arch/arm64/Kconfig | 3 -
arch/arm64/include/asm/hugetlb.h | 44 ++----
arch/arm64/include/asm/pgtable-hwdef.h | 18 ++-
arch/arm64/include/asm/pgtable.h | 10 +-
arch/arm64/mm/hugetlbpage.c | 267 ++++++++++++++++++++++++++++++++-
include/linux/hugetlb.h | 2 -
6 files changed, 306 insertions(+), 38 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 4876459..ffa3c54 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -530,9 +530,6 @@ config HW_PERF_EVENTS
config SYS_SUPPORTS_HUGETLBFS
def_bool y
-config ARCH_WANT_GENERAL_HUGETLB
- def_bool y
-
config ARCH_WANT_HUGE_PMD_SHARE
def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index bb4052e..bbc1e35 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -26,36 +26,7 @@ static inline pte_t huge_ptep_get(pte_t *ptep)
return *ptep;
}
-static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
- pte_t *ptep, pte_t pte)
-{
- set_pte_at(mm, addr, ptep, pte);
-}
-
-static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
- unsigned long addr, pte_t *ptep)
-{
- ptep_clear_flush(vma, addr, ptep);
-}
-
-static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
- unsigned long addr, pte_t *ptep)
-{
- ptep_set_wrprotect(mm, addr, ptep);
-}
-static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
- unsigned long addr, pte_t *ptep)
-{
- return ptep_get_and_clear(mm, addr, ptep);
-}
-
-static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
- unsigned long addr, pte_t *ptep,
- pte_t pte, int dirty)
-{
- return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
-}
static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
unsigned long addr, unsigned long end,
@@ -97,4 +68,19 @@ static inline void arch_clear_hugepage_flags(struct page *page)
clear_bit(PG_dcache_clean, &page->flags);
}
+extern pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
+ struct page *page, int writable);
+#define arch_make_huge_pte arch_make_huge_pte
+extern void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte);
+extern int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t pte, int dirty);
+extern pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep);
+extern void huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep);
+
#endif /* __ASM_HUGETLB_H */
diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h
index d6739e8..5c25b83 100644
--- a/arch/arm64/include/asm/pgtable-hwdef.h
+++ b/arch/arm64/include/asm/pgtable-hwdef.h
@@ -90,7 +90,23 @@
/*
* Contiguous page definitions.
*/
-#define CONT_PTES (_AC(1, UL) << CONT_SHIFT)
+#ifdef CONFIG_ARM64_64K_PAGES
+#define CONT_PTE_SHIFT 5
+#define CONT_PMD_SHIFT 5
+#elif defined(CONFIG_ARM64_16K_PAGES)
+#define CONT_PTE_SHIFT 7
+#define CONT_PMD_SHIFT 5
+#else
+#define CONT_PTE_SHIFT 4
+#define CONT_PMD_SHIFT 4
+#endif
+
+#define CONT_PTES (1 << CONT_PTE_SHIFT)
+#define CONT_PTE_SIZE (CONT_PTES * PAGE_SIZE)
+#define CONT_PTE_MASK (~(CONT_PTE_SIZE - 1))
+#define CONT_PMDS (1 << CONT_PMD_SHIFT)
+#define CONT_PMD_SIZE (CONT_PMDS * PMD_SIZE)
+#define CONT_PMD_MASK (~(CONT_PMD_SIZE - 1))
/* the the numerical offset of the PTE within a range of CONT_PTES */
#define CONT_RANGE_OFFSET(addr) (((addr)>>PAGE_SHIFT)&(CONT_PTES-1))
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 450b355..35a318c 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -227,7 +227,8 @@ static inline pte_t pte_mkspecial(pte_t pte)
static inline pte_t pte_mkcont(pte_t pte)
{
- return set_pte_bit(pte, __pgprot(PTE_CONT));
+ pte = set_pte_bit(pte, __pgprot(PTE_CONT));
+ return set_pte_bit(pte, __pgprot(PTE_TYPE_PAGE));
}
static inline pte_t pte_mknoncont(pte_t pte)
@@ -235,6 +236,11 @@ static inline pte_t pte_mknoncont(pte_t pte)
return clear_pte_bit(pte, __pgprot(PTE_CONT));
}
+static inline pmd_t pmd_mkcont(pmd_t pmd)
+{
+ return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
+}
+
static inline void set_pte(pte_t *ptep, pte_t pte)
{
*ptep = pte;
@@ -304,7 +310,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
/*
* Hugetlb definitions.
*/
-#define HUGE_MAX_HSTATE 2
+#define HUGE_MAX_HSTATE 4
#define HPAGE_SHIFT PMD_SHIFT
#define HPAGE_SIZE (_AC(1, UL) << HPAGE_SHIFT)
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 383b03f..39a5e67 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -41,17 +41,282 @@ int pud_huge(pud_t pud)
#endif
}
+static int find_num_contig(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, size_t *pgsize)
+{
+ pgd_t *pgd = pgd_offset(mm, addr);
+ pud_t *pud;
+ pmd_t *pmd;
+
nit: We should probably set *pgsize = PAGE_SIZE here that way it's
defined on early return.
(Not a problem now, but may help if this code needs to be tweaked in future).
+ if (!pte_cont(pte))
+ return 1;
+ if (!pgd_present(*pgd)) {
+ VM_BUG_ON(!pgd_present(*pgd));
+ return 1;
+ }
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud)) {
+ VM_BUG_ON(!pud_present(*pud));
+ return 1;
+ }
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd)) {
+ VM_BUG_ON(!pmd_present(*pmd));
+ return 1;
+ }
+ if ((pte_t *)pmd == ptep) {
+ *pgsize = PMD_SIZE;
+ return CONT_PMDS;
+ }
+ *pgsize = PAGE_SIZE;
+ return CONT_PTES;
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte)
+{
+ size_t pgsize;
+ int i;
+ int ncontig = find_num_contig(mm, addr, ptep, pte, &pgsize);
+ unsigned long pfn;
+ pgprot_t hugeprot;
+
+ if (ncontig == 1) {
+ set_pte_at(mm, addr, ptep, pte);
+ return;
+ }
+
+ pfn = pte_pfn(pte);
+ hugeprot = __pgprot(pte_val(pfn_pte(pfn, 0)) ^ pte_val(pte));
For pfn_pte, we need the following to satisfy the strict mm checks:
pfn_pte(pfn, __pgprot(0))
+ for (i = 0; i < ncontig; i++) {
+ pr_debug("%s: set pte %p to 0x%llx\n", __func__, ptep,
+ pfn_pte(pfn, hugeprot));
We need to wrap the last argument with pte_val(.);
+ set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
+ ptep++;
+ pfn += pgsize >> PAGE_SHIFT;
+ addr += pgsize;
+ }
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ unsigned long addr, unsigned long sz)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pte_t *pte = NULL;
+
+ pr_debug("%s: addr:0x%lx sz:0x%lx\n", __func__, addr, sz);
+ pgd = pgd_offset(mm, addr);
+ pud = pud_alloc(mm, pgd, addr);
+ if (!pud)
+ return NULL;
+
+ if (sz == PUD_SIZE) {
+ pte = (pte_t *)pud;
+ } else if (sz == (PAGE_SIZE * CONT_PTES)) {
+ pmd_t *pmd = pmd_alloc(mm, pud, addr);
+
+ WARN_ON(addr & (sz - 1));
+ pte = pte_alloc_map(mm, NULL, pmd, addr);
We get away with this on arm64 because we don't have high memory.
If one were to port this to 32-bit ARM, then this would break as it
would leave a mapping open.
(i.e. there's no corresponding pte_unmap(.) to line up with the
pte_offset_map from pte_alloc_map).
Maybe worth a quick comment for potential porters that they need to
either disable CONFIG_HIGHPTE or rework the page table page allocation
for contiguous ptes (tricky as one may already have non-contiguous
ptes present).
+ } else if (sz == PMD_SIZE) {
+ if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
+ pud_none(*pud))
+ pte = huge_pmd_share(mm, addr, pud);
+ else
+ pte = (pte_t *)pmd_alloc(mm, pud, addr);
+ } else if (sz == (PMD_SIZE * CONT_PMDS)) {
+ pmd_t *pmd;
+
+ pmd = pmd_alloc(mm, pud, addr);
+ WARN_ON(addr & (sz - 1));
+ return (pte_t *)pmd;
+ }
+
+ pr_debug("%s: addr:0x%lx sz:0x%lx ret pte=%p/0x%llx\n", __func__, addr,
+ sz, pte, pte_val(*pte));
+ return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+ pte_t *pte = NULL;
+
+ pgd = pgd_offset(mm, addr);
+ pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);
+ if (!pgd_present(*pgd))
+ return NULL;
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud))
+ return NULL;
+
+ if (pud_huge(*pud))
+ return (pte_t *)pud;
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return NULL;
+
+ if (pte_cont(pmd_pte(*pmd))) {
+ pmd = pmd_offset(
+ pud, (addr & CONT_PMD_MASK));
+ return (pte_t *)pmd;
+ }
+ if (pmd_huge(*pmd))
+ return (pte_t *)pmd;
+ pte = pte_offset_kernel(pmd, addr);
+ if (pte_present(*pte) && pte_cont(*pte)) {
+ pte = pte_offset_kernel(
+ pmd, (addr & CONT_PTE_MASK));
Probably best return pte here.
+ }
+ return pte;
and NULL here to signify an error (as we get to the point where we
know that addr isn't referring to a huge page).
+}
+
+pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
+ struct page *page, int writable)
+{
+ size_t pagesize = huge_page_size(hstate_vma(vma));
+
+ if (pagesize == CONT_PTE_SIZE) {
+ entry = pte_mkcont(entry);
+ } else if (pagesize == CONT_PMD_SIZE) {
+ entry = pmd_pte(pmd_mkcont(pte_pmd(entry)));
+ } else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) {
+ pr_warn("%s: unrecognized huge page size 0x%lx\n",
+ __func__, pagesize);
+ }
+ return entry;
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ pte_t pte;
+
+ if (pte_cont(*ptep)) {
+ int ncontig, i;
+ size_t pgsize;
+ pte_t *cpte;
+ bool is_dirty = false;
+
+ cpte = huge_pte_offset(mm, addr);
+ ncontig = find_num_contig(mm, addr, cpte,
+ pte_val(*cpte), &pgsize);
The call to pte_val is spurious.
+ /* save the 1st pte to return */
+ pte = ptep_get_and_clear(mm, addr, cpte);
+ for (i = 1; i < ncontig; ++i) {
+ /*
+ * If HW_AFDBM is enabled, then the HW could
+ * turn on the dirty bit for any of the page
+ * in the set, so check them all.
+ */
+ ++cpte;
+ if (pte_dirty(ptep_get_and_clear(mm, addr, cpte)))
+ is_dirty = true;
Okay, ptep_get_and_clear uses the exclusive monitor to guard against
updates from AFDBM. The above looks good to me.
+ }
+ if (is_dirty)
+ return pte_mkdirty(pte);
+ else
+ return pte;
+ } else {
+ return ptep_get_and_clear(mm, addr, ptep);
+ }
+}
+
+int huge_ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep,
+ pte_t pte, int dirty)
+{
+ pte_t *cpte;
+
+ if (pte_cont(pte)) {
+ int ncontig, i, changed = 0;
+ size_t pgsize = 0;
+ unsigned long pfn = pte_pfn(pte);
+ /* Select all bits except the pfn */
+ pgprot_t hugeprot =
+ __pgprot(pte_val(pfn_pte(pfn, 0) ^ pte_val(pte)));
pfn_pte needs the second argument wrapping with __pgprot(.)
+
+ cpte = huge_pte_offset(vma->vm_mm, addr);
+ pfn = pte_pfn(*cpte);
+ ncontig = find_num_contig(vma->vm_mm, addr, cpte,
+ pte_val(*cpte), &pgsize);
The call to pte_val(.) is spurious.
+ for (i = 0; i < ncontig; ++i, ++cpte) {
+ changed = ptep_set_access_flags(vma, addr, cpte,
+ pfn_pte(pfn,
+ hugeprot),
+ dirty);
ptep_set_access_flags calls through to set_pte_at which will warn if
we are in a scenario where we can lose dirty information. So this code
looks okay for AFDBM to me.
+ pfn += pgsize >> PAGE_SHIFT;
+ }
+ return changed;
+ } else {
+ return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
+ }
+}
+
+void huge_ptep_set_wrprotect(struct mm_struct *mm,
+ unsigned long addr, pte_t *ptep)
+{
+ if (pte_cont(*ptep)) {
+ int ncontig, i;
+ pte_t *cpte;
+ size_t pgsize = 0;
+
+ cpte = huge_pte_offset(mm, addr);
+ ncontig = find_num_contig(mm, addr, cpte,
+ pte_val(*cpte), &pgsize);
The call to pte_val is spurious(.).
+ for (i = 0; i < ncontig; ++i, ++cpte)
+ ptep_set_wrprotect(mm, addr, cpte);
+ } else {
+ ptep_set_wrprotect(mm, addr, ptep);
+ }
ptep_set_wrprotect uses the exclusive monitor, thus is protected from
AFDBM. This looks good to me.
+}
+
+void huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *ptep)
+{
+ if (pte_cont(*ptep)) {
+ int ncontig, i;
+ pte_t *cpte;
+ size_t pgsize = 0;
+
+ cpte = huge_pte_offset(vma->vm_mm, addr);
+ ncontig = find_num_contig(vma->vm_mm, addr, cpte,
+ pte_val(*cpte), &pgsize);
Call to pte_val is spurious.
+ for (i = 0; i < ncontig; ++i, ++cpte)
+ ptep_clear_flush(vma, addr, cpte);
+ } else {
+ ptep_clear_flush(vma, addr, ptep);
+ }
+}
+
static __init int setup_hugepagesz(char *opt)
{
unsigned long ps = memparse(opt, &opt);
+
if (ps == PMD_SIZE) {
hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
} else if (ps == PUD_SIZE) {
hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
+ } else if (ps == (PAGE_SIZE * CONT_PTES)) {
+ hugetlb_add_hstate(CONT_PTE_SHIFT);
+ } else if (ps == (PMD_SIZE * CONT_PMDS)) {
+ hugetlb_add_hstate((PMD_SHIFT + CONT_PMD_SHIFT) - PAGE_SHIFT);
} else {
- pr_err("hugepagesz: Unsupported page size %lu M\n", ps >> 20);
+ pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
return 0;
}
return 1;
}
__setup("hugepagesz=", setup_hugepagesz);
+
+#ifdef CONFIG_ARM64_64K_PAGES
+static __init int add_default_hugepagesz(void)
+{
+ if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
+ hugetlb_add_hstate(CONT_PMD_SHIFT);
+ return 0;
+}
+arch_initcall(add_default_hugepagesz);
+#endif
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 685c262..b0eb064 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -96,9 +96,7 @@ u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
struct address_space *mapping,
pgoff_t idx, unsigned long address);
-#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
-#endif
extern int hugepages_treat_as_movable;
extern int sysctl_hugetlb_shm_group;
--
2.1.2