The 32-bit x86 PAT code uses __set_pmd_pte() to update pmds.
This uses pgd_list currently, but we don't need the global
list as we can walk the task list under RCU.
(This code already holds the pgd_lock.)
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Waiman Long <Waiman.Long@xxxxxx>
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/mm/pageattr.c | 26 ++++++++++++++++++++------
1 file changed, 20 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 997fc97e9072..4ff6a1808f1d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -438,17 +438,31 @@ static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
set_pte_atomic(kpte, pte);
#ifdef CONFIG_X86_32
if (!SHARED_KERNEL_PMD) {
- struct page *page;
+ struct task_struct *g, *p;
- list_for_each_entry(page, &pgd_list, lru) {
+ /* We are holding pgd_lock, which implies rcu_read_lock(): */
+
+ for_each_process_thread(g, p) {
+ struct mm_struct *mm;
+ spinlock_t *pgt_lock;
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pgd = (pgd_t *)page_address(page) + pgd_index(address);
- pud = pud_offset(pgd, address);
- pmd = pmd_offset(pud, address);
- set_pte_atomic((pte_t *)pmd, pte);
+ task_lock(p);
+ mm = p->mm;
+ if (mm) {
+ pgt_lock = &mm->page_table_lock;
+ spin_lock(pgt_lock);
+
+ pgd = mm->pgd + pgd_index(address);
+ pud = pud_offset(pgd, address);
+ pmd = pmd_offset(pud, address);
+ set_pte_atomic((pte_t *)pmd, pte);
+
+ spin_unlock(pgt_lock);
+ }
+ task_unlock(p);
}
}
#endif
--
2.1.4
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