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arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade

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NestMMU requires us to mark the pte invalid and flush the tlb when we do
a RW upgrade of pte.  We fixed a variant of this in the fault path in
bd5050e38a ("powerpc/mm/radix: Change pte relax sequence to handle
nest MMU hang").

Link: http://lkml.kernel.org/r/20190116085035.29729-6-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Aneesh Kumar K.V 2019-03-05 15:46:40 -08:00 committed by Linus Torvalds
parent 023bdd0023
commit 8ef5cbde6d
3 changed files with 54 additions and 0 deletions
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12
arch/powerpc/include/asm/book3s/64/hugetlb.h
View File

@ -13,6 +13,10 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff,
unsigned long flags);
extern void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t old_pte, pte_t pte);
static inline int hstate_get_psize(struct hstate *hstate)
{
unsigned long shift;
@ -42,4 +46,12 @@ static inline bool gigantic_page_supported(void)
/* hugepd entry valid bit */
#define HUGEPD_VAL_BITS (0x8000000000000000UL)
#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start
extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep);
#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit
extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t old_pte, pte_t new_pte);
#endif

25
arch/powerpc/mm/hugetlbpage-hash64.c
View File

@ -121,3 +121,28 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
*ptep = __pte(new_pte & ~H_PAGE_BUSY);
return 0;
}
pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
unsigned long pte_val;
/*
* Clear the _PAGE_PRESENT so that no hardware parallel update is
* possible. Also keep the pte_present true so that we don't take
* wrong fault.
*/
pte_val = pte_update(vma->vm_mm, addr, ptep,
_PAGE_PRESENT, _PAGE_INVALID, 1);
return __pte(pte_val);
}
void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
pte_t *ptep, pte_t old_pte, pte_t pte)
{
if (radix_enabled())
return radix__huge_ptep_modify_prot_commit(vma, addr, ptep,
old_pte, pte);
set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
}

17
arch/powerpc/mm/hugetlbpage-radix.c
View File

@ -90,3 +90,20 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
return vm_unmapped_area(&info);
}
void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t old_pte, pte_t pte)
{
struct mm_struct *mm = vma->vm_mm;
/*
* To avoid NMMU hang while relaxing access we need to flush the tlb before
* we set the new value.
*/
if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&
(atomic_read(&mm->context.copros) > 0))
radix__flush_hugetlb_page(vma, addr);
set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
}