6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
[ Upstream commit 1458eb2c9d88ad4b35eb6d6a4aa1d43d8fbf7f62 ]
As stated by the privileged specification, we must clear a NAPOT
mapping and emit a sfence.vma before setting a new translation.
Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page")
Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240117195741.1926459-2-alexghiti@xxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/riscv/mm/hugetlbpage.c | 42 +++++++++++++++++++++++++++++++++++--
1 file changed, 40 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index b52f0210481f..24c0179565d8 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -177,13 +177,36 @@ pte_t arch_make_huge_pte(pte_t entry, unsigned int shift, vm_flags_t flags)
return entry;
}
+static void clear_flush(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep,
+ unsigned long pgsize,
+ unsigned long ncontig)
+{
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+ unsigned long i, saddr = addr;
+
+ for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
+ ptep_get_and_clear(mm, addr, ptep);
+
+ flush_tlb_range(&vma, saddr, addr);
+}
+
+/*
+ * When dealing with NAPOT mappings, the privileged specification indicates that
+ * "if an update needs to be made, the OS generally should first mark all of the
+ * PTEs invalid, then issue SFENCE.VMA instruction(s) covering all 4 KiB regions
+ * within the range, [...] then update the PTE(s), as described in Section
+ * 4.2.1.". That's the equivalent of the Break-Before-Make approach used by
+ * arm64.
+ */
void set_huge_pte_at(struct mm_struct *mm,
unsigned long addr,
pte_t *ptep,
pte_t pte,
unsigned long sz)
{
- unsigned long hugepage_shift;
+ unsigned long hugepage_shift, pgsize;
int i, pte_num;
if (sz >= PGDIR_SIZE)
@@ -198,7 +221,22 @@ void set_huge_pte_at(struct mm_struct *mm,
hugepage_shift = PAGE_SHIFT;
pte_num = sz >> hugepage_shift;
- for (i = 0; i < pte_num; i++, ptep++, addr += (1 << hugepage_shift))
+ pgsize = 1 << hugepage_shift;
+
+ if (!pte_present(pte)) {
+ for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
+ set_ptes(mm, addr, ptep, pte, 1);
+ return;
+ }
+
+ if (!pte_napot(pte)) {
+ set_ptes(mm, addr, ptep, pte, 1);
+ return;
+ }
+
+ clear_flush(mm, addr, ptep, pgsize, pte_num);
+
+ for (i = 0; i < pte_num; i++, ptep++, addr += pgsize)
set_pte_at(mm, addr, ptep, pte);
}
--
2.43.0
