The vmalloc() code uses vmalloc_sync_all() to synchronize changes to
the global reference kernel PGD to task PGDs.
This uses pgd_list currently, but we don't need the global list,
as we can walk the task list under RCU.
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Waiman Long <waiman.l...@hp.com>
Cc: linux...@vger.kernel.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/mm/fault.c | 21 ++++++++++++++-------
arch/x86/mm/init_64.c | 3 ++-
2 files changed, 16 insertions(+), 8 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 50342825f221..2d587e548b59 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -235,24 +235,31 @@ void vmalloc_sync_all(void)
for (address = VMALLOC_START & PMD_MASK;
address >= TASK_SIZE && address < FIXADDR_TOP;
address += PMD_SIZE) {
- struct page *page;
+ struct task_struct *g, *p;
+
+ rcu_read_lock();
spin_lock(&pgd_lock);
- list_for_each_entry(page, &pgd_list, lru) {
+
+ for_each_process_thread(g, p) {
spinlock_t *pgt_lock;
- pmd_t *ret;
+ pmd_t *pmd_ret;
- /* the pgt_lock only for Xen */
- pgt_lock = &pgd_page_get_mm(page)->page_table_lock;
+ if (!p->mm)
+ continue;
+ /* The pgt_lock is only used on Xen: */
+ pgt_lock = &p->mm->page_table_lock;
spin_lock(pgt_lock);
- ret = vmalloc_sync_one(page_address(page), address);
+ pmd_ret = vmalloc_sync_one(p->mm->pgd, address);
spin_unlock(pgt_lock);
- if (!ret)
+ if (!pmd_ret)
break;
}
+
spin_unlock(&pgd_lock);
+ rcu_read_unlock();
}
}
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index beee532b76a7..730560c4873e 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -184,11 +184,12 @@ void sync_global_pgds(unsigned long start, unsigned long
end)
spin_lock(&pgd_lock);
for_each_process_thread(g, p) {
- pgd_t *pgd = p->mm->pgd;
+ pgd_t *pgd;
spinlock_t *pgt_lock;
if (!p->mm)
continue;
+ pgd = p->mm->pgd;
/* The pgt_lock is only used by Xen: */
pgt_lock = &p->mm->page_table_lock;
--
2.1.4
--
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