Patch "riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set" has been added to the 6.5-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set

to the 6.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     riscv-fix-set_huge_pte_at-for-napot-mappings-when-a-.patch
and it can be found in the queue-6.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6b227295b4c6294efce1a5ec1b1a050ebbbb23ac
Author: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date:   Thu Sep 28 17:18:46 2023 +0200

    riscv: fix set_huge_pte_at() for NAPOT mappings when a swap entry is set
    
    [ Upstream commit 1de195dd0e05d9cba43dec16f83d4ee32af94dd2 ]
    
    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@xxxxxxxxxxxx
    Fixes: 82a1a1f3bfb6 ("riscv: mm: support Svnapot in hugetlb page")
    Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
    Reported-by: Ryan Roberts <ryan.roberts@xxxxxxx>
    Closes: https://lore.kernel.org/linux-arm-kernel/20230922115804.2043771-1-ryan.roberts@xxxxxxx/ [1]
    Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
    Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
    Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
    Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
    Cc: Qinglin Pan <panqinglin2020@xxxxxxxxxxx>
    Cc: Conor Dooley <conor@xxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/riscv/mm/hugetlbpage.c b/arch/riscv/mm/hugetlbpage.c
index 96225a8533ad8..e92e89461c3bc 100644
--- a/arch/riscv/mm/hugetlbpage.c
+++ b/arch/riscv/mm/hugetlbpage.c
@@ -182,15 +182,22 @@ void set_huge_pte_at(struct mm_struct *mm,
 		     pte_t *ptep,
 		     pte_t pte)
 {
+	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);
 }