From: David Hildenbrand <david@redhat.com>
To: Mike Rapoport <rppt@kernel.org>, linux-arm-kernel@lists.infradead.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Ard Biesheuvel <ardb@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mike Rapoport <rppt@linux.ibm.com>, Will Deacon <will@kernel.org>,
kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v3 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid()
Date: Thu, 22 Apr 2021 10:57:34 +0200 [thread overview]
Message-ID: <041411e9-0fba-f053-d901-10f1d7a8cc5e@redhat.com> (raw)
In-Reply-To: <20210422061902.21614-4-rppt@kernel.org>
On 22.04.21 08:19, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> 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 <rppt@linux.ibm.com>
> ---
> 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 0aabc3be9a75..194f9f993d30 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -351,7 +351,7 @@ 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 <asm/memory.h>
>
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 8711894db8c2..23dd99e29b23 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);
> }
>
> /*
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 3685e12aba9b..966a7a18d528 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -258,6 +258,18 @@ 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 5d9550fdb9cf..26045e9adbd7 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -81,7 +81,7 @@ 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);
>
Acked-by: David Hildenbrand <david@redhat.com>
--
Thanks,
David / dhildenb
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next prev parent reply other threads:[~2021-04-22 8:59 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 6:18 [PATCH v3 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-22 6:18 ` [PATCH v3 1/4] include/linux/mmzone.h: add documentation for pfn_valid() Mike Rapoport
2021-04-22 6:19 ` [PATCH v3 2/4] memblock: update initialization of reserved pages Mike Rapoport
2021-04-22 6:19 ` [PATCH v3 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid() Mike Rapoport
2021-04-22 8:57 ` David Hildenbrand [this message]
2021-04-22 6:19 ` [PATCH v3 4/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-22 7:50 ` [RFC V2] mm: Enable generic pfn_valid() to handle early sections with memmap holes Anshuman Khandual
2021-04-22 8:27 ` Mike Rapoport
2021-04-22 11:23 ` Anshuman Khandual
2021-04-22 12:19 ` Mike Rapoport
2021-04-22 9:03 ` David Hildenbrand
2021-04-22 9:42 ` Mike Rapoport
2021-04-22 9:48 ` David Hildenbrand
2021-04-22 10:03 ` Mike Rapoport
2021-04-22 9:59 ` Anshuman Khandual
2021-05-24 4:58 ` Anshuman Khandual
2021-05-24 6:52 ` Mike Rapoport
2021-05-25 6:00 ` Anshuman Khandual
2021-05-25 6:32 ` Mike Rapoport
2021-05-25 9:52 ` Anshuman Khandual
2021-05-25 10:03 ` Mike Rapoport
2021-05-25 10:04 ` David Hildenbrand
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