3 files changed, 50 insertions, 57 deletions

diff --git a/arch/x86/include/asm/set_memory.h b/arch/x86/include/asm/set_memory.h
index 78ca53512486..b45c4d27fd46 100644
--- a/arch/x86/include/asm/set_memory.h
+++ b/arch/x86/include/asm/set_memory.h
@@ -86,56 +86,4 @@ bool kernel_page_present(struct page *page);
 
 extern int kernel_set_to_readonly;
 
-#ifdef CONFIG_X86_64
-/*
- * Prevent speculative access to the page by either unmapping
- * it (if we do not require access to any part of the page) or
- * marking it uncacheable (if we want to try to retrieve data
- * from non-poisoned lines in the page).
- */
-static inline int set_mce_nospec(unsigned long pfn, bool unmap)
-{
-	unsigned long decoy_addr;
-	int rc;
-
-	/* SGX pages are not in the 1:1 map */
-	if (arch_is_platform_page(pfn << PAGE_SHIFT))
-		return 0;
-	/*
-	 * We would like to just call:
-	 *      set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
-	 * but doing that would radically increase the odds of a
-	 * speculative access to the poison page because we'd have
-	 * the virtual address of the kernel 1:1 mapping sitting
-	 * around in registers.
-	 * Instead we get tricky.  We create a non-canonical address
-	 * that looks just like the one we want, but has bit 63 flipped.
-	 * This relies on set_memory_XX() properly sanitizing any __pa()
-	 * results with __PHYSICAL_MASK or PTE_PFN_MASK.
-	 */
-	decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
-
-	if (unmap)
-		rc = set_memory_np(decoy_addr, 1);
-	else
-		rc = set_memory_uc(decoy_addr, 1);
-	if (rc)
-		pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
-	return rc;
-}
-#define set_mce_nospec set_mce_nospec
-
-/* Restore full speculative operation to the pfn. */
-static inline int clear_mce_nospec(unsigned long pfn)
-{
-	return set_memory_wb((unsigned long) pfn_to_kaddr(pfn), 1);
-}
-#define clear_mce_nospec clear_mce_nospec
-#else
-/*
- * Few people would run a 32-bit kernel on a machine that supports
- * recoverable errors because they have too much memory to boot 32-bit.
- */
-#endif
-
 #endif /* _ASM_X86_SET_MEMORY_H */
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index d775fcd74e98..2c8ec5c71712 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -581,7 +581,7 @@ static int uc_decode_notifier(struct notifier_block *nb, unsigned long val,
 
 	pfn = mce->addr >> PAGE_SHIFT;
 	if (!memory_failure(pfn, 0)) {
-		set_mce_nospec(pfn, whole_page(mce));
+		set_mce_nospec(pfn);
 		mce->kflags |= MCE_HANDLED_UC;
 	}
 
@@ -1318,7 +1318,7 @@ static void kill_me_maybe(struct callback_head *cb)
 
 	ret = memory_failure(p->mce_addr >> PAGE_SHIFT, flags);
 	if (!ret) {
-		set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page);
+		set_mce_nospec(p->mce_addr >> PAGE_SHIFT);
 		sync_core();
 		return;
 	}
@@ -1344,7 +1344,7 @@ static void kill_me_never(struct callback_head *cb)
 	p->mce_count = 0;
 	pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr);
 	if (!memory_failure(p->mce_addr >> PAGE_SHIFT, 0))
-		set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page);
+		set_mce_nospec(p->mce_addr >> PAGE_SHIFT);
 }
 
 static void queue_task_work(struct mce *m, char *msg, void (*func)(struct callback_head *))
diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c
index 0656db33574d..1abd5438f126 100644
--- a/arch/x86/mm/pat/set_memory.c
+++ b/arch/x86/mm/pat/set_memory.c
@@ -19,6 +19,7 @@
 #include <linux/vmstat.h>
 #include <linux/kernel.h>
 #include <linux/cc_platform.h>
+#include <linux/set_memory.h>
 
 #include <asm/e820/api.h>
 #include <asm/processor.h>
@@ -29,7 +30,6 @@
 #include <asm/pgalloc.h>
 #include <asm/proto.h>
 #include <asm/memtype.h>
-#include <asm/set_memory.h>
 #include <asm/hyperv-tlfs.h>
 #include <asm/mshyperv.h>
 
@@ -1805,7 +1805,7 @@ static inline int cpa_clear_pages_array(struct page **pages, int numpages,
 }
 
 /*
- * _set_memory_prot is an internal helper for callers that have been passed
+ * __set_memory_prot is an internal helper for callers that have been passed
  * a pgprot_t value from upper layers and a reservation has already been taken.
  * If you want to set the pgprot to a specific page protocol, use the
  * set_memory_xx() functions.
@@ -1914,6 +1914,51 @@ int set_memory_wb(unsigned long addr, int numpages)
 }
 EXPORT_SYMBOL(set_memory_wb);
 
+/* Prevent speculative access to a page by marking it not-present */
+#ifdef CONFIG_X86_64
+int set_mce_nospec(unsigned long pfn)
+{
+	unsigned long decoy_addr;
+	int rc;
+
+	/* SGX pages are not in the 1:1 map */
+	if (arch_is_platform_page(pfn << PAGE_SHIFT))
+		return 0;
+	/*
+	 * We would like to just call:
+	 *      set_memory_XX((unsigned long)pfn_to_kaddr(pfn), 1);
+	 * but doing that would radically increase the odds of a
+	 * speculative access to the poison page because we'd have
+	 * the virtual address of the kernel 1:1 mapping sitting
+	 * around in registers.
+	 * Instead we get tricky.  We create a non-canonical address
+	 * that looks just like the one we want, but has bit 63 flipped.
+	 * This relies on set_memory_XX() properly sanitizing any __pa()
+	 * results with __PHYSICAL_MASK or PTE_PFN_MASK.
+	 */
+	decoy_addr = (pfn << PAGE_SHIFT) + (PAGE_OFFSET ^ BIT(63));
+
+	rc = set_memory_np(decoy_addr, 1);
+	if (rc)
+		pr_warn("Could not invalidate pfn=0x%lx from 1:1 map\n", pfn);
+	return rc;
+}
+
+static int set_memory_present(unsigned long *addr, int numpages)
+{
+	return change_page_attr_set(addr, numpages, __pgprot(_PAGE_PRESENT), 0);
+}
+
+/* Restore full speculative operation to the pfn. */
+int clear_mce_nospec(unsigned long pfn)
+{
+	unsigned long addr = (unsigned long) pfn_to_kaddr(pfn);
+
+	return set_memory_present(&addr, 1);
+}
+EXPORT_SYMBOL_GPL(clear_mce_nospec);
+#endif /* CONFIG_X86_64 */
+
 int set_memory_x(unsigned long addr, int numpages)
 {
 	if (!(__supported_pte_mask & _PAGE_NX))