Commit 668208b1 authored by Alexandre Ghiti's avatar Alexandre Ghiti Committed by Andrew Morton
Browse files

riscv: use an atomic xchg in pudp_huge_get_and_clear() 

Make sure we return the right pud value and not a value that could have
been overwritten in between by a different core.

Link: https://lkml.kernel.org/r/20250814-dev-alex-thp_pud_xchg-v1-1-b4704dfae206@rivosinc.com


Fixes: c3cc2a4a ("riscv: Add support for PUD THP")
Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 0ee82798

arch/riscv/include/asm/pgtable.h

+11 −0
Original line number Diff line number Diff line
@@ -942,6 +942,17 @@ static inline int pudp_test_and_clear_young(struct vm_area_struct *vma, 
	return ptep_test_and_clear_young(vma, address, (pte_t *)pudp);

}



#define __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR

static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm,

					    unsigned long address, pud_t *pudp)

{

	pud_t pud = __pud(atomic_long_xchg((atomic_long_t *)pudp, 0));



	page_table_check_pud_clear(mm, pud);



	return pud;

}



static inline int pud_young(pud_t pud)

{

	return pte_young(pud_pte(pud));