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Commit e611939f authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/mm: Ensure change_page_attr() doesn't invalidate pinned TLBs 



__change_page_attr() uses flush_tlb_page().
flush_tlb_page() uses tlbie instruction, which also invalidates
pinned TLBs, which is not what we expect.

This patch modifies the implementation to use flush_tlb_kernel_range()
instead. This will make use of tlbia which will preserve pinned TLBs.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 2ef973a9

arch/powerpc/mm/pgtable_32.c

+6 −4
Original line number Diff line number Diff line
@@ -325,7 +325,7 @@ get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp) 


#ifdef CONFIG_DEBUG_PAGEALLOC



static int __change_page_attr(struct page *page, pgprot_t prot)

static int __change_page_attr_noflush(struct page *page, pgprot_t prot)

{

	pte_t *kpte;

	pmd_t *kpmd;
@@ -339,8 +339,6 @@ static int __change_page_attr(struct page *page, pgprot_t prot) 
	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))

		return -EINVAL;

	__set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);

	wmb();

	flush_tlb_page(NULL, address);

	pte_unmap(kpte);



	return 0;
@@ -355,13 +353,17 @@ static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 
{

	int i, err = 0;

	unsigned long flags;

	struct page *start = page;



	local_irq_save(flags);

	for (i = 0; i < numpages; i++, page++) {

		err = __change_page_attr(page, prot);

		err = __change_page_attr_noflush(page, prot);

		if (err)

			break;

	}

	wmb();

	flush_tlb_kernel_range((unsigned long)page_address(start),

			       (unsigned long)page_address(page));

	local_irq_restore(flags);

	return err;

}