From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 6/7] acpi, apei, ghes: Make unmapping functionality independent from architecture. Date: Wed, 14 May 2014 13:48:34 +0100 Message-ID: <20140514124834.GH10145@arm.com> References: <1397056476-9183-1-git-send-email-tomasz.nowicki@linaro.org> <1397056476-9183-7-git-send-email-tomasz.nowicki@linaro.org> <20140513201118.GF8760@pd.tnic> <5373625B.4050401@linaro.org> <20140514123542.GG10145@arm.com> <20140514124505.GA19866@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20140514124505.GA19866@localhost> Sender: linux-kernel-owner@vger.kernel.org To: Catalin Marinas Cc: Tomasz Nowicki , Borislav Petkov , Russell King - ARM Linux , "rjw@rjwysocki.net" , "lenb@kernel.org" , "tony.luck@intel.com" , "bp@suse.de" , "m.chehab@samsung.com" , "linux-edac@vger.kernel.org" , "x86@kernel.org" , "linux-acpi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" List-Id: linux-acpi@vger.kernel.org On Wed, May 14, 2014 at 01:45:07PM +0100, Catalin Marinas wrote: > On Wed, May 14, 2014 at 01:35:42PM +0100, Will Deacon wrote: > > On Wed, May 14, 2014 at 01:32:27PM +0100, Tomasz Nowicki wrote: > > > On 13.05.2014 22:11, Borislav Petkov wrote: > > > > On Wed, Apr 09, 2014 at 05:14:34PM +0200, Tomasz Nowicki wrote: > > > >> Till now __flush_tlb_one was used for unmapping virtual memory which > > > >> is x86 specific function. Replace it with more generic > > > >> flush_tlb_kernel_range. > > > >> > > > >> Signed-off-by: Tomasz Nowicki > > > >> --- > > > >> drivers/acpi/apei/ghes.c | 4 ++-- > > > >> 1 file changed, 2 insertions(+), 2 deletions(-) > > > >> > > > >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c > > > >> index aaf8db3..624878b 100644 > > > >> --- a/drivers/acpi/apei/ghes.c > > > >> +++ b/drivers/acpi/apei/ghes.c > > > >> @@ -185,7 +185,7 @@ static void ghes_iounmap_nmi(void __iomem *vaddr_ptr) > > > >> > > > >> BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_NMI_PAGE(base)); > > > >> unmap_kernel_range_noflush(vaddr, PAGE_SIZE); > > > >> - __flush_tlb_one(vaddr); > > > >> + flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE); > > > >> } > > > >> > > > >> static void ghes_iounmap_irq(void __iomem *vaddr_ptr) > > > >> @@ -195,7 +195,7 @@ static void ghes_iounmap_irq(void __iomem *vaddr_ptr) > > > >> > > > >> BUG_ON(vaddr != (unsigned long)GHES_IOREMAP_IRQ_PAGE(base)); > > > >> unmap_kernel_range_noflush(vaddr, PAGE_SIZE); > > > >> - __flush_tlb_one(vaddr); > > > >> + flush_tlb_kernel_range(vaddr, vaddr + PAGE_SIZE); > > > > > > > > flush_tlb_kernel_range() does send an IPI to every core on x86 which is > > > > much more expensive than what __flush_tlb_one does. > > > > > > > > Fairer it would be if you added a __flush_tlb_one() version for arm > > > > which does flush_tlb_kernel_range for you. > > > > > > > > > > Thanks for comment. I am not sure if maintainers will allow me to add > > > sth like __flush_tlb_one() for arm/arm64. Let me ask them directly. > > > Catalin, Russell what do you think? > > > > I don't have the background for this, but if you don't need broadcasting > > (if this avoids IPIs on x86, I guess you don't) then why not use > > local_flush_tlb_kernel_range instead? > > Is this generic enough (we don't have it on arm64)? Well, it's more popular than __flush_tlb_one and the naming is more descriptive imo. Will