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[77.154.202.106]) by smtp.gmail.com with ESMTPSA id g203sm13430927wmf.23.2016.03.21.10.38.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 21 Mar 2016 10:38:52 -0700 (PDT) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com Subject: [PATCH 1/2] arm64/mm: ensure memstart_addr remains sufficiently aligned Date: Mon, 21 Mar 2016 18:38:43 +0100 Message-Id: <1458581924-14462-1-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 1.9.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160321_103919_205363_47F5C4BD X-CRM114-Status: GOOD ( 14.87 ) X-Spam-Score: -2.7 (--) X-Spam-Report: SpamAssassin version 3.4.0 on bombadil.infradead.org summary: Content analysis details: (-2.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [2a00:1450:400c:c09:0:0:0:232 listed in] [list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ard Biesheuvel MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patch=linaro.org@lists.infradead.org After choosing memstart_addr to be the highest multiple of ARM64_MEMSTART_ALIGN less than or equal to the first usable physical memory address, we clip the memblocks to the maximum size of the linear region. Since the kernel may be high up in memory, we take care not to clip the kernel itself, which means we have to clip some memory from the bottom if this occurs, to ensure that the distance between the first and the last usable physical memory address can be covered by the linear region. However, we fail to update memstart_addr if this clipping from the bottom occurs, which means that we may still end up with virtual addresses that wrap into the userland range. So increment memstart_addr as appropriate to prevent this from happening. Signed-off-by: Ard Biesheuvel --- arch/arm64/mm/init.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) -- 1.9.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 61a38eaf0895..ef1f70f860b0 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -190,8 +190,12 @@ void __init arm64_memblock_init(void) */ memblock_remove(max_t(u64, memstart_addr + linear_region_size, __pa(_end)), ULLONG_MAX); - if (memblock_end_of_DRAM() > linear_region_size) - memblock_remove(0, memblock_end_of_DRAM() - linear_region_size); + if (memstart_addr + linear_region_size < memblock_end_of_DRAM()) { + /* ensure that memstart_addr remains sufficiently aligned */ + memstart_addr = round_up(memblock_end_of_DRAM() - linear_region_size, + ARM64_MEMSTART_ALIGN); + memblock_remove(0, memstart_addr); + } /* * Apply the memory limit if it was set. Since the kernel may be loaded