The patch titled
Subject: arm64: mm: implement pte_devmap support
has been added to the -mm tree. Its filename is
arm64-mm-implement-pte_devmap-support.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-mm-implement-pte_devmap-support.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-mm-implement-pte_devmap-support.patch
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------------------------------------------------------
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.
Link: http://lkml.kernel.org/r/817d92886fc3b33bcbf6e105ee83a74babb3a5aa.1558547956.git.robin.murphy@xxxxxxx
Signed-off-by: Robin Murphy <robin.murphy@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>
Cc: Will Deacon <will.deacon@xxxxxxx>
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 | 19 +++++++++++++++++++
3 files changed, 21 insertions(+)
--- a/arch/arm64/include/asm/pgtable.h~arm64-mm-implement-pte_devmap-support
+++ a/arch/arm64/include/asm/pgtable.h
@@ -90,6 +90,7 @@ 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; \
@@ -217,6 +218,11 @@ 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);
@@ -381,6 +387,9 @@ static inline int pmd_protnone(pmd_t pmd
#define pmd_mkhuge(pmd) (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
+#define pmd_devmap(pmd) pte_devmap(pmd_pte(pmd))
+#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)
@@ -537,6 +546,11 @@ static inline phys_addr_t pud_page_paddr
return __pud_to_phys(pud);
}
+static inline int pud_devmap(pud_t pud)
+{
+ return 0;
+}
+
/* Find an entry in the second-level page table. */
#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
@@ -624,6 +638,11 @@ static inline phys_addr_t pgd_page_paddr
#define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
+static inline int pgd_devmap(pgd_t pgd)
+{
+ return 0;
+}
+
/* to find an entry in a page-table-directory */
#define pgd_index(addr) (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
--- a/arch/arm64/include/asm/pgtable-prot.h~arm64-mm-implement-pte_devmap-support
+++ a/arch/arm64/include/asm/pgtable-prot.h
@@ -28,6 +28,7 @@
#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_MEMORY
_
Patches currently in -mm which might be from robin.murphy@xxxxxxx are
mm-memremap-rename-and-consolidate-section_size.patch
mm-clean-up-is_device__page-definitions.patch
mm-introduce-arch_has_pte_devmap.patch
arm64-mm-implement-pte_devmap-support.patch
arm64-mm-implement-pte_devmap-support-fix.patch
