[Qemu-devel] [kvm-unit-tests PATCH v14 2/5] arm: Add support for read_sysreg() and write_sysreg()

[Wei Huang]

This patch adds two new macros to support read/write operations of ARMv7
and ARMv8 system registers. As part of the change, xstr() is revised to
support variable arguments. With it, ARMv7 system register can be defined
with __ACCESS_CP15() or __ACCESS_CP15_64() depending if it is 32-bit or
64-bit. get_mpidr() is re-written with new macros.

Suggested-by: Andrew Jones <address@hidden>
Signed-off-by: Wei Huang <address@hidden>
---
 lib/arm/asm/processor.h   |  6 +++---
 lib/arm/asm/sysreg.h      | 19 +++++++++++++++++++
 lib/arm64/asm/processor.h | 11 ++++-------
 lib/arm64/asm/sysreg.h    | 26 ++++++++++++++++++++++++++
 lib/libcflat.h            |  4 ++--
 5 files changed, 54 insertions(+), 12 deletions(-)
 create mode 100644 lib/arm64/asm/sysreg.h

diff --git a/lib/arm/asm/processor.h b/lib/arm/asm/processor.h
index f25e7ee..c831749 100644
--- a/lib/arm/asm/processor.h
+++ b/lib/arm/asm/processor.h
@@ -6,6 +6,7 @@
  * This work is licensed under the terms of the GNU LGPL, version 2.
  */
 #include <asm/ptrace.h>
+#include <asm/sysreg.h>
 
 enum vector {
        EXCPTN_RST,
@@ -33,11 +34,10 @@ static inline unsigned long current_cpsr(void)
 
 #define current_mode() (current_cpsr() & MODE_MASK)
 
+#define MPIDR __ACCESS_CP15(c0, 0, c0, 5)
 static inline unsigned int get_mpidr(void)
 {
-       unsigned int mpidr;
-       asm volatile("mrc p15, 0, %0, c0, c0, 5" : "=r" (mpidr));
-       return mpidr;
+       return read_sysreg(MPIDR);
 }
 
 /* Only support Aff0 for now, up to 4 cpus */
diff --git a/lib/arm/asm/sysreg.h b/lib/arm/asm/sysreg.h
index 3e1ad3a..02dbe3d 100644
--- a/lib/arm/asm/sysreg.h
+++ b/lib/arm/asm/sysreg.h
@@ -34,4 +34,23 @@
 #define CR_AFE (1 << 29)       /* Access flag enable                   */
 #define CR_TE  (1 << 30)       /* Thumb exception enable               */
 
+#ifndef __ASSEMBLY__
+#include <libcflat.h>
+
+#define __ACCESS_CP15(CRn, Op1, CRm, Op2)                      \
+       "mrc", "mcr", xstr(p15, Op1, %0, CRn, CRm, Op2), u32
+#define __ACCESS_CP15_64(Op1, CRm)                                     \
+       "mrrc", "mcrr", xstr(p15, Op1, %Q0, %R0, CRm), u64
+
+#define __read_sysreg(r, w, c, t) ({                           \
+                       t __val;                                \
+                       asm volatile(r " " c : "=r" (__val));   \
+                       __val;                                  \
+               })
+#define read_sysreg(...)                 __read_sysreg(__VA_ARGS__)
+
+#define __write_sysreg(v, r, w, c, t)   asm volatile(w " " c : : "r" ((t)(v)))
+#define write_sysreg(v, ...)            __write_sysreg(v, __VA_ARGS__)
+#endif /* !__ASSEMBLY__ */
+
 #endif /* _ASMARM_SYSREG_H_ */
diff --git a/lib/arm64/asm/processor.h b/lib/arm64/asm/processor.h
index 84d5c7c..ed59ad2 100644
--- a/lib/arm64/asm/processor.h
+++ b/lib/arm64/asm/processor.h
@@ -19,6 +19,7 @@
 #ifndef __ASSEMBLY__
 #include <asm/ptrace.h>
 #include <asm/esr.h>
+#include <asm/sysreg.h>
 
 enum vector {
        EL1T_SYNC,
@@ -66,14 +67,10 @@ static inline unsigned long current_level(void)
        return el & 0xc;
 }
 
-#define DEFINE_GET_SYSREG32(reg)                               \
-static inline unsigned int get_##reg(void)                     \
-{                                                              \
-       unsigned int reg;                                       \
-       asm volatile("mrs %0, " #reg "_el1" : "=r" (reg));      \
-       return reg;                                             \
+static inline unsigned int get_mpidr(void)
+{
+       return read_sysreg(mpidr_el1);
 }
-DEFINE_GET_SYSREG32(mpidr)
 
 /* Only support Aff0 for now, gicv2 only */
 #define mpidr_to_cpu(mpidr) ((int)((mpidr) & 0xff))
diff --git a/lib/arm64/asm/sysreg.h b/lib/arm64/asm/sysreg.h
new file mode 100644
index 0000000..05b9fcb
--- /dev/null
+++ b/lib/arm64/asm/sysreg.h
@@ -0,0 +1,26 @@
+/*
+ * Ripped off from arch/arm64/include/asm/sysreg.h
+ *
+ * Copyright (C) 2016, Red Hat Inc, Andrew Jones <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#ifndef _ASMARM64_SYSREG_H_
+#define _ASMARM64_SYSREG_H_
+
+#ifndef __ASSEMBLY__
+#include <libcflat.h>
+
+#define read_sysreg(r) ({                                      \
+       u64 __val;                                              \
+       asm volatile("mrs %0, " xstr(r) : "=r" (__val));        \
+       __val;                                                  \
+})
+
+#define write_sysreg(v, r) do {                                        \
+       u64 __val = (u64)v;                                     \
+       asm volatile("msr " xstr(r) ", %x0" : : "rZ" (__val));  \
+} while (0)
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _ASMARM64_SYSREG_H_ */
diff --git a/lib/libcflat.h b/lib/libcflat.h
index c622198..c3fa4f2 100644
--- a/lib/libcflat.h
+++ b/lib/libcflat.h
@@ -27,8 +27,8 @@
 
 #define __unused __attribute__((__unused__))
 
-#define xstr(s) xxstr(s)
-#define xxstr(s) #s
+#define xstr(s...) xxstr(s)
+#define xxstr(s...) #s
 
 #define __ALIGN_MASK(x, mask)  (((x) + (mask)) & ~(mask))
 #define __ALIGN(x, a)          __ALIGN_MASK(x, (typeof(x))(a) - 1)
-- 
1.8.3.1