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Commit da7ad366 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

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



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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 8139046a

arch/powerpc/include/asm/book3s/64/hash.h

+5 −0
Original line number Diff line number Diff line
@@ -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.

 */

arch/powerpc/include/asm/book3s/64/pgtable.h

+11 −3
Original line number Diff line number Diff line
@@ -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)

arch/powerpc/mm/hash_utils_64.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/mm/pgtable-book3s64.c

+6 −2
Original line number Diff line number Diff line
@@ -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

arch/powerpc/mm/pgtable.c

+3 −4
Original line number Diff line number Diff line
@@ -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);