[PATCH 3/5] x86/percpu, x86/irq: Relax {set,get}_irq_regs()

From: Peter Zijlstra
Date: Wed Feb 27 2019 - 05:17:02 EST


Nadav reported that since the this_cpu_*() ops got asm-volatile
constraints on, code generation suffered for do_IRQ(), but since this
is all with IRQs disabled we can use __this_cpu_*().

Reported-by: Nadav Amit <nadav.amit@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/include/asm/irq_regs.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/irq_regs.h
+++ b/arch/x86/include/asm/irq_regs.h
@@ -16,7 +16,7 @@ DECLARE_PER_CPU(struct pt_regs *, irq_re

static inline struct pt_regs *get_irq_regs(void)
{
- return this_cpu_read(irq_regs);
+ return __this_cpu_read(irq_regs);
}

static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs)
@@ -24,7 +24,7 @@ static inline struct pt_regs *set_irq_re
struct pt_regs *old_regs;

old_regs = get_irq_regs();
- this_cpu_write(irq_regs, new_regs);
+ __this_cpu_write(irq_regs, new_regs);

return old_regs;
}