5 files changed, 36 insertions, 9 deletions

diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index 5b5e9cb774b5..653668d140f9 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -14,13 +14,29 @@
  * analysis of kexec-tools; if other broken bootloaders initialize a
  * different set of fields we will need to figure out how to disambiguate.
  *
+ * Note: efi_info is commonly left uninitialized, but that field has a
+ * private magic, so it is better to leave it unchanged.
  */
 static void sanitize_boot_params(struct boot_params *boot_params)
 {
+	/* 
+	 * IMPORTANT NOTE TO BOOTLOADER AUTHORS: do not simply clear
+	 * this field.  The purpose of this field is to guarantee
+	 * compliance with the x86 boot spec located in
+	 * Documentation/x86/boot.txt .  That spec says that the
+	 * *whole* structure should be cleared, after which only the
+	 * portion defined by struct setup_header (boot_params->hdr)
+	 * should be copied in.
+	 *
+	 * If you're having an issue because the sentinel is set, you
+	 * need to change the whole structure to be cleared, not this
+	 * (or any other) individual field, or you will soon have
+	 * problems again.
+	 */
 	if (boot_params->sentinel) {
-		/*fields in boot_params are not valid, clear them */
+		/* fields in boot_params are left uninitialized, clear them */
 		memset(&boot_params->olpc_ofw_header, 0,
-		       (char *)&boot_params->alt_mem_k -
+		       (char *)&boot_params->efi_info -
 			(char *)&boot_params->olpc_ofw_header);
 		memset(&boot_params->kbd_status, 0,
 		       (char *)&boot_params->hdr -
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 84d32855f65c..90d8cc930f5e 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -171,9 +171,15 @@ static struct resource bss_resource = {
 
 #ifdef CONFIG_X86_32
 /* cpu data as detected by the assembly code in head.S */
-struct cpuinfo_x86 new_cpu_data __cpuinitdata = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 new_cpu_data __cpuinitdata = {
+	.wp_works_ok = -1,
+	.fdiv_bug = -1,
+};
 /* common cpu data for all cpus */
-struct cpuinfo_x86 boot_cpu_data __read_mostly = {0, 0, 0, 0, -1, 1, 0, 0, -1};
+struct cpuinfo_x86 boot_cpu_data __read_mostly = {
+	.wp_works_ok = -1,
+	.fdiv_bug = -1,
+};
 EXPORT_SYMBOL(boot_cpu_data);
 
 unsigned int def_to_bigsmp;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a6ceaedc396a..9f190a2a00e9 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1365,9 +1365,8 @@ static inline void mwait_play_dead(void)
 	unsigned int eax, ebx, ecx, edx;
 	unsigned int highest_cstate = 0;
 	unsigned int highest_subcstate = 0;
-	int i;
 	void *mwait_ptr;
-	struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info);
+	int i;
 
 	if (!this_cpu_has(X86_FEATURE_MWAIT))
 		return;
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 4903a03ae876..59b7fc453277 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -410,9 +410,8 @@ void __init init_mem_mapping(void)
 	/* the ISA range is always mapped regardless of memory holes */
 	init_memory_mapping(0, ISA_END_ADDRESS);
 
-	/* xen has big range in reserved near end of ram, skip it at first */
-	addr = memblock_find_in_range(ISA_END_ADDRESS, end, PMD_SIZE,
-			 PAGE_SIZE);
+	/* xen has big range in reserved near end of ram, skip it at first.*/
+	addr = memblock_find_in_range(ISA_END_ADDRESS, end, PMD_SIZE, PMD_SIZE);
 	real_end = addr + PMD_SIZE;
 
 	/* step_size need to be small so pgt_buf from BRK could cover it */
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 2610bd93c896..657438858e83 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -563,6 +563,13 @@ int kernel_map_sync_memtype(u64 base, unsigned long size, unsigned long flags)
 	if (base > __pa(high_memory-1))
 		return 0;
 
+	/*
+	 * some areas in the middle of the kernel identity range
+	 * are not mapped, like the PCI space.
+	 */
+	if (!page_is_ram(base >> PAGE_SHIFT))
+		return 0;
+
 	id_sz = (__pa(high_memory-1) <= base + size) ?
 				__pa(high_memory) - base :
 				size;