From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guo Ren Subject: Re: [PATCH v3 07/33] nds32: MMU initialization Date: Mon, 18 Dec 2017 17:08:48 +0800 Message-ID: <20171218090848.GA5823@gary-OptiPlex-3050> References: <0964714c3dcac46ac700085717b0f414b7978112.1512723245.git.green.hu@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <0964714c3dcac46ac700085717b0f414b7978112.1512723245.git.green.hu@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Greentime Hu Cc: greentime@andestech.com, linux-kernel@vger.kernel.org, arnd@arndb.de, linux-arch@vger.kernel.org, tglx@linutronix.de, jason@lakedaemon.net, marc.zyngier@arm.com, robh+dt@kernel.org, netdev@vger.kernel.org, deanbo422@gmail.com, devicetree@vger.kernel.org, viro@zeniv.linux.org.uk, dhowells@redhat.com, will.deacon@arm.com, daniel.lezcano@linaro.org, linux-serial@vger.kernel.org, geert.uytterhoeven@gmail.com, linus.walleij@linaro.org, mark.rutland@arm.com, greg@kroah.com, Vincent Chen List-Id: devicetree@vger.kernel.org Hi Greentime, On Fri, Dec 08, 2017 at 05:11:50PM +0800, Greentime Hu wrote: [...] > > diff --git a/arch/nds32/mm/highmem.c b/arch/nds32/mm/highmem.c [...] > +void *kmap(struct page *page) > +{ > + unsigned long vaddr; > + might_sleep(); > + if (!PageHighMem(page)) > + return page_address(page); > + vaddr = (unsigned long)kmap_high(page); Here should invalid the cpu_mmu_tlb's entry, Or invalid it in the set_pte(). eg: vaddr0 = kmap(page0) *vaddr0 = val0 //It will cause tlb-miss, and hard-refill to MMU-tlb kunmap(page0) vaddr1 = kmap(page1) // Mostly vaddr1 = vaddr0 val = vaddr1; //No tlb-miss and it will get page0's val not page1, because last expired vaddr0's entry is left in CPU-MMU-tlb. Best Regards Guo Ren