Targetting paravirt, this patch introduces native_read_tscp, in
place of rdtscp() macro. When in a paravirt guest, this will
involve a function call, and thus, cannot be done in the vdso area.
These users then have to call the native version directly
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
---
arch/x86/kernel/vsyscall_64.c | 4 ++--
arch/x86/vdso/vgetcpu.c | 4 ++--
include/asm-x86/msr.h | 29 +++++++++++++++++++++--------
3 files changed, 25 insertions(+), 12 deletions(-)
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index ad4005c..1425d02 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -190,7 +190,7 @@ time_t __vsyscall(1) vtime(time_t *t)
long __vsyscall(2)
vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
{
- unsigned int dummy, p;
+ unsigned int p;
unsigned long j = 0;
/* Fast cache - only recompute value once per jiffies and avoid
@@ -205,7 +205,7 @@ vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
p = tcache->blob[1];
} else if (__vgetcpu_mode == VGETCPU_RDTSCP) {
/* Load per CPU data from RDTSCP */
- rdtscp(dummy, dummy, p);
+ native_read_tscp(&p);
} else {
/* Load per CPU data from GDT */
asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
diff --git a/arch/x86/vdso/vgetcpu.c b/arch/x86/vdso/vgetcpu.c
index 3b1ae1a..c8097f1 100644
--- a/arch/x86/vdso/vgetcpu.c
+++ b/arch/x86/vdso/vgetcpu.c
@@ -15,11 +15,11 @@
long __vdso_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *unused)
{
- unsigned int dummy, p;
+ unsigned int p;
if (*vdso_vgetcpu_mode == VGETCPU_RDTSCP) {
/* Load per CPU data from RDTSCP */
- rdtscp(dummy, dummy, p);
+ native_read_tscp(&p);
} else {
/* Load per CPU data from GDT */
asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h
index 5fa30bd..0296358 100644
--- a/include/asm-x86/msr.h
+++ b/include/asm-x86/msr.h
@@ -3,6 +3,27 @@
#include <asm/msr-index.h>
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+static inline unsigned long long native_read_tscp(int *aux)
+{
+ unsigned long low, high;
+ asm volatile (".byte 0x0f,0x01,0xf9"
+ : "=a" (low), "=d" (high), "=c" (*aux));
+ return low | ((u64)high >> 32);
+}
+
+#define rdtscp(low, high, aux) \
+ do { \
+ unsigned long long _val = native_read_tscp(&(aux)); \
+ (low) = (u32)_val; \
+ (high) = (u32)(_val >> 32); \
+ } while (0)
+
+#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))
+#endif
+#endif
+
#ifdef __i386__
#ifdef __KERNEL__
@@ -206,8 +227,6 @@ static inline int wrmsr_safe(u32 __msr, u32 __low, u32 __high)
#define rdtscl(low) \
__asm__ __volatile__ ("rdtsc" : "=a" (low) : : "edx")
-#define rdtscp(low,high,aux) \
- asm volatile (".byte 0x0f,0x01,0xf9" : "=a" (low), "=d" (high), "=c" (aux))
#define rdtscll(val) do { \
unsigned int __a,__d; \
@@ -215,12 +234,6 @@ static inline int wrmsr_safe(u32 __msr, u32 __low, u32 __high)
(val) = ((unsigned long)__a) | (((unsigned long)__d)<<32); \
} while(0)
-#define rdtscpll(val, aux) do { \
- unsigned long __a, __d; \
- asm volatile (".byte 0x0f,0x01,0xf9" : "=a" (__a), "=d" (__d), "=c" (aux)); \
- (val) = (__d << 32) | __a; \
-} while (0)
-
#define write_tsc(val1,val2) wrmsr(0x10, val1, val2)
#define write_rdtscp_aux(val) wrmsr(0xc0000103, val, 0)
--
1.4.4.2
--
