On 4/7/21 10:56 PM, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
>
> The intended semantics of pfn_valid() is to verify whether there is a
> struct page for the pfn in question and nothing else.
Should there be a comment affirming this semantics interpretation, above the
generic pfn_valid() in include/linux/mmzone.h ?
>
> 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_memory() to perform such check and use it
> where appropriate.
>
> Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
> ---
> arch/arm64/include/asm/memory.h | 2 +-
> arch/arm64/include/asm/page.h | 1 +
> arch/arm64/kvm/mmu.c | 2 +-
> arch/arm64/mm/init.c | 6 ++++++
> arch/arm64/mm/ioremap.c | 4 ++--
> arch/arm64/mm/mmu.c | 2 +-
> 6 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index 0aabc3be9a75..7e77fdf71b9d 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_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..32b485bcc6ff 100644
> --- a/arch/arm64/include/asm/page.h
> +++ b/arch/arm64/include/asm/page.h
> @@ -38,6 +38,7 @@ void copy_highpage(struct page *to, struct page *from);
> typedef struct page *pgtable_t;
>
> extern int pfn_valid(unsigned long);
> +extern int pfn_is_memory(unsigned long);
>
> #include <asm/memory.h>
>
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 8711894db8c2..ad2ea65a3937 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_memory(pfn);
> }
>
> /*
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 3685e12aba9b..258b1905ed4a 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -258,6 +258,12 @@ int pfn_valid(unsigned long pfn)
> }
> EXPORT_SYMBOL(pfn_valid);
>
> +int pfn_is_memory(unsigned long pfn)
> +{
> + return memblock_is_map_memory(PFN_PHYS(pfn));
> +}
> +EXPORT_SYMBOL(pfn_is_memory);> +
Should not this be generic though ? There is nothing platform or arm64
specific in here. Wondering as pfn_is_memory() just indicates that the
pfn is linear mapped, should not it be renamed as pfn_is_linear_memory()
instead ? Regardless, it's fine either way.
> 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..82a369b22ef5 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_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_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..038d20fe163f 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_memory(pfn))
> return pgprot_noncached(vma_prot);
> else if (file->f_flags & O_SYNC)
> return pgprot_writecombine(vma_prot);
>
