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/*
* Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
*
* 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/sched.h>
#include <linux/mm_types.h>
#include <misc/cxl-base.h>
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include "mmu_decl.h"
#include <trace/events/thp.h>
int (*register_process_table)(unsigned long base, unsigned long page_size,
unsigned long tbl_size);
#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) && !pmd_devmap(*pmdp));
assert_spin_locked(&vma->vm_mm->page_table_lock);
#endif
changed = !pmd_same(*(pmdp), entry);
if (changed) {
__ptep_set_access_flags(vma->vm_mm, pmdp_ptep(pmdp),
pmd_pte(entry), address);
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
return changed;
}
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);
}
/*
* 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(pte_present(pmd_pte(*pmdp)) && !pte_protnone(pmd_pte(*pmdp)));
assert_spin_locked(&mm->page_table_lock);
WARN_ON(!(pmd_trans_huge(pmd) || pmd_devmap(pmd)));
#endif
trace_hugepage_set_pmd(addr, pmd_val(pmd));
return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
}
static void do_nothing(void *unused)
{
}
/*
* Serialize against find_current_mm_pte 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_current_mm_pte to finish.
*/
void serialize_against_pte_lookup(struct mm_struct *mm)
{
smp_mb();
smp_call_function_many(mm_cpumask(mm), do_nothing, NULL, 1);
}
/*
* We use this to invalidate a pmdp entry before switching from a
* hugepte to regular pmd entry.
*/
pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
{
unsigned long old_pmd;
old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
/*
* This ensures that generic code that rely on IRQ disabling
* to prevent a parallel THP split work as expected.
*/
serialize_against_pte_lookup(vma->vm_mm);
return __pmd(old_pmd);
}
static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
{
return __pmd(pmd_val(pmd) | pgprot_val(pgprot));
}
pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
{
unsigned long pmdv;
pmdv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK;
return pmd_set_protbits(__pmd(pmdv), pgprot);
}
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)
{
unsigned long pmdv;
pmdv = pmd_val(pmd);
pmdv &= _HPAGE_CHG_MASK;
return pmd_set_protbits(__pmd(pmdv), newprot);
}
/*
* 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;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/* For use by kexec */
void mmu_cleanup_all(void)
{
if (radix_enabled())
radix__mmu_cleanup_all();
else if (mmu_hash_ops.hpte_clear_all)
mmu_hash_ops.hpte_clear_all();
}
#ifdef CONFIG_MEMORY_HOTPLUG
int create_section_mapping(unsigned long start, unsigned long end)
{
if (radix_enabled())
return radix__create_section_mapping(start, end);
return hash__create_section_mapping(start, end);
}
int remove_section_mapping(unsigned long start, unsigned long end)
{
if (radix_enabled())
return radix__remove_section_mapping(start, end);
return hash__remove_section_mapping(start, end);
}
#endif /* CONFIG_MEMORY_HOTPLUG */
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