arm64: Add macros to read/write system registers

Rather than crafting custom macros for reading/writing each system
register provide generics accessors, read_sysreg and write_sysreg, for
this purpose.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index d48ab5b41f521c23819c0b3927a9ea0f73db242c..4aeebec3d8828431a59b757f421b6260511f3455 100644 (file)
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -20,6 +20,8 @@
 #ifndef __ASM_SYSREG_H
 #define __ASM_SYSREG_H
 
+#include <linux/stringify.h>
+
 #include <asm/opcodes.h>
 
 /*
@@ -208,6 +210,8 @@
 
 #else
 
+#include <linux/types.h>
+
 asm(
 "      .irp    num,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"
 "      .equ    __reg_num_x\\num, \\num\n"
@@ -232,6 +236,23 @@ static inline void config_sctlr_el1(u32 clear, u32 set)
        val |= set;
        asm volatile("msr sctlr_el1, %0" : : "r" (val));
 }
+
+/*
+ * Unlike read_cpuid, calls to read_sysreg are never expected to be
+ * optimized away or replaced with synthetic values.
+ */
+#define read_sysreg(r) ({                                      \
+       u64 __val;                                              \
+       asm volatile("mrs %0, " __stringify(r) : "=r" (__val)); \
+       __val;                                                  \
+})
+
+#define write_sysreg(v, r) do {                                        \
+       u64 __val = (u64)v;                                     \
+       asm volatile("msr " __stringify(r) ", %0"               \
+                    : : "r" (__val));                          \
+} while (0)
+
 #endif
 
 #endif /* __ASM_SYSREG_H */