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powerpc/mm/book3s: Update pmd_present to look at _PAGE_PRESENT bit

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With this patch we use 0x8000000000000000UL (_PAGE_PRESENT) to indicate a valid
pgd/pud/pmd entry. We also switch the p**_present() to look at this bit.

With pmd_present, we have a special case. We need to make sure we consider a
pmd marked invalid during THP split as present. Right now we clear the
_PAGE_PRESENT bit during a pmdp_invalidate. Inorder to consider this special
case we add a new pte bit _PAGE_INVALID (mapped to _RPAGE_SW0). This bit is
only used with _PAGE_PRESENT cleared. Hence we are not really losing a pte bit
for this special case. pmd_present is also updated to look at _PAGE_INVALID.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V 2018-09-20 23:39:42 +05:30 committed by Michael Ellerman
parent 8139046a5a
commit da7ad366b4
5 changed files with 28 additions and 12 deletions
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5
arch/powerpc/include/asm/book3s/64/hash.h
View File

@ -18,6 +18,11 @@
#include <asm/book3s/64/hash-4k.h>
#endif
/* Bits to set in a PMD/PUD/PGD entry valid bit*/
#define HASH_PMD_VAL_BITS (0x8000000000000000UL)
#define HASH_PUD_VAL_BITS (0x8000000000000000UL)
#define HASH_PGD_VAL_BITS (0x8000000000000000UL)
/*
* Size of EA range mapped by our pagetables.
*/

14
arch/powerpc/include/asm/book3s/64/pgtable.h
View File

@ -875,8 +875,16 @@ static inline int pmd_none(pmd_t pmd)
static inline int pmd_present(pmd_t pmd)
{
/*
* A pmd is considerent present if _PAGE_PRESENT is set.
* We also need to consider the pmd present which is marked
* invalid during a split. Hence we look for _PAGE_INVALID
* if we find _PAGE_PRESENT cleared.
*/
if (pmd_raw(pmd) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID))
return true;
return !pmd_none(pmd);
return false;
}
static inline int pmd_bad(pmd_t pmd)
@ -903,7 +911,7 @@ static inline int pud_none(pud_t pud)
static inline int pud_present(pud_t pud)
{
return !pud_none(pud);
return (pud_raw(pud) & cpu_to_be64(_PAGE_PRESENT));
}
extern struct page *pud_page(pud_t pud);
@ -950,7 +958,7 @@ static inline int pgd_none(pgd_t pgd)
static inline int pgd_present(pgd_t pgd)
{
return !pgd_none(pgd);
return (pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
}
static inline pte_t pgd_pte(pgd_t pgd)

6
arch/powerpc/mm/hash_utils_64.c
View File

@ -1001,9 +1001,9 @@ void __init hash__early_init_mmu(void)
* 4k use hugepd format, so for hash set then to
* zero
*/
__pmd_val_bits = 0;
__pud_val_bits = 0;
__pgd_val_bits = 0;
__pmd_val_bits = HASH_PMD_VAL_BITS;
__pud_val_bits = HASH_PUD_VAL_BITS;
__pgd_val_bits = HASH_PGD_VAL_BITS;
__kernel_virt_start = H_KERN_VIRT_START;
__kernel_virt_size = H_KERN_VIRT_SIZE;

8
arch/powerpc/mm/pgtable-book3s64.c
View File

@ -69,7 +69,11 @@ 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)));
/*
* Make sure hardware valid bit is not set. We don't do
* tlb flush for this update.
*/
WARN_ON(pte_val(pmd_pte(*pmdp)) & _PAGE_PRESENT);
assert_spin_locked(pmd_lockptr(mm, pmdp));
WARN_ON(!(pmd_trans_huge(pmd) || pmd_devmap(pmd)));
#endif
@ -106,7 +110,7 @@ pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
{
unsigned long old_pmd;
old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, 0);
old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, _PAGE_INVALID);
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
/*
* This ensures that generic code that rely on IRQ disabling

7
arch/powerpc/mm/pgtable.c
View File

@ -188,11 +188,10 @@ void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
pte_t pte)
{
/*
* When handling numa faults, we already have the pte marked
* _PAGE_PRESENT, but we can be sure that it is not in hpte.
* Hence we can use set_pte_at for them.
* Make sure hardware valid bit is not set. We don't do
* tlb flush for this update.
*/
VM_WARN_ON(pte_present(*ptep) && !pte_protnone(*ptep));
VM_WARN_ON(pte_val(*ptep) & _PAGE_PRESENT);
/* Add the pte bit when trying to set a pte */
pte = __pte(pte_val(pte) | _PAGE_PTE);