Unverified Commit c30fa83b authored by Alexandre Ghiti's avatar Alexandre Ghiti Committed by Palmer Dabbelt
Browse files

riscv: Use WRITE_ONCE() when setting page table entries 



To avoid any compiler "weirdness" when accessing page table entries which
are concurrently modified by the HW, let's use WRITE_ONCE() macro
(commit 20a004e7 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing
page tables") gives a great explanation with more details).

Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20231213203001.179237-2-alexghiti@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent b85ea95d

arch/riscv/include/asm/pgtable-64.h

+3 −3
Original line number Diff line number Diff line
@@ -202,7 +202,7 @@ static inline int pud_user(pud_t pud) 


static inline void set_pud(pud_t *pudp, pud_t pud)

{

	*pudp = pud;

	WRITE_ONCE(*pudp, pud);

}



static inline void pud_clear(pud_t *pudp)
@@ -278,7 +278,7 @@ static inline unsigned long _pmd_pfn(pmd_t pmd) 
static inline void set_p4d(p4d_t *p4dp, p4d_t p4d)

{

	if (pgtable_l4_enabled)

		*p4dp = p4d;

		WRITE_ONCE(*p4dp, p4d);

	else

		set_pud((pud_t *)p4dp, (pud_t){ p4d_val(p4d) });

}
@@ -351,7 +351,7 @@ static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) 
static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)

{

	if (pgtable_l5_enabled)

		*pgdp = pgd;

		WRITE_ONCE(*pgdp, pgd);

	else

		set_p4d((p4d_t *)pgdp, (p4d_t){ pgd_val(pgd) });

}

arch/riscv/include/asm/pgtable.h

+2 −2
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ static inline int pmd_leaf(pmd_t pmd) 


static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)

{

	*pmdp = pmd;

	WRITE_ONCE(*pmdp, pmd);

}



static inline void pmd_clear(pmd_t *pmdp)
@@ -510,7 +510,7 @@ static inline int pte_same(pte_t pte_a, pte_t pte_b) 
 */

static inline void set_pte(pte_t *ptep, pte_t pteval)

{

	*ptep = pteval;

	WRITE_ONCE(*ptep, pteval);

}



void flush_icache_pte(pte_t pte);