Re: [RFC/RFT PATCH 2/3] arm64: decouple check whether pfn is normal memory from pfn_valid()
From: Anshuman Khandual <hidden>
Date: 2021-04-08 05:14:14
Also in:
kvmarm, linux-mm, lkml
On 4/7/21 10:56 PM, Mike Rapoport wrote:
From: Mike Rapoport <redacted> 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 ?
quoted hunk ↗ jump to hunk
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 <redacted> --- 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.
quoted hunk ↗ jump to hunk
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);
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