Merge branch 'tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip into trace/tip/tracing/ftrace-merge

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7be47d1a97e..9c4294986af 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -482,6 +482,13 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	pbase = (pte_t *)page_address(base);
 	paravirt_alloc_pte(&init_mm, page_to_pfn(base));
 	ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+	/*
+	 * If we ever want to utilize the PAT bit, we need to
+	 * update this function to make sure it's converted from
+	 * bit 12 to bit 7 when we cross from the 2MB level to
+	 * the 4K level:
+	 */
+	WARN_ON_ONCE(pgprot_val(ref_prot) & _PAGE_PAT_LARGE);
 
 #ifdef CONFIG_X86_64
 	if (level == PG_LEVEL_1G) {
@@ -515,6 +522,17 @@ static int split_large_page(pte_t *kpte, unsigned long address)
 	 * primary protection behavior:
 	 */
 	__set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE)));
+
+	/*
+	 * Intel Atom errata AAH41 workaround.
+	 *
+	 * The real fix should be in hw or in a microcode update, but
+	 * we also probabilistically try to reduce the window of having
+	 * a large TLB mixed with 4K TLBs while instruction fetches are
+	 * going on.
+	 */
+	__flush_tlb_all();
+
 	base = NULL;
 
 out_unlock: