With some architectures like ppc64, set_pmd_at() cannot cope with a situation where there is already some (different) valid entry present.
Use pmdp_set_access_flags() instead to modify the pfn which is built to deal with modifying existing PMD entries.
This is similar to commit cae85cb8add3 ("mm/memory.c: fix modifying of page protection by insert_pfn()")
We also do similar update w.r.t insert_pfn_pud eventhough ppc64 don't support pud pfn entries now.
CC: stable@vger.kernel.org Signed-off-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com --- mm/huge_memory.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 404acdcd0455..f7dca413c4b2 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -755,6 +755,20 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr, spinlock_t *ptl;
ptl = pmd_lock(mm, pmd); + if (!pmd_none(*pmd)) { + if (write) { + if (pmd_pfn(*pmd) != pfn_t_to_pfn(pfn)) { + WARN_ON_ONCE(!is_huge_zero_pmd(*pmd)); + goto out_unlock; + } + entry = pmd_mkyoung(*pmd); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + if (pmdp_set_access_flags(vma, addr, pmd, entry, 1)) + update_mmu_cache_pmd(vma, addr, pmd); + } + goto out_unlock; + } + entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); if (pfn_t_devmap(pfn)) entry = pmd_mkdevmap(entry); @@ -770,6 +784,7 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
set_pmd_at(mm, addr, pmd, entry); update_mmu_cache_pmd(vma, addr, pmd); +out_unlock: spin_unlock(ptl); }
@@ -821,6 +836,20 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, spinlock_t *ptl;
ptl = pud_lock(mm, pud); + if (!pud_none(*pud)) { + if (write) { + if (pud_pfn(*pud) != pfn_t_to_pfn(pfn)) { + WARN_ON_ONCE(!is_huge_zero_pud(*pud)); + goto out_unlock; + } + entry = pud_mkyoung(*pud); + entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma); + if (pudp_set_access_flags(vma, addr, pud, entry, 1)) + update_mmu_cache_pud(vma, addr, pud); + } + goto out_unlock; + } + entry = pud_mkhuge(pfn_t_pud(pfn, prot)); if (pfn_t_devmap(pfn)) entry = pud_mkdevmap(entry); @@ -830,6 +859,8 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr, } set_pud_at(mm, addr, pud, entry); update_mmu_cache_pud(vma, addr, pud); + +out_unlock: spin_unlock(ptl); }