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

Pull x86 fixes from Thomas Gleixner:
 "A couple of fixes addressing the following issues:

   - The last polishing for the TLB code, removing the last BUG_ON() and
     the debug file along with tidying up the lazy TLB code.

   - Prevent triple fault on 1st Gen. 486 caused by stupidly calling the
     early IDT setup after the first function which causes a fault which
     should be caught by the exception table.

   - Limit the mmap of /dev/mem to valid addresses

   - Prevent late microcode loading on Broadwell X

   - Remove a redundant assignment in the cache info code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Limit mmap() of /dev/mem to valid physical addresses
  x86/mm: Remove debug/x86/tlb_defer_switch_to_init_mm
  x86/mm: Tidy up "x86/mm: Flush more aggressively in lazy TLB mode"
  x86/mm/64: Remove the last VM_BUG_ON() from the TLB code
  x86/microcode/intel: Disable late loading on model 79
  x86/idt: Initialize early IDT before cr4_init_shadow()
  x86/cpu/intel_cacheinfo: Remove redundant assignment to 'this_leaf'

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 8f7a9bbad514..7dbcb7adf797 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -34,6 +34,7 @@
 #include <linux/mm.h>
 
 #include <asm/microcode_intel.h>
+#include <asm/intel-family.h>
 #include <asm/processor.h>
 #include <asm/tlbflush.h>
 #include <asm/setup.h>
@@ -918,6 +919,18 @@ static int get_ucode_fw(void *to, const void *from, size_t n)
         return 0;
 }
 
+static bool is_blacklisted(unsigned int cpu)
+{
+        struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+        if (c->x86 == 6 && c->x86_model == INTEL_FAM6_BROADWELL_X) {
+                pr_err_once("late loading on model 79 is disabled.\n");
+                return true;
+        }
+
+        return false;
+}
+
 static enum ucode_state request_microcode_fw(int cpu, struct device *device,
                                              bool refresh_fw)
 {
@@ -926,6 +939,9 @@ static enum ucode_state request_microcode_fw(int cpu, struct device *device,
         const struct firmware *firmware;
         enum ucode_state ret;
 
+        if (is_blacklisted(cpu))
+                return UCODE_NFOUND;
+
         sprintf(name, "intel-ucode/%02x-%02x-%02x",
                 c->x86, c->x86_model, c->x86_mask);
 
@@ -950,6 +966,9 @@ static int get_ucode_user(void *to, const void *from, size_t n)
 static enum ucode_state
 request_microcode_user(int cpu, const void __user *buf, size_t size)
 {
+        if (is_blacklisted(cpu))
+                return UCODE_NFOUND;
+
         return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
 }