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

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
  x86: Disable large pages on CPUs with Atom erratum AAE44
  x86-64: Clear a 64-bit FS/GS base on fork if selector is nonzero
  x86, mrst: Conditionally register cpu hotplug notifier for apbt

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index ff469e4..a353475 100644 (file)
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -429,7 +429,7 @@ static int apbt_cpuhp_notify(struct notifier_block *n,
 
 static __init int apbt_late_init(void)
 {
-       if (disable_apbt_percpu)
+       if (disable_apbt_percpu || !apb_timer_block_enabled)
                return 0;
        /* This notifier should be called after workqueue is ready */
        hotcpu_notifier(apbt_cpuhp_notify, -20);

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 7e1cca1..1366c7c 100644 (file)
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -47,6 +47,27 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
                (c->x86 == 0x6 && c->x86_model >= 0x0e))
                set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
 
+       /*
+        * Atom erratum AAE44/AAF40/AAG38/AAH41:
+        *
+        * A race condition between speculative fetches and invalidating
+        * a large page.  This is worked around in microcode, but we
+        * need the microcode to have already been loaded... so if it is
+        * not, recommend a BIOS update and disable large pages.
+        */
+       if (c->x86 == 6 && c->x86_model == 0x1c && c->x86_mask <= 2) {
+               u32 ucode, junk;
+
+               wrmsr(MSR_IA32_UCODE_REV, 0, 0);
+               sync_core();
+               rdmsr(MSR_IA32_UCODE_REV, junk, ucode);
+
+               if (ucode < 0x20e) {
+                       printk(KERN_WARNING "Atom PSE erratum detected, BIOS microcode update recommended\n");
+                       clear_cpu_cap(c, X86_FEATURE_PSE);
+               }
+       }
+
 #ifdef CONFIG_X86_64
        set_cpu_cap(c, X86_FEATURE_SYSENTER32);
 #else

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index dc9690b..17cb329 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -276,12 +276,12 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 
        set_tsk_thread_flag(p, TIF_FORK);
 
-       p->thread.fs = me->thread.fs;
-       p->thread.gs = me->thread.gs;
        p->thread.io_bitmap_ptr = NULL;
 
        savesegment(gs, p->thread.gsindex);
+       p->thread.gs = p->thread.gsindex ? 0 : me->thread.gs;
        savesegment(fs, p->thread.fsindex);
+       p->thread.fs = p->thread.fsindex ? 0 : me->thread.fs;
        savesegment(es, p->thread.es);
        savesegment(ds, p->thread.ds);