From: Alexandre Ghiti alexghiti@rivosinc.com

[ Upstream commit c30fa83b49897e708a52e122dd10616a52a4c82b ]

To avoid any compiler "weirdness" when accessing page table entries which are concurrently modified by the HW, let's use WRITE_ONCE() macro (commit 20a004e7b017 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables") gives a great explanation with more details).

Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Link: https://lore.kernel.org/r/20231213203001.179237-2-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: WangYuli wangyuli@uniontech.com --- arch/riscv/include/asm/pgtable-64.h | 6 +++--- arch/riscv/include/asm/pgtable.h | 4 ++-- 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h index 7a5097202e15..a65a352dcfbf 100644 --- a/arch/riscv/include/asm/pgtable-64.h +++ b/arch/riscv/include/asm/pgtable-64.h @@ -198,7 +198,7 @@ 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) @@ -274,7 +274,7 @@ 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) }); } @@ -347,7 +347,7 @@ 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) }); } diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 719c3041ae1c..f8e72df4113a 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -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) @@ -515,7 +515,7 @@ 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);