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  */
  29 static 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
  48 static 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  */
  68 static 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
  83 static 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
  98 static inline unsigned long arch_local_irq_save(void)
  99 {
 100         unsigned long flags;
 101
 102         flags = arch_local_save_flags();
 103
 104         /*
 105          * There are too many states with IRQs disabled, just keep the current
 106          * state if interrupts are already disabled/masked.
 107          */
 108         if (!arch_irqs_disabled_flags(flags))
 109                 arch_local_irq_disable();
 110
 111         return flags;
 112 }
 113
 114 /*
 115  * restore saved IRQ state
 116  */
 117 static inline void arch_local_irq_restore(unsigned long flags)
 118 {
 119         asm volatile(ALTERNATIVE(
 120                 "msr    daif, %0",
 121                 __msr_s(SYS_ICC_PMR_EL1, "%0"),
 122                 ARM64_HAS_IRQ_PRIO_MASKING)
 123                 :
 124                 : "r" (flags)
 125                 : "memory");
 126
 127         pmr_sync();
 128 }
 129
 130 #endif /* __ASM_IRQFLAGS_H */