1 files changed, 72 insertions, 28 deletions

diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
index 24692edf1a69..43d8366c1e87 100644
--- a/arch/arm64/include/asm/irqflags.h
+++ b/arch/arm64/include/asm/irqflags.h
@@ -18,7 +18,9 @@
 
 #ifdef __KERNEL__
 
+#include <asm/alternative.h>
 #include <asm/ptrace.h>
+#include <asm/sysreg.h>
 
 /*
  * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and
@@ -36,33 +38,27 @@
 /*
  * 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"
-		:
+	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(
-		"msr	daifset, #2		// arch_local_irq_disable"
-		:
+	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");
 }
 
@@ -71,12 +67,44 @@ static inline void arch_local_irq_disable(void)
  */
 static inline unsigned long arch_local_save_flags(void)
 {
+	unsigned long daif_bits;
 	unsigned long flags;
-	asm volatile(
-		"mrs	%0, daif		// arch_local_save_flags"
-		: "=r" (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;
 }
 
@@ -85,16 +113,32 @@ static inline unsigned long arch_local_save_flags(void)
  */
 static inline void arch_local_irq_restore(unsigned long flags)
 {
-	asm volatile(
-		"msr	daif, %0		// arch_local_irq_restore"
-	:
-	: "r" (flags)
-	: "memory");
+	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)
 {
-	return flags & PSR_I_BIT;
+	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