[PATCH v6 37/46] MIPS: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-02-18 12:45:40
Also in:
linux-arch, linux-arm-kernel, linux-pm, linuxppc-dev, lkml
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
Once stop_machine() is gone from the CPU offline path, we won't be able to depend on preempt_disable() or local_irq_disable() to prevent CPUs fom 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 <redacted> Cc: David Daney <redacted> Cc: linux-mips@linux-mips.org Signed-off-by: Srivatsa S. Bhat <redacted> --- arch/mips/kernel/cevt-smtc.c | 8 ++++++++ arch/mips/kernel/smp.c | 16 ++++++++-------- arch/mips/kernel/smtc.c | 3 +++ arch/mips/mm/c-octeon.c | 4 ++-- 4 files changed, 21 insertions(+), 10 deletions(-)
diff --git a/arch/mips/kernel/cevt-smtc.c b/arch/mips/kernel/cevt-smtc.c
index 2e72d30..6fb311b 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; }
@@ -180,6 +184,7 @@ void smtc_distribute_timer(int vpe) repeat: nextstamp = 0L; + get_online_cpus_atomic(); for_each_online_cpu(cpu) { /* * Find virtual CPUs within the current VPE who have
@@ -221,6 +226,9 @@ repeat: } } + + put_online_cpus_atomic() + /* Reprogram for interrupt at next soonest timestamp for VPE */ if (ISVALID(nextstamp)) { write_c0_compare(nextstamp);
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 66bf4e2..3828afa 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c@@ -248,12 +248,12 @@ 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(); } /*
@@ -271,7 +271,7 @@ 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);
@@ -285,7 +285,7 @@ void flush_tlb_mm(struct mm_struct *mm) } local_flush_tlb_mm(mm); - preempt_enable(); + put_online_cpus_atomic(); } struct flush_tlb_data {
@@ -305,7 +305,7 @@ 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,
@@ -323,7 +323,7 @@ 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)
@@ -352,7 +352,7 @@ 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,
@@ -369,7 +369,7 @@ 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 1d47843..caf081e 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c@@ -22,6 +22,7 @@ #include <linux/sched.h> #include <linux/smp.h> #include <linux/cpumask.h> +#include <linux/cpu.h> #include <linux/interrupt.h> #include <linux/kernel_stat.h> #include <linux/module.h>
@@ -1143,6 +1144,7 @@ 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;
@@ -1179,6 +1181,7 @@ static irqreturn_t ipi_interrupt(int irq, void *dev_idm) } } } + put_online_cpus_atomic(); return IRQ_HANDLED; }
diff --git a/arch/mips/mm/c-octeon.c b/arch/mips/mm/c-octeon.c
index 6ec04da..cd2c1ce 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 }