From: Robin Murphy <robin.murphy@xxxxxxx> Subject: arm64: mm: implement pte_devmap support In order for things like get_user_pages() to work on ZONE_DEVICE memory, we need a software PTE bit to identify device-backed PFNs. Hook this up along with the relevant helpers to join in with ARCH_HAS_PTE_DEVMAP. [robin.murphy@xxxxxxx: build fixes] Link: http://lkml.kernel.org/r/13026c4e64abc17133bbfa07d7731ec6691c0bcd.1559050949.git.robin.murphy@xxxxxxx Link: http://lkml.kernel.org/r/817d92886fc3b33bcbf6e105ee83a74babb3a5aa.1558547956.git.robin.murphy@xxxxxxx Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx> Acked-by: Will Deacon <will.deacon@xxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Ira Weiny <ira.weiny@xxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Oliver O'Halloran <oohall@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/pgtable-prot.h | 1 + arch/arm64/include/asm/pgtable.h | 21 +++++++++++++++++++++ 3 files changed, 23 insertions(+) --- a/arch/arm64/include/asm/pgtable.h~arm64-mm-implement-pte_devmap-support +++ a/arch/arm64/include/asm/pgtable.h @@ -79,6 +79,7 @@ extern unsigned long empty_zero_page[PAG #define pte_write(pte) (!!(pte_val(pte) & PTE_WRITE)) #define pte_user_exec(pte) (!(pte_val(pte) & PTE_UXN)) #define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT)) +#define pte_devmap(pte) (!!(pte_val(pte) & PTE_DEVMAP)) #define pte_cont_addr_end(addr, end) \ ({ unsigned long __boundary = ((addr) + CONT_PTE_SIZE) & CONT_PTE_MASK; \ @@ -206,6 +207,11 @@ static inline pmd_t pmd_mkcont(pmd_t pmd return __pmd(pmd_val(pmd) | PMD_SECT_CONT); } +static inline pte_t pte_mkdevmap(pte_t pte) +{ + return set_pte_bit(pte, __pgprot(PTE_DEVMAP)); +} + static inline void set_pte(pte_t *ptep, pte_t pte) { WRITE_ONCE(*ptep, pte); @@ -388,6 +394,11 @@ static inline int pmd_protnone(pmd_t pmd #define pmd_mkhuge(pmd) (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT)) +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define pmd_devmap(pmd) pte_devmap(pmd_pte(pmd)) +#endif +#define pmd_mkdevmap(pmd) pte_pmd(pte_mkdevmap(pmd_pte(pmd))) + #define __pmd_to_phys(pmd) __pte_to_phys(pmd_pte(pmd)) #define __phys_to_pmd_val(phys) __phys_to_pte_val(phys) #define pmd_pfn(pmd) ((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT) @@ -673,6 +684,16 @@ static inline int pmdp_set_access_flags( { return ptep_set_access_flags(vma, address, (pte_t *)pmdp, pmd_pte(entry), dirty); } + +static inline int pud_devmap(pud_t pud) +{ + return 0; +} + +static inline int pgd_devmap(pgd_t pgd) +{ + return 0; +} #endif /* --- a/arch/arm64/include/asm/pgtable-prot.h~arm64-mm-implement-pte_devmap-support +++ a/arch/arm64/include/asm/pgtable-prot.h @@ -16,6 +16,7 @@ #define PTE_WRITE (PTE_DBM) /* same as DBM (51) */ #define PTE_DIRTY (_AT(pteval_t, 1) << 55) #define PTE_SPECIAL (_AT(pteval_t, 1) << 56) +#define PTE_DEVMAP (_AT(pteval_t, 1) << 57) #define PTE_PROT_NONE (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */ #ifndef __ASSEMBLY__ --- a/arch/arm64/Kconfig~arm64-mm-implement-pte_devmap-support +++ a/arch/arm64/Kconfig @@ -24,6 +24,7 @@ config ARM64 select ARCH_HAS_KCOV select ARCH_HAS_KEEPINITRD select ARCH_HAS_MEMBARRIER_SYNC_CORE + select ARCH_HAS_PTE_DEVMAP select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_SETUP_DMA_OPS select ARCH_HAS_SET_DIRECT_MAP _
