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authorMichael Ellerman <mpe@ellerman.id.au>2023-05-11 21:42:24 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2023-05-11 22:17:38 +1000
commit66b2ca086210732954a7790d63d35542936fc664 (patch)
tree920d5a743b2fd03dd89fdf4ace627f50fa358022 /arch
parent536d948a8dee21166d9c5b5a4189af56beba16e3 (diff)
powerpc/64s/radix: Fix soft dirty tracking
It was reported that soft dirty tracking doesn't work when using the Radix MMU. The tracking is supposed to work by clearing the soft dirty bit for a mapping and then write protecting the PTE. If/when the page is written to, a page fault occurs and the soft dirty bit is added back via pte_mkdirty(). For example in wp_page_reuse(): entry = maybe_mkwrite(pte_mkdirty(entry), vma); if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1)) update_mmu_cache(vma, vmf->address, vmf->pte); Unfortunately on radix _PAGE_SOFTDIRTY is being dropped by radix__ptep_set_access_flags(), called from ptep_set_access_flags(), meaning the soft dirty bit is not set even though the page has been written to. Fix it by adding _PAGE_SOFTDIRTY to the set of bits that are able to be changed in radix__ptep_set_access_flags(). Fixes: b0b5e9b13047 ("powerpc/mm/radix: Add radix pte #defines") Cc: stable@vger.kernel.org # v4.7+ Reported-by: Dan HorĂ¡k <dan@danny.cz> Link: https://lore.kernel.org/r/20230511095558.56663a50f86bdc4cd97700b7@danny.cz Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/20230511114224.977423-1-mpe@ellerman.id.au
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/mm/book3s64/radix_pgtable.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 26245aaf12b8..2297aa764ecd 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -1040,8 +1040,8 @@ void radix__ptep_set_access_flags(struct vm_area_struct *vma, pte_t *ptep,
pte_t entry, unsigned long address, int psize)
{
struct mm_struct *mm = vma->vm_mm;
- unsigned long set = pte_val(entry) & (_PAGE_DIRTY | _PAGE_ACCESSED |
- _PAGE_RW | _PAGE_EXEC);
+ unsigned long set = pte_val(entry) & (_PAGE_DIRTY | _PAGE_SOFT_DIRTY |
+ _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
unsigned long change = pte_val(entry) ^ pte_val(*ptep);
/*