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.,

  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@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>

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 8871147..d1afac7 100644 (file)
--- 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 d143bfa..c2be037 100644 (file)
--- 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 a6b8f9f..ce029e4 100644 (file)
--- 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 58bcfb6..f68e48f 100644 (file)
--- 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 e1b0136..c89f50a 100644 (file)
--- 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 0b95c9b..32136bf 100644 (file)
--- 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,