[PATCH 4.4 22/57] parisc/mm: Ensure IRQs are off in switch_mm()

Greg Kroah-Hartman
2017-07-19T11:36:18Z

From: Helge Deller <deller@gmx.de>

commit 649aa24254e85bf6bd7807dd372d083707852b1f upstream.

This is because of commit f98db6013c55 ("sched/core: Add switch_mm_irqs_off()
and use it in the scheduler") in which switch_mm_irqs_off() is called by the
scheduler, vs switch_mm() which is used by use_mm().

This patch lets the parisc code mirror the x86 and powerpc code, ie. it
disables interrupts in switch_mm(), and optimises the scheduler case by
defining switch_mm_irqs_off().

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/parisc/include/asm/mmu_context.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

--- a/arch/parisc/include/asm/mmu_context.h
+++ b/arch/parisc/include/asm/mmu_context.h
@@ -49,15 +49,26 @@ static inline void load_context(mm_conte
mtctl(__space_to_prot(context), 8);
}

-static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, struct task_struct *tsk)
+static inline void switch_mm_irqs_off(struct mm_struct *prev,
+ struct mm_struct *next, struct task_struct *tsk)
{
-
if (prev != next) {
mtctl(__pa(next->pgd), 25);
load_context(next->context);
}
}

+static inline void switch_mm(struct mm_struct *prev,
+ struct mm_struct *next, struct task_struct *tsk)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ switch_mm_irqs_off(prev, next, tsk);
+ local_irq_restore(flags);
+}
+#define switch_mm_irqs_off switch_mm_irqs_off
+
#define deactivate_mm(tsk,mm) do { } while (0)

static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)