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 <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: Fenghua Yu <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Oleg Nesterov <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Quentin Casasnovas <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Rusty Russell <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: kvm list <[email protected]> Link: http://lkml.kernel.org/r/3d3c8ca62f17579b9849a013d71e59a4d5d1b079.1477951965.git.luto@kernel.org Signed-off-by: Ingo Molnar <[email protected]>
cluon · Nov 1, 2016 · af25ed5 · af25ed5
1 parent 0d50612
commit af25ed5
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Showing 8 changed files with 0 additions and 48 deletions.
diff --git 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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -517,17 +517,6 @@ static unsigned long lguest_read_cr0(void)
 	return 0;
 }
 
-/*
- * 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
@@ -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
@@ -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,