From: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
commit c30fa83b49897e708a52e122dd10616a52a4c82b upstream.
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@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231213203001.179237-2-alexghiti@xxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: WangYuli <wangyuli@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/riscv/include/asm/pgtable-64.h | 6 +++---
arch/riscv/include/asm/pgtable.h | 4 ++--
2 files changed, 5 insertions(+), 5 deletions(-)
--- 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
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 *p
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) });
}
--- 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,
*/
static inline void set_pte(pte_t *ptep, pte_t pteval)
{
- *ptep = pteval;
+ WRITE_ONCE(*ptep, pteval);
}
void flush_icache_pte(pte_t pte);
Patches currently in stable-queue which might be from alexghiti@xxxxxxxxxxxx are
queue-6.6/riscv-mm-only-compile-pgtable.c-if-mmu.patch
queue-6.6/riscv-set-trap-vector-earlier.patch
queue-6.6/riscv-use-accessors-to-page-table-entries-instead-of-direct-dereference.patch
queue-6.6/riscv-use-write_once-when-setting-page-table-entries.patch
queue-6.6/mm-introduce-pudp-p4dp-pgdp_get-functions.patch
