[PATCH] x86/smpboot: Make the code more consistent

From: Ingo Molnar
Date: Tue Nov 12 2013 - 07:36:38 EST

Over the last decade the smpboot.c code has become a disjunct set of
often conflicting, inconsistent style elements, making it harder to
read.

Unify the variable namings, simplify code, clean up comments, to
make it all more hackable.

Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/smpboot.c | 402 +++++++++++++++++++++-------------------------
1 file changed, 179 insertions(+), 223 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2a16558..12863e1 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1,4 +1,4 @@
- /*
+/*
* x86 SMP booting functions
*
* (c) 1995 Alan Cox, Building #3 <alan@xxxxxxxxxxxxxxxxxxx>
@@ -31,11 +31,11 @@
* Tigran Aivazian : fixed "0.00 in /proc/uptime on SMP" bug.
* Maciej W. Rozycki : Bits for genuine 82489DX APICs
* Andi Kleen : Changed for SMP boot into long mode.
- * Martin J. Bligh : Added support for multi-quad systems
+ * Martin J. Bligh : Added support for multi-quad systems
* Dave Jones : Report invalid combinations of Athlon CPUs.
* Rusty Russell : Hacked into shape for new "hotplug" boot process.
* Andi Kleen : Converted to new state machine.
- * Ashok Raj : CPU hotplug support
+ * Ashok Raj : CPU hotplug support
* Glauber Costa : i386 and x86_64 integration
*/

@@ -78,8 +78,8 @@
#include <asm/realmode.h>
#include <asm/misc.h>

-/* State of each CPU */
-DEFINE_PER_CPU(int, cpu_state) = { 0 };
+/* State of each CPU: */
+DEFINE_PER_CPU(int, cpu_state);

#ifdef CONFIG_HOTPLUG_CPU
/*
@@ -125,6 +125,9 @@ EXPORT_PER_CPU_SYMBOL(cpu_info);

atomic_t init_deasserted;

+static int cpu0_logical_apicid;
+static int enable_start_cpu0;
+
/*
* Report back to the Boot Processor during boot time or to the caller processor
* during CPU online.
@@ -150,10 +153,9 @@ static void smp_callin(void)
* (This works even if the APIC is not enabled.)
*/
phys_id = read_apic_id();
- if (cpumask_test_cpu(cpuid, cpu_callin_mask)) {
- panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
- phys_id, cpuid);
- }
+ if (cpumask_test_cpu(cpuid, cpu_callin_mask))
+ panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__, phys_id, cpuid);
+
pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);

/*
@@ -177,13 +179,11 @@ static void smp_callin(void)
cpu_relax();
}

- if (!time_before(jiffies, timeout)) {
- panic("%s: CPU%d started up but did not get a callout!\n",
- __func__, cpuid);
- }
+ if (!time_before(jiffies, timeout))
+ panic("%s: CPU%d started up but did not get a callout!\n", __func__, cpuid);

/*
- * the boot CPU has finished the init stage and is spinning
+ * 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)
@@ -195,9 +195,7 @@ static void smp_callin(void)
setup_local_APIC();
end_local_APIC_setup();

- /*
- * Need to setup vector mappings before we enable interrupts.
- */
+ /* Need to setup vector mappings before we enable interrupts. */
setup_vector_irq(smp_processor_id());

/*
@@ -225,14 +223,10 @@ static void smp_callin(void)

notify_cpu_starting(cpuid);

- /*
- * Allow the master to continue.
- */
+ /* Allow the boot CPU to continue: */
cpumask_set_cpu(cpuid, cpu_callin_mask);
}

-static int cpu0_logical_apicid;
-static int enable_start_cpu0;
/*
* Activate a secondary processor.
*/
@@ -274,10 +268,10 @@ static void notrace start_secondary(void *unused)
per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
x86_platform.nmi_init();

- /* enable local interrupts */
+ /* Enable local interrupts */
local_irq_enable();

- /* to prevent fake stack check failure in clock setup */
+ /* Prevent fake stack check failure in clock setup */
boot_init_stack_canary();

x86_cpuinit.setup_percpu_clockev();
@@ -289,10 +283,10 @@ static void notrace start_secondary(void *unused)
void __init smp_store_boot_cpu_info(void)
{
int id = 0; /* CPU 0 */
- struct cpuinfo_x86 *c = &cpu_data(id);
+ struct cpuinfo_x86 *c_this = &cpu_data(id);

- *c = boot_cpu_data;
- c->cpu_index = id;
+ *c_this = boot_cpu_data;
+ c_this->cpu_index = id;
}

/*
@@ -301,100 +295,106 @@ void __init smp_store_boot_cpu_info(void)
*/
void smp_store_cpu_info(int id)
{
- struct cpuinfo_x86 *c = &cpu_data(id);
+ struct cpuinfo_x86 *c_this = &cpu_data(id);

- *c = boot_cpu_data;
- c->cpu_index = id;
+ *c_this = boot_cpu_data;
+ c_this->cpu_index = id;
/*
* During boot time, CPU0 has this setup already. Save the info when
* bringing up AP or offlined CPU0.
*/
- identify_secondary_cpu(c);
+ identify_secondary_cpu(c_this);
}

static bool
-topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
+topology_sane(struct cpuinfo_x86 *c_this, struct cpuinfo_x86 *c_sibling, const char *name)
{
- int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+ int cpu_this = c_this->cpu_index, cpu_sibling = c_sibling->cpu_index;

- return !WARN_ONCE(cpu_to_node(cpu1) != cpu_to_node(cpu2),
- "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
- "[node: %d != %d]. Ignoring dependency.\n",
- cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
+ return !WARN_ONCE(cpu_to_node(cpu_this) != cpu_to_node(cpu_sibling),
+ "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! [node: %d != %d]. Ignoring dependency.\n",
+ cpu_this, name, cpu_sibling, cpu_to_node(cpu_this), cpu_to_node(cpu_sibling));
}

-#define link_mask(_m, c1, c2) \
-do { \
- cpumask_set_cpu((c1), cpu_##_m##_mask(c2)); \
- cpumask_set_cpu((c2), cpu_##_m##_mask(c1)); \
-} while (0)
-
-static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+static bool match_smt(struct cpuinfo_x86 *c_this, struct cpuinfo_x86 *c_sibling)
{
if (cpu_has_topoext) {
- int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+ int cpu_this = c_this->cpu_index, cpu_sibling = c_sibling->cpu_index;

- if (c->phys_proc_id == o->phys_proc_id &&
- per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2) &&
- c->compute_unit_id == o->compute_unit_id)
- return topology_sane(c, o, "smt");
+ if (c_this->phys_proc_id == c_sibling->phys_proc_id &&
+ per_cpu(cpu_llc_id, cpu_this) == per_cpu(cpu_llc_id, cpu_sibling) &&
+ c_this->compute_unit_id == c_sibling->compute_unit_id)
+ return topology_sane(c_this, c_sibling, "smt");

- } else if (c->phys_proc_id == o->phys_proc_id &&
- c->cpu_core_id == o->cpu_core_id) {
- return topology_sane(c, o, "smt");
+ } else {
+ if (c_this->phys_proc_id == c_sibling->phys_proc_id &&
+ c_this->cpu_core_id == c_sibling->cpu_core_id)
+ return topology_sane(c_this, c_sibling, "smt");
}

return false;
}

-static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+static bool match_llc(struct cpuinfo_x86 *c_this, struct cpuinfo_x86 *c_sibling)
{
- int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
+ int cpu_this = c_this->cpu_index, cpu_sibling = c_sibling->cpu_index;

- if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID &&
- per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2))
- return topology_sane(c, o, "llc");
+ if (per_cpu(cpu_llc_id, cpu_this) != BAD_APICID &&
+ per_cpu(cpu_llc_id, cpu_this) == per_cpu(cpu_llc_id, cpu_sibling))
+ return topology_sane(c_this, c_sibling, "llc");

return false;
}

-static bool match_mc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
+static bool match_mc(struct cpuinfo_x86 *c_this, struct cpuinfo_x86 *c_sibling)
{
- if (c->phys_proc_id == o->phys_proc_id) {
- if (cpu_has(c, X86_FEATURE_AMD_DCM))
+ if (c_this->phys_proc_id == c_sibling->phys_proc_id) {
+ if (cpu_has(c_this, X86_FEATURE_AMD_DCM))
return true;

- return topology_sane(c, o, "mc");
+ return topology_sane(c_this, c_sibling, "mc");
}
return false;
}

-void set_cpu_sibling_map(int cpu)
+/* Set both CPUs in a topology cpumask array: */
+#define link_cpus(mask_fn, cpu_this, cpu_sibling) \
+do { \
+ cpumask_set_cpu((cpu_this), mask_fn(cpu_sibling)); \
+ cpumask_set_cpu((cpu_sibling), mask_fn(cpu_this)); \
+} while (0)
+
+/*
+ * Add a CPU to the various CPU topology data structures,
+ * after it has booted up successfully:
+ */
+void set_cpu_sibling_map(int cpu_this)
{
bool has_smt = smp_num_siblings > 1;
bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
- struct cpuinfo_x86 *c = &cpu_data(cpu);
- struct cpuinfo_x86 *o;
- int i;
+ struct cpuinfo_x86 *c_this = &cpu_data(cpu_this);
+ struct cpuinfo_x86 *c_sibling;
+ int cpu_sibling;

- cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
+ cpumask_set_cpu(cpu_this, cpu_sibling_setup_mask);

if (!has_mp) {
- cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
- cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
- cpumask_set_cpu(cpu, cpu_core_mask(cpu));
- c->booted_cores = 1;
+ cpumask_set_cpu(cpu_this, cpu_sibling_mask(cpu_this));
+ cpumask_set_cpu(cpu_this, cpu_llc_shared_mask(cpu_this));
+ cpumask_set_cpu(cpu_this, cpu_core_mask(cpu_this));
+ c_this->booted_cores = 1;
+
return;
}

- for_each_cpu(i, cpu_sibling_setup_mask) {
- o = &cpu_data(i);
+ for_each_cpu(cpu_sibling, cpu_sibling_setup_mask) {
+ c_sibling = &cpu_data(cpu_sibling);

- if ((i == cpu) || (has_smt && match_smt(c, o)))
- link_mask(sibling, cpu, i);
+ if ((cpu_sibling == cpu_this) || (has_smt && match_smt(c_this, c_sibling)))
+ link_cpus(cpu_sibling_mask, cpu_this, cpu_sibling);

- if ((i == cpu) || (has_mp && match_llc(c, o)))
- link_mask(llc_shared, cpu, i);
+ if ((cpu_sibling == cpu_this) || (has_mp && match_llc(c_this, c_sibling)))
+ link_cpus(cpu_llc_shared_mask, cpu_this, cpu_sibling);

}

@@ -402,35 +402,35 @@ void set_cpu_sibling_map(int cpu)
* This needs a separate iteration over the cpus because we rely on all
* cpu_sibling_mask links to be set-up.
*/
- for_each_cpu(i, cpu_sibling_setup_mask) {
- o = &cpu_data(i);
+ for_each_cpu(cpu_sibling, cpu_sibling_setup_mask) {
+ c_sibling = &cpu_data(cpu_sibling);

- if ((i == cpu) || (has_mp && match_mc(c, o))) {
- link_mask(core, cpu, i);
+ if ((cpu_sibling == cpu_this) || (has_mp && match_mc(c_this, c_sibling))) {
+ link_cpus(cpu_core_mask, cpu_this, cpu_sibling);

- /*
- * Does this new cpu bringup a new core?
- */
- if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) {
+ /* Does this new cpu bring up a new core? */
+ if (cpumask_weight(cpu_sibling_mask(cpu_this)) == 1) {
/*
- * for each core in package, increment
- * the booted_cores for this new cpu
+ * For each core in package, increment
+ * the booted_cores for this new cpu_this
*/
- if (cpumask_first(cpu_sibling_mask(i)) == i)
- c->booted_cores++;
+ if (cpumask_first(cpu_sibling_mask(cpu_sibling)) == cpu_sibling)
+ c_this->booted_cores++;
/*
- * increment the core count for all
+ * Increment the core count for all
* the other cpus in this package
*/
- if (i != cpu)
- cpu_data(i).booted_cores++;
- } else if (i != cpu && !c->booted_cores)
- c->booted_cores = cpu_data(i).booted_cores;
+ if (cpu_sibling != cpu_this)
+ cpu_data(cpu_sibling).booted_cores++;
+ } else {
+ if (cpu_sibling != cpu_this && !c_this->booted_cores)
+ c_this->booted_cores = cpu_data(cpu_sibling).booted_cores;
+ }
}
}
}

-/* maps the cpu to the sched domain representing multi-core */
+/* Maps the cpu to the sched domain representing multi-core */
const struct cpumask *cpu_coregroup_mask(int cpu)
{
return cpu_llc_shared_mask(cpu);
@@ -438,21 +438,21 @@ const struct cpumask *cpu_coregroup_mask(int cpu)

static void impress_friends(void)
{
- int cpu;
unsigned long bogosum = 0;
+ int cpu;
+
/*
* Allow the user to impress friends.
*/
- pr_debug("Before bogomips\n");
- for_each_possible_cpu(cpu)
+ for_each_possible_cpu(cpu) {
if (cpumask_test_cpu(cpu, cpu_callout_mask))
bogosum += cpu_data(cpu).loops_per_jiffy;
+ }
+
pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
num_online_cpus(),
bogosum/(500000/HZ),
(bogosum/(5000/HZ))%100);
-
- pr_debug("Before bogocount - setting activated=1\n");
}

void __inquire_remote_apic(int apicid)
@@ -467,9 +467,7 @@ void __inquire_remote_apic(int apicid)
for (i = 0; i < ARRAY_SIZE(regs); i++) {
pr_info("... APIC 0x%x %s: ", apicid, names[i]);

- /*
- * Wait for idle.
- */
+ /* Wait for idle. */
status = safe_apic_wait_icr_idle();
if (status)
pr_cont("a previous APIC delivery may have failed\n");
@@ -498,8 +496,7 @@ void __inquire_remote_apic(int apicid)
* INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
* won't ... remember to clear down the APIC, etc later.
*/
-int
-wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
+int wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
{
unsigned long send_status, accept_status = 0;
int maxlvt;
@@ -529,36 +526,27 @@ wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
if (accept_status)
pr_err("APIC delivery error (%lx)\n", accept_status);

- return (send_status | accept_status);
+ return send_status | accept_status;
}

-static int
-wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
+static int wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
{
unsigned long send_status, accept_status = 0;
int maxlvt, num_starts, j;

maxlvt = lapic_get_maxlvt();

- /*
- * Be paranoid about clearing APIC errors.
- */
+ /* Be paranoid about clearing APIC errors. */
if (APIC_INTEGRATED(apic_version[phys_apicid])) {
- if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
+ if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
}

pr_debug("Asserting INIT\n");

- /*
- * Turn INIT on target chip
- */
- /*
- * Send IPI
- */
- apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
- phys_apicid);
+ /* Send INIT IPI */
+ apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid);

pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();
@@ -567,8 +555,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)

pr_debug("Deasserting INIT\n");

- /* Target chip */
- /* Send IPI */
+ /* Send deassert INIT IPI: */
apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);

pr_debug("Waiting for send to finish...\n");
@@ -578,7 +565,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
atomic_set(&init_deasserted, 1);

/*
- * Should we send STARTUP IPIs ?
+ * Should we send STARTUP IPIs?
*
* Determine this based on the APIC version.
* If we don't have an integrated APIC, don't send the STARTUP IPIs.
@@ -592,34 +579,22 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
* Paravirt / VMI wants a startup IPI hook here to set up the
* target processor state.
*/
- startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
- stack_start);
+ startup_ipi_hook(phys_apicid, (unsigned long)start_secondary, stack_start);

- /*
- * Run STARTUP IPI loop.
- */
+ /* Run STARTUP IPI loop. */
pr_debug("#startup loops: %d\n", num_starts);

for (j = 1; j <= num_starts; j++) {
pr_debug("Sending STARTUP #%d\n", j);
- if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
+ if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
apic_read(APIC_ESR);
pr_debug("After apic_write\n");

- /*
- * STARTUP IPI
- */
-
- /* Target chip */
- /* Boot on the stack */
- /* Kick the second */
- apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
- phys_apicid);
+ /* Send STARTUP IPI to the secondary CPU: */
+ apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12), phys_apicid);

- /*
- * Give the other CPU some time to accept the IPI.
- */
+ /* Give the other CPU some time to accept the IPI. */
udelay(300);

pr_debug("Startup point 1\n");
@@ -627,11 +602,9 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
pr_debug("Waiting for send to finish...\n");
send_status = safe_apic_wait_icr_idle();

- /*
- * Give the other CPU some time to accept the IPI.
- */
+ /* Give the other CPU more time to accept the IPI. */
udelay(200);
- if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
+ if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
apic_write(APIC_ESR, 0);
accept_status = (apic_read(APIC_ESR) & 0xEF);
if (send_status || accept_status)
@@ -644,7 +617,7 @@ wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
if (accept_status)
pr_err("APIC delivery error (%lx)\n", accept_status);

- return (send_status | accept_status);
+ return send_status | accept_status;
}

void smp_announce(void)
@@ -655,7 +628,13 @@ void smp_announce(void)
num_nodes, (num_nodes > 1 ? "s" : ""), num_online_cpus());
}

-/* reduce the number of lines printed when booting a large cpu count system */
+/*
+ * Print a successful bootup of a secondary CPU.
+ *
+ * ( The field width magic is due to the tabulated per node output we print,
+ * which we do to reduce the number of lines printed when booting a large
+ * cpu count system and also because it's prettier. )
+ */
static void announce_cpu(int cpu, int apicid)
{
static int current_node = -1;
@@ -673,7 +652,7 @@ static void announce_cpu(int cpu, int apicid)

if (system_state == SYSTEM_BOOTING) {
if (node != current_node) {
- if (current_node > (-1))
+ if (current_node > -1)
pr_cont("\n");
current_node = node;

@@ -687,17 +666,17 @@ static void announce_cpu(int cpu, int apicid)

pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);

- } else
+ } else {
pr_info("Booting Node %d Processor %d APIC 0x%x\n",
node, cpu, apicid);
+ }
}

static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
{
- int cpu;
+ int this_cpu = smp_processor_id();

- cpu = smp_processor_id();
- if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0)
+ if (this_cpu == 0 && !cpu_online(this_cpu) && enable_start_cpu0)
return NMI_HANDLED;

return NMI_DONE;
@@ -716,8 +695,7 @@ static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
* real platform and request are available.
*/
static int
-wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
- int *cpu0_nmi_registered)
+wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid, int *cpu0_nmi_registered)
{
int id;
int boot_error;
@@ -733,8 +711,7 @@ wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
*
* Register a NMI handler to help wake up CPU0.
*/
- boot_error = register_nmi_handler(NMI_LOCAL,
- wakeup_cpu0_nmi, 0, "wake_cpu0");
+ boot_error = register_nmi_handler(NMI_LOCAL, wakeup_cpu0_nmi, 0, "wake_cpu0");

if (!boot_error) {
enable_start_cpu0 = 1;
@@ -794,7 +771,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
* This grunge runs the startup process for
* the targeted processor.
*/
-
atomic_set(&init_deasserted, 0);

if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
@@ -831,9 +807,7 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
cpumask_set_cpu(cpu, cpu_callout_mask);
pr_debug("After Callout %d\n", cpu);

- /*
- * Wait 5s total for a response
- */
+ /* Wait 5s total for a response: */
for (timeout = 0; timeout < 50000; timeout++) {
if (cpumask_test_cpu(cpu, cpu_callin_mask))
break; /* It has booted */
@@ -853,10 +827,10 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
} else {
boot_error = 1;
if (*trampoline_status == 0xA5A5A5A5)
- /* trampoline started but...? */
+ /* Trampoline started but...? */
pr_err("CPU%d: Stuck ??\n", cpu);
else
- /* trampoline code not run */
+ /* Trampoline code not run */
pr_err("CPU%d: Not responding\n", cpu);
if (apic->inquire_remote_apic)
apic->inquire_remote_apic(apicid);
@@ -867,23 +841,21 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
/* Try to put things back the way they were before ... */
numa_remove_cpu(cpu); /* was set by numa_add_cpu */

- /* was set by do_boot_cpu() */
+ /* Was set by do_boot_cpu() */
cpumask_clear_cpu(cpu, cpu_callout_mask);

- /* was set by cpu_init() */
+ /* Was set by cpu_init() */
cpumask_clear_cpu(cpu, cpu_initialized_mask);

set_cpu_present(cpu, false);
per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
}

- /* mark "stuck" area as not stuck */
+ /* Mark "stuck" area as not stuck */
*trampoline_status = 0;

if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
- /*
- * Cleanup possible dangling ends...
- */
+ /* Clean up possible dangling ends... */
smpboot_restore_warm_reset_vector();
}
/*
@@ -913,9 +885,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
return -EINVAL;
}

- /*
- * Already booted CPU?
- */
+ /* Already booted CPU? */
if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
pr_debug("do_boot_cpu %d Already started\n", cpu);
return -ENOSYS;
@@ -929,7 +899,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle)

per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;

- /* the FPU context is blank, nobody can own it */
+ /* The FPU context is blank, nobody can own it */
__cpu_disable_lazy_restore(cpu);

err = do_boot_cpu(apicid, cpu, tidle);
@@ -993,8 +963,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
unsigned int cpu;
unsigned nr;

- pr_warn("More than 8 CPUs detected - skipping them\n"
- "Use CONFIG_X86_BIGSMP\n");
+ pr_warn("More than 8 CPUs detected - skipping them, use CONFIG_X86_BIGSMP.\n");

nr = 0;
for_each_present_cpu(cpu) {
@@ -1015,8 +984,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
#endif

if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
- pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n",
- hard_smp_processor_id());
+ pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n", hard_smp_processor_id());

physid_set(hard_smp_processor_id(), phys_cpu_present_map);
}
@@ -1045,9 +1013,7 @@ static int __init smp_sanity_check(unsigned max_cpus)
}
preempt_enable();

- /*
- * If we couldn't find a local APIC, then get out of here now!
- */
+ /* If we couldn't find a local APIC, then get out of here now! */
if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
!cpu_has_apic) {
if (!disable_apic) {
@@ -1062,9 +1028,7 @@ static int __init smp_sanity_check(unsigned max_cpus)

verify_local_APIC();

- /*
- * If SMP should be disabled, then really disable it!
- */
+ /* If SMP should be disabled, then really disable it! */
if (!max_cpus) {
pr_info("SMP mode deactivated\n");
smpboot_clear_io_apic();
@@ -1081,12 +1045,12 @@ static int __init smp_sanity_check(unsigned max_cpus)
static void __init smp_cpu_index_default(void)
{
int i;
- struct cpuinfo_x86 *c;
+ struct cpuinfo_x86 *c_this;

for_each_possible_cpu(i) {
- c = &cpu_data(i);
- /* mark all to hotplug */
- c->cpu_index = nr_cpu_ids;
+ c_this = &cpu_data(i);
+ /* Mark all to hotplug */
+ c_this->cpu_index = nr_cpu_ids;
}
}

@@ -1101,9 +1065,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
preempt_disable();
smp_cpu_index_default();

- /*
- * Setup boot CPU information
- */
+ /* Setup boot CPU information */
smp_store_boot_cpu_info(); /* Final full version of the data */
cpumask_copy(cpu_callin_mask, cpumask_of(0));
mb();
@@ -1135,9 +1097,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)

connect_bsp_APIC();

- /*
- * Switch from PIC to APIC mode.
- */
+ /* Switch from PIC to APIC mode. */
setup_local_APIC();

if (x2apic_mode)
@@ -1145,9 +1105,7 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
else
cpu0_logical_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));

- /*
- * Enable IO APIC before setting up error vector
- */
+ /* Enable IO APIC before setting up error vector */
if (!skip_ioapic_setup && nr_ioapics)
enable_IO_APIC();

@@ -1157,12 +1115,10 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus)
apic->setup_portio_remap();

smpboot_setup_io_apic();
- /*
- * Set up local APIC timer on boot CPU.
- */
-
pr_info("CPU%d: ", 0);
print_cpu_info(&cpu_data(0));
+
+ /* Set up local APIC timer on boot CPU. */
x86_init.timers.setup_percpu_clockev();

if (is_uv_system())
@@ -1189,8 +1145,9 @@ void arch_enable_nonboot_cpus_end(void)
void __init native_smp_prepare_boot_cpu(void)
{
int me = smp_processor_id();
+
switch_to_new_gdt(me);
- /* already set me in cpu_online_mask in boot_cpu_init() */
+ /* Already set me in cpu_online_mask in boot_cpu_init() */
cpumask_set_cpu(me, cpu_callout_mask);
per_cpu(cpu_state, me) = CPU_ONLINE;
}
@@ -1237,7 +1194,7 @@ __init void prefill_possible_map(void)
{
int i, possible;

- /* no processor from mptable or madt */
+ /* No processor from mptable or madt */
if (!num_processors)
num_processors = 1;

@@ -1251,8 +1208,9 @@ __init void prefill_possible_map(void)
if (possible > i)
possible = i;
#endif
- } else
+ } else {
possible = setup_possible_cpus;
+ }

total_cpus = max_t(int, possible, num_processors + disabled_cpus);

@@ -1277,6 +1235,7 @@ __init void prefill_possible_map(void)

for (i = 0; i < possible; i++)
set_cpu_possible(i, true);
+
for (; i < NR_CPUS; i++)
set_cpu_possible(i, false);

@@ -1287,24 +1246,24 @@ __init void prefill_possible_map(void)

static void remove_siblinginfo(int cpu)
{
- int sibling;
- struct cpuinfo_x86 *c = &cpu_data(cpu);
+ int cpu_sibling;
+ struct cpuinfo_x86 *c_this = &cpu_data(cpu);

- for_each_cpu(sibling, cpu_core_mask(cpu)) {
- cpumask_clear_cpu(cpu, cpu_core_mask(sibling));
- /*/
- * last thread sibling in this cpu core going down
- */
+ for_each_cpu(cpu_sibling, cpu_core_mask(cpu)) {
+ cpumask_clear_cpu(cpu, cpu_core_mask(cpu_sibling));
+
+ /* last thread cpu_sibling in this cpu core going down */
if (cpumask_weight(cpu_sibling_mask(cpu)) == 1)
- cpu_data(sibling).booted_cores--;
+ cpu_data(cpu_sibling).booted_cores--;
}

- for_each_cpu(sibling, cpu_sibling_mask(cpu))
- cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
+ for_each_cpu(cpu_sibling, cpu_sibling_mask(cpu))
+ cpumask_clear_cpu(cpu, cpu_sibling_mask(cpu_sibling));
+
cpumask_clear(cpu_sibling_mask(cpu));
cpumask_clear(cpu_core_mask(cpu));
- c->phys_proc_id = 0;
- c->cpu_core_id = 0;
+ c_this->phys_proc_id = 0;
+ c_this->cpu_core_id = 0;
cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
}

@@ -1334,8 +1293,8 @@ void cpu_disable_common(void)
int native_cpu_disable(void)
{
clear_local_APIC();
-
cpu_disable_common();
+
return 0;
}

@@ -1366,9 +1325,7 @@ void play_dead_common(void)
/* Ack it */
__this_cpu_write(cpu_state, CPU_DEAD);

- /*
- * With physical CPU hotplug, we should halt the cpu
- */
+ /* With physical CPU hotplug, we should halt the cpu */
local_irq_disable();
}

@@ -1442,9 +1399,8 @@ static inline void mwait_play_dead(void)
__monitor(mwait_ptr, 0, 0);
mb();
__mwait(eax, 0);
- /*
- * If NMI wants to wake up CPU0, start CPU0.
- */
+
+ /* If NMI wants to wake up CPU0, start CPU0. */
if (wakeup_cpu0())
start_cpu0();
}
@@ -1457,9 +1413,8 @@ static inline void hlt_play_dead(void)

while (1) {
native_halt();
- /*
- * If NMI wants to wake up CPU0, start CPU0.
- */
+
+ /* If NMI wants to wake up CPU0, start CPU0. */
if (wakeup_cpu0())
start_cpu0();
}
@@ -1476,6 +1431,7 @@ void native_play_dead(void)
}

#else /* ... !CONFIG_HOTPLUG_CPU */
+
int native_cpu_disable(void)
{
return -ENOSYS;
--
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