UPSTREAM: 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>
Change-Id: I1d6cf948bc6660dfd096ff5a18eba682941098c1
(cherry picked from commit 3600c2fdc09a43a30909743569e35a29121602ed)
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index b9fd8ec790336569ee8fdedb4573e25b3045c29b..1a78d6e2a78b58bf21113de3810785a81a35a29d 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>
 
 /*
@@ -215,6 +217,8 @@
 
 #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    .L__reg_num_x\\num, \\num\n"
@@ -239,6 +243,23 @@ 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 */