[PATCH v2 38/45] MIPS: Use get/put_online_cpus_atomic() to prevent CPU offline
From: Srivatsa S. Bhat <hidden>
Date: 2013-06-25 20:36:26
Also in:
linux-mips, linux-pm, linuxppc-dev, lkml, netdev
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 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 <redacted> Cc: David Daney <redacted> Cc: Yong Zhang <redacted> Cc: Thomas Gleixner <redacted> Cc: Sanjay Lal <redacted> Cc: "Steven J. Hill" <redacted> Cc: John Crispin <redacted> Cc: Florian Fainelli <florian@openwrt.org> Cc: linux-mips@linux-mips.org Signed-off-by: Srivatsa S. Bhat <redacted> --- 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 }