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authorThomas Gleixner <tglx@linutronix.de>2008-09-22 18:54:29 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-09-23 11:38:52 +0200
commit4faac97d44ac27bdbb010a9c3597401a8f89341f (patch)
tree680f128d2bf1cec0fdc77f7a8cb3f3f54264d282
parent6441402b1f173fa38e561d3cee7c01c32e5281ad (diff)
downloadlinux-4faac97d44ac27bdbb010a9c3597401a8f89341f.tar.bz2
x86: prevent stale state of c1e_mask across CPU offline/online
Impact: hang which happens across CPU offline/online on AMD C1E systems. When a CPU goes offline then the corresponding bit in the broadcast mask is cleared. For AMD C1E enabled CPUs we do not reenable the broadcast when the CPU comes online again as we do not clear the corresponding bit in the c1e_mask, which keeps track which CPUs have been switched to broadcast already. So on those !$@#& machines we never switch back to broadcasting after a CPU offline/online cycle. Clear the bit when the CPU plays dead. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/kernel/process.c11
-rw-r--r--arch/x86/kernel/process_32.c1
-rw-r--r--arch/x86/kernel/process_64.c2
-rw-r--r--include/asm-x86/idle.h2
4 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 7fc4d5b0a6a0..2e2247117f6e 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -246,6 +246,14 @@ static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
return 1;
}
+static cpumask_t c1e_mask = CPU_MASK_NONE;
+static int c1e_detected;
+
+void c1e_remove_cpu(int cpu)
+{
+ cpu_clear(cpu, c1e_mask);
+}
+
/*
* C1E aware idle routine. We check for C1E active in the interrupt
* pending message MSR. If we detect C1E, then we handle it the same
@@ -253,9 +261,6 @@ static int __cpuinit check_c1e_idle(const struct cpuinfo_x86 *c)
*/
static void c1e_idle(void)
{
- static cpumask_t c1e_mask = CPU_MASK_NONE;
- static int c1e_detected;
-
if (need_resched())
return;
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 3b7a1ddcc0bc..4b3cfdf54216 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -88,6 +88,7 @@ static void cpu_exit_clear(void)
cpu_clear(cpu, cpu_callin_map);
numa_remove_cpu(cpu);
+ c1e_remove_cpu(cpu);
}
/* We don't actually take CPU down, just spin without interrupts. */
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 71553b664e2a..e12e0e4dd256 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -93,6 +93,8 @@ DECLARE_PER_CPU(int, cpu_state);
static inline void play_dead(void)
{
idle_task_exit();
+ c1e_remove_cpu(raw_smp_processor_id());
+
mb();
/* Ack it */
__get_cpu_var(cpu_state) = CPU_DEAD;
diff --git a/include/asm-x86/idle.h b/include/asm-x86/idle.h
index d240e5b30a45..cbb649123612 100644
--- a/include/asm-x86/idle.h
+++ b/include/asm-x86/idle.h
@@ -10,4 +10,6 @@ void idle_notifier_register(struct notifier_block *n);
void enter_idle(void);
void exit_idle(void);
+void c1e_remove_cpu(int cpu);
+
#endif