Commit f2b67ef9 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/hugetlb: Fix 512k hugepages on 8xx with 16k page size 



Commit 55c8fc3f ("powerpc/8xx: reintroduce 16K pages with HW
assistance") redefined pte_t as a struct of 4 pte_basic_t, because
in 16K pages mode there are four identical entries in the
page table. But the size of hugepage tables is calculated based
of the size of (void *). Therefore, we end up with page tables
of size 1k instead of 4k for 512k pages.

As 512k hugepage tables are the same size as standard page tables,
ie 4k, use the standard page tables instead of PGT_CACHE tables.

Fixes: 3fb69c6a ("powerpc/8xx: Enable 512k hugepage support with HW assistance")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/90ec56a2315be602494619ed0223bba3b0b8d619.1580997007.git.christophe.leroy@c-s.fr
parent d4f194ed

arch/powerpc/mm/hugetlbpage.c

+18 −11
Original line number Original line Diff line number Diff line
@@ -53,19 +53,23 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 
	if (pshift >= pdshift) {

	if (pshift >= pdshift) {

		cachep = PGT_CACHE(PTE_T_ORDER);

		cachep = PGT_CACHE(PTE_T_ORDER);

		num_hugepd = 1 << (pshift - pdshift);

		num_hugepd = 1 << (pshift - pdshift);

		new = NULL;

	} else if (IS_ENABLED(CONFIG_PPC_8xx)) {

	} else if (IS_ENABLED(CONFIG_PPC_8xx)) {

		cachep = PGT_CACHE(PTE_INDEX_SIZE);

		cachep = NULL;

		num_hugepd = 1;

		num_hugepd = 1;

		new = pte_alloc_one(mm);

	} else {

	} else {

		cachep = PGT_CACHE(pdshift - pshift);

		cachep = PGT_CACHE(pdshift - pshift);

		num_hugepd = 1;

		num_hugepd = 1;

		new = NULL;

	}

	}





	if (!cachep) {

	if (!cachep && !new) {

		WARN_ONCE(1, "No page table cache created for hugetlb tables");

		WARN_ONCE(1, "No page table cache created for hugetlb tables");

		return -ENOMEM;

		return -ENOMEM;

	}

	}





	if (cachep)

		new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));

		new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));





	BUG_ON(pshift > HUGEPD_SHIFT_MASK);

	BUG_ON(pshift > HUGEPD_SHIFT_MASK);
@@ -97,7 +101,10 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 
	if (i < num_hugepd) {

	if (i < num_hugepd) {

		for (i = i - 1 ; i >= 0; i--, hpdp--)

		for (i = i - 1 ; i >= 0; i--, hpdp--)

			*hpdp = __hugepd(0);

			*hpdp = __hugepd(0);

		if (cachep)

			kmem_cache_free(cachep, new);

			kmem_cache_free(cachep, new);

		else

			pte_free(mm, new);

	} else {

	} else {

		kmemleak_ignore(new);

		kmemleak_ignore(new);

	}

	}
@@ -324,8 +331,7 @@ static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshif 
	if (shift >= pdshift)

	if (shift >= pdshift)

		hugepd_free(tlb, hugepte);

		hugepd_free(tlb, hugepte);

	else if (IS_ENABLED(CONFIG_PPC_8xx))

	else if (IS_ENABLED(CONFIG_PPC_8xx))

		pgtable_free_tlb(tlb, hugepte,

		pgtable_free_tlb(tlb, hugepte, 0);

				 get_hugepd_cache_index(PTE_INDEX_SIZE));

	else

	else

		pgtable_free_tlb(tlb, hugepte,

		pgtable_free_tlb(tlb, hugepte,

				 get_hugepd_cache_index(pdshift - shift));

				 get_hugepd_cache_index(pdshift - shift));
@@ -639,12 +645,13 @@ static int __init hugetlbpage_init(void) 
		 * if we have pdshift and shift value same, we don't

		 * if we have pdshift and shift value same, we don't

		 * use pgt cache for hugepd.

		 * use pgt cache for hugepd.

		 */

		 */

		if (pdshift > shift && IS_ENABLED(CONFIG_PPC_8xx))

		if (pdshift > shift) {

			pgtable_cache_add(PTE_INDEX_SIZE);

			if (!IS_ENABLED(CONFIG_PPC_8xx))

		else if (pdshift > shift)

				pgtable_cache_add(pdshift - shift);

				pgtable_cache_add(pdshift - shift);

		else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) || IS_ENABLED(CONFIG_PPC_8xx))

		} else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) ||

			   IS_ENABLED(CONFIG_PPC_8xx)) {

			pgtable_cache_add(PTE_T_ORDER);

			pgtable_cache_add(PTE_T_ORDER);

		}





		configured = true;

		configured = true;

	}

	}

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