Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: x...@kernel.org
Cc: Tony Luck <tony.l...@intel.com>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Sebastian Andrzej Siewior <sebast...@breakpoint.cc>
Cc: Joerg Roedel <j...@8bytes.org>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Joonsoo Kim <js1...@gmail.com>
Cc: linux-e...@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat <srivatsa.b...@linux.vnet.ibm.com>
---
arch/x86/kernel/apic/io_apic.c | 21 ++++++++++++++++++---
arch/x86/kernel/cpu/mcheck/therm_throt.c | 4 ++--
arch/x86/mm/tlb.c | 14 +++++++-------
3 files changed, 27 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 9ed796c..4c71c1e 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -25,6 +25,7 @@
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/sched.h>
+#include <linux/cpu.h>
#include <linux/pci.h>
#include <linux/mc146818rtc.h>
#include <linux/compiler.h>
@@ -1169,9 +1170,11 @@ int assign_irq_vector(int irq, struct irq_cfg *cfg,
const struct cpumask *mask)
int err;
unsigned long flags;
+ get_online_cpus_atomic();
raw_spin_lock_irqsave(&vector_lock, flags);
err = __assign_irq_vector(irq, cfg, mask);
raw_spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
return err;
}
@@ -1757,13 +1760,13 @@ __apicdebuginit(void) print_local_APICs(int maxcpu)
if (!maxcpu)
return;
- preempt_disable();
+ get_online_cpus_atomic();
for_each_online_cpu(cpu) {
if (cpu >= maxcpu)
break;
smp_call_function_single(cpu, print_local_APIC, NULL, 1);
}
- preempt_enable();
+ put_online_cpus_atomic();
}
__apicdebuginit(void) print_PIC(void)
@@ -2153,10 +2156,12 @@ static int ioapic_retrigger_irq(struct irq_data *data)
unsigned long flags;
int cpu;
+ get_online_cpus_atomic();
raw_spin_lock_irqsave(&vector_lock, flags);
cpu = cpumask_first_and(cfg->domain, cpu_online_mask);
apic->send_IPI_mask(cpumask_of(cpu), cfg->vector);
raw_spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
return 1;
}
@@ -2175,6 +2180,7 @@ void send_cleanup_vector(struct irq_cfg *cfg)
{
cpumask_var_t cleanup_mask;
+ get_online_cpus_atomic();
if (unlikely(!alloc_cpumask_var(&cleanup_mask, GFP_ATOMIC))) {
unsigned int i;
for_each_cpu_and(i, cfg->old_domain, cpu_online_mask)
@@ -2185,6 +2191,7 @@ void send_cleanup_vector(struct irq_cfg *cfg)
free_cpumask_var(cleanup_mask);
}
cfg->move_in_progress = 0;
+ put_online_cpus_atomic();
}
asmlinkage void smp_irq_move_cleanup_interrupt(void)
@@ -2939,11 +2946,13 @@ unsigned int __create_irqs(unsigned int from, unsigned
int count, int node)
goto out_irqs;
}
+ get_online_cpus_atomic();
raw_spin_lock_irqsave(&vector_lock, flags);
for (i = 0; i < count; i++)
if (__assign_irq_vector(irq + i, cfg[i], apic->target_cpus()))
goto out_vecs;
raw_spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
for (i = 0; i < count; i++) {
irq_set_chip_data(irq + i, cfg[i]);
@@ -2957,6 +2966,7 @@ out_vecs:
for (i--; i >= 0; i--)
__clear_irq_vector(irq + i, cfg[i]);
raw_spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
out_irqs:
for (i = 0; i < count; i++)
free_irq_at(irq + i, cfg[i]);
@@ -2994,9 +3004,11 @@ void destroy_irq(unsigned int irq)
free_remapped_irq(irq);
+ get_online_cpus_atomic();
raw_spin_lock_irqsave(&vector_lock, flags);
__clear_irq_vector(irq, cfg);
raw_spin_unlock_irqrestore(&vector_lock, flags);
+ put_online_cpus_atomic();
free_irq_at(irq, cfg);
}
@@ -3365,8 +3377,11 @@ io_apic_setup_irq_pin(unsigned int irq, int node, struct
io_apic_irq_attr *attr)
if (!cfg)
return -EINVAL;
ret = __add_pin_to_irq_node(cfg, node, attr->ioapic, attr->ioapic_pin);
- if (!ret)
+ if (!ret) {
+ get_online_cpus_atomic();
setup_ioapic_irq(irq, cfg, attr);
+ put_online_cpus_atomic();
+ }
return ret;
}
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c
b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 47a1870..d128ba4 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -82,13 +82,13 @@ static ssize_t therm_throt_device_show_##event##_##name(
\
unsigned int cpu = dev->id; \
ssize_t ret; \
\
- preempt_disable(); /* CPU hotplug */ \
+ get_online_cpus_atomic(); /* CPU hotplug */ \
if (cpu_online(cpu)) { \
ret = sprintf(buf, "%lu\n", \
per_cpu(thermal_state, cpu).event.name); \
} else \
ret = 0; \
- preempt_enable(); \
+ put_online_cpus_atomic(); \
\
return ret; \
}
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 282375f..8126374 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -147,12 +147,12 @@ void flush_tlb_current_task(void)
{
struct mm_struct *mm = current->mm;
- preempt_disable();
+ get_online_cpus_atomic();
local_flush_tlb();
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, 0UL, TLB_FLUSH_ALL);
- preempt_enable();
+ put_online_cpus_atomic();
}
/*
@@ -187,7 +187,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long
start,
unsigned long addr;
unsigned act_entries, tlb_entries = 0;
- preempt_disable();
+ get_online_cpus_atomic();
if (current->active_mm != mm)
goto flush_all;
@@ -225,21 +225,21 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned
long start,
if (cpumask_any_but(mm_cpumask(mm),
smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, start, end);
- preempt_enable();
+ put_online_cpus_atomic();
return;
}
flush_all:
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, 0UL, TLB_FLUSH_ALL);
- preempt_enable();
+ put_online_cpus_atomic();
}
void flush_tlb_page(struct vm_area_struct *vma, unsigned long start)
{
struct mm_struct *mm = vma->vm_mm;
- preempt_disable();
+ get_online_cpus_atomic();
if (current->active_mm == mm) {
if (current->mm)
@@ -251,7 +251,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned
long start)
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, start, 0UL);
- preempt_enable();
+ put_online_cpus_atomic();
}
static void do_flush_tlb_all(void *info)
--
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