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arm64: mm: implement pte_devmap support

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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@arm.com: build fixes]
  Link: http://lkml.kernel.org/r/13026c4e64abc17133bbfa07d7731ec6691c0bcd.1559050949.git.robin.murphy@arm.com
Link: http://lkml.kernel.org/r/817d92886fc3b33bcbf6e105ee83a74babb3a5aa.1558547956.git.robin.murphy@arm.com
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Robin Murphy 2019-07-16 16:30:51 -07:00 committed by Linus Torvalds
parent 175967318c
commit 73b20c84d4
3 changed files with 23 additions and 0 deletions
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1
arch/arm64/Kconfig
View file

@ -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

1
arch/arm64/include/asm/pgtable-prot.h
View file

@ -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__

21
arch/arm64/include/asm/pgtable.h
View file

@ -79,6 +79,7 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
#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(struct vm_area_struct *vma,
{
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
/*