1 files changed, 37 insertions, 5 deletions

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 74b157ac078d..7a8fc26c1115 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -4,6 +4,8 @@
 #include <linux/swap.h>
 #include <linux/memblock.h>
 #include <linux/bootmem.h>	/* for max_low_pfn */
+#include <linux/swapfile.h>
+#include <linux/swapops.h>
 
 #include <asm/set_memory.h>
 #include <asm/e820/api.h>
@@ -97,15 +99,22 @@ __ref void *alloc_low_pages(unsigned int num)
 	}
 
 	if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
-		unsigned long ret;
-		if (min_pfn_mapped >= max_pfn_mapped)
-			panic("alloc_low_pages: ran out of memory");
-		ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT,
+		unsigned long ret = 0;
+
+		if (min_pfn_mapped < max_pfn_mapped) {
+			ret = memblock_find_in_range(
+					min_pfn_mapped << PAGE_SHIFT,
 					max_pfn_mapped << PAGE_SHIFT,
 					PAGE_SIZE * num , PAGE_SIZE);
+		}
+		if (ret)
+			memblock_reserve(ret, PAGE_SIZE * num);
+		else if (can_use_brk_pgt)
+			ret = __pa(extend_brk(PAGE_SIZE * num, PAGE_SIZE));
+
 		if (!ret)
 			panic("alloc_low_pages: can not alloc memory");
-		memblock_reserve(ret, PAGE_SIZE * num);
+
 		pfn = ret >> PAGE_SHIFT;
 	} else {
 		pfn = pgt_buf_end;
@@ -911,3 +920,26 @@ void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache)
 	__cachemode2pte_tbl[cache] = __cm_idx2pte(entry);
 	__pte2cachemode_tbl[entry] = cache;
 }
+
+#ifdef CONFIG_SWAP
+unsigned long max_swapfile_size(void)
+{
+	unsigned long pages;
+
+	pages = generic_max_swapfile_size();
+
+	if (boot_cpu_has_bug(X86_BUG_L1TF)) {
+		/* Limit the swap file size to MAX_PA/2 for L1TF workaround */
+		unsigned long long l1tf_limit = l1tf_pfn_limit();
+		/*
+		 * We encode swap offsets also with 3 bits below those for pfn
+		 * which makes the usable limit higher.
+		 */
+#if CONFIG_PGTABLE_LEVELS > 2
+		l1tf_limit <<= PAGE_SHIFT - SWP_OFFSET_FIRST_BIT;
+#endif
+		pages = min_t(unsigned long long, l1tf_limit, pages);
+	}
+	return pages;
+}
+#endif