LXR linux/arch/arm64/include/asm/irqflags.h

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Copyright (C) 2012 ARM Ltd.
   4 */
   5#ifndef __ASM_IRQFLAGS_H
   6#define __ASM_IRQFLAGS_H
   7
   8#include <asm/alternative.h>
   9#include <asm/barrier.h>
  10#include <asm/ptrace.h>
  11#include <asm/sysreg.h>
  12
  13/*
  14 * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and
  15 * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'dai'
  16 * order:
  17 * Masking debug exceptions causes all other exceptions to be masked too/
  18 * Masking SError masks irq, but not debug exceptions. Masking irqs has no
  19 * side effects for other flags. Keeping to this order makes it easier for
  20 * entry.S to know which exceptions should be unmasked.
  21 *
  22 * FIQ is never expected, but we mask it when we disable debug exceptions, and
  23 * unmask it at all other times.
  24 */
  25
  26/*
  27 * CPU interrupt mask handling.
  28 */
  29static inline void arch_local_irq_enable(void)
  30{
  31        if (system_has_prio_mask_debugging()) {
  32                u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
  33
  34                WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
  35        }
  36
  37        asm volatile(ALTERNATIVE(
  38                "msr    daifclr, #2             // arch_local_irq_enable",
  39                __msr_s(SYS_ICC_PMR_EL1, "%0"),
  40                ARM64_HAS_IRQ_PRIO_MASKING)
  41                :
  42                : "r" ((unsigned long) GIC_PRIO_IRQON)
  43                : "memory");
  44
  45        pmr_sync();
  46}
  47
  48static inline void arch_local_irq_disable(void)
  49{
  50        if (system_has_prio_mask_debugging()) {
  51                u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
  52
  53                WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
  54        }
  55
  56        asm volatile(ALTERNATIVE(
  57                "msr    daifset, #2             // arch_local_irq_disable",
  58                __msr_s(SYS_ICC_PMR_EL1, "%0"),
  59                ARM64_HAS_IRQ_PRIO_MASKING)
  60                :
  61                : "r" ((unsigned long) GIC_PRIO_IRQOFF)
  62                : "memory");
  63}
  64
  65/*
  66 * Save the current interrupt enable state.
  67 */
  68static inline unsigned long arch_local_save_flags(void)
  69{
  70        unsigned long flags;
  71
  72        asm volatile(ALTERNATIVE(
  73                "mrs    %0, daif",
  74                __mrs_s("%0", SYS_ICC_PMR_EL1),
  75                ARM64_HAS_IRQ_PRIO_MASKING)
  76                : "=&r" (flags)
  77                :
  78                : "memory");
  79
  80        return flags;
  81}
  82
  83static inline int arch_irqs_disabled_flags(unsigned long flags)
  84{
  85        int res;
  86
  87        asm volatile(ALTERNATIVE(
  88                "and    %w0, %w1, #" __stringify(PSR_I_BIT),
  89                "eor    %w0, %w1, #" __stringify(GIC_PRIO_IRQON),
  90                ARM64_HAS_IRQ_PRIO_MASKING)
  91                : "=&r" (res)
  92                : "r" ((int) flags)
  93                : "memory");
  94
  95        return res;
  96}
  97
  98static inline int arch_irqs_disabled(void)
  99{
 100        return arch_irqs_disabled_flags(arch_local_save_flags());
 101}
 102
 103static inline unsigned long arch_local_irq_save(void)
 104{
 105        unsigned long flags;
 106
 107        flags = arch_local_save_flags();
 108
 109        /*
 110         * There are too many states with IRQs disabled, just keep the current
 111         * state if interrupts are already disabled/masked.
 112         */
 113        if (!arch_irqs_disabled_flags(flags))
 114                arch_local_irq_disable();
 115
 116        return flags;
 117}
 118
 119/*
 120 * restore saved IRQ state
 121 */
 122static inline void arch_local_irq_restore(unsigned long flags)
 123{
 124        asm volatile(ALTERNATIVE(
 125                "msr    daif, %0",
 126                __msr_s(SYS_ICC_PMR_EL1, "%0"),
 127                ARM64_HAS_IRQ_PRIO_MASKING)
 128                :
 129                : "r" (flags)
 130                : "memory");
 131
 132        pmr_sync();
 133}
 134
 135#endif /* __ASM_IRQFLAGS_H */
 136