[PATCH 03/19] x86/kernel/paravirt: Remove read_tsc() and read_tscp() paravirt hooks
From: Borislav Petkov
Date: Thu Jun 25 2015 - 12:45:37 EST
From: Andy Lutomirski <luto@xxxxxxxxxx>
We've had ->read_tsc() and ->read_tscp() paravirt hooks since the very
beginning of paravirt, i.e.,
d3561b7fa0fb ("[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@xxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: kvm ML <kvm@xxxxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@xxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
arch/x86/include/asm/msr.h | 16 ++++++++--------
arch/x86/include/asm/paravirt.h | 34 ----------------------------------
arch/x86/include/asm/paravirt_types.h | 2 --
arch/x86/kernel/paravirt.c | 2 --
arch/x86/kernel/paravirt_patch_32.c | 2 --
arch/x86/xen/enlighten.c | 3 ---
6 files changed, 8 insertions(+), 51 deletions(-)
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 88711470af7f..d1afac7df484 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -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():
*/
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index d143bfad45d7..c2be0375bcad 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -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);
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index a6b8f9fadb06..ce029e4fa7c6 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -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
/*
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 58bcfb67c01f..f68e48f5f6c2 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -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,
diff --git a/arch/x86/kernel/paravirt_patch_32.c b/arch/x86/kernel/paravirt_patch_32.c
index e1b013696dde..c89f50a76e97 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -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()) {
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 0b95c9b8283f..32136bfca43f 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -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,
--
2.3.5
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