[PATCH 6.7 044/162] riscv: tlb: fix __p*d_free_tlb()

Greg Kroah-Hartman
2024-03-04T21:28:52Z

From: Jisheng Zhang <jszhang@kernel.org>

[ Upstream commit 8246601a7d391ce8207408149d65732f28af81a1 ]

If non-leaf PTEs I.E pmd, pud or p4d is modified, a sfence.vma is
a must for safe, imagine if an implementation caches the non-leaf
translation in TLB, although I didn't meet this HW so far, but it's
possible in theory.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Fixes: c5e9b2c2ae82 ("riscv: Improve tlb_flush()")
Link: https://lore.kernel.org/r/20231219175046.2496-2-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/riscv/include/asm/pgalloc.h | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index d169a4f41a2e7..c80bb9990d32e 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -95,7 +95,13 @@ static inline void pud_free(struct mm_struct *mm, pud_t *pud)
__pud_free(mm, pud);
}

-#define __pud_free_tlb(tlb, pud, addr) pud_free((tlb)->mm, pud)
+#define __pud_free_tlb(tlb, pud, addr) \
+do { \
+ if (pgtable_l4_enabled) { \
+ pagetable_pud_dtor(virt_to_ptdesc(pud)); \
+ tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(pud)); \
+ } \
+} while (0)

#define p4d_alloc_one p4d_alloc_one
static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr)
@@ -124,7 +130,11 @@ static inline void p4d_free(struct mm_struct *mm, p4d_t *p4d)
__p4d_free(mm, p4d);
}

-#define __p4d_free_tlb(tlb, p4d, addr) p4d_free((tlb)->mm, p4d)
+#define __p4d_free_tlb(tlb, p4d, addr) \
+do { \
+ if (pgtable_l5_enabled) \
+ tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(p4d)); \
+} while (0)
#endif /* __PAGETABLE_PMD_FOLDED */

static inline void sync_kernel_mappings(pgd_t *pgd)
@@ -149,7 +159,11 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)

#ifndef __PAGETABLE_PMD_FOLDED

-#define __pmd_free_tlb(tlb, pmd, addr) pmd_free((tlb)->mm, pmd)
+#define __pmd_free_tlb(tlb, pmd, addr) \
+do { \
+ pagetable_pmd_dtor(virt_to_ptdesc(pmd)); \
+ tlb_remove_page_ptdesc((tlb), virt_to_ptdesc(pmd)); \
+} while (0)

#endif /* __PAGETABLE_PMD_FOLDED */

--
2.43.0