arm64: ptrace: Provide definitions for PMR values

task #25552995

commit cdbc81ddef43c8fdcbd3a26e1a7530c70b629cfc upstream

Introduce fixed values for PMR that are going to be used to mask and
unmask interrupts by priority.

The current priority given to GIC interrupts is 0xa0, so clearing PMR's
most significant bit is enough to mask interrupts.
Signed-off-by: NJulien Thierry <julien.thierry@arm.com>
Suggested-by: NDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NMarc Zyngier <marc.zyngier@arm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NZou Cao <zoucao@linux.alibaba.com>
Reviewed-by: Nluanshi <zhangliguang@linux.alibaba.com>

arch/arm64/include/asm/ptrace.h

@@ -25,6 +25,18 @@
 #define CurrentEL_EL1		(1 << 2)
 #define CurrentEL_EL2		(2 << 2)
 
+/*
+ * PMR values used to mask/unmask interrupts.
+ *
+ * GIC priority masking works as follows: if an IRQ's priority is a higher value
+ * than the value held in PMR, that IRQ is masked. Lowering the value of PMR
+ * means masking more IRQs (or at least that the same IRQs remain masked).
+ *
+ * To mask interrupts, we clear the most significant bit of PMR.
+ */
+#define GIC_PRIO_IRQON		0xf0
+#define GIC_PRIO_IRQOFF		(GIC_PRIO_IRQON & ~0x80)
+
 /* AArch32-specific ptrace requests */
 #define COMPAT_PTRACE_GETREGS		12
 #define COMPAT_PTRACE_SETREGS		13