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/*
* 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/alternative.h>
#include <asm/ptrace.h>
#include <asm/sysreg.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 void arch_local_irq_enable(void)
{
asm volatile(ALTERNATIVE(
"msr daifclr, #2 // arch_local_irq_enable\n"
"nop",
"msr_s " __stringify(SYS_ICC_PMR_EL1) ",%0\n"
"dsb sy",
ARM64_HAS_IRQ_PRIO_MASKING)
:
: "r" ((unsigned long) GIC_PRIO_IRQON)
: "memory");
}
static inline void arch_local_irq_disable(void)
{
asm volatile(ALTERNATIVE(
"msr daifset, #2 // arch_local_irq_disable",
"msr_s " __stringify(SYS_ICC_PMR_EL1) ", %0",
ARM64_HAS_IRQ_PRIO_MASKING)
:
: "r" ((unsigned long) GIC_PRIO_IRQOFF)
: "memory");
}
/*
* Save the current interrupt enable state.
*/
static inline unsigned long arch_local_save_flags(void)
{
unsigned long daif_bits;
unsigned long flags;
daif_bits = read_sysreg(daif);
/*
* The asm is logically equivalent to:
*
* if (system_uses_irq_prio_masking())
* flags = (daif_bits & PSR_I_BIT) ?
* GIC_PRIO_IRQOFF :
* read_sysreg_s(SYS_ICC_PMR_EL1);
* else
* flags = daif_bits;
*/
asm volatile(ALTERNATIVE(
"mov %0, %1\n"
"nop\n"
"nop",
"mrs_s %0, " __stringify(SYS_ICC_PMR_EL1) "\n"
"ands %1, %1, " __stringify(PSR_I_BIT) "\n"
"csel %0, %0, %2, eq",
ARM64_HAS_IRQ_PRIO_MASKING)
: "=&r" (flags), "+r" (daif_bits)
: "r" ((unsigned long) GIC_PRIO_IRQOFF)
: "memory");
return flags;
}
static inline unsigned long arch_local_irq_save(void)
{
unsigned long flags;
flags = arch_local_save_flags();
arch_local_irq_disable();
return flags;
}
/*
* restore saved IRQ state
*/
static inline void arch_local_irq_restore(unsigned long flags)
{
asm volatile(ALTERNATIVE(
"msr daif, %0\n"
"nop",
"msr_s " __stringify(SYS_ICC_PMR_EL1) ", %0\n"
"dsb sy",
ARM64_HAS_IRQ_PRIO_MASKING)
: "+r" (flags)
:
: "memory");
}
static inline int arch_irqs_disabled_flags(unsigned long flags)
{
int res;
asm volatile(ALTERNATIVE(
"and %w0, %w1, #" __stringify(PSR_I_BIT) "\n"
"nop",
"cmp %w1, #" __stringify(GIC_PRIO_IRQOFF) "\n"
"cset %w0, ls",
ARM64_HAS_IRQ_PRIO_MASKING)
: "=&r" (res)
: "r" ((int) flags)
: "memory");
return res;
}
#endif
#endif
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