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x86/asm/tsc, x86/paravirt: Remove read_tsc() and read_tscp() paravirt hooks

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

  d3561b7fa0 ("[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: 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>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2015-06-25 18:43:57 +02:00 committed by Ingo Molnar
parent 881d7bf843
commit 9261e050b6
6 changed files with 8 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
arch/x86/include/asm/msr.h
View File

@ -178,12 +178,6 @@ static inline int rdmsrl_safe(unsigned msr, unsigned long long *p)
return err;
}
#define rdtscl(low) \
((low) = (u32)native_read_tsc())
#define rdtscll(val) \
((val) = native_read_tsc())
#define rdpmc(counter, low, high) \
do { \
u64 _l = native_read_pmc((counter)); \
@ -193,6 +187,14 @@ do { \
#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) \
do { \
unsigned long long _val = native_read_tscp(&(aux)); \
@ -202,8 +204,6 @@ do { \
#define rdtscpll(val, aux) (val) = native_read_tscp(&(aux))
#endif /* !CONFIG_PARAVIRT */
/*
* 64-bit version of wrmsr_safe():
*/

34
arch/x86/include/asm/paravirt.h
View File

@ -174,19 +174,6 @@ static inline int rdmsrl_safe(unsigned msr, unsigned long long *p)
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)
{
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))
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)
{
PVOP_VCALL2(pv_cpu_ops.alloc_ldt, ldt, entries);

2
arch/x86/include/asm/paravirt_types.h
View File

@ -156,9 +156,7 @@ struct pv_cpu_ops {
u64 (*read_msr)(unsigned int msr, int *err);
int (*write_msr)(unsigned int msr, unsigned low, unsigned high);
u64 (*read_tsc)(void);
u64 (*read_pmc)(int counter);
unsigned long long (*read_tscp)(unsigned int *aux);
#ifdef CONFIG_X86_32
/*

2
arch/x86/kernel/paravirt.c
View File

@ -351,9 +351,7 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
.wbinvd = native_wbinvd,
.read_msr = native_read_msr_safe,
.write_msr = native_write_msr_safe,
.read_tsc = native_read_tsc,
.read_pmc = native_read_pmc,
.read_tscp = native_read_tscp,
.load_tr_desc = native_load_tr_desc,
.set_ldt = native_set_ldt,
.load_gdt = native_load_gdt,

2
arch/x86/kernel/paravirt_patch_32.c
View File

@ -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, read_cr3, "mov %cr3, %eax");
DEF_NATIVE(pv_cpu_ops, clts, "clts");
DEF_NATIVE(pv_cpu_ops, read_tsc, "rdtsc");
#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)
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, write_cr3);
PATCH_SITE(pv_cpu_ops, clts);
PATCH_SITE(pv_cpu_ops, read_tsc);
#if defined(CONFIG_PARAVIRT_SPINLOCKS) && defined(CONFIG_QUEUED_SPINLOCKS)
case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
if (pv_is_native_spin_unlock()) {

3
arch/x86/xen/enlighten.c
View File

@ -1175,11 +1175,8 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
.read_msr = xen_read_msr_safe,
.write_msr = xen_write_msr_safe,
.read_tsc = native_read_tsc,
.read_pmc = native_read_pmc,
.read_tscp = native_read_tscp,
.iret = xen_iret,
#ifdef CONFIG_X86_64
.usergs_sysret32 = xen_sysret32,