aarch64: add system register accessors

We open code the use of mrs/msr for specific registers, which is
somewhat tedious. Add macros to do this generically, along with a helper
to extract a specific register field. Existing C usage is converted to
the new helpers, and register definitions moved to a common location.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>

2 files changed, 32 insertions, 19 deletions

diff --git a/arch/aarch64/include/asm/cpu.h b/arch/aarch64/include/asm/cpu.h
index 49d3f86..341a545 100644
--- a/arch/aarch64/include/asm/cpu.h
+++ b/arch/aarch64/include/asm/cpu.h
@@ -9,10 +9,14 @@
 #ifndef __ASM_AARCH64_CPU_H
 #define __ASM_AARCH64_CPU_H
 
+#include <bits.h>
+
 #define MPIDR_ID_BITS		0xff00ffffff
 
 #define CURRENTEL_EL3		(3 << 2)
 
+#define ID_AA64PFR0_EL1_GIC	BITS(27, 24)
+
 /*
  * RES1 bits,  little-endian, caches and MMU off, no alignment checking,
  * no WXN.
@@ -29,6 +33,12 @@
 
 #define CPTR_EL3_EZ		(1 << 8)
 
+#define ICC_SRE_EL2		S3_4_C12_C9_5
+#define ICC_SRE_EL3		S3_6_C12_C12_5
+#define ICC_CTLR_EL1		S3_0_C12_C12_4
+#define ICC_CTLR_EL3		S3_6_C12_C12_4
+#define ICC_PMR_EL1		S3_0_C4_C6_0
+
 #define ZCR_EL3			s3_6_c1_c2_0
 #define ZCR_EL3_LEN_MAX		0xf
 
@@ -57,20 +67,27 @@
 
 #define sevl()		asm volatile ("sevl\n" : : : "memory")
 
-static inline unsigned long read_mpidr(void)
-{
-	unsigned long mpidr;
+#define __str(def)	#def
 
-	asm volatile ("mrs	%0, mpidr_el1\n" : "=r" (mpidr));
-	return mpidr & MPIDR_ID_BITS;
-}
+#define mrs(reg)							\
+({									\
+	unsigned long __mrs_val;					\
+	asm volatile("mrs %0, " __str(reg) : "=r" (__mrs_val));		\
+	__mrs_val;							\
+})
 
-static inline uint64_t read_id_aa64pfr0(void)
-{
-	uint64_t val;
+#define msr(reg, val)							\
+do {									\
+	unsigned long __msr_val = val;					\
+	asm volatile("msr " __str(reg) ", %0" : : "r" (__msr_val));	\
+} while (0)
+
+#define mrs_field(reg, field) \
+	BITS_EXTRACT(mrs(reg), (reg##_##field))
 
-	asm volatile ("mrs	%0, id_aa64pfr0_el1\n" : "=r" (val));
-	return val;
+static inline unsigned long read_mpidr(void)
+{
+	return mrs(mpidr_el1) & MPIDR_ID_BITS;
 }
 
 static inline void iciallu(void)
@@ -80,7 +97,7 @@ static inline void iciallu(void)
 
 static inline int has_gicv3_sysreg(void)
 {
-	return !!((read_id_aa64pfr0() >> 24) & 0xf);
+	return !!mrs_field(ID_AA64PFR0_EL1, GIC);
 }
 
 #endif /* !__ASSEMBLY__ */
diff --git a/arch/aarch64/include/asm/gic-v3.h b/arch/aarch64/include/asm/gic-v3.h
index 5b32380..2447480 100644
--- a/arch/aarch64/include/asm/gic-v3.h
+++ b/arch/aarch64/include/asm/gic-v3.h
@@ -9,20 +9,16 @@
 #ifndef __ASM_AARCH64_GICV3_H
 #define __ASM_AARCH64_GICV3_H
 
-#define ICC_SRE_EL2	"S3_4_C12_C9_5"
-#define ICC_SRE_EL3	"S3_6_C12_C12_5"
-#define ICC_CTLR_EL1	"S3_0_C12_C12_4"
-#define ICC_CTLR_EL3	"S3_6_C12_C12_4"
-#define ICC_PMR_EL1	"S3_0_C4_C6_0"
+#include <asm/cpu.h>
 
 static inline void gic_write_icc_sre(uint32_t val)
 {
-	asm volatile ("msr " ICC_SRE_EL3 ", %0" : : "r" (val));
+	msr(ICC_SRE_EL3, val);
 }
 
 static inline void gic_write_icc_ctlr(uint32_t val)
 {
-	asm volatile ("msr " ICC_CTLR_EL3 ", %0" : : "r" (val));
+	msr(ICC_CTLR_EL3, val);
 }
 
 #endif