linux/arch/arm64/include/asm/irqflags.h
James Morse 65be7a1b79 arm64: introduce an order for exceptions
Currently SError is always masked in the kernel. To support RAS exceptions
using SError on hardware with the v8.2 RAS Extensions we need to unmask
SError as much as possible.

Let's define an order for masking and unmasking exceptions. 'dai' is
memorable and effectively what we have today.

Disabling debug exceptions should cause all other exceptions to be masked.
Masking SError should mask irq, but not disable debug exceptions.
Masking irqs has no side effects for other flags. Keeping to this order
makes it easier for entry.S to know which exceptions should be unmasked.

FIQ is never expected, but we mask it when we mask debug exceptions, and
unmask it at all other times.

Given masking debug exceptions masks everything, we don't need macros
to save/restore that bit independently. Remove them and switch the last
caller over to use the daif calls.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-11-02 15:55:41 +00:00

107 lines
2.6 KiB
C

/*
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_IRQFLAGS_H
#define __ASM_IRQFLAGS_H
#ifdef __KERNEL__
#include <asm/ptrace.h>
/*
* Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and
* FIQ exceptions, in the 'daif' register. We mask and unmask them in 'dai'
* order:
* Masking debug exceptions causes all other exceptions to be masked too/
* Masking SError masks irq, but not debug exceptions. Masking irqs has no
* side effects for other flags. Keeping to this order makes it easier for
* entry.S to know which exceptions should be unmasked.
*
* FIQ is never expected, but we mask it when we disable debug exceptions, and
* unmask it at all other times.
*/
/*
* CPU interrupt mask handling.
*/
static inline unsigned long arch_local_irq_save(void)
{
unsigned long flags;
asm volatile(
"mrs %0, daif // arch_local_irq_save\n"
"msr daifset, #2"
: "=r" (flags)
:
: "memory");
return flags;
}
static inline void arch_local_irq_enable(void)
{
asm volatile(
"msr daifclr, #2 // arch_local_irq_enable"
:
:
: "memory");
}
static inline void arch_local_irq_disable(void)
{
asm volatile(
"msr daifset, #2 // arch_local_irq_disable"
:
:
: "memory");
}
#define local_fiq_enable() asm("msr daifclr, #1" : : : "memory")
#define local_fiq_disable() asm("msr daifset, #1" : : : "memory")
#define local_async_enable() asm("msr daifclr, #4" : : : "memory")
#define local_async_disable() asm("msr daifset, #4" : : : "memory")
/*
* Save the current interrupt enable state.
*/
static inline unsigned long arch_local_save_flags(void)
{
unsigned long flags;
asm volatile(
"mrs %0, daif // arch_local_save_flags"
: "=r" (flags)
:
: "memory");
return flags;
}
/*
* restore saved IRQ state
*/
static inline void arch_local_irq_restore(unsigned long flags)
{
asm volatile(
"msr daif, %0 // arch_local_irq_restore"
:
: "r" (flags)
: "memory");
}
static inline int arch_irqs_disabled_flags(unsigned long flags)
{
return flags & PSR_I_BIT;
}
#endif
#endif