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: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: David Daney <david.daney@xxxxxxxxxx>
Cc: Yong Zhang <yong.zhang0@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Sanjay Lal <sanjayl@xxxxxxxxxxx>
Cc: "Steven J. Hill" <sjhill@xxxxxxxx>
Cc: John Crispin <blogic@xxxxxxxxxxx>
Cc: Florian Fainelli <florian@xxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---
arch/mips/kernel/cevt-smtc.c | 7 +++++++
arch/mips/kernel/smp.c | 16 ++++++++--------
arch/mips/kernel/smtc.c | 12 ++++++++++++
arch/mips/mm/c-octeon.c | 4 ++--
4 files changed, 29 insertions(+), 10 deletions(-)
diff --git a/arch/mips/kernel/cevt-smtc.c b/arch/mips/kernel/cevt-smtc.c
index 9de5ed7..2e6c0cd 100644
--- a/arch/mips/kernel/cevt-smtc.c
+++ b/arch/mips/kernel/cevt-smtc.c
@@ -11,6 +11,7 @@
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/irq.h>
#include <asm/smtc_ipi.h>
@@ -84,6 +85,8 @@ static int mips_next_event(unsigned long delta,
unsigned long nextcomp = 0L;
int vpe = current_cpu_data.vpe_id;
int cpu = smp_processor_id();
+
+ get_online_cpus_atomic();
local_irq_save(flags);
mtflags = dmt();
@@ -164,6 +167,7 @@ static int mips_next_event(unsigned long delta,
}
emt(mtflags);
local_irq_restore(flags);
+ put_online_cpus_atomic();
return 0;
}
@@ -177,6 +181,7 @@ void smtc_distribute_timer(int vpe)
unsigned long nextstamp;
unsigned long reference;
+ get_online_cpus_atomic();
repeat:
nextstamp = 0L;
@@ -229,6 +234,8 @@ repeat:
> (unsigned long)LONG_MAX)
goto repeat;
}
+
+ put_online_cpus_atomic();
}
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 6e7862a..be152b6 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -250,12 +250,12 @@ static inline void smp_on_other_tlbs(void (*func) (void *info), void *info)
static inline void smp_on_each_tlb(void (*func) (void *info), void *info)
{
- preempt_disable();
+ get_online_cpus_atomic();
smp_on_other_tlbs(func, info);
func(info);
- preempt_enable();
+ put_online_cpus_atomic();
}
/*
@@ -273,7 +273,7 @@ static inline void smp_on_each_tlb(void (*func) (void *info), void *info)
void flush_tlb_mm(struct mm_struct *mm)
{
- preempt_disable();
+ get_online_cpus_atomic();
if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
smp_on_other_tlbs(flush_tlb_mm_ipi, mm);
@@ -287,7 +287,7 @@ void flush_tlb_mm(struct mm_struct *mm)
}
local_flush_tlb_mm(mm);
- preempt_enable();
+ put_online_cpus_atomic();
}
struct flush_tlb_data {
@@ -307,7 +307,7 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned l
{
struct mm_struct *mm = vma->vm_mm;
- preempt_disable();
+ get_online_cpus_atomic();
if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
struct flush_tlb_data fd = {
.vma = vma,
@@ -325,7 +325,7 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned l
}
}
local_flush_tlb_range(vma, start, end);
- preempt_enable();
+ put_online_cpus_atomic();
}
static void flush_tlb_kernel_range_ipi(void *info)
@@ -354,7 +354,7 @@ static void flush_tlb_page_ipi(void *info)
void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
- preempt_disable();
+ get_online_cpus_atomic();
if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
struct flush_tlb_data fd = {
.vma = vma,
@@ -371,7 +371,7 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
}
}
local_flush_tlb_page(vma, page);
- preempt_enable();
+ put_online_cpus_atomic();
}
static void flush_tlb_one_ipi(void *info)
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c
index 75a4fd7..3cda8eb 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c
@@ -21,6 +21,7 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
+#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
@@ -1143,6 +1144,8 @@ static irqreturn_t ipi_interrupt(int irq, void *dev_idm)
* for the current TC, so we ought not to have to do it explicitly here.
*/
+ get_online_cpus_atomic();
+
for_each_online_cpu(cpu) {
if (cpu_data[cpu].vpe_id != my_vpe)
continue;
@@ -1180,6 +1183,8 @@ static irqreturn_t ipi_interrupt(int irq, void *dev_idm)
}
}
+ put_online_cpus_atomic();
+
return IRQ_HANDLED;
}
@@ -1383,6 +1388,7 @@ void smtc_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
* them, let's be really careful...
*/
+ get_online_cpus_atomic();
local_irq_save(flags);
if (smtc_status & SMTC_TLB_SHARED) {
mtflags = dvpe();
@@ -1438,6 +1444,7 @@ void smtc_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
else
emt(mtflags);
local_irq_restore(flags);
+ put_online_cpus_atomic();
}
/*
@@ -1496,6 +1503,7 @@ void smtc_cflush_lockdown(void)
{
int cpu;
+ get_online_cpus_atomic();
for_each_online_cpu(cpu) {
if (cpu != smp_processor_id()) {
settc(cpu_data[cpu].tc_id);
@@ -1504,6 +1512,7 @@ void smtc_cflush_lockdown(void)
}
}
mips_ihb();
+ put_online_cpus_atomic();
}
/* It would be cheating to change the cpu_online states during a flush! */
@@ -1512,6 +1521,8 @@ void smtc_cflush_release(void)
{
int cpu;
+ get_online_cpus_atomic();
+
/*
* Start with a hazard barrier to ensure
* that all CACHE ops have played through.
@@ -1525,4 +1536,5 @@ void smtc_cflush_release(void)
}
}
mips_ihb();
+ put_online_cpus_atomic();
}
diff --git a/arch/mips/mm/c-octeon.c b/arch/mips/mm/c-octeon.c
index 8557fb5..8e1bcf6 100644
--- a/arch/mips/mm/c-octeon.c
+++ b/arch/mips/mm/c-octeon.c
@@ -73,7 +73,7 @@ static void octeon_flush_icache_all_cores(struct vm_area_struct *vma)
mb();
octeon_local_flush_icache();
#ifdef CONFIG_SMP
- preempt_disable();
+ get_online_cpus_atomic();
cpu = smp_processor_id();
/*
@@ -88,7 +88,7 @@ static void octeon_flush_icache_all_cores(struct vm_area_struct *vma)
for_each_cpu(cpu, &mask)
octeon_send_ipi_single(cpu, SMP_ICACHE_FLUSH);
- preempt_enable();
+ put_online_cpus_atomic();
#endif
}
