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Commit 9261e050 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/asm/tsc, x86/paravirt: Remove read_tsc() and read_tscp() paravirt hooks 



We've had ->read_tsc() and ->read_tscp() paravirt hooks since
the very beginning of paravirt, i.e.,

  d3561b7f ("[PATCH] paravirt: header and stubs for paravirtualisation").

AFAICT, the only paravirt guest implementation that ever
replaced these calls was vmware, and it's gone. Arguably even
vmware shouldn't have hooked RDTSC -- we fully support systems
that don't have a TSC at all, so there's no point for a paravirt
implementation to pretend that we have a TSC but to replace it.

I also doubt that these hooks actually worked. Calls to rdtscl()
and rdtscll(), which respected the hooks, were used seemingly
interchangeably with native_read_tsc(), which did not.

Just remove them. If anyone ever needs them again, they can try
to make a case for why they need them.

Before, on a paravirt config:
  text    	data     bss     dec     hex filename
  12618257      1816384 1093632 15528273 ecf151 vmlinux

After:
  text		data     bss     dec     hex filename
  12617207      1816384 1093632 15527223 eced37 vmlinux

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarBorislav 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>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 881d7bf8

arch/x86/include/asm/msr.h

+8 −8
Original line number Original line Diff line number Diff line
@@ -178,12 +178,6 @@ static inline int rdmsrl_safe(unsigned msr, unsigned long long *p) 
	return err;

	return err;

}

}





#define rdtscl(low)						\

	((low) = (u32)native_read_tsc())



#define rdtscll(val)						\

	((val) = native_read_tsc())



#define rdpmc(counter, low, high)			\

#define rdpmc(counter, low, high)			\

do {							\

do {							\

	u64 _l = native_read_pmc((counter));		\

	u64 _l = native_read_pmc((counter));		\
@@ -193,6 +187,14 @@ do { \ 




#define rdpmcl(counter, val) ((val) = native_read_pmc(counter))

#define rdpmcl(counter, val) ((val) = native_read_pmc(counter))





#endif	/* !CONFIG_PARAVIRT */



#define rdtscl(low)						\

	((low) = (u32)native_read_tsc())



#define rdtscll(val)						\

	((val) = native_read_tsc())



#define rdtscp(low, high, aux)					\

#define rdtscp(low, high, aux)					\

do {                                                            \

do {                                                            \

	unsigned long long _val = native_read_tscp(&(aux));     \

	unsigned long long _val = native_read_tscp(&(aux));     \
@@ -202,8 +204,6 @@ do { \ 




#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))

#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))





#endif	/* !CONFIG_PARAVIRT */



/*

/*

 * 64-bit version of wrmsr_safe():

 * 64-bit version of wrmsr_safe():

 */

 */

arch/x86/include/asm/paravirt.h

+0 −34
Original line number Original line Diff line number Diff line
@@ -174,19 +174,6 @@ static inline int rdmsrl_safe(unsigned msr, unsigned long long *p) 
	return err;

	return err;

}

}





static inline u64 paravirt_read_tsc(void)

{

	return PVOP_CALL0(u64, pv_cpu_ops.read_tsc);

}



#define rdtscl(low)				\

do {						\

	u64 _l = paravirt_read_tsc();		\

	low = (int)_l;				\

} while (0)



#define rdtscll(val) (val = paravirt_read_tsc())



static inline unsigned long long paravirt_sched_clock(void)

static inline unsigned long long paravirt_sched_clock(void)

{

{

	return PVOP_CALL0(unsigned long long, pv_time_ops.sched_clock);

	return PVOP_CALL0(unsigned long long, pv_time_ops.sched_clock);
@@ -215,27 +202,6 @@ do { \ 




#define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter))

#define rdpmcl(counter, val) ((val) = paravirt_read_pmc(counter))





static inline unsigned long long paravirt_rdtscp(unsigned int *aux)

{

	return PVOP_CALL1(u64, pv_cpu_ops.read_tscp, aux);

}



#define rdtscp(low, high, aux)				\

do {							\

	int __aux;					\

	unsigned long __val = paravirt_rdtscp(&__aux);	\

	(low) = (u32)__val;				\

	(high) = (u32)(__val >> 32);			\

	(aux) = __aux;					\

} while (0)



#define rdtscpll(val, aux)				\

do {							\

	unsigned long __aux; 				\

	val = paravirt_rdtscp(&__aux);			\

	(aux) = __aux;					\

} while (0)



static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)

static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)

{

{

	PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries);

	PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries);

arch/x86/include/asm/paravirt_types.h

+0 −2
Original line number Original line Diff line number Diff line
@@ -156,9 +156,7 @@ struct pv_cpu_ops { 
	u64 (*read_msr)(unsigned int msr, int *err);

	u64 (*read_msr)(unsigned int msr, int *err);

	int (*write_msr)(unsigned int msr, unsigned low, unsigned high);

	int (*write_msr)(unsigned int msr, unsigned low, unsigned high);





	u64 (*read_tsc)(void);

	u64 (*read_pmc)(int counter);

	u64 (*read_pmc)(int counter);

	unsigned long long (*read_tscp)(unsigned int *aux);





#ifdef CONFIG_X86_32

#ifdef CONFIG_X86_32

	/*

	/*

arch/x86/kernel/paravirt.c

+0 −2
Original line number Original line Diff line number Diff line
@@ -351,9 +351,7 @@ __visible struct pv_cpu_ops pv_cpu_ops = { 
	.wbinvd = native_wbinvd,

	.wbinvd = native_wbinvd,

	.read_msr = native_read_msr_safe,

	.read_msr = native_read_msr_safe,

	.write_msr = native_write_msr_safe,

	.write_msr = native_write_msr_safe,

	.read_tsc = native_read_tsc,

	.read_pmc = native_read_pmc,

	.read_pmc = native_read_pmc,

	.read_tscp = native_read_tscp,

	.load_tr_desc = native_load_tr_desc,

	.load_tr_desc = native_load_tr_desc,

	.set_ldt = native_set_ldt,

	.set_ldt = native_set_ldt,

	.load_gdt = native_load_gdt,

	.load_gdt = native_load_gdt,

arch/x86/kernel/paravirt_patch_32.c

+0 −2
Original line number Original line Diff line number Diff line
@@ -10,7 +10,6 @@ DEF_NATIVE(pv_mmu_ops, read_cr2, "mov %cr2, %eax"); 
DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");

DEF_NATIVE(pv_mmu_ops, write_cr3, "mov %eax, %cr3");

DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");

DEF_NATIVE(pv_mmu_ops, read_cr3, "mov %cr3, %eax");

DEF_NATIVE(pv_cpu_ops, clts, "clts");

DEF_NATIVE(pv_cpu_ops, clts, "clts");

DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");





#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)

#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)

DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");

DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");
@@ -52,7 +51,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf, 
		PATCH_SITE(pv_mmu_ops, read_cr3);

		PATCH_SITE(pv_mmu_ops, read_cr3);

		PATCH_SITE(pv_mmu_ops, write_cr3);

		PATCH_SITE(pv_mmu_ops, write_cr3);

		PATCH_SITE(pv_cpu_ops, clts);

		PATCH_SITE(pv_cpu_ops, clts);

		PATCH_SITE(pv_cpu_ops, read_tsc);

#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)

#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)

		case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):

		case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):

			if (pv_is_native_spin_unlock()) {

			if (pv_is_native_spin_unlock()) {