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arm64/mm: Ensure adequate HUGE_MAX_HSTATE

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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: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20241202064407.53807-1-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Anshuman Khandual
2024-12-02 12:14:07 +05:30
committed by Will Deacon
parent a0e33f528e
commit 1e5823c8e8
1 changed files with 12 additions and 0 deletions
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12
arch/arm64/mm/hugetlbpage.c
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@@ -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);