1 files changed, 135 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
new file mode 100644
index 000000000..ff328e5bb
--- /dev/null
+++ b/arch/arm64/include/asm/irqflags.h
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#ifndef __ASM_IRQFLAGS_H
+#define __ASM_IRQFLAGS_H
+
+#include <asm/alternative.h>
+#include <asm/barrier.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)
+{
+	if (system_has_prio_mask_debugging()) {
+		u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
+
+		WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
+	}
+
+	asm volatile(ALTERNATIVE(
+		"msr	daifclr, #2		// arch_local_irq_enable",
+		__msr_s(SYS_ICC_PMR_EL1, "%0"),
+		ARM64_HAS_IRQ_PRIO_MASKING)
+		:
+		: "r" ((unsigned long) GIC_PRIO_IRQON)
+		: "memory");
+
+	pmr_sync();
+}
+
+static inline void arch_local_irq_disable(void)
+{
+	if (system_has_prio_mask_debugging()) {
+		u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
+
+		WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
+	}
+
+	asm volatile(ALTERNATIVE(
+		"msr	daifset, #2		// arch_local_irq_disable",
+		__msr_s(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 flags;
+
+	asm volatile(ALTERNATIVE(
+		"mrs	%0, daif",
+		__mrs_s("%0", SYS_ICC_PMR_EL1),
+		ARM64_HAS_IRQ_PRIO_MASKING)
+		: "=&r" (flags)
+		:
+		: "memory");
+
+	return flags;
+}
+
+static inline int arch_irqs_disabled_flags(unsigned long flags)
+{
+	int res;
+
+	asm volatile(ALTERNATIVE(
+		"and	%w0, %w1, #" __stringify(PSR_I_BIT),
+		"eor	%w0, %w1, #" __stringify(GIC_PRIO_IRQON),
+		ARM64_HAS_IRQ_PRIO_MASKING)
+		: "=&r" (res)
+		: "r" ((int) flags)
+		: "memory");
+
+	return res;
+}
+
+static inline int arch_irqs_disabled(void)
+{
+	return arch_irqs_disabled_flags(arch_local_save_flags());
+}
+
+static inline unsigned long arch_local_irq_save(void)
+{
+	unsigned long flags;
+
+	flags = arch_local_save_flags();
+
+	/*
+	 * There are too many states with IRQs disabled, just keep the current
+	 * state if interrupts are already disabled/masked.
+	 */
+	if (!arch_irqs_disabled_flags(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",
+		__msr_s(SYS_ICC_PMR_EL1, "%0"),
+		ARM64_HAS_IRQ_PRIO_MASKING)
+		:
+		: "r" (flags)
+		: "memory");
+
+	pmr_sync();
+}
+
+#endif /* __ASM_IRQFLAGS_H */