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Subject[tip:x86/fpu] x86/fpu: Remove clts()
Commit-ID:  af25ed59b5616b389d90877f7085dc5d457a3d49
Gitweb: http://git.kernel.org/tip/af25ed59b5616b389d90877f7085dc5d457a3d49
Author: Andy Lutomirski <luto@kernel.org>
AuthorDate: Mon, 31 Oct 2016 15:18:49 -0700
Committer: Ingo Molnar <mingo@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 <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm list <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/3d3c8ca62f17579b9849a013d71e59a4d5d1b079.1477951965.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@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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