path: root/arch/powerpc/mm/book3s64/pgtable.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2015-2016, Aneesh Kumar K.V, IBM Corporation.
 */

#include <linux/sched.h>
#include <linux/mm_types.h>
#include <linux/memblock.h>
#include <linux/memremap.h>
#include <linux/pkeys.h>
#include <linux/debugfs.h>
#include <linux/proc_fs.h>
#include <misc/cxl-base.h>

#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/trace.h>
#include <asm/powernv.h>
#include <asm/firmware.h>
#include <asm/ultravisor.h>
#include <asm/kexec.h>

#include <mm/mmu_decl.h>
#include <trace/events/thp.h>

#include "internal.h"

struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
EXPORT_SYMBOL_GPL(mmu_psize_defs);

#ifdef CONFIG_SPARSEMEM_VMEMMAP
int mmu_vmemmap_psize = MMU_PAGE_4K;
#endif

unsigned long __pmd_frag_nr;
EXPORT_SYMBOL(__pmd_frag_nr);
unsigned long __pmd_frag_size_shift;
EXPORT_SYMBOL(__pmd_frag_size_shift);

#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(pmd_lockptr(vma->vm_mm, pmdp));
#endif
	changed = !pmd_same(*(pmdp), entry);
	if (changed) {
		/*
		 * We can use MMU_PAGE_2M here, because only radix
		 * path look at the psize.
		 */
		__ptep_set_access_flags(vma, pmdp_ptep(pmdp),
					pmd_pte(entry), address, MMU_PAGE_2M);
	}
	return changed;
}

int pudp_set_access_flags(struct vm_area_struct *vma, unsigned long address,
			  pud_t *pudp, pud_t entry, int dirty)
{
	int changed;
#ifdef CONFIG_DEBUG_VM
	WARN_ON(!pud_devmap(*pudp));
	assert_spin_locked(pud_lockptr(vma->vm_mm, pudp));
#endif
	changed = !pud_same(*(pudp), entry);
	if (changed) {
		/*
		 * We can use MMU_PAGE_1G here, because only radix
		 * path look at the psize.
		 */
		__ptep_set_access_flags(vma, pudp_ptep(pudp),
					pud_pte(entry), address, MMU_PAGE_1G);
	}
	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);
}

int pudp_test_and_clear_young(struct vm_area_struct *vma,
			      unsigned long address, pud_t *pudp)
{
	return __pudp_test_and_clear_young(vma->vm_mm, address, pudp);
}

/*
 * 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
	/*
	 * Make sure hardware valid bit is not set. We don't do
	 * tlb flush for this update.
	 */

	WARN_ON(pte_hw_valid(pmd_pte(*pmdp)) && !pte_protnone(pmd_pte(*pmdp)));
	assert_spin_locked(pmd_lockptr(mm, pmdp));
	WARN_ON(!(pmd_leaf(pmd)));
#endif
	trace_hugepage_set_pmd(addr, pmd_val(pmd));
	return set_pte_at(mm, addr, pmdp_ptep(pmdp), pmd_pte(pmd));
}

void set_pud_at(struct mm_struct *mm, unsigned long addr,
		pud_t *pudp, pud_t pud)
{
#ifdef CONFIG_DEBUG_VM
	/*
	 * Make sure hardware valid bit is not set. We don't do
	 * tlb flush for this update.
	 */

	WARN_ON(pte_hw_valid(pud_pte(*pudp)));
	assert_spin_locked(pud_lockptr(mm, pudp));
	WARN_ON(!(pud_leaf(pud)));
#endif
	trace_hugepage_set_pud(addr, pud_val(pud));
	return set_pte_at(mm, addr, pudp_ptep(pudp), pud_pte(pud));
}

static void do_serialize(void *arg)
{
	/* We've taken the IPI, so try to trim the mask while here */
	if (radix_enabled()) {
		struct mm_struct *mm = arg;
		exit_lazy_flush_tlb(mm, false);
	}
}

/*
 * Serialize against __find_linux_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_linux_pte() to finish.
 */
void serialize_against_pte_lookup(struct mm_struct *mm)
{
	smp_mb();
	smp_call_function_many(mm_cpumask(mm), do_serialize, mm, 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;

	VM_WARN_ON_ONCE(!pmd_present(*pmdp));
	old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, _PAGE_INVALID);
	flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
	return __pmd(old_pmd);
}

pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
		      pud_t *pudp)
{
	unsigned long old_pud;

	VM_WARN_ON_ONCE(!pud_present(*pudp));
	old_pud = pud_hugepage_update(vma->vm_mm, address, pudp, _PAGE_PRESENT, _PAGE_INVALID);
	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
	return __pud(old_pud);
}

pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,
				   unsigned long addr, pmd_t *pmdp, int full)
{
	pmd_t pmd;
	VM_BUG_ON(addr & ~HPAGE_PMD_MASK);
	VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
		   !pmd_devmap(*pmdp)) || !pmd_present(*pmdp));
	pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
	/*
	 * if it not a fullmm flush, then we can possibly end up converting
	 * this PMD pte entry to a regular level 0 PTE by a parallel page fault.
	 * Make sure we flush the tlb in this case.
	 */
	if (!full)
		flush_pmd_tlb_range(vma, addr, addr + HPAGE_PMD_SIZE);
	return pmd;
}

pud_t pudp_huge_get_and_clear_full(struct vm_area_struct *vma,
				   unsigned long addr, pud_t *pudp, int full)
{
	pud_t pud;

	VM_BUG_ON(addr & ~HPAGE_PMD_MASK);
	VM_BUG_ON((pud_present(*pudp) && !pud_devmap(*pudp)) ||
		  !pud_present(*pudp));
	pud = pudp_huge_get_and_clear(vma->vm_mm, addr, pudp);
	/*
	 * if it not a fullmm flush, then we can possibly end up converting
	 * this PMD pte entry to a regular level 0 PTE by a parallel page fault.
	 * Make sure we flush the tlb in this case.
	 */
	if (!full)
		flush_pud_tlb_range(vma, addr, addr + HPAGE_PUD_SIZE);
	return pud;
}

static pmd_t pmd_set_protbits(pmd_t pmd, pgprot_t pgprot)
{
	return __pmd(pmd_val(pmd) | pgprot_val(pgprot));
}

static pud_t pud_set_protbits(pud_t pud, pgprot_t pgprot)
{
	return __pud(pud_val(pud) | pgprot_val(pgprot));
}

/*
 * At some point we should be able to get rid of
 * pmd_mkhuge() and mk_huge_pmd() when we update all the
 * other archs to mark the pmd huge in pfn_pmd()
 */
pmd_t pfn_pmd(unsigned long pfn, pgprot_t pgprot)
{
	unsigned long pmdv;

	pmdv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK;

	return __pmd_mkhuge(pmd_set_protbits(__pmd(pmdv), pgprot));
}

pud_t pfn_pud(unsigned long pfn, pgprot_t pgprot)
{
	unsigned long pudv;

	pudv = (pfn << PAGE_SHIFT) & PTE_RPN_MASK;

	return __pud_mkhuge(pud_set_protbits(__pud(pudv), 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);
}

pud_t pud_modify(pud_t pud, pgprot_t newprot)
{
	unsigned long pudv;

	pudv = pud_val(pud);
	pudv &= _HPAGE_CHG_MASK;
	return pud_set_protbits(__pud(pudv), newprot);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

/* For use by kexec, called with MMU off */
notrace 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();

	reset_sprs();
}

#ifdef CONFIG_MEMORY_HOTPLUG
int __meminit create_section_mapping(unsigned long