# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1274280123 -3600
# Node ID 163ac18c8c25d0ead826658a23107a54366f9dea
# Parent 287a7069503d25a6d30983d690253fd5a88a20be
x86: Streamline the CPU early boot process.
Mainly this involves getting rid of a bunch of cpumasks and replacing
with a single 'cpu_state' enumeration to track progress and allow
master-slave handshaking.
Cleaning this stuff up is a prerequisite for safely handling slave
failure (e.g., out of memory, invalid slave CPU capabilities,
...). This will get fixed up in a future patch.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/cpu/mtrr/main.c | 6 -
xen/arch/x86/domain.c | 9 -
xen/arch/x86/nmi.c | 7 -
xen/arch/x86/smpboot.c | 125 +++++++-----------------
xen/include/asm-x86/mach-default/mach_wakecpu.h | 11 --
xen/include/asm-x86/smp.h | 12 --
6 files changed, 44 insertions(+), 126 deletions(-)
diff -r 287a7069503d -r 163ac18c8c25 xen/arch/x86/cpu/mtrr/main.c
--- a/xen/arch/x86/cpu/mtrr/main.c Wed May 19 14:18:56 2010 +0100
+++ b/xen/arch/x86/cpu/mtrr/main.c Wed May 19 15:42:03 2010 +0100
@@ -236,7 +236,7 @@ static void set_mtrr(unsigned int reg, u
data.smp_base = base;
data.smp_size = size;
data.smp_type = type;
- atomic_set(&data.count, num_booting_cpus() - 1);
+ atomic_set(&data.count, num_online_cpus() - 1);
/* make sure data.count is visible before unleashing other CPUs */
smp_wmb();
atomic_set(&data.gate,0);
@@ -251,7 +251,7 @@ static void set_mtrr(unsigned int reg, u
cpu_relax();
/* ok, reset count and toggle gate */
- atomic_set(&data.count, num_booting_cpus() - 1);
+ atomic_set(&data.count, num_online_cpus() - 1);
smp_wmb();
atomic_set(&data.gate,1);
@@ -274,7 +274,7 @@ static void set_mtrr(unsigned int reg, u
while(atomic_read(&data.count))
cpu_relax();
- atomic_set(&data.count, num_booting_cpus() - 1);
+ atomic_set(&data.count, num_online_cpus() - 1);
smp_wmb();
atomic_set(&data.gate,0);
diff -r 287a7069503d -r 163ac18c8c25 xen/arch/x86/domain.c
--- a/xen/arch/x86/domain.c Wed May 19 14:18:56 2010 +0100
+++ b/xen/arch/x86/domain.c Wed May 19 15:42:03 2010 +0100
@@ -98,15 +98,10 @@ static void default_dead_idle(void)
static void play_dead(void)
{
- /* This must be done before dead CPU ack */
cpu_exit_clear(smp_processor_id());
+ mb();
+ local_irq_disable();
wbinvd();
- mb();
- /* Ack it */
- __get_cpu_var(cpu_state) = CPU_DEAD;
-
- /* With physical CPU hotplug, we should halt the cpu. */
- local_irq_disable();
(*dead_idle)();
}
diff -r 287a7069503d -r 163ac18c8c25 xen/arch/x86/nmi.c
--- a/xen/arch/x86/nmi.c Wed May 19 14:18:56 2010 +0100
+++ b/xen/arch/x86/nmi.c Wed May 19 15:42:03 2010 +0100
@@ -105,16 +105,13 @@ int __init check_nmi_watchdog (void)
printk("Testing NMI watchdog --- ");
- for ( cpu = 0; cpu < NR_CPUS; cpu++ )
+ for_each_online_cpu ( cpu )
prev_nmi_count[cpu] = nmi_count(cpu);
local_irq_enable();
mdelay((10*1000)/nmi_hz); /* wait 10 ticks */
- for ( cpu = 0; cpu < NR_CPUS; cpu++ )
+ for_each_online_cpu ( cpu )
{
- if ( !cpu_isset(cpu, cpu_callin_map) &&
- !cpu_isset(cpu, cpu_online_map) )
- continue;
if ( nmi_count(cpu) - prev_nmi_count[cpu] <= 5 )
printk("CPU#%d stuck. ", cpu);
else
diff -r 287a7069503d -r 163ac18c8c25 xen/arch/x86/smpboot.c
--- a/xen/arch/x86/smpboot.c Wed May 19 14:18:56 2010 +0100
+++ b/xen/arch/x86/smpboot.c Wed May 19 15:42:03 2010 +0100
@@ -65,17 +65,20 @@ cpumask_t cpu_online_map __read_mostly;
cpumask_t cpu_online_map __read_mostly;
EXPORT_SYMBOL(cpu_online_map);
-cpumask_t cpu_callin_map;
-cpumask_t cpu_callout_map;
-static cpumask_t smp_commenced_mask;
-
struct cpuinfo_x86 cpu_data[NR_CPUS];
u32 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = -1U };
static void map_cpu_to_logical_apicid(void);
-DEFINE_PER_CPU(int, cpu_state);
+enum cpu_state {
+ CPU_STATE_DEAD = 0, /* slave -> master: I am completely dead */
+ CPU_STATE_INIT, /* master -> slave: Early bringup phase 1 */
+ CPU_STATE_CALLOUT, /* master -> slave: Early bringup phase 2 */
+ CPU_STATE_CALLIN, /* slave -> master: Completed phase 2 */
+ CPU_STATE_ONLINE /* master -> slave: Go fully online now. */
+} cpu_state;
+#define set_cpu_state(state) do { mb(); cpu_state = (state); } while (0)
void *stack_base[NR_CPUS];
@@ -128,75 +131,38 @@ static void smp_store_cpu_info(int id)
;
}
-static atomic_t init_deasserted;
-
void smp_callin(void)
{
- int cpuid, phys_id, i;
-
- /*
- * If waken up by an INIT in an 82489DX configuration
- * we may get here before an INIT-deassert IPI reaches
- * our local APIC. We have to wait for the IPI or we'll
- * lock up on an APIC access.
- */
- wait_for_init_deassert(&init_deasserted);
-
+ int i;
+
+ /* Wait 2s total for startup. */
+ Dprintk("Waiting for CALLOUT.\n");
+ for ( i = 0; cpu_state != CPU_STATE_CALLOUT; i++ )
+ {
+ BUG_ON(i >= 200);
+ cpu_relax();
+ mdelay(10);
+ }
+
+ /*
+ * The boot CPU has finished the init stage and is spinning on cpu_state
+ * update until we finish. We are free to set up this CPU: first the APIC.
+ */
+ Dprintk("CALLIN, before setup_local_APIC().\n");
if ( x2apic_enabled )
enable_x2apic();
-
- /*
- * (This works even if the APIC is not enabled.)
- */
- phys_id = get_apic_id();
- cpuid = smp_processor_id();
- if ( cpu_isset(cpuid, cpu_callin_map) )
- {
- printk("huh, phys CPU#%d, CPU#%d already present??\n",
- phys_id, cpuid);
- BUG();
- }
- Dprintk("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
-
- /*
- * STARTUP IPIs are fragile beasts as they might sometimes
- * trigger some glue motherboard logic. Complete APIC bus
- * silence for 1 second, this overestimates the time the
- * boot CPU is spending to send the up to 2 STARTUP IPIs
- * by a factor of two. This should be enough.
- */
-
- /* Wait 2s total for startup. */
- for ( i = 0; (i < 200) && !cpu_isset(cpuid, cpu_callout_map); i++ )
- {
- cpu_relax();
- mdelay(10);
- }
-
- if ( !cpu_isset(cpuid, cpu_callout_map) )
- {
- printk("BUG: CPU%d started up but did not get a callout!\n",
- cpuid);
- BUG();
- }
-
- /*
- * the boot CPU has finished the init stage and is spinning
- * on callin_map until we finish. We are free to set up this
- * CPU, first the APIC. (this is probably redundant on most
- * boards)
- */
-
- Dprintk("CALLIN, before setup_local_APIC().\n");
- smp_callin_clear_local_apic();
setup_local_APIC();
map_cpu_to_logical_apicid();
/* Save our processor parameters. */
- smp_store_cpu_info(cpuid);
+ smp_store_cpu_info(smp_processor_id());
/* Allow the master to continue. */
- cpu_set(cpuid, cpu_callin_map);
+ set_cpu_state(CPU_STATE_CALLIN);
+
+ /* And wait for our final Ack. */
+ while ( cpu_state != CPU_STATE_ONLINE )
+ cpu_relax();
}
static int booting_cpu;
@@ -316,8 +282,6 @@ void start_secondary(void *unused)
cpu_init();
smp_callin();
- while (!cpu_isset(smp_processor_id(), smp_commenced_mask))
- cpu_relax();
/*
* At this point, boot CPU has fully initialised the IDT. It is
@@ -347,8 +311,6 @@ void start_secondary(void *unused)
__setup_vector_irq(smp_processor_id());
cpu_set(smp_processor_id(), cpu_online_map);
unlock_vector_lock();
-
- per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
init_percpu_time();
@@ -469,8 +431,6 @@ static int wakeup_secondary_cpu(int phys
send_status = apic_read(APIC_ICR) & APIC_ICR_BUSY;
} while ( send_status && (timeout++ < 1000) );
- atomic_set(&init_deasserted, 1);
-
/*
* Should we send STARTUP IPIs ?
*
@@ -570,7 +530,7 @@ static int do_boot_cpu(int apicid, int c
/* This grunge runs the startup process for the targeted processor. */
- atomic_set(&init_deasserted, 0);
+ set_cpu_state(CPU_STATE_INIT);
Dprintk("Setting warm reset code and vector.\n");
@@ -582,19 +542,18 @@ static int do_boot_cpu(int apicid, int c
if ( !boot_error )
{
/* Allow AP to start initializing. */
- Dprintk("Before Callout %d.\n", cpu);
- cpu_set(cpu, cpu_callout_map);
+ set_cpu_state(CPU_STATE_CALLOUT);
Dprintk("After Callout %d.\n", cpu);
/* Wait 5s total for a response. */
for ( timeout = 0; timeout < 50000; timeout++ )
{
- if ( cpu_isset(cpu, cpu_callin_map) )
+ if ( cpu_state == CPU_STATE_CALLIN )
break; /* It has booted */
udelay(100);
}
- if ( cpu_isset(cpu, cpu_callin_map) )
+ if ( cpu_state == CPU_STATE_CALLIN )
{
/* number CPUs logically, starting from 1 (BSP is 0) */
Dprintk("OK.\n");
@@ -630,12 +589,8 @@ void cpu_exit_clear(unsigned int cpu)
void cpu_exit_clear(unsigned int cpu)
{
cpu_uninit(cpu);
-
- cpu_clear(cpu, cpu_callout_map);
- cpu_clear(cpu, cpu_callin_map);
-
- cpu_clear(cpu, smp_commenced_mask);
unmap_cpu_to_logical_apicid(cpu);
+ set_cpu_state(CPU_STATE_DEAD);
}
static void cpu_smpboot_free(unsigned int cpu)
@@ -828,12 +783,8 @@ void __init smp_prepare_cpus(unsigned in
void __init smp_prepare_boot_cpu(void)
{
- cpu_set(smp_processor_id(), smp_commenced_mask);
- cpu_set(smp_processor_id(), cpu_callin_map);
cpu_set(smp_processor_id(), cpu_online_map);
- cpu_set(smp_processor_id(), cpu_callout_map);
cpu_set(smp_processor_id(), cpu_present_map);
- per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
}
static void
@@ -888,7 +839,7 @@ void __cpu_die(unsigned int cpu)
/* We don't do anything here: idle task is faking death itself. */
unsigned int i = 0;
- while ( per_cpu(cpu_state, cpu) != CPU_DEAD )
+ while ( cpu_state != CPU_STATE_DEAD )
{
mdelay(100);
cpu_relax();
@@ -957,15 +908,13 @@ int __cpu_up(unsigned int cpu)
{
int apicid, ret;
- BUG_ON(cpu_isset(cpu, cpu_callin_map));
-
if ( (apicid = x86_cpu_to_apicid[cpu]) == BAD_APICID )
return -ENODEV;
if ( (ret = do_boot_cpu(apicid, cpu)) != 0 )
return ret;
- cpu_set(cpu, smp_commenced_mask);
+ set_cpu_state(CPU_STATE_ONLINE);
while ( !cpu_isset(cpu, cpu_online_map) )
{
cpu_relax();
diff -r 287a7069503d -r 163ac18c8c25
xen/include/asm-x86/mach-default/mach_wakecpu.h
--- a/xen/include/asm-x86/mach-default/mach_wakecpu.h Wed May 19 14:18:56
2010 +0100
+++ b/xen/include/asm-x86/mach-default/mach_wakecpu.h Wed May 19 15:42:03
2010 +0100
@@ -13,17 +13,6 @@
#define boot_cpu_apicid boot_cpu_physical_apicid
-static inline void wait_for_init_deassert(atomic_t *deassert)
-{
- while (!atomic_read(deassert));
- return;
-}
-
-/* Nothing to do for most platforms, since cleared by the INIT cycle */
-static inline void smp_callin_clear_local_apic(void)
-{
-}
-
#if APIC_DEBUG
#define inquire_remote_apic(apicid) __inquire_remote_apic(apicid)
#else
diff -r 287a7069503d -r 163ac18c8c25 xen/include/asm-x86/smp.h
--- a/xen/include/asm-x86/smp.h Wed May 19 14:18:56 2010 +0100
+++ b/xen/include/asm-x86/smp.h Wed May 19 15:42:03 2010 +0100
@@ -52,9 +52,6 @@ extern u32 cpu_2_logical_apicid[];
#define cpu_physical_id(cpu) x86_cpu_to_apicid[cpu]
-/* State of each CPU. */
-DECLARE_PER_CPU(int, cpu_state);
-
#define cpu_is_offline(cpu) unlikely(!cpu_online(cpu))
extern void cpu_exit_clear(unsigned int cpu);
extern void cpu_uninit(unsigned int cpu);
@@ -66,15 +63,6 @@ int cpu_add(uint32_t apic_id, uint32_t a
* so this is correct in the x86 case.
*/
#define raw_smp_processor_id() (get_processor_id())
-
-extern cpumask_t cpu_callout_map;
-extern cpumask_t cpu_callin_map;
-
-/* We don't mark CPUs online until __cpu_up(), so we need another measure */
-static inline int num_booting_cpus(void)
-{
- return cpus_weight(cpu_callout_map);
-}
#ifdef CONFIG_X86_LOCAL_APIC
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