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

Pull x86 apic changes from Ingo Molnar:
 "An xAPIC CPU hotplug race fix, plus cleanups and minor fixes"

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/apic: Plug racy xAPIC access of CPU hotplug code
  x86/apic: Always define nox2apic and define it as initdata
  x86/apic: Remove unused function prototypes
  x86/apic: Switch wait_for_init_deassert() to a bool flag
  x86/apic: Only use default_wait_for_init_deassert()

14 files changed, 36 insertions, 46 deletions

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 1d2091a226bc..19b0ebafcd3e 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -93,9 +93,6 @@ static inline int is_vsmp_box(void)
         return 0;
 }
 #endif
-extern void xapic_wait_icr_idle(void);
-extern u32 safe_xapic_wait_icr_idle(void);
-extern void xapic_icr_write(u32, u32);
 extern int setup_profiling_timer(unsigned int);
 
 static inline void native_apic_mem_write(u32 reg, u32 v)
@@ -184,7 +181,6 @@ extern int x2apic_phys;
 extern int x2apic_preenabled;
 extern void check_x2apic(void);
 extern void enable_x2apic(void);
-extern void x2apic_icr_write(u32 low, u32 id);
 static inline int x2apic_enabled(void)
 {
         u64 msr;
@@ -221,7 +217,6 @@ static inline void x2apic_force_phys(void)
 {
 }
 
-#define nox2apic        0
 #define x2apic_preenabled 0
 #define x2apic_supported()      0
 #endif
@@ -351,7 +346,7 @@ struct apic {
         int trampoline_phys_low;
         int trampoline_phys_high;
 
-        void (*wait_for_init_deassert)(atomic_t *deassert);
+        bool wait_for_init_deassert;
         void (*smp_callin_clear_local_apic)(void);
         void (*inquire_remote_apic)(int apicid);
 
@@ -517,13 +512,6 @@ extern int default_cpu_present_to_apicid(int mps_cpu);
 extern int default_check_phys_apicid_present(int phys_apicid);
 #endif
 
-static inline void default_wait_for_init_deassert(atomic_t *deassert)
-{
-        while (!atomic_read(deassert))
-                cpu_relax();
-        return;
-}
-
 extern void generic_bigsmp_probe(void);
 
 
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 7f26c9a70a9e..53e20531470e 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -133,6 +133,10 @@ static inline void imcr_apic_to_pic(void)
  * +1=force-enable
  */
 static int force_enable_local_apic __initdata;
+
+/* Control whether x2APIC mode is enabled or not */
+static bool nox2apic __initdata;
+
 /*
  * APIC command line parameters
  */
@@ -162,8 +166,7 @@ int x2apic_mode;
 /* x2apic enabled before OS handover */
 int x2apic_preenabled;
 static int x2apic_disabled;
-static int nox2apic;
-static __init int setup_nox2apic(char *str)
+static int __init setup_nox2apic(char *str)
 {
         if (x2apic_enabled()) {
                 int apicid = native_apic_msr_read(APIC_ID);
@@ -178,7 +181,7 @@ static __init int setup_nox2apic(char *str)
         } else
                 setup_clear_cpu_cap(X86_FEATURE_X2APIC);
 
-        nox2apic = 1;
+        nox2apic = true;
 
         return 0;
 }
@@ -283,8 +286,12 @@ u32 native_safe_apic_wait_icr_idle(void)
 
 void native_apic_icr_write(u32 low, u32 id)
 {
+        unsigned long flags;
+
+        local_irq_save(flags);
         apic_write(APIC_ICR2, SET_APIC_DEST_FIELD(id));
         apic_write(APIC_ICR, low);
+        local_irq_restore(flags);
 }
 
 u64 native_apic_icr_read(void)
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
index 2c621a6b901a..7c1b29479513 100644
--- a/arch/x86/kernel/apic/apic_flat_64.c
+++ b/arch/x86/kernel/apic/apic_flat_64.c
@@ -198,7 +198,7 @@ static struct apic apic_flat =  {
 
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
 
@@ -314,7 +314,7 @@ static struct apic apic_physflat =  {
 
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
 
diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c
index 191ce75c0e54..8c7c98249c20 100644
--- a/arch/x86/kernel/apic/apic_noop.c
+++ b/arch/x86/kernel/apic/apic_noop.c
@@ -172,8 +172,7 @@ struct apic apic_noop = {
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
 
-        .wait_for_init_deassert         = NULL,
-
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = NULL,
 
diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
index 3e67f9e3d7ef..a5b45df8bc88 100644
--- a/arch/x86/kernel/apic/apic_numachip.c
+++ b/arch/x86/kernel/apic/apic_numachip.c
@@ -248,7 +248,7 @@ static const struct apic apic_numachip __refconst = {
         .wakeup_secondary_cpu           = numachip_wakeup_secondary,
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = NULL, /* REMRD not supported */
 
diff --git a/arch/x86/kernel/apic/bigsmp_32.c b/arch/x86/kernel/apic/bigsmp_32.c
index d50e3640d5ae..e4840aa7a255 100644
--- a/arch/x86/kernel/apic/bigsmp_32.c
+++ b/arch/x86/kernel/apic/bigsmp_32.c
@@ -199,8 +199,7 @@ static struct apic apic_bigsmp = {
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
 
-        .wait_for_init_deassert         = default_wait_for_init_deassert,
-
+        .wait_for_init_deassert         = true,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
 
diff --git a/arch/x86/kernel/apic/es7000_32.c b/arch/x86/kernel/apic/es7000_32.c
index c55224731b2d..6f8f8b348a39 100644
--- a/arch/x86/kernel/apic/es7000_32.c
+++ b/arch/x86/kernel/apic/es7000_32.c
@@ -394,12 +394,6 @@ static void es7000_enable_apic_mode(void)
                 WARN(1, "Command failed, status = %x\n", mip_status);
 }
 
-static void es7000_wait_for_init_deassert(atomic_t *deassert)
-{
-        while (!atomic_read(deassert))
-                cpu_relax();
-}
-
 static unsigned int es7000_get_apic_id(unsigned long x)
 {
         return (x >> 24) & 0xFF;
@@ -658,8 +652,7 @@ static struct apic __refdata apic_es7000_cluster = {
         .trampoline_phys_low            = 0x467,
         .trampoline_phys_high           = 0x469,
 
-        .wait_for_init_deassert         = NULL,
-
+        .wait_for_init_deassert         = false,
         /* Nothing to do for most platforms, since cleared by the INIT cycle: */
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
@@ -722,8 +715,7 @@ static struct apic __refdata apic_es7000 = {
         .trampoline_phys_low            = 0x467,
         .trampoline_phys_high           = 0x469,
 
-        .wait_for_init_deassert         = es7000_wait_for_init_deassert,
-
+        .wait_for_init_deassert         = true,
         /* Nothing to do for most platforms, since cleared by the INIT cycle: */
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
diff --git a/arch/x86/kernel/apic/numaq_32.c b/arch/x86/kernel/apic/numaq_32.c
index 1e42e8f305ee..030ea1c04f72 100644
--- a/arch/x86/kernel/apic/numaq_32.c
+++ b/arch/x86/kernel/apic/numaq_32.c
@@ -505,8 +505,7 @@ static struct apic __refdata apic_numaq = {
         .trampoline_phys_high           = NUMAQ_TRAMPOLINE_PHYS_HIGH,
 
         /* We don't do anything here because we use NMI's to boot instead */
-        .wait_for_init_deassert         = NULL,
-
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = numaq_smp_callin_clear_local_apic,
         .inquire_remote_apic            = NULL,
 
diff --git a/arch/x86/kernel/apic/probe_32.c b/arch/x86/kernel/apic/probe_32.c
index eb35ef9ee63f..cceb352c968c 100644
--- a/arch/x86/kernel/apic/probe_32.c
+++ b/arch/x86/kernel/apic/probe_32.c
@@ -119,8 +119,7 @@ static struct apic apic_default = {
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
 
-        .wait_for_init_deassert         = default_wait_for_init_deassert,
-
+        .wait_for_init_deassert         = true,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
 
diff --git a/arch/x86/kernel/apic/summit_32.c b/arch/x86/kernel/apic/summit_32.c
index 00146f9b0254..b656128611cd 100644
--- a/arch/x86/kernel/apic/summit_32.c
+++ b/arch/x86/kernel/apic/summit_32.c
@@ -532,8 +532,7 @@ static struct apic apic_summit = {
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
 
-        .wait_for_init_deassert         = default_wait_for_init_deassert,
-
+        .wait_for_init_deassert         = true,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = default_inquire_remote_apic,
 
diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
index cac85ee6913f..e66766bf1641 100644
--- a/arch/x86/kernel/apic/x2apic_cluster.c
+++ b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -279,7 +279,7 @@ static struct apic apic_x2apic_cluster = {
 
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = NULL,
 
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index de231e328cae..6d600ebf6c12 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -133,7 +133,7 @@ static struct apic apic_x2apic_phys = {
 
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = NULL,
 
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index d263b1307de1..7834389ba5be 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -396,7 +396,7 @@ static struct apic __refdata apic_x2apic_uv_x = {
         .wakeup_secondary_cpu           = uv_wakeup_secondary,
         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
-        .wait_for_init_deassert         = NULL,
+        .wait_for_init_deassert         = false,
         .smp_callin_clear_local_apic    = NULL,
         .inquire_remote_apic            = NULL,
 
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a32da804252e..60179ec39d4c 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -122,8 +122,9 @@ static void smp_callin(void)
          * Since CPU0 is not wakened up by INIT, it doesn't wait for the IPI.
          */
         cpuid = smp_processor_id();
-        if (apic->wait_for_init_deassert && cpuid != 0)
-                apic->wait_for_init_deassert(&init_deasserted);
+        if (apic->wait_for_init_deassert && cpuid)
+                while (!atomic_read(&init_deasserted))
+                        cpu_relax();
 
         /*
          * (This works even if the APIC is not enabled.)
@@ -701,11 +702,15 @@ wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
         int id;
         int boot_error;
 
+        preempt_disable();
+
         /*
          * Wake up AP by INIT, INIT, STARTUP sequence.
          */
-        if (cpu)
-                return wakeup_secondary_cpu_via_init(apicid, start_ip);
+        if (cpu) {
+                boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
+                goto out;
+        }
 
         /*
          * Wake up BSP by nmi.
@@ -725,6 +730,9 @@ wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
                 boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip);
         }
 
+out:
+        preempt_enable();
+
         return boot_error;
 }