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powerpc/64: Improve inline asm in arch_local_irq_disable

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arch_local_irq_disable is implemented strangely, with a temporary
output register being set to the desired soft_enabled value via an
immediate input, which is then used to store to memory. This is not
required, the immediate can be specified directly as a register input.

For simple cases at least, assembly is unchanged except register
mapping.

Reviewed-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2017-12-20 09:25:43 +05:30 committed by Michael Ellerman
parent c2e480ba82
commit 9f83e00f4c
1 changed files with 5 additions and 5 deletions
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10
arch/powerpc/include/asm/hw_irq.h
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@ -63,13 +63,13 @@ static inline unsigned long arch_local_save_flags(void)
static inline unsigned long arch_local_irq_disable(void)
{
unsigned long flags, zero;
unsigned long flags;
asm volatile(
"li %1,%3; lbz %0,%2(13); stb %1,%2(13)"
: "=r" (flags), "=&r" (zero)
: "i" (offsetof(struct paca_struct, soft_enabled)),\
"i" (IRQS_DISABLED)
"lbz %0,%1(13); stb %2,%1(13)"
: "=&r" (flags)
: "i" (offsetof(struct paca_struct, soft_enabled)),
"r" (IRQS_DISABLED)
: "memory");
return flags;