6 files changed, 35 insertions, 7 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b961af86bfea..b9338b8cf420 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -390,7 +390,8 @@ static unsigned int reserve_eilvt_offset(int offset, unsigned int new)
 
 /*
  * If mask=1, the LVT entry does not generate interrupts while mask=0
- * enables the vector. See also the BKDGs.
+ * enables the vector. See also the BKDGs. Must be called with
+ * preemption disabled.
  */
 
 int setup_APIC_eilvt(u8 offset, u8 vector, u8 msg_type, u8 mask)
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 690bc8461835..9aeb78a23de4 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/pci.h>
 #include <linux/of_pci.h>
+#include <linux/initrd.h>
 
 #include <asm/hpet.h>
 #include <asm/irq_controller.h>
@@ -98,6 +99,16 @@ void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
         return __alloc_bootmem(size, align, __pa(MAX_DMA_ADDRESS));
 }
 
+#ifdef CONFIG_BLK_DEV_INITRD
+void __init early_init_dt_setup_initrd_arch(unsigned long start,
+                                            unsigned long end)
+{
+        initrd_start = (unsigned long)__va(start);
+        initrd_end = (unsigned long)__va(end);
+        initrd_below_start_ok = 1;
+}
+#endif
+
 void __init add_dtb(u64 data)
 {
         initial_dtb = data + offsetof(struct setup_data, data);
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8d128783af47..a3d0dc59067b 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -245,7 +245,6 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
 {
         set_user_gs(regs, 0);
         regs->fs                = 0;
-        set_fs(USER_DS);
         regs->ds                = __USER_DS;
         regs->es                = __USER_DS;
         regs->ss                = __USER_DS;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6c9dd922ac0d..ca6f7ab8df33 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -338,7 +338,6 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip,
         regs->cs                = _cs;
         regs->ss                = _ss;
         regs->flags             = X86_EFLAGS_IF;
-        set_fs(USER_DS);
         /*
          * Free the old FP and other extended state
          */
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 33a0c11797de..9fd3137230d4 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -285,6 +285,19 @@ notrace static void __cpuinit start_secondary(void *unused)
         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
         x86_platform.nmi_init();
 
+        /*
+         * Wait until the cpu which brought this one up marked it
+         * online before enabling interrupts. If we don't do that then
+         * we can end up waking up the softirq thread before this cpu
+         * reached the active state, which makes the scheduler unhappy
+         * and schedule the softirq thread on the wrong cpu. This is
+         * only observable with forced threaded interrupts, but in
+         * theory it could also happen w/o them. It's just way harder
+         * to achieve.
+         */
+        while (!cpumask_test_cpu(smp_processor_id(), cpu_active_mask))
+                cpu_relax();
+
         /* enable local interrupts */
         local_irq_enable();
 
diff --git a/arch/x86/oprofile/op_model_amd.c b/arch/x86/oprofile/op_model_amd.c
index 9fd8a567fe1e..9cbb710dc94b 100644
--- a/arch/x86/oprofile/op_model_amd.c
+++ b/arch/x86/oprofile/op_model_amd.c
@@ -609,16 +609,21 @@ static int setup_ibs_ctl(int ibs_eilvt_off)
         return 0;
 }
 
+/*
+ * This runs only on the current cpu. We try to find an LVT offset and
+ * setup the local APIC. For this we must disable preemption. On
+ * success we initialize all nodes with this offset. This updates then
+ * the offset in the IBS_CTL per-node msr. The per-core APIC setup of
+ * the IBS interrupt vector is called from op_amd_setup_ctrs()/op_-
+ * amd_cpu_shutdown() using the new offset.
+ */
 static int force_ibs_eilvt_setup(void)
 {
         int offset;
         int ret;
 
-        /*
-         * find the next free available EILVT entry, skip offset 0,
-         * pin search to this cpu
-         */
         preempt_disable();
+        /* find the next free available EILVT entry, skip offset 0 */
         for (offset = 1; offset < APIC_EILVT_NR_MAX; offset++) {
                 if (get_eilvt(offset))
                         break;