Commit-ID:  af25ed59b5616b389d90877f7085dc5d457a3d49
Gitweb:     http://git.kernel.org/tip/af25ed59b5616b389d90877f7085dc5d457a3d49
Author:     Andy Lutomirski <l...@kernel.org>
AuthorDate: Mon, 31 Oct 2016 15:18:49 -0700
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 1 Nov 2016 07:47:55 +0100

x86/fpu: Remove clts()

The kernel doesn't use clts() any more.  Remove it and all of its
paravirt infrastructure.

A careful reader may notice that xen_clts() appears to have been
buggy -- it didn't update xen_cr0_value.

Signed-off-by: Andy Lutomirski <l...@kernel.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Brian Gerst <brge...@gmail.com>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Denys Vlasenko <dvlas...@redhat.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Quentin Casasnovas <quentin.casasno...@oracle.com>
Cc: Rik van Riel <r...@redhat.com>
Cc: Rusty Russell <ru...@rustcorp.com.au>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: kvm list <k...@vger.kernel.org>
Link: 
http://lkml.kernel.org/r/3d3c8ca62f17579b9849a013d71e59a4d5d1b079.1477951965.git.l...@kernel.org
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 arch/x86/include/asm/paravirt.h       |  5 -----
 arch/x86/include/asm/paravirt_types.h |  2 --
 arch/x86/include/asm/special_insns.h  | 11 -----------
 arch/x86/kernel/paravirt.c            |  1 -
 arch/x86/kernel/paravirt_patch_32.c   |  2 --
 arch/x86/kernel/paravirt_patch_64.c   |  2 --
 arch/x86/lguest/boot.c                | 12 ------------
 arch/x86/xen/enlighten.c              | 13 -------------
 8 files changed, 48 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index ce93281..f1fb4db 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -41,11 +41,6 @@ static inline void set_debugreg(unsigned long val, int reg)
        PVOP_VCALL2(pv_cpu_ops.set_debugreg, reg, val);
 }
 
-static inline void clts(void)
-{
-       PVOP_VCALL0(pv_cpu_ops.clts);
-}
-
 static inline unsigned long read_cr0(void)
 {
        return PVOP_CALL0(unsigned long, pv_cpu_ops.read_cr0);
diff --git a/arch/x86/include/asm/paravirt_types.h 
b/arch/x86/include/asm/paravirt_types.h
index 0f400c0..545426a 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -103,8 +103,6 @@ struct pv_cpu_ops {
        unsigned long (*get_debugreg)(int regno);
        void (*set_debugreg)(int regno, unsigned long value);
 
-       void (*clts)(void);
-
        unsigned long (*read_cr0)(void);
        void (*write_cr0)(unsigned long);
 
diff --git a/arch/x86/include/asm/special_insns.h 
b/arch/x86/include/asm/special_insns.h
index 29b417b..12af3e3 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -6,11 +6,6 @@
 
 #include <asm/nops.h>
 
-static inline void native_clts(void)
-{
-       asm volatile("clts");
-}
-
 /*
  * Volatile isn't enough to prevent the compiler from reordering the
  * read/write functions for the control registers and messing everything up.
@@ -208,12 +203,6 @@ static inline void load_gs_index(unsigned selector)
 
 #endif
 
-/* Clear the 'TS' bit */
-static inline void clts(void)
-{
-       native_clts();
-}
-
 #endif/* CONFIG_PARAVIRT */
 
 static inline void clflush(volatile void *__p)
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index bbf3d59..a1bfba0 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -328,7 +328,6 @@ __visible struct pv_cpu_ops pv_cpu_ops = {
        .cpuid = native_cpuid,
        .get_debugreg = native_get_debugreg,
        .set_debugreg = native_set_debugreg,
-       .clts = native_clts,
        .read_cr0 = native_read_cr0,
        .write_cr0 = native_write_cr0,
        .read_cr4 = native_read_cr4,
diff --git a/arch/x86/kernel/paravirt_patch_32.c 
b/arch/x86/kernel/paravirt_patch_32.c
index 920c6ae..d3f7f14 100644
--- a/arch/x86/kernel/paravirt_patch_32.c
+++ b/arch/x86/kernel/paravirt_patch_32.c
@@ -8,7 +8,6 @@ DEF_NATIVE(pv_cpu_ops, iret, "iret");
 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");
 
 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
 DEF_NATIVE(pv_lock_ops, queued_spin_unlock, "movb $0, (%eax)");
@@ -48,7 +47,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
                PATCH_SITE(pv_mmu_ops, read_cr2);
                PATCH_SITE(pv_mmu_ops, read_cr3);
                PATCH_SITE(pv_mmu_ops, write_cr3);
-               PATCH_SITE(pv_cpu_ops, clts);
 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
                case PARAVIRT_PATCH(pv_lock_ops.queued_spin_unlock):
                        if (pv_is_native_spin_unlock()) {
diff --git a/arch/x86/kernel/paravirt_patch_64.c 
b/arch/x86/kernel/paravirt_patch_64.c
index bb3840c..915a4c0 100644
--- a/arch/x86/kernel/paravirt_patch_64.c
+++ b/arch/x86/kernel/paravirt_patch_64.c
@@ -10,7 +10,6 @@ DEF_NATIVE(pv_mmu_ops, read_cr2, "movq %cr2, %rax");
 DEF_NATIVE(pv_mmu_ops, read_cr3, "movq %cr3, %rax");
 DEF_NATIVE(pv_mmu_ops, write_cr3, "movq %rdi, %cr3");
 DEF_NATIVE(pv_mmu_ops, flush_tlb_single, "invlpg (%rdi)");
-DEF_NATIVE(pv_cpu_ops, clts, "clts");
 DEF_NATIVE(pv_cpu_ops, wbinvd, "wbinvd");
 
 DEF_NATIVE(pv_cpu_ops, usergs_sysret64, "swapgs; sysretq");
@@ -58,7 +57,6 @@ unsigned native_patch(u8 type, u16 clobbers, void *ibuf,
                PATCH_SITE(pv_mmu_ops, read_cr2);
                PATCH_SITE(pv_mmu_ops, read_cr3);
                PATCH_SITE(pv_mmu_ops, write_cr3);
-               PATCH_SITE(pv_cpu_ops, clts);
                PATCH_SITE(pv_mmu_ops, flush_tlb_single);
                PATCH_SITE(pv_cpu_ops, wbinvd);
 #if defined(CONFIG_PARAVIRT_SPINLOCKS)
diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index d74afcd..4ca0d78 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -518,17 +518,6 @@ static unsigned long lguest_read_cr0(void)
 }
 
 /*
- * Intel provided a special instruction to clear the TS bit for people too cool
- * to use write_cr0() to do it.  This "clts" instruction is faster, because all
- * the vowels have been optimized out.
- */
-static void lguest_clts(void)
-{
-       lazy_hcall1(LHCALL_TS, 0);
-       current_cr0 &= ~X86_CR0_TS;
-}
-
-/*
  * cr2 is the virtual address of the last page fault, which the Guest only ever
  * reads.  The Host kindly writes this into our "struct lguest_data", so we
  * just read it out of there.
@@ -1429,7 +1418,6 @@ __init void lguest_init(void)
        pv_cpu_ops.load_tls = lguest_load_tls;
        pv_cpu_ops.get_debugreg = lguest_get_debugreg;
        pv_cpu_ops.set_debugreg = lguest_set_debugreg;
-       pv_cpu_ops.clts = lguest_clts;
        pv_cpu_ops.read_cr0 = lguest_read_cr0;
        pv_cpu_ops.write_cr0 = lguest_write_cr0;
        pv_cpu_ops.read_cr4 = lguest_read_cr4;
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bdd8556..ced7027 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -980,17 +980,6 @@ static void xen_io_delay(void)
 {
 }
 
-static void xen_clts(void)
-{
-       struct multicall_space mcs;
-
-       mcs = xen_mc_entry(0);
-
-       MULTI_fpu_taskswitch(mcs.mc, 0);
-
-       xen_mc_issue(PARAVIRT_LAZY_CPU);
-}
-
 static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
 
 static unsigned long xen_read_cr0(void)
@@ -1233,8 +1222,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
        .set_debugreg = xen_set_debugreg,
        .get_debugreg = xen_get_debugreg,
 
-       .clts = xen_clts,
-
        .read_cr0 = xen_read_cr0,
        .write_cr0 = xen_write_cr0,
 

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