Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Peter Anvin:
 "Several boot fixes (MacBook, legacy EFI bootloaders), another
  please-don't-brick fix, and some minor stuff."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Do not try to sync identity map for non-mapped pages
  x86, doc: Be explicit about what the x86 struct boot_params requires
  x86: Don't clear efi_info even if the sentinel hits
  x86, mm: Make sure to find a 2M free block for the first mapped area
  x86: Fix 32-bit *_cpu_data initializers
  efivarfs: return accurate error code in efivarfs_fill_super()
  efivars: efivarfs_valid_name() should handle pstore syntax
  efi: be more paranoid about available space when creating variables
  iommu, x86: Add DMA remap fault reason
  x86, smpboot: Remove unused variable

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;