1 files changed, 38 insertions, 15 deletions

diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index e7b9b464a82f..0302491d799d 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -316,10 +316,33 @@ void __init kasan_early_init(void)
 	kasan_map_early_shadow(init_top_pgt);
 }
 
+static unsigned long kasan_mem_to_shadow_align_down(unsigned long va)
+{
+	unsigned long shadow = (unsigned long)kasan_mem_to_shadow((void *)va);
+
+	return round_down(shadow, PAGE_SIZE);
+}
+
+static unsigned long kasan_mem_to_shadow_align_up(unsigned long va)
+{
+	unsigned long shadow = (unsigned long)kasan_mem_to_shadow((void *)va);
+
+	return round_up(shadow, PAGE_SIZE);
+}
+
+void __init kasan_populate_shadow_for_vaddr(void *va, size_t size, int nid)
+{
+	unsigned long shadow_start, shadow_end;
+
+	shadow_start = kasan_mem_to_shadow_align_down((unsigned long)va);
+	shadow_end = kasan_mem_to_shadow_align_up((unsigned long)va + size);
+	kasan_populate_shadow(shadow_start, shadow_end, nid);
+}
+
 void __init kasan_init(void)
 {
+	unsigned long shadow_cea_begin, shadow_cea_per_cpu_begin, shadow_cea_end;
 	int i;
-	void *shadow_cpu_entry_begin, *shadow_cpu_entry_end;
 
 	memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt));
 
@@ -360,16 +383,10 @@ void __init kasan_init(void)
 		map_range(&pfn_mapped[i]);
 	}
 
-	shadow_cpu_entry_begin = (void *)CPU_ENTRY_AREA_BASE;
-	shadow_cpu_entry_begin = kasan_mem_to_shadow(shadow_cpu_entry_begin);
-	shadow_cpu_entry_begin = (void *)round_down(
-			(unsigned long)shadow_cpu_entry_begin, PAGE_SIZE);
-
-	shadow_cpu_entry_end = (void *)(CPU_ENTRY_AREA_BASE +
-					CPU_ENTRY_AREA_MAP_SIZE);
-	shadow_cpu_entry_end = kasan_mem_to_shadow(shadow_cpu_entry_end);
-	shadow_cpu_entry_end = (void *)round_up(
-			(unsigned long)shadow_cpu_entry_end, PAGE_SIZE);
+	shadow_cea_begin = kasan_mem_to_shadow_align_down(CPU_ENTRY_AREA_BASE);
+	shadow_cea_per_cpu_begin = kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_PER_CPU);
+	shadow_cea_end = kasan_mem_to_shadow_align_up(CPU_ENTRY_AREA_BASE +
+						      CPU_ENTRY_AREA_MAP_SIZE);
 
 	kasan_populate_early_shadow(
 		kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
@@ -391,12 +408,18 @@ void __init kasan_init(void)
 
 	kasan_populate_early_shadow(
 		kasan_mem_to_shadow((void *)VMALLOC_END + 1),
-		shadow_cpu_entry_begin);
+		(void *)shadow_cea_begin);
 
-	kasan_populate_shadow((unsigned long)shadow_cpu_entry_begin,
-			      (unsigned long)shadow_cpu_entry_end, 0);
+	/*
+	 * Populate the shadow for the shared portion of the CPU entry area.
+	 * Shadows for the per-CPU areas are mapped on-demand, as each CPU's
+	 * area is randomly placed somewhere in the 512GiB range and mapping
+	 * the entire 512GiB range is prohibitively expensive.
+	 */
+	kasan_populate_shadow(shadow_cea_begin,
+			      shadow_cea_per_cpu_begin, 0);
 
-	kasan_populate_early_shadow(shadow_cpu_entry_end,
+	kasan_populate_early_shadow((void *)shadow_cea_end,
 			kasan_mem_to_shadow((void *)__START_KERNEL_map));
 
 	kasan_populate_shadow((unsigned long)kasan_mem_to_shadow(_stext),