As on allocation of encrypted page, we need to flush cache before
returning page to free pool. Failing to do this may lead to data
corruption.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 arch/x86/mm/mktme.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
index 1129ad25b22a..ef0eb1eb8d6e 100644
--- a/arch/x86/mm/mktme.c
+++ b/arch/x86/mm/mktme.c
@@ -45,6 +45,19 @@ void prep_encrypt_page(struct page *page, gfp_t gfp, 
unsigned int order)
        WARN_ONCE(gfp & __GFP_ZERO, "__GFP_ZERO is useless for encrypted 
pages");
 }
 
+void free_encrypt_page(struct page *page, int keyid, unsigned int order)
+{
+       int i;
+       void *v;
+
+       for (i = 0; i < (1 << order); i++) {
+               v = kmap_atomic_keyid(page, keyid + i);
+               /* See comment in prep_encrypt_page() */
+               clflush_cache_range(v, PAGE_SIZE);
+               kunmap_atomic(v);
+       }
+}
+
 struct page *__alloc_zeroed_encrypted_user_highpage(gfp_t gfp,
                struct vm_area_struct *vma, unsigned long vaddr)
 {
-- 
2.16.1

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