+ riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set.patch added to mm-hotfixes-unstable branch

+ riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Alexandre Ghiti <alexghiti@rivosinc.com>
Subject: riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set
Date: Thu, 28 Sep 2023 17:18:46 +0200

We used to determine the number of page table entries to set for a NAPOT
hugepage by using the pte value which actually fails when the pte to set
is a swap entry.

So take advantage of a recent fix for arm64 reported in [1] which
introduces the size of the mapping as an argument of set_huge_pte_at(): we
can then use this size to compute the number of page table entries to set
for a NAPOT region.

Link: https://lkml.kernel.org/r/20230928151846.8229-3-alexghiti@rivosinc.com
Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reported-by: Ryan Roberts <ryan.roberts@arm.com>
Closes: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@arm.com/ [1]
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Qinglin Pan <panqinglin2020@iscas.ac.cn>
Cc: Conor Dooley <conor@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/riscv/mm/hugetlbpage.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

--- a/arch/riscv/mm/hugetlbpage.c~riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set
+++ a/arch/riscv/mm/hugetlbpage.c
@@ -183,15 +183,22 @@ void set_huge_pte_at(struct mm_struct *m
 		     pte_t pte,
 		     unsigned long sz)
 {
+	unsigned long hugepage_shift;
 	int i, pte_num;
 
-	if (!pte_napot(pte)) {
-		set_pte_at(mm, addr, ptep, pte);
-		return;
-	}
+	if (sz >= PGDIR_SIZE)
+		hugepage_shift = PGDIR_SHIFT;
+	else if (sz >= P4D_SIZE)
+		hugepage_shift = P4D_SHIFT;
+	else if (sz >= PUD_SIZE)
+		hugepage_shift = PUD_SHIFT;
+	else if (sz >= PMD_SIZE)
+		hugepage_shift = PMD_SHIFT;
+	else
+		hugepage_shift = PAGE_SHIFT;
 
-	pte_num = napot_pte_num(napot_cont_order(pte));
-	for (i = 0; i < pte_num; i++, ptep++, addr += PAGE_SIZE)
+	pte_num = sz >> hugepage_shift;
+	for (i = 0; i < pte_num; i++, ptep++, addr += (1 << hugepage_shift))
 		set_pte_at(mm, addr, ptep, pte);
 }
 
_

Patches currently in -mm which might be from alexghiti@rivosinc.com are

riscv-handle-vm_fault_-faults-instead-of-panicking.patch
riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-swap-entry-is-set.patch