x86/MSR: Carve out bare minimum accessors

[people/arne_f/kernel.git] / arch / x86 / include / asm / msr.h

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index db0b90c3b03e2f092fdcb10c7021e8fb569321bc..898dba2e2e2cd4df06bb4e05298f01a97ff85e7a 100644 (file)
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -80,7 +80,14 @@ static inline void do_trace_read_msr(unsigned int msr, u64 val, int failed) {}
 static inline void do_trace_rdpmc(unsigned int msr, u64 val, int failed) {}
 #endif
 
-static inline unsigned long long native_read_msr(unsigned int msr)
+/*
+ * __rdmsr() and __wrmsr() are the two primitives which are the bare minimum MSR
+ * accessors and should not have any tracing or other functionality piggybacking
+ * on them - those are *purely* for accessing MSRs and nothing more. So don't even
+ * think of extending them - you will be slapped with a stinking trout or a frozen
+ * shark will reach you, wherever you are! You've been warned.
+ */
+static inline unsigned long long notrace __rdmsr(unsigned int msr)
 {
        DECLARE_ARGS(val, low, high);
 
@@ -88,11 +95,30 @@ static inline unsigned long long native_read_msr(unsigned int msr)
                     "2:\n"
                     _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_unsafe)
                     : EAX_EDX_RET(val, low, high) : "c" (msr));
-       if (msr_tracepoint_active(__tracepoint_read_msr))
-               do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), 0);
+
        return EAX_EDX_VAL(val, low, high);
 }
 
+static inline void notrace __wrmsr(unsigned int msr, u32 low, u32 high)
+{
+       asm volatile("1: wrmsr\n"
+                    "2:\n"
+                    _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe)
+                    : : "c" (msr), "a"(low), "d" (high) : "memory");
+}
+
+static inline unsigned long long native_read_msr(unsigned int msr)
+{
+       unsigned long long val;
+
+       val = __rdmsr(msr);
+
+       if (msr_tracepoint_active(__tracepoint_read_msr))
+               do_trace_read_msr(msr, val, 0);
+
+       return val;
+}
+
 static inline unsigned long long native_read_msr_safe(unsigned int msr,
                                                      int *err)
 {
@@ -114,31 +140,16 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr,
        return EAX_EDX_VAL(val, low, high);
 }
 
-/* Can be uninlined because referenced by paravirt */
-static inline void notrace
-__native_write_msr_notrace(unsigned int msr, u32 low, u32 high)
-{
-       asm volatile("1: wrmsr\n"
-                    "2:\n"
-                    _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe)
-                    : : "c" (msr), "a"(low), "d" (high) : "memory");
-}
-
 /* Can be uninlined because referenced by paravirt */
 static inline void notrace
 native_write_msr(unsigned int msr, u32 low, u32 high)
 {
-       __native_write_msr_notrace(msr, low, high);
+       __wrmsr(msr, low, high);
+
        if (msr_tracepoint_active(__tracepoint_write_msr))
                do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
 }
 
-static inline void
-wrmsr_notrace(unsigned int msr, u32 low, u32 high)
-{
-       __native_write_msr_notrace(msr, low, high);
-}
-
 /* Can be uninlined because referenced by paravirt */
 static inline int notrace
 native_write_msr_safe(unsigned int msr, u32 low, u32 high)