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-rw-r--r--arch/powerpc/mm/pgtable_64.c884
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diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
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+/*
+ * This file contains ioremap and related functions for 64-bit machines.
+ *
+ * Derived from arch/ppc64/mm/init.c
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
+ * and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ * Copyright (C) 1996 Paul Mackerras
+ *
+ * Derived from "arch/i386/mm/init.c"
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ *
+ * Dave Engebretsen <engebret@us.ibm.com>
+ * Rework for PPC64 port.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/memblock.h>
+#include <linux/slab.h>
+#include <linux/hugetlb.h>
+
+#include <asm/pgalloc.h>
+#include <asm/page.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/tlb.h>
+#include <asm/processor.h>
+#include <asm/cputable.h>
+#include <asm/sections.h>
+#include <asm/firmware.h>
+#include <asm/dma.h>
+
+#include "mmu_decl.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/thp.h>
+
+/* Some sanity checking */
+#if TASK_SIZE_USER64 > PGTABLE_RANGE
+#error TASK_SIZE_USER64 exceeds pagetable range
+#endif
+
+#ifdef CONFIG_PPC_STD_MMU_64
+#if TASK_SIZE_USER64 > (1UL << (ESID_BITS + SID_SHIFT))
+#error TASK_SIZE_USER64 exceeds user VSID range
+#endif
+#endif
+
+unsigned long ioremap_bot = IOREMAP_BASE;
+
+#ifdef CONFIG_PPC_MMU_NOHASH
+static __ref void *early_alloc_pgtable(unsigned long size)
+{
+ void *pt;
+
+ pt = __va(memblock_alloc_base(size, size, __pa(MAX_DMA_ADDRESS)));
+ memset(pt, 0, size);
+
+ return pt;
+}
+#endif /* CONFIG_PPC_MMU_NOHASH */
+
+/*
+ * map_kernel_page currently only called by __ioremap
+ * map_kernel_page adds an entry to the ioremap page table
+ * and adds an entry to the HPT, possibly bolting it
+ */
+int map_kernel_page(unsigned long ea, unsigned long pa, int flags)
+{
+ pgd_t *pgdp;
+ pud_t *pudp;
+ pmd_t *pmdp;
+ pte_t *ptep;
+
+ if (slab_is_available()) {
+ pgdp = pgd_offset_k(ea);
+ pudp = pud_alloc(&init_mm, pgdp, ea);
+ if (!pudp)
+ return -ENOMEM;
+ pmdp = pmd_alloc(&init_mm, pudp, ea);
+ if (!pmdp)
+ return -ENOMEM;
+ ptep = pte_alloc_kernel(pmdp, ea);
+ if (!ptep)
+ return -ENOMEM;
+ set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
+ __pgprot(flags)));
+ } else {
+#ifdef CONFIG_PPC_MMU_NOHASH
+ pgdp = pgd_offset_k(ea);
+#ifdef PUD_TABLE_SIZE
+ if (pgd_none(*pgdp)) {
+ pudp = early_alloc_pgtable(PUD_TABLE_SIZE);
+ BUG_ON(pudp == NULL);
+ pgd_populate(&init_mm, pgdp, pudp);
+ }
+#endif /* PUD_TABLE_SIZE */
+ pudp = pud_offset(pgdp, ea);
+ if (pud_none(*pudp)) {
+ pmdp = early_alloc_pgtable(PMD_TABLE_SIZE);
+ BUG_ON(pmdp == NULL);
+ pud_populate(&init_mm, pudp, pmdp);
+ }
+ pmdp = pmd_offset(pudp, ea);
+ if (!pmd_present(*pmdp)) {
+ ptep = early_alloc_pgtable(PAGE_SIZE);
+ BUG_ON(ptep == NULL);
+ pmd_populate_kernel(&init_mm, pmdp, ptep);
+ }
+ ptep = pte_offset_kernel(pmdp, ea);
+ set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
+ __pgprot(flags)));
+#else /* CONFIG_PPC_MMU_NOHASH */
+ /*
+ * If the mm subsystem is not fully up, we cannot create a
+ * linux page table entry for this mapping. Simply bolt an
+ * entry in the hardware page table.
+ *
+ */
+ if (htab_bolt_mapping(ea, ea + PAGE_SIZE, pa, flags,
+ mmu_io_psize, mmu_kernel_ssize)) {
+ printk(KERN_ERR "Failed to do bolted mapping IO "
+ "memory at %016lx !\n", pa);
+ return -ENOMEM;
+ }
+#endif /* !CONFIG_PPC_MMU_NOHASH */
+ }
+
+#ifdef CONFIG_PPC_BOOK3E_64
+ /*
+ * With hardware tablewalk, a sync is needed to ensure that
+ * subsequent accesses see the PTE we just wrote. Unlike userspace
+ * mappings, we can't tolerate spurious faults, so make sure
+ * the new PTE will be seen the first time.
+ */
+ mb();
+#else
+ smp_wmb();
+#endif
+ return 0;
+}
+
+
+/**
+ * __ioremap_at - Low level function to establish the page tables
+ * for an IO mapping
+ */
+void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
+ unsigned long flags)
+{
+ unsigned long i;
+
+ /* Make sure we have the base flags */
+ if ((flags & _PAGE_PRESENT) == 0)
+ flags |= pgprot_val(PAGE_KERNEL);
+
+ /* Non-cacheable page cannot be coherent */
+ if (flags & _PAGE_NO_CACHE)
+ flags &= ~_PAGE_COHERENT;
+
+ /* We don't support the 4K PFN hack with ioremap */
+ if (flags & _PAGE_4K_PFN)
+ return NULL;
+
+ WARN_ON(pa & ~PAGE_MASK);
+ WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
+ WARN_ON(size & ~PAGE_MASK);
+
+ for (i = 0; i < size; i += PAGE_SIZE)
+ if (map_kernel_page((unsigned long)ea+i, pa+i, flags))
+ return NULL;
+
+ return (void __iomem *)ea;
+}
+
+/**
+ * __iounmap_from - Low level function to tear down the page tables
+ * for an IO mapping. This is used for mappings that
+ * are manipulated manually, like partial unmapping of
+ * PCI IOs or ISA space.
+ */
+void __iounmap_at(void *ea, unsigned long size)
+{
+ WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
+ WARN_ON(size & ~PAGE_MASK);
+
+ unmap_kernel_range((unsigned long)ea, size);
+}
+
+void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
+ unsigned long flags, void *caller)
+{
+ phys_addr_t paligned;
+ void __iomem *ret;
+
+ /*
+ * Choose an address to map it to.
+ * Once the imalloc system is running, we use it.
+ * Before that, we map using addresses going
+ * up from ioremap_bot. imalloc will use
+ * the addresses from ioremap_bot through
+ * IMALLOC_END
+ *
+ */
+ paligned = addr & PAGE_MASK;
+ size = PAGE_ALIGN(addr + size) - paligned;
+
+ if ((size == 0) || (paligned == 0))
+ return NULL;
+
+ if (slab_is_available()) {
+ struct vm_struct *area;
+
+ area = __get_vm_area_caller(size, VM_IOREMAP,
+ ioremap_bot, IOREMAP_END,
+ caller);
+ if (area == NULL)
+ return NULL;
+
+ area->phys_addr = paligned;
+ ret = __ioremap_at(paligned, area->addr, size, flags);
+ if (!ret)
+ vunmap(area->addr);
+ } else {
+ ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
+ if (ret)
+ ioremap_bot += size;
+ }
+
+ if (ret)
+ ret += addr & ~PAGE_MASK;
+ return ret;
+}
+
+void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
+ unsigned long flags)
+{
+ return __ioremap_caller(addr, size, flags, __builtin_return_address(0));
+}
+
+void __iomem * ioremap(phys_addr_t addr, unsigned long size)
+{
+ unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
+ void *caller = __builtin_return_address(0);
+
+ if (ppc_md.ioremap)
+ return ppc_md.ioremap(addr, size, flags, caller);
+ return __ioremap_caller(addr, size, flags, caller);
+}
+
+void __iomem * ioremap_wc(phys_addr_t addr, unsigned long size)
+{
+ unsigned long flags = _PAGE_NO_CACHE;
+ void *caller = __builtin_return_address(0);
+
+ if (ppc_md.ioremap)
+ return ppc_md.ioremap(addr, size, flags, caller);
+ return __ioremap_caller(addr, size, flags, caller);
+}
+
+void __iomem * ioremap_prot(phys_addr_t addr, unsigned long size,
+ unsigned long flags)
+{
+ void *caller = __builtin_return_address(0);
+
+ /* writeable implies dirty for kernel addresses */
+ if (flags & _PAGE_RW)
+ flags |= _PAGE_DIRTY;
+
+ /* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
+ flags &= ~(_PAGE_USER | _PAGE_EXEC);
+
+#ifdef _PAGE_BAP_SR
+ /* _PAGE_USER contains _PAGE_BAP_SR on BookE using the new PTE format
+ * which means that we just cleared supervisor access... oops ;-) This
+ * restores it
+ */
+ flags |= _PAGE_BAP_SR;
+#endif
+
+ if (ppc_md.ioremap)
+ return ppc_md.ioremap(addr, size, flags, caller);
+ return __ioremap_caller(addr, size, flags, caller);
+}
+
+
+/*
+ * Unmap an IO region and remove it from imalloc'd list.
+ * Access to IO memory should be serialized by driver.
+ */
+void __iounmap(volatile void __iomem *token)
+{
+ void *addr;
+
+ if (!slab_is_available())
+ return;
+
+ addr = (void *) ((unsigned long __force)
+ PCI_FIX_ADDR(token) & PAGE_MASK);
+ if ((unsigned long)addr < ioremap_bot) {
+ printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
+ " at 0x%p\n", addr);
+ return;
+ }
+ vunmap(addr);
+}
+
+void iounmap(volatile void __iomem *token)
+{
+ if (ppc_md.iounmap)
+ ppc_md.iounmap(token);
+ else
+ __iounmap(token);
+}
+
+EXPORT_SYMBOL(ioremap);
+EXPORT_SYMBOL(ioremap_wc);
+EXPORT_SYMBOL(ioremap_prot);
+EXPORT_SYMBOL(__ioremap);
+EXPORT_SYMBOL(__ioremap_at);
+EXPORT_SYMBOL(iounmap);
+EXPORT_SYMBOL(__iounmap);
+EXPORT_SYMBOL(__iounmap_at);
+
+#ifndef __PAGETABLE_PUD_FOLDED
+/* 4 level page table */
+struct page *pgd_page(pgd_t pgd)
+{
+ if (pgd_huge(pgd))
+ return pte_page(pgd_pte(pgd));
+ return virt_to_page(pgd_page_vaddr(pgd));
+}
+#endif
+
+struct page *pud_page(pud_t pud)
+{
+ if (pud_huge(pud))
+ return pte_page(pud_pte(pud));
+ return virt_to_page(pud_page_vaddr(pud));
+}
+
+/*
+ * For hugepage we have pfn in the pmd, we use PTE_RPN_SHIFT bits for flags
+ * For PTE page, we have a PTE_FRAG_SIZE (4K) aligned virtual address.
+ */
+struct page *pmd_page(pmd_t pmd)
+{
+ if (pmd_trans_huge(pmd) || pmd_huge(pmd))
+ return pfn_to_page(pmd_pfn(pmd));
+ return virt_to_page(pmd_page_vaddr(pmd));
+}
+
+#ifdef CONFIG_PPC_64K_PAGES
+static pte_t *get_from_cache(struct mm_struct *mm)
+{
+ void *pte_frag, *ret;
+
+ spin_lock(&mm->page_table_lock);
+ ret = mm->context.pte_frag;
+ if (ret) {
+ pte_frag = ret + PTE_FRAG_SIZE;
+ /*
+ * If we have taken up all the fragments mark PTE page NULL
+ */
+ if (((unsigned long)pte_frag & ~PAGE_MASK) == 0)
+ pte_frag = NULL;
+ mm->context.pte_frag = pte_frag;
+ }
+ spin_unlock(&mm->page_table_lock);
+ return (pte_t *)ret;
+}
+
+static pte_t *__alloc_for_cache(struct mm_struct *mm, int kernel)
+{
+ void *ret = NULL;
+ struct page *page = alloc_page(GFP_KERNEL | __GFP_NOTRACK |
+ __GFP_REPEAT | __GFP_ZERO);
+ if (!page)
+ return NULL;
+ if (!kernel && !pgtable_page_ctor(page)) {
+ __free_page(page);
+ return NULL;
+ }
+
+ ret = page_address(page);
+ spin_lock(&mm->page_table_lock);
+ /*
+ * If we find pgtable_page set, we return
+ * the allocated page with single fragement
+ * count.
+ */
+ if (likely(!mm->context.pte_frag)) {
+ atomic_set(&page->_count, PTE_FRAG_NR);
+ mm->context.pte_frag = ret + PTE_FRAG_SIZE;
+ }
+ spin_unlock(&mm->page_table_lock);
+
+ return (pte_t *)ret;
+}
+
+pte_t *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr, int kernel)
+{
+ pte_t *pte;
+
+ pte = get_from_cache(mm);
+ if (pte)
+ return pte;
+
+ return __alloc_for_cache(mm, kernel);
+}
+
+void page_table_free(struct mm_struct *mm, unsigned long *table, int kernel)
+{
+ struct page *page = virt_to_page(table);
+ if (put_page_testzero(page)) {
+ if (!kernel)
+ pgtable_page_dtor(page);
+ free_hot_cold_page(page, 0);
+ }
+}
+
+#ifdef CONFIG_SMP
+static void page_table_free_rcu(void *table)
+{
+ struct page *page = virt_to_page(table);
+ if (put_page_testzero(page)) {
+ pgtable_page_dtor(page);
+ free_hot_cold_page(page, 0);
+ }
+}
+
+void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
+{
+ unsigned long pgf = (unsigned long)table;
+
+ BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
+ pgf |= shift;
+ tlb_remove_table(tlb, (void *)pgf);
+}
+
+void __tlb_remove_table(void *_table)
+{
+ void *table = (void *)((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE);
+ unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE;
+
+ if (!shift)
+ /* PTE page needs special handling */
+ page_table_free_rcu(table);
+ else {
+ BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
+ kmem_cache_free(PGT_CACHE(shift), table);
+ }
+}
+#else
+void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int shift)
+{
+ if (!shift) {
+ /* PTE page needs special handling */
+ struct page *page = virt_to_page(table);
+ if (put_page_testzero(page)) {
+ pgtable_page_dtor(page);
+ free_hot_cold_page(page, 0);
+ }
+ } else {
+ BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
+ kmem_cache_free(PGT_CACHE(shift), table);
+ }
+}
+#endif
+#endif /* CONFIG_PPC_64K_PAGES */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+
+/*
+ * This is called when relaxing access to a hugepage. It's also called in the page
+ * fault path when we don't hit any of the major fault cases, ie, a minor
+ * update of _PAGE_ACCESSED, _PAGE_DIRTY, etc... The generic code will have
+ * handled those two for us, we additionally deal with missing execute
+ * permission here on some processors
+ */
+int pmdp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp, pmd_t entry, int dirty)
+{
+ int changed;
+#ifdef CONFIG_DEBUG_VM
+ WARN_ON(!pmd_trans_huge(*pmdp));
+ assert_spin_locked(&vma->vm_mm->page_table_lock);
+#endif
+ changed = !pmd_same(*(pmdp), entry);
+ if (changed) {
+ __ptep_set_access_flags(pmdp_ptep(pmdp), pmd_pte(entry));
+ /*
+ * Since we are not supporting SW TLB systems, we don't
+ * have any thing similar to flush_tlb_page_nohash()
+ */
+ }
+ return changed;
+}
+
+unsigned long pmd_hugepage_update(struct mm_struct *mm, unsigned long addr,
+ pmd_t *pmdp, unsigned long clr,
+ unsigned long set)
+{
+
+ unsigned long old, tmp;
+
+#ifdef CONFIG_DEBUG_VM
+ WARN_ON(!pmd_trans_huge(*pmdp));
+ assert_spin_locked(&mm->page_table_lock);
+#endif
+
+#ifdef PTE_ATOMIC_UPDATES
+ __asm__ __volatile__(
+ "1: ldarx %0,0,%3\n\
+ andi. %1,%0,%6\n\
+ bne- 1b \n\
+ andc %1,%0,%4 \n\
+ or %1,%1,%7\n\
+ stdcx. %1,0,%3 \n\
+ bne- 1b"
+ : "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
+ : "r" (pmdp), "r" (clr), "m" (*pmdp), "i" (_PAGE_BUSY), "r" (set)
+ : "cc" );
+#else
+ old = pmd_val(*pmdp);
+ *pmdp = __pmd((old & ~clr) | set);
+#endif
+ trace_hugepage_update(addr, old, clr, set);
+ if (old & _PAGE_HASHPTE)
+ hpte_do_hugepage_flush(mm, addr, pmdp, old);
+ return old;
+}
+
+pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp)
+{
+ pmd_t pmd;
+
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ if (pmd_trans_huge(*pmdp)) {
+ pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp);
+ } else {
+ /*
+ * khugepaged calls this for normal pmd
+ */
+ pmd = *pmdp;
+ pmd_clear(pmdp);
+ /*
+ * Wait for all pending hash_page to finish. This is needed
+ * in case of subpage collapse. When we collapse normal pages
+ * to hugepage, we first clear the pmd, then invalidate all
+ * the PTE entries. The assumption here is that any low level
+ * page fault will see a none pmd and take the slow path that
+ * will wait on mmap_sem. But we could very well be in a
+ * hash_page with local ptep pointer value. Such a hash page
+ * can result in adding new HPTE entries for normal subpages.
+ * That means we could be modifying the page content as we
+ * copy them to a huge page. So wait for parallel hash_page
+ * to finish before invalidating HPTE entries. We can do this
+ * by sending an IPI to all the cpus and executing a dummy
+ * function there.
+ */
+ kick_all_cpus_sync();
+ /*
+ * Now invalidate the hpte entries in the range
+ * covered by pmd. This make sure we take a
+ * fault and will find the pmd as none, which will
+ * result in a major fault which takes mmap_sem and
+ * hence wait for collapse to complete. Without this
+ * the __collapse_huge_page_copy can result in copying
+ * the old content.
+ */
+ flush_tlb_pmd_range(vma->vm_mm, &pmd, address);
+ }
+ return pmd;
+}
+
+int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
+}
+
+/*
+ * We currently remove entries from the hashtable regardless of whether
+ * the entry was young or dirty. The generic routines only flush if the
+ * entry was young or dirty which is not good enough.
+ *
+ * We should be more intelligent about this but for the moment we override
+ * these functions and force a tlb flush unconditionally
+ */
+int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ return __pmdp_test_and_clear_young(vma->vm_mm, address, pmdp);
+}
+
+/*
+ * We mark the pmd splitting and invalidate all the hpte
+ * entries for this hugepage.
+ */
+void pmdp_splitting_flush(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ unsigned long old, tmp;
+
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+
+#ifdef CONFIG_DEBUG_VM
+ WARN_ON(!pmd_trans_huge(*pmdp));
+ assert_spin_locked(&vma->vm_mm->page_table_lock);
+#endif
+
+#ifdef PTE_ATOMIC_UPDATES
+
+ __asm__ __volatile__(
+ "1: ldarx %0,0,%3\n\
+ andi. %1,%0,%6\n\
+ bne- 1b \n\
+ ori %1,%0,%4 \n\
+ stdcx. %1,0,%3 \n\
+ bne- 1b"
+ : "=&r" (old), "=&r" (tmp), "=m" (*pmdp)
+ : "r" (pmdp), "i" (_PAGE_SPLITTING), "m" (*pmdp), "i" (_PAGE_BUSY)
+ : "cc" );
+#else
+ old = pmd_val(*pmdp);
+ *pmdp = __pmd(old | _PAGE_SPLITTING);
+#endif
+ /*
+ * If we didn't had the splitting flag set, go and flush the
+ * HPTE entries.
+ */
+ trace_hugepage_splitting(address, old);
+ if (!(old & _PAGE_SPLITTING)) {
+ /* We need to flush the hpte */
+ if (old & _PAGE_HASHPTE)
+ hpte_do_hugepage_flush(vma->vm_mm, address, pmdp, old);
+ }
+ /*
+ * This ensures that generic code that rely on IRQ disabling
+ * to prevent a parallel THP split work as expected.
+ */
+ kick_all_cpus_sync();
+}
+
+/*
+ * We want to put the pgtable in pmd and use pgtable for tracking
+ * the base page size hptes
+ */
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
+ pgtable_t pgtable)
+{
+ pgtable_t *pgtable_slot;
+ assert_spin_locked(&mm->page_table_lock);
+ /*
+ * we store the pgtable in the second half of PMD
+ */
+ pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+ *pgtable_slot = pgtable;
+ /*
+ * expose the deposited pgtable to other cpus.
+ * before we set the hugepage PTE at pmd level
+ * hash fault code looks at the deposted pgtable
+ * to store hash index values.
+ */
+ smp_wmb();
+}
+
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
+{
+ pgtable_t pgtable;
+ pgtable_t *pgtable_slot;
+
+ assert_spin_locked(&mm->page_table_lock);
+ pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+ pgtable = *pgtable_slot;
+ /*
+ * Once we withdraw, mark the entry NULL.
+ */
+ *pgtable_slot = NULL;
+ /*
+ * We store HPTE information in the deposited PTE fragment.
+ * zero out the content on withdraw.
+ */
+ memset(pgtable, 0, PTE_FRAG_SIZE);
+ return pgtable;
+}
+
+/*
+ * set a new huge pmd. We should not be called for updating
+ * an existing pmd entry. That should go via pmd_hugepage_update.
+ */
+void set_pmd_at(struct mm_struct *mm, unsigned long addr,
+ pmd_t *pmdp, pmd_t pmd)
+{
+#ifdef CONFIG_DEBUG_VM
+ WARN_ON((pmd_val(*pmdp) & (_PAGE_PRESENT | _PAGE_USER)) ==
+ (_PAGE_PRESENT | _PAGE_USER));
+ assert_spin_locked(&mm->page_table_lock);
+ WARN_ON(!pmd_trans_huge(pmd));
+#endif
+ trace_hugepage_set_pmd(addr, pmd_val(pmd));
+ return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
+}
+
+void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp)
+{
+ pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
+}
+
+/*
+ * A linux hugepage PMD was changed and the corresponding hash table entries
+ * neesd to be flushed.
+ */
+void hpte_do_hugepage_flush(struct mm_struct *mm, unsigned long addr,
+ pmd_t *pmdp, unsigned long old_pmd)
+{
+ int ssize;
+ unsigned int psize;
+ unsigned long vsid;
+ unsigned long flags = 0;
+ const struct cpumask *tmp;
+
+ /* get the base page size,vsid and segment size */
+#ifdef CONFIG_DEBUG_VM
+ psize = get_slice_psize(mm, addr);
+ BUG_ON(psize == MMU_PAGE_16M);
+#endif
+ if (old_pmd & _PAGE_COMBO)
+ psize = MMU_PAGE_4K;
+ else
+ psize = MMU_PAGE_64K;
+
+ if (!is_kernel_addr(addr)) {
+ ssize = user_segment_size(addr);
+ vsid = get_vsid(mm->context.id, addr, ssize);
+ WARN_ON(vsid == 0);
+ } else {
+ vsid = get_kernel_vsid(addr, mmu_kernel_ssize);
+ ssize = mmu_kernel_ssize;
+ }
+
+ tmp = cpumask_of(smp_processor_id());
+ if (cpumask_equal(mm_cpumask(mm), tmp))
+ flags |= HPTE_LOCAL_UPDATE;
+
+ return flush_hash_hugepage(vsid, addr, pmdp, psize, ssize, flags);
+}
+
+static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
+{
+ pmd_val(pmd) |= pgprot_val(pgprot);
+ return pmd;
+}
+
+pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
+{
+ pmd_t pmd;
+ /*
+ * For a valid pte, we would have _PAGE_PRESENT always
+ * set. We use this to check THP page at pmd level.
+ * leaf pte for huge page, bottom two bits != 00
+ */
+ pmd_val(pmd) = pfn << PTE_RPN_SHIFT;
+ pmd_val(pmd) |= _PAGE_THP_HUGE;
+ pmd = pmd_set_protbits(pmd, pgprot);
+ return pmd;
+}
+
+pmd_t mk_pmd(struct page *page, pgprot_t pgprot)
+{
+ return pfn_pmd(page_to_pfn(page), pgprot);
+}
+
+pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
+{
+
+ pmd_val(pmd) &= _HPAGE_CHG_MASK;
+ pmd = pmd_set_protbits(pmd, newprot);
+ return pmd;
+}
+
+/*
+ * This is called at the end of handling a user page fault, when the
+ * fault has been handled by updating a HUGE PMD entry in the linux page tables.
+ * We use it to preload an HPTE into the hash table corresponding to
+ * the updated linux HUGE PMD entry.
+ */
+void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
+ pmd_t *pmd)
+{
+ return;
+}
+
+pmd_t pmdp_get_and_clear(struct mm_struct *mm,
+ unsigned long addr, pmd_t *pmdp)
+{
+ pmd_t old_pmd;
+ pgtable_t pgtable;
+ unsigned long old;
+ pgtable_t *pgtable_slot;
+
+ old = pmd_hugepage_update(mm, addr, pmdp, ~0UL, 0);
+ old_pmd = __pmd(old);
+ /*
+ * We have pmd == none and we are holding page_table_lock.
+ * So we can safely go and clear the pgtable hash
+ * index info.
+ */
+ pgtable_slot = (pgtable_t *)pmdp + PTRS_PER_PMD;
+ pgtable = *pgtable_slot;
+ /*
+ * Let's zero out old valid and hash index details
+ * hash fault look at them.
+ */
+ memset(pgtable, 0, PTE_FRAG_SIZE);
+ /*
+ * Serialize against find_linux_pte_or_hugepte which does lock-less
+ * lookup in page tables with local interrupts disabled. For huge pages
+ * it casts pmd_t to pte_t. Since format of pte_t is different from
+ * pmd_t we want to prevent transit from pmd pointing to page table
+ * to pmd pointing to huge page (and back) while interrupts are disabled.
+ * We clear pmd to possibly replace it with page table pointer in
+ * different code paths. So make sure we wait for the parallel
+ * find_linux_pte_or_hugepage to finish.
+ */
+ kick_all_cpus_sync();
+ return old_pmd;
+}
+
+int has_transparent_hugepage(void)
+{
+ if (!mmu_has_feature(MMU_FTR_16M_PAGE))
+ return 0;
+ /*
+ * We support THP only if PMD_SIZE is 16MB.
+ */
+ if (mmu_psize_defs[MMU_PAGE_16M].shift != PMD_SHIFT)
+ return 0;
+ /*
+ * We need to make sure that we support 16MB hugepage in a segement
+ * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE
+ * of 64K.
+ */
+ /*
+ * If we have 64K HPTE, we will be using that by default
+ */
+ if (mmu_psize_defs[MMU_PAGE_64K].shift &&
+ (mmu_psize_defs[MMU_PAGE_64K].penc[MMU_PAGE_16M] == -1))
+ return 0;
+ /*
+ * Ok we only have 4K HPTE
+ */
+ if (mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M] == -1)
+ return 0;
+
+ return 1;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-01 23:57:08 +0000