0WeOz+mCR06bICVGTN2un9t0GMWJa1c= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Q7IH6/xTf1GePlnJ/3j5K7imhtOtvixDiswbo8LtUq4=; b=TryI862tCVa7S/BuCpVKLtXq3BCy7tyrcCtvldVjAMx+JIqEnc+KsN8oEOZaiojJRn b1B1lzw51H7EZ+6XdneAfs2yDjN2d9UaRCE3vzcRySOjdEUJSkk6Zy/tt/hAp+/qOmx+ 9DGn64aA6jZ5xPQciUG/1Woj00/M+V1U3M8SObKxCBfpx5tOxu/Td5Mpi4G+fRbe3Rpz kMZWAf2Ivunt4xitiLBhbKZ/D5+XHuTZoPbdWHwXr4f94u0iaDGUcUJTLJIw8xFr3r4O uBBqbufBubf2PE+Aotjhf5yGrxejhpltsbgZc0iA+n4uuyD/Kcwg96hJnMNOPLhqKceJ gCgw== X-Gm-Message-State: AFeK/H0EynpS90MJcwwdY5h5AOIKw4prdjmLL62P5fFejOcHb/7nw8oEtALlwblWUMEUEC22 X-Received: by 10.99.136.199 with SMTP id l190mr28511569pgd.92.1490683734585; Mon, 27 Mar 2017 23:48:54 -0700 (PDT) Received: from linaro.org ([121.95.100.191]) by smtp.googlemail.com with ESMTPSA id q4sm4881621pgc.63.2017.03.27.23.48.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 27 Mar 2017 23:48:54 -0700 (PDT) From: AKASHI Takahiro To: catalin.marinas@arm.com, will.deacon@arm.com Subject: [PATCH v34 06/14] arm64: kdump: protect crash dump kernel memory Date: Tue, 28 Mar 2017 15:51:24 +0900 Message-Id: <20170328065130.16019-4-takahiro.akashi@linaro.org> X-Mailer: git-send-email 2.11.1 In-Reply-To: <20170328064831.15894-1-takahiro.akashi@linaro.org> References: <20170328064831.15894-1-takahiro.akashi@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170327_234916_015478_C7E65441 X-CRM114-Status: GOOD ( 18.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, panand@redhat.com, ard.biesheuvel@linaro.org, geoff@infradead.org, dwmw2@infradead.org, kexec@lists.infradead.org, AKASHI Takahiro , james.morse@arm.com, bauerman@linux.vnet.ibm.com, sgoel@codeaurora.org, dyoung@redhat.com, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP arch_kexec_protect_crashkres() and arch_kexec_unprotect_crashkres() are meant to be called by kexec_load() in order to protect the memory allocated for crash dump kernel once the image is loaded. The protection is implemented by unmapping the relevant segments in crash dump kernel memory, rather than making it read-only as other archs do, to prevent any corruption due to potential cache alias (with different attributes) problem. Page-level mappings are consistently used here so that we can change the attributes of segments in page granularity as well as shrink the region also in page granularity through /sys/kernel/kexec_crash_size, putting the freed memory back to buddy system. Signed-off-by: AKASHI Takahiro --- arch/arm64/kernel/machine_kexec.c | 32 +++++++++++--- arch/arm64/mm/mmu.c | 90 ++++++++++++++++++++------------------- 2 files changed, 72 insertions(+), 50 deletions(-) diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index bc96c8a7fc79..b63baa749609 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -14,7 +14,9 @@ #include #include +#include #include +#include #include "cpu-reset.h" @@ -22,8 +24,6 @@ extern const unsigned char arm64_relocate_new_kernel[]; extern const unsigned long arm64_relocate_new_kernel_size; -static unsigned long kimage_start; - /** * kexec_image_info - For debugging output. */ @@ -64,8 +64,6 @@ void machine_kexec_cleanup(struct kimage *kimage) */ int machine_kexec_prepare(struct kimage *kimage) { - kimage_start = kimage->start; - kexec_image_info(kimage); if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) { @@ -183,7 +181,7 @@ void machine_kexec(struct kimage *kimage) kexec_list_flush(kimage); /* Flush the new image if already in place. */ - if (kimage->head & IND_DONE) + if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE)) kexec_segment_flush(kimage); pr_info("Bye!\n"); @@ -201,7 +199,7 @@ void machine_kexec(struct kimage *kimage) */ cpu_soft_restart(1, reboot_code_buffer_phys, kimage->head, - kimage_start, 0); + kimage->start, 0); BUG(); /* Should never get here. */ } @@ -210,3 +208,25 @@ void machine_crash_shutdown(struct pt_regs *regs) { /* Empty routine needed to avoid build errors. */ } + +void arch_kexec_protect_crashkres(void) +{ + int i; + + kexec_segment_flush(kexec_crash_image); + + for (i = 0; i < kexec_crash_image->nr_segments; i++) + set_memory_valid( + __phys_to_virt(kexec_crash_image->segment[i].mem), + kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0); +} + +void arch_kexec_unprotect_crashkres(void) +{ + int i; + + for (i = 0; i < kexec_crash_image->nr_segments; i++) + set_memory_valid( + __phys_to_virt(kexec_crash_image->segment[i].mem), + kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1); +} diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index d28dbcf596b6..f6a3c0e9d37f 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -22,6 +22,8 @@ #include #include #include +#include +#include #include #include #include @@ -332,56 +334,31 @@ static void create_mapping_late(phys_addr_t phys, unsigned long virt, NULL, debug_pagealloc_enabled()); } -static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end) +static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, + phys_addr_t end, pgprot_t prot, + bool page_mappings_only) +{ + __create_pgd_mapping(pgd, start, __phys_to_virt(start), end - start, + prot, early_pgtable_alloc, + page_mappings_only); +} + +static void __init map_mem(pgd_t *pgd) { phys_addr_t kernel_start = __pa_symbol(_text); phys_addr_t kernel_end = __pa_symbol(__init_begin); + struct memblock_region *reg; /* - * Take care not to create a writable alias for the - * read-only text and rodata sections of the kernel image. + * Temporarily marked as NOMAP to skip mapping in the next for-loop */ + memblock_mark_nomap(kernel_start, kernel_end - kernel_start); - /* No overlap with the kernel text/rodata */ - if (end < kernel_start || start >= kernel_end) { - __create_pgd_mapping(pgd, start, __phys_to_virt(start), - end - start, PAGE_KERNEL, - early_pgtable_alloc, - debug_pagealloc_enabled()); - return; - } - - /* - * This block overlaps the kernel text/rodata mappings. - * Map the portion(s) which don't overlap. - */ - if (start < kernel_start) - __create_pgd_mapping(pgd, start, - __phys_to_virt(start), - kernel_start - start, PAGE_KERNEL, - early_pgtable_alloc, - debug_pagealloc_enabled()); - if (kernel_end < end) - __create_pgd_mapping(pgd, kernel_end, - __phys_to_virt(kernel_end), - end - kernel_end, PAGE_KERNEL, - early_pgtable_alloc, - debug_pagealloc_enabled()); - - /* - * Map the linear alias of the [_text, __init_begin) interval as - * read-only/non-executable. This makes the contents of the - * region accessible to subsystems such as hibernate, but - * protects it from inadvertent modification or execution. - */ - __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start), - kernel_end - kernel_start, PAGE_KERNEL_RO, - early_pgtable_alloc, debug_pagealloc_enabled()); -} - -static void __init map_mem(pgd_t *pgd) -{ - struct memblock_region *reg; +#ifdef CONFIG_KEXEC_CORE + if (crashk_res.end) + memblock_mark_nomap(crashk_res.start, + resource_size(&crashk_res)); +#endif /* map all the memory banks */ for_each_memblock(memory, reg) { @@ -393,8 +370,33 @@ static void __init map_mem(pgd_t *pgd) if (memblock_is_nomap(reg)) continue; - __map_memblock(pgd, start, end); + __map_memblock(pgd, start, end, + PAGE_KERNEL, debug_pagealloc_enabled()); + } + + /* + * Map the linear alias of the [_text, __init_begin) interval as + * read-only/non-executable. This makes the contents of the + * region accessible to subsystems such as hibernate, but + * protects it from inadvertent modification or execution. + */ + __map_memblock(pgd, kernel_start, kernel_end, + PAGE_KERNEL_RO, debug_pagealloc_enabled()); + memblock_clear_nomap(kernel_start, kernel_end - kernel_start); + +#ifdef CONFIG_KEXEC_CORE + /* + * User page-level mappings here so that we can shrink the region + * in page granularity and put back unused memory to buddy system + * through /sys/kernel/kexec_crash_size interface. + */ + if (crashk_res.end) { + __map_memblock(pgd, crashk_res.start, crashk_res.end + 1, + PAGE_KERNEL, true); + memblock_clear_nomap(crashk_res.start, + resource_size(&crashk_res)); } +#endif } void mark_rodata_ro(void)