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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620728720; bh=JV3oIYlPRhAEEPVctWNPV/cOycFyYs1Lq6DGChiCd+g=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=DmYACPuIeG6DUf3e9aSCRKD4sAXZdKw4RqF6Pp00JLxdMo2YhXtCrwAXNpr/NHMqZ oDldT6x/cS0KPsVlOjNNNacP62Pn/6s4/9Dtr/nMv6QNvTDIfo+1DuXY+Owpv0Oomq t7cH1Ux8nSmob7o/jDbNynCu6GQt5eC2SLSqk9y8EnyptvliHdxwbANdSfFReShuuf ZnW/vrbHs+PASPY+A4JKR+qnEyxPSI/lla+nFpB8wzyuiuCWGgY2lIR1VXMBLaYTJt pT/DL2qD7qzYkzrAvR/290AS6znOUJ3Fs68ZhEpe90J4d0bracvkNvC4Vmj4OI7WXT BWZYO6ccSYXqA== Received: by mail-ot1-f42.google.com with SMTP id i23-20020a9d68d70000b02902dc19ed4c15so13080378oto.0 for ; Tue, 11 May 2021 03:25:20 -0700 (PDT) X-Gm-Message-State: AOAM532YWjRyyrtK4N0r/spnL3bIKHlKPGuuGeX/9E0XAsdOYasbjGlQ 8xp4zfTSVRkjudLxlbLh4AItME+3zJRwMN1biTA= X-Google-Smtp-Source: ABdhPJytWz1IVkHqKkcpbQyOgm8jLChtkDskRM+4A0ChV/Q2KAjwVVeEAON+ryI7vhB7a9AgJZb69e4AhTOmXsHGZbY= X-Received: by 2002:a05:6830:4da:: with SMTP id s26mr25288213otd.77.1620728719935; Tue, 11 May 2021 03:25:19 -0700 (PDT) MIME-Version: 1.0 References: <20210511100550.28178-1-rppt@kernel.org> <20210511100550.28178-4-rppt@kernel.org> In-Reply-To: <20210511100550.28178-4-rppt@kernel.org> From: Ard Biesheuvel Date: Tue, 11 May 2021 12:25:09 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v4 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid() To: Mike Rapoport Cc: Andrew Morton , Anshuman Khandual , Catalin Marinas , David Hildenbrand , Marc Zyngier , Mark Rutland , Mike Rapoport , Will Deacon , kvmarm , Linux ARM , Linux Kernel Mailing List , Linux Memory Management List Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=DmYACPuI; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf12.hostedemail.com: domain of ardb@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=ardb@kernel.org X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E7873DD X-Stat-Signature: hftmbo1hyfrdhudcuoyowmewyombpyhh Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf12; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620728705-111014 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 11 May 2021 at 12:06, Mike Rapoport wrote: > > From: Mike Rapoport > > The intended semantics of pfn_valid() is to verify whether there is a > struct page for the pfn in question and nothing else. > > Yet, on arm64 it is used to distinguish memory areas that are mapped in the > linear map vs those that require ioremap() to access them. > > Introduce a dedicated pfn_is_map_memory() wrapper for > memblock_is_map_memory() to perform such check and use it where > appropriate. > > Using a wrapper allows to avoid cyclic include dependencies. > > While here also update style of pfn_valid() so that both pfn_valid() and > pfn_is_map_memory() declarations will be consistent. > > Signed-off-by: Mike Rapoport > Acked-by: David Hildenbrand Acked-by: Ard Biesheuvel > --- > arch/arm64/include/asm/memory.h | 2 +- > arch/arm64/include/asm/page.h | 3 ++- > arch/arm64/kvm/mmu.c | 2 +- > arch/arm64/mm/init.c | 12 ++++++++++++ > arch/arm64/mm/ioremap.c | 4 ++-- > arch/arm64/mm/mmu.c | 2 +- > 6 files changed, 19 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 87b90dc27a43..9027b7e16c4c 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -369,7 +369,7 @@ static inline void *phys_to_virt(phys_addr_t x) > > #define virt_addr_valid(addr) ({ \ > __typeof__(addr) __addr = __tag_reset(addr); \ > - __is_lm_address(__addr) && pfn_valid(virt_to_pfn(__addr)); \ > + __is_lm_address(__addr) && pfn_is_map_memory(virt_to_pfn(__addr)); \ > }) > > void dump_mem_limit(void); > diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h > index 012cffc574e8..75ddfe671393 100644 > --- a/arch/arm64/include/asm/page.h > +++ b/arch/arm64/include/asm/page.h > @@ -37,7 +37,8 @@ void copy_highpage(struct page *to, struct page *from); > > typedef struct page *pgtable_t; > > -extern int pfn_valid(unsigned long); > +int pfn_valid(unsigned long pfn); > +int pfn_is_map_memory(unsigned long pfn); > > #include > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index c5d1f3c87dbd..470070073085 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -85,7 +85,7 @@ void kvm_flush_remote_tlbs(struct kvm *kvm) > > static bool kvm_is_device_pfn(unsigned long pfn) > { > - return !pfn_valid(pfn); > + return !pfn_is_map_memory(pfn); > } > > static void *stage2_memcache_zalloc_page(void *arg) > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 16a2b2b1c54d..798f74f501d5 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -255,6 +255,18 @@ int pfn_valid(unsigned long pfn) > } > EXPORT_SYMBOL(pfn_valid); > > +int pfn_is_map_memory(unsigned long pfn) > +{ > + phys_addr_t addr = PFN_PHYS(pfn); > + > + /* avoid false positives for bogus PFNs, see comment in pfn_valid() */ > + if (PHYS_PFN(addr) != pfn) > + return 0; > + > + return memblock_is_map_memory(addr); > +} > +EXPORT_SYMBOL(pfn_is_map_memory); > + > static phys_addr_t memory_limit = PHYS_ADDR_MAX; > > /* > diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c > index b5e83c46b23e..b7c81dacabf0 100644 > --- a/arch/arm64/mm/ioremap.c > +++ b/arch/arm64/mm/ioremap.c > @@ -43,7 +43,7 @@ static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size, > /* > * Don't allow RAM to be mapped. > */ > - if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr)))) > + if (WARN_ON(pfn_is_map_memory(__phys_to_pfn(phys_addr)))) > return NULL; > > area = get_vm_area_caller(size, VM_IOREMAP, caller); > @@ -84,7 +84,7 @@ EXPORT_SYMBOL(iounmap); > void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size) > { > /* For normal memory we already have a cacheable mapping. */ > - if (pfn_valid(__phys_to_pfn(phys_addr))) > + if (pfn_is_map_memory(__phys_to_pfn(phys_addr))) > return (void __iomem *)__phys_to_virt(phys_addr); > > return __ioremap_caller(phys_addr, size, __pgprot(PROT_NORMAL), > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 6dd9369e3ea0..ab5914cebd3c 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -82,7 +82,7 @@ void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) > pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, > unsigned long size, pgprot_t vma_prot) > { > - if (!pfn_valid(pfn)) > + if (!pfn_is_map_memory(pfn)) > return pgprot_noncached(vma_prot); > else if (file->f_flags & O_SYNC) > return pgprot_writecombine(vma_prot); > -- > 2.28.0 >