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Commit 8f12dea6 authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Ingo Molnar
Browse files

x86: introduce native_read_tscp 



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: default avatarGlauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent c758ecf6

arch/x86/kernel/vsyscall_64.c

+2 −2
Original line number Diff line number Diff line
@@ -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));

arch/x86/vdso/vgetcpu.c

+2 −2
Original line number Diff line number Diff line
@@ -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));

include/asm-x86/msr.h

+21 −8
Original line number Diff line number Diff line
@@ -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)