From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 4B51F6B025F for ; Wed, 11 Oct 2017 04:24:49 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id u23so2822747pgo.7 for ; Wed, 11 Oct 2017 01:24:49 -0700 (PDT) Received: from szxga05-in.huawei.com (szxga05-in.huawei.com. [45.249.212.191]) by mx.google.com with ESMTPS id i35si10582989plg.645.2017.10.11.01.24.47 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 11 Oct 2017 01:24:48 -0700 (PDT) From: Abbott Liu Subject: [PATCH 10/11] Change mapping of kasan_zero_page int readonly Date: Wed, 11 Oct 2017 16:22:26 +0800 Message-ID: <20171011082227.20546-11-liuwenliang@huawei.com> In-Reply-To: <20171011082227.20546-1-liuwenliang@huawei.com> References: <20171011082227.20546-1-liuwenliang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: linux@armlinux.org.uk, aryabinin@virtuozzo.com, liuwenliang@huawei.com, afzal.mohd.ma@gmail.com, f.fainelli@gmail.com, labbott@redhat.com, kirill.shutemov@linux.intel.com, mhocko@suse.com, cdall@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, akpm@linux-foundation.org, mawilcox@microsoft.com, tglx@linutronix.de, thgarnie@google.com, keescook@chromium.org, arnd@arndb.de, vladimir.murzin@arm.com, tixy@linaro.org, ard.biesheuvel@linaro.org, robin.murphy@arm.com, mingo@kernel.org, grygorii.strashko@linaro.org Cc: glider@google.com, dvyukov@google.com, opendmb@gmail.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, jiazhenghua@huawei.com, dylix.dailei@huawei.com, zengweilin@huawei.com, heshaoliang@huawei.com Because the kasan_zero_page(which is used as the shadow region for some memory that KASan doesn't need to track.) won't be writen after kasan_init, so change the mapping of kasan_zero_page into readonly. Cc: Andrey Ryabinin --- arch/arm/mm/kasan_init.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/arm/mm/kasan_init.c b/arch/arm/mm/kasan_init.c index 7cfdc39..c11826a 100644 --- a/arch/arm/mm/kasan_init.c +++ b/arch/arm/mm/kasan_init.c @@ -200,6 +200,7 @@ void __init kasan_init(void) { struct memblock_region *reg; u64 orig_ttbr0; + int i; orig_ttbr0 = cpu_get_ttbr(0); @@ -243,6 +244,17 @@ void __init kasan_init(void) create_mapping((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR), (unsigned long)kasan_mem_to_shadow((void *)(PKMAP_BASE+PMD_SIZE)), NUMA_NO_NODE); + + /* + * KAsan may reuse the contents of kasan_zero_pte directly, so we + * should make sure that it maps the zero page read-only. + */ + for (i = 0; i < PTRS_PER_PTE; i++) + set_pte_at(&init_mm, KASAN_SHADOW_START + i*PAGE_SIZE, + &kasan_zero_pte[i], pfn_pte( + virt_to_pfn(kasan_zero_page), + __pgprot(_L_PTE_DEFAULT | L_PTE_DIRTY | L_PTE_XN | L_PTE_RDONLY))); + memset(kasan_zero_page, 0, PAGE_SIZE); cpu_set_ttbr0(orig_ttbr0); flush_cache_all(); local_flush_bp_all(); -- 2.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org