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.
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
Fix to build correctly under all combinations of
CONFIG_PGTABLE_LEVELS and CONFIG_TRANSPARENT_HUGEPAGE.
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/pgtable-prot.h | 1 +
arch/arm64/include/asm/pgtable.h | 21 +++++++++++++++++++++
3 files changed, 23 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4780eb7af842..b5a4611fa4c6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -23,6 +23,7 @@ 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
diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
index 986e41c4c32b..af0b372d15e5 100644
--- a/arch/arm64/include/asm/pgtable-prot.h
+++ b/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__
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 2c41b04708fe..7a2cf6939311 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -90,6 +90,7 @@ 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; \
@@ -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 +387,11 @@ 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)
@@ -666,6 +677,16 @@ 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
/*
--
2.21.0.dirty
