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x86: introduce native_read_tscp

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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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Glauber de Oliveira Costa 2008-01-30 13:31:06 +01:00 committed by Ingo Molnar
parent c758ecf62a
commit 8f12dea613
3 changed files with 25 additions and 12 deletions
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4
arch/x86/kernel/vsyscall_64.c
View file

@ -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));

4
arch/x86/vdso/vgetcpu.c
View file

@ -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));

29
include/asm-x86/msr.h
View file

@ -7,6 +7,27 @@
# include <linux/types.h>
#endif
#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__
@ -178,8 +199,6 @@ 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; \
@ -187,12 +206,6 @@ 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)