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-rw-r--r--arch/powerpc/mm/hugetlbpage.c658
1 files changed, 658 insertions, 0 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
new file mode 100644
index 000000000..5852a86d9
--- /dev/null
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -0,0 +1,658 @@
+/*
+ * PPC Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2003 David Gibson, IBM Corporation.
+ * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor
+ *
+ * Based on the IA-32 version:
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/hugetlb.h>
+#include <linux/export.h>
+#include <linux/of_fdt.h>
+#include <linux/memblock.h>
+#include <linux/moduleparam.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/kmemleak.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/setup.h>
+#include <asm/hugetlb.h>
+#include <asm/pte-walk.h>
+#include <asm/firmware.h>
+
+bool hugetlb_disabled = false;
+
+#define hugepd_none(hpd) (hpd_val(hpd) == 0)
+
+#define PTE_T_ORDER (__builtin_ffs(sizeof(pte_basic_t)) - \
+ __builtin_ffs(sizeof(void *)))
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz)
+{
+ /*
+ * Only called for hugetlbfs pages, hence can ignore THP and the
+ * irq disabled walk.
+ */
+ return __find_linux_pte(mm->pgd, addr, NULL, NULL);
+}
+
+static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
+ unsigned long address, unsigned int pdshift,
+ unsigned int pshift, spinlock_t *ptl)
+{
+ struct kmem_cache *cachep;
+ pte_t *new;
+ int i;
+ int num_hugepd;
+
+ if (pshift >= pdshift) {
+ cachep = PGT_CACHE(PTE_T_ORDER);
+ num_hugepd = 1 << (pshift - pdshift);
+ } else {
+ cachep = PGT_CACHE(pdshift - pshift);
+ num_hugepd = 1;
+ }
+
+ if (!cachep) {
+ WARN_ONCE(1, "No page table cache created for hugetlb tables");
+ return -ENOMEM;
+ }
+
+ new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
+
+ BUG_ON(pshift > HUGEPD_SHIFT_MASK);
+ BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
+
+ if (!new)
+ return -ENOMEM;
+
+ /*
+ * Make sure other cpus find the hugepd set only after a
+ * properly initialized page table is visible to them.
+ * For more details look for comment in __pte_alloc().
+ */
+ smp_wmb();
+
+ spin_lock(ptl);
+ /*
+ * We have multiple higher-level entries that point to the same
+ * actual pte location. Fill in each as we go and backtrack on error.
+ * We need all of these so the DTLB pgtable walk code can find the
+ * right higher-level entry without knowing if it's a hugepage or not.
+ */
+ for (i = 0; i < num_hugepd; i++, hpdp++) {
+ if (unlikely(!hugepd_none(*hpdp)))
+ break;
+ hugepd_populate(hpdp, new, pshift);
+ }
+ /* If we bailed from the for loop early, an error occurred, clean up */
+ if (i < num_hugepd) {
+ for (i = i - 1 ; i >= 0; i--, hpdp--)
+ *hpdp = __hugepd(0);
+ kmem_cache_free(cachep, new);
+ } else {
+ kmemleak_ignore(new);
+ }
+ spin_unlock(ptl);
+ return 0;
+}
+
+/*
+ * At this point we do the placement change only for BOOK3S 64. This would
+ * possibly work on other subarchs.
+ */
+pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long sz)
+{
+ pgd_t *pg;
+ p4d_t *p4;
+ pud_t *pu;
+ pmd_t *pm;
+ hugepd_t *hpdp = NULL;
+ unsigned pshift = __ffs(sz);
+ unsigned pdshift = PGDIR_SHIFT;
+ spinlock_t *ptl;
+
+ addr &= ~(sz-1);
+ pg = pgd_offset(mm, addr);
+ p4 = p4d_offset(pg, addr);
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (pshift == PGDIR_SHIFT)
+ /* 16GB huge page */
+ return (pte_t *) p4;
+ else if (pshift > PUD_SHIFT) {
+ /*
+ * We need to use hugepd table
+ */
+ ptl = &mm->page_table_lock;
+ hpdp = (hugepd_t *)p4;
+ } else {
+ pdshift = PUD_SHIFT;
+ pu = pud_alloc(mm, p4, addr);
+ if (!pu)
+ return NULL;
+ if (pshift == PUD_SHIFT)
+ return (pte_t *)pu;
+ else if (pshift > PMD_SHIFT) {
+ ptl = pud_lockptr(mm, pu);
+ hpdp = (hugepd_t *)pu;
+ } else {
+ pdshift = PMD_SHIFT;
+ pm = pmd_alloc(mm, pu, addr);
+ if (!pm)
+ return NULL;
+ if (pshift == PMD_SHIFT)
+ /* 16MB hugepage */
+ return (pte_t *)pm;
+ else {
+ ptl = pmd_lockptr(mm, pm);
+ hpdp = (hugepd_t *)pm;
+ }
+ }
+ }
+#else
+ if (pshift >= PGDIR_SHIFT) {
+ ptl = &mm->page_table_lock;
+ hpdp = (hugepd_t *)p4;
+ } else {
+ pdshift = PUD_SHIFT;
+ pu = pud_alloc(mm, p4, addr);
+ if (!pu)
+ return NULL;
+ if (pshift >= PUD_SHIFT) {
+ ptl = pud_lockptr(mm, pu);
+ hpdp = (hugepd_t *)pu;
+ } else {
+ pdshift = PMD_SHIFT;
+ pm = pmd_alloc(mm, pu, addr);
+ if (!pm)
+ return NULL;
+ ptl = pmd_lockptr(mm, pm);
+ hpdp = (hugepd_t *)pm;
+ }
+ }
+#endif
+ if (!hpdp)
+ return NULL;
+
+ if (IS_ENABLED(CONFIG_PPC_8xx) && pshift < PMD_SHIFT)
+ return pte_alloc_map(mm, (pmd_t *)hpdp, addr);
+
+ BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
+
+ if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
+ pdshift, pshift, ptl))
+ return NULL;
+
+ return hugepte_offset(*hpdp, addr, pdshift);
+}
+
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * Tracks gpages after the device tree is scanned and before the
+ * huge_boot_pages list is ready on pseries.
+ */
+#define MAX_NUMBER_GPAGES 1024
+__initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES];
+__initdata static unsigned nr_gpages;
+
+/*
+ * Build list of addresses of gigantic pages. This function is used in early
+ * boot before the buddy allocator is setup.
+ */
+void __init pseries_add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
+{
+ if (!addr)
+ return;
+ while (number_of_pages > 0) {
+ gpage_freearray[nr_gpages] = addr;
+ nr_gpages++;
+ number_of_pages--;
+ addr += page_size;
+ }
+}
+
+static int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
+{
+ struct huge_bootmem_page *m;
+ if (nr_gpages == 0)
+ return 0;
+ m = phys_to_virt(gpage_freearray[--nr_gpages]);
+ gpage_freearray[nr_gpages] = 0;
+ list_add(&m->list, &huge_boot_pages);
+ m->hstate = hstate;
+ return 1;
+}
+
+bool __init hugetlb_node_alloc_supported(void)
+{
+ return false;
+}
+#endif
+
+
+int __init alloc_bootmem_huge_page(struct hstate *h, int nid)
+{
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
+ return pseries_alloc_bootmem_huge_page(h);
+#endif
+ return __alloc_bootmem_huge_page(h, nid);
+}
+
+#ifndef CONFIG_PPC_BOOK3S_64
+#define HUGEPD_FREELIST_SIZE \
+ ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
+
+struct hugepd_freelist {
+ struct rcu_head rcu;
+ unsigned int index;
+ void *ptes[];
+};
+
+static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
+
+static void hugepd_free_rcu_callback(struct rcu_head *head)
+{
+ struct hugepd_freelist *batch =
+ container_of(head, struct hugepd_freelist, rcu);
+ unsigned int i;
+
+ for (i = 0; i < batch->index; i++)
+ kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
+
+ free_page((unsigned long)batch);
+}
+
+static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
+{
+ struct hugepd_freelist **batchp;
+
+ batchp = &get_cpu_var(hugepd_freelist_cur);
+
+ if (atomic_read(&tlb->mm->mm_users) < 2 ||
+ mm_is_thread_local(tlb->mm)) {
+ kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
+ put_cpu_var(hugepd_freelist_cur);
+ return;
+ }
+
+ if (*batchp == NULL) {
+ *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
+ (*batchp)->index = 0;
+ }
+
+ (*batchp)->ptes[(*batchp)->index++] = hugepte;
+ if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
+ call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
+ *batchp = NULL;
+ }
+ put_cpu_var(hugepd_freelist_cur);
+}
+#else
+static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
+#endif
+
+/* Return true when the entry to be freed maps more than the area being freed */
+static bool range_is_outside_limits(unsigned long start, unsigned long end,
+ unsigned long floor, unsigned long ceiling,
+ unsigned long mask)
+{
+ if ((start & mask) < floor)
+ return true;
+ if (ceiling) {
+ ceiling &= mask;
+ if (!ceiling)
+ return true;
+ }
+ return end - 1 > ceiling - 1;
+}
+
+static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
+ unsigned long start, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pte_t *hugepte = hugepd_page(*hpdp);
+ int i;
+
+ unsigned long pdmask = ~((1UL << pdshift) - 1);
+ unsigned int num_hugepd = 1;
+ unsigned int shift = hugepd_shift(*hpdp);
+
+ /* Note: On fsl the hpdp may be the first of several */
+ if (shift > pdshift)
+ num_hugepd = 1 << (shift - pdshift);
+
+ if (range_is_outside_limits(start, end, floor, ceiling, pdmask))
+ return;
+
+ for (i = 0; i < num_hugepd; i++, hpdp++)
+ *hpdp = __hugepd(0);
+
+ if (shift >= pdshift)
+ hugepd_free(tlb, hugepte);
+ else
+ pgtable_free_tlb(tlb, hugepte,
+ get_hugepd_cache_index(pdshift - shift));
+}
+
+static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pgtable_t token = pmd_pgtable(*pmd);
+
+ if (range_is_outside_limits(addr, end, floor, ceiling, PMD_MASK))
+ return;
+
+ pmd_clear(pmd);
+ pte_free_tlb(tlb, token, addr);
+ mm_dec_nr_ptes(tlb->mm);
+}
+
+static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pmd_t *pmd;
+ unsigned long next;
+ unsigned long start;
+
+ start = addr;
+ do {
+ unsigned long more;
+
+ pmd = pmd_offset(pud, addr);
+ next = pmd_addr_end(addr, end);
+ if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
+ if (pmd_none_or_clear_bad(pmd))
+ continue;
+
+ /*
+ * if it is not hugepd pointer, we should already find
+ * it cleared.
+ */
+ WARN_ON(!IS_ENABLED(CONFIG_PPC_8xx));
+
+ hugetlb_free_pte_range(tlb, pmd, addr, end, floor, ceiling);
+
+ continue;
+ }
+ /*
+ * Increment next by the size of the huge mapping since
+ * there may be more than one entry at this level for a
+ * single hugepage, but all of them point to
+ * the same kmem cache that holds the hugepte.
+ */
+ more = addr + (1UL << hugepd_shift(*(hugepd_t *)pmd));
+ if (more > next)
+ next = more;
+
+ free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
+ addr, next, floor, ceiling);
+ } while (addr = next, addr != end);
+
+ if (range_is_outside_limits(start, end, floor, ceiling, PUD_MASK))
+ return;
+
+ pmd = pmd_offset(pud, start & PUD_MASK);
+ pud_clear(pud);
+ pmd_free_tlb(tlb, pmd, start & PUD_MASK);
+ mm_dec_nr_pmds(tlb->mm);
+}
+
+static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pud_t *pud;
+ unsigned long next;
+ unsigned long start;
+
+ start = addr;
+ do {
+ pud = pud_offset(p4d, addr);
+ next = pud_addr_end(addr, end);
+ if (!is_hugepd(__hugepd(pud_val(*pud)))) {
+ if (pud_none_or_clear_bad(pud))
+ continue;
+ hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
+ ceiling);
+ } else {
+ unsigned long more;
+ /*
+ * Increment next by the size of the huge mapping since
+ * there may be more than one entry at this level for a
+ * single hugepage, but all of them point to
+ * the same kmem cache that holds the hugepte.
+ */
+ more = addr + (1UL << hugepd_shift(*(hugepd_t *)pud));
+ if (more > next)
+ next = more;
+
+ free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
+ addr, next, floor, ceiling);
+ }
+ } while (addr = next, addr != end);
+
+ if (range_is_outside_limits(start, end, floor, ceiling, PGDIR_MASK))
+ return;
+
+ pud = pud_offset(p4d, start & PGDIR_MASK);
+ p4d_clear(p4d);
+ pud_free_tlb(tlb, pud, start & PGDIR_MASK);
+ mm_dec_nr_puds(tlb->mm);
+}
+
+/*
+ * This function frees user-level page tables of a process.
+ */
+void hugetlb_free_pgd_range(struct mmu_gather *tlb,
+ unsigned long addr, unsigned long end,
+ unsigned long floor, unsigned long ceiling)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ unsigned long next;
+
+ /*
+ * Because there are a number of different possible pagetable
+ * layouts for hugepage ranges, we limit knowledge of how
+ * things should be laid out to the allocation path
+ * (huge_pte_alloc(), above). Everything else works out the
+ * structure as it goes from information in the hugepd
+ * pointers. That means that we can't here use the
+ * optimization used in the normal page free_pgd_range(), of
+ * checking whether we're actually covering a large enough
+ * range to have to do anything at the top level of the walk
+ * instead of at the bottom.
+ *
+ * To make sense of this, you should probably go read the big
+ * block comment at the top of the normal free_pgd_range(),
+ * too.
+ */
+
+ do {
+ next = pgd_addr_end(addr, end);
+ pgd = pgd_offset(tlb->mm, addr);
+ p4d = p4d_offset(pgd, addr);
+ if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
+ if (p4d_none_or_clear_bad(p4d))
+ continue;
+ hugetlb_free_pud_range(tlb, p4d, addr, next, floor, ceiling);
+ } else {
+ unsigned long more;
+ /*
+ * Increment next by the size of the huge mapping since
+ * there may be more than one entry at the pgd level
+ * for a single hugepage, but all of them point to the
+ * same kmem cache that holds the hugepte.
+ */
+ more = addr + (1UL << hugepd_shift(*(hugepd_t *)pgd));
+ if (more > next)
+ next = more;
+
+ free_hugepd_range(tlb, (hugepd_t *)p4d, PGDIR_SHIFT,
+ addr, next, floor, ceiling);
+ }
+ } while (addr = next, addr != end);
+}
+
+struct page *follow_huge_pd(struct vm_area_struct *vma,
+ unsigned long address, hugepd_t hpd,
+ int flags, int pdshift)
+{
+ pte_t *ptep;
+ spinlock_t *ptl;
+ struct page *page = NULL;
+ unsigned long mask;
+ int shift = hugepd_shift(hpd);
+ struct mm_struct *mm = vma->vm_mm;
+
+retry:
+ /*
+ * hugepage directory entries are protected by mm->page_table_lock
+ * Use this instead of huge_pte_lockptr
+ */
+ ptl = &mm->page_table_lock;
+ spin_lock(ptl);
+
+ ptep = hugepte_offset(hpd, address, pdshift);
+ if (pte_present(*ptep)) {
+ mask = (1UL << shift) - 1;
+ page = pte_page(*ptep);
+ page += ((address & mask) >> PAGE_SHIFT);
+ if (flags & FOLL_GET)
+ get_page(page);
+ } else {
+ if (is_hugetlb_entry_migration(*ptep)) {
+ spin_unlock(ptl);
+ __migration_entry_wait(mm, ptep, ptl);
+ goto retry;
+ }
+ }
+ spin_unlock(ptl);
+ return page;
+}
+
+bool __init arch_hugetlb_valid_size(unsigned long size)
+{
+ int shift = __ffs(size);
+ int mmu_psize;
+
+ /* Check that it is a page size supported by the hardware and
+ * that it fits within pagetable and slice limits. */
+ if (size <= PAGE_SIZE || !is_power_of_2(size))
+ return false;
+
+ mmu_psize = check_and_get_huge_psize(shift);
+ if (mmu_psize < 0)
+ return false;
+
+ BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
+
+ return true;
+}
+
+static int __init add_huge_page_size(unsigned long long size)
+{
+ int shift = __ffs(size);
+
+ if (!arch_hugetlb_valid_size((unsigned long)size))
+ return -EINVAL;
+
+ hugetlb_add_hstate(shift - PAGE_SHIFT);
+ return 0;
+}
+
+static int __init hugetlbpage_init(void)
+{
+ bool configured = false;
+ int psize;
+
+ if (hugetlb_disabled) {
+ pr_info("HugeTLB support is disabled!\n");
+ return 0;
+ }
+
+ if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled() &&
+ !mmu_has_feature(MMU_FTR_16M_PAGE))
+ return -ENODEV;
+
+ for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
+ unsigned shift;
+ unsigned pdshift;
+
+ if (!mmu_psize_defs[psize].shift)
+ continue;
+
+ shift = mmu_psize_to_shift(psize);
+
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (shift > PGDIR_SHIFT)
+ continue;
+ else if (shift > PUD_SHIFT)
+ pdshift = PGDIR_SHIFT;
+ else if (shift > PMD_SHIFT)
+ pdshift = PUD_SHIFT;
+ else
+ pdshift = PMD_SHIFT;
+#else
+ if (shift < PUD_SHIFT)
+ pdshift = PMD_SHIFT;
+ else if (shift < PGDIR_SHIFT)
+ pdshift = PUD_SHIFT;
+ else
+ pdshift = PGDIR_SHIFT;
+#endif
+
+ if (add_huge_page_size(1ULL << shift) < 0)
+ continue;
+ /*
+ * if we have pdshift and shift value same, we don't
+ * use pgt cache for hugepd.
+ */
+ if (pdshift > shift) {
+ if (!IS_ENABLED(CONFIG_PPC_8xx))
+ pgtable_cache_add(pdshift - shift);
+ } else if (IS_ENABLED(CONFIG_PPC_E500) ||
+ IS_ENABLED(CONFIG_PPC_8xx)) {
+ pgtable_cache_add(PTE_T_ORDER);
+ }
+
+ configured = true;
+ }
+
+ if (!configured)
+ pr_info("Failed to initialize. Disabling HugeTLB");
+
+ return 0;
+}
+
+arch_initcall(hugetlbpage_init);
+
+void __init gigantic_hugetlb_cma_reserve(void)
+{
+ unsigned long order = 0;
+
+ if (radix_enabled())
+ order = PUD_SHIFT - PAGE_SHIFT;
+ else if (!firmware_has_feature(FW_FEATURE_LPAR) && mmu_psize_defs[MMU_PAGE_16G].shift)
+ /*
+ * For pseries we do use ibm,expected#pages for reserving 16G pages.
+ */
+ order = mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT;
+
+ if (order) {
+ VM_WARN_ON(order < MAX_ORDER);
+ hugetlb_cma_reserve(order);
+ }
+}
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