x86/asm/tsc: Rename native_read_tsc() to rdtsc()

Now that there is no paravirt TSC, the "native" is
inappropriate. The function does RDTSC, so give it the obvious
name: rdtsc().

Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/fd43e16281991f096c1e4d21574d9e1402c62d39.1434501121.git.luto@kernel.org
[ Ported it to v4.2-rc1. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 13 insertions, 4 deletions

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index c89ed6ceed02..ff0c120dafe5 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -109,7 +109,16 @@ notrace static inline int native_write_msr_safe(unsigned int msr,
 extern int rdmsr_safe_regs(u32 regs[8]);
 extern int wrmsr_safe_regs(u32 regs[8]);
 
-static __always_inline unsigned long long native_read_tsc(void)
+/**
+ * rdtsc() - returns the current TSC without ordering constraints
+ *
+ * rdtsc() returns the result of RDTSC as a 64-bit integer.  The
+ * only ordering constraint it supplies is the ordering implied by
+ * "asm volatile": it will put the RDTSC in the place you expect.  The
+ * CPU can and will speculatively execute that RDTSC, though, so the
+ * results can be non-monotonic if compared on different CPUs.
+ */
+static __always_inline unsigned long long rdtsc(void)
 {
 	DECLARE_ARGS(val, low, high);
 
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index 2bd69d62c623..5c490db62e32 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -62,7 +62,7 @@ static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)
 static __always_inline
 u64 pvclock_get_nsec_offset(const struct pvclock_vcpu_time_info *src)
 {
-	u64 delta = native_read_tsc() - src->tsc_timestamp;
+	u64 delta = rdtsc() - src->tsc_timestamp;
 	return pvclock_scale_delta(delta, src->tsc_to_system_mul,
 				   src->tsc_shift);
 }
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h
index bc5fa2af112e..58505f01962f 100644
--- a/arch/x86/include/asm/stackprotector.h
+++ b/arch/x86/include/asm/stackprotector.h
@@ -72,7 +72,7 @@ static __always_inline void boot_init_stack_canary(void)
 	 * on during the bootup the random pool has true entropy too.
 	 */
 	get_random_bytes(&canary, sizeof(canary));
-	tsc = native_read_tsc();
+	tsc = rdtsc();
 	canary += tsc + (tsc << 32UL);
 
 	current->stack_canary = canary;
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index b4883902948b..3df7675debcf 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -26,7 +26,7 @@ static inline cycles_t get_cycles(void)
 		return 0;
 #endif
 
-	return native_read_tsc();
+	return rdtsc();
 }
 
 extern void tsc_init(void);