Commit 1e5823c8 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Will Deacon
Browse files

arm64/mm: Ensure adequate HUGE_MAX_HSTATE 



This asserts that HUGE_MAX_HSTATE is sufficient enough preventing potential
hugetlb_max_hstate runtime overflow in hugetlb_add_hstate() thus triggering
a BUG_ON() there after.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: default avatarRyan Roberts <ryan.roberts@arm.com>
Reviewed-by: default avatarGavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20241202064407.53807-1-anshuman.khandual@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent a0e33f52

arch/arm64/mm/hugetlbpage.c

+12 −0
Original line number Diff line number Diff line
@@ -519,6 +519,18 @@ pte_t huge_ptep_clear_flush(struct vm_area_struct *vma, 


static int __init hugetlbpage_init(void)

{

	/*

	 * HugeTLB pages are supported on maximum four page table

	 * levels (PUD, CONT PMD, PMD, CONT PTE) for a given base

	 * page size, corresponding to hugetlb_add_hstate() calls

	 * here.

	 *

	 * HUGE_MAX_HSTATE should at least match maximum supported

	 * HugeTLB page sizes on the platform. Any new addition to

	 * supported HugeTLB page sizes will also require changing

	 * HUGE_MAX_HSTATE as well.

	 */

	BUILD_BUG_ON(HUGE_MAX_HSTATE < 4);

	if (pud_sect_supported())

		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);