arch/x86/kernel/paravirt.c - arm/linux-arm64-legacy - Git at Google

 /*  Paravirtualization interfaces
     Copyright (C) 2006 Rusty Russell IBM Corporation

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

     2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
 */

 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/efi.h>
 #include <linux/bcd.h>
 #include <linux/highmem.h>

 #include <asm/bug.h>
 #include <asm/paravirt.h>
 #include <asm/desc.h>
 #include <asm/setup.h>
 #include <asm/pgtable.h>
 #include <asm/time.h>
 #include <asm/pgalloc.h>
 #include <asm/irq.h>
 #include <asm/delay.h>
 #include <asm/fixmap.h>
 #include <asm/apic.h>
 #include <asm/tlbflush.h>
 #include <asm/timer.h>

 /* nop stub */
 void _paravirt_nop(void)
 {
 }

 /* identity function, which can be inlined */
 u32 _paravirt_ident_32(u32 x)
 {
 	return x;
 }

 u64 _paravirt_ident_64(u64 x)
 {
 	return x;
 }

 void __init default_banner(void)
 {
 	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
 	       pv_info.name);
 }

 /* Simple instruction patching code. */
 #define DEF_NATIVE(ops, name, code)					\
 	extern const char start_##ops##_##name[], end_##ops##_##name[];	\
 	asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")

 /* Undefined instruction for dealing with missing ops pointers. */
 static const unsigned char ud2a[] = { 0x0f, 0x0b };

 unsigned paravirt_patch_nop(void)
 {
 	return 0;
 }

 unsigned paravirt_patch_ignore(unsigned len)
 {
 	return len;
 }

 struct branch {
 	unsigned char opcode;
 	u32 delta;
 } __attribute__((packed));

 unsigned paravirt_patch_call(void *insnbuf,
 			     const void *target, u16 tgt_clobbers,
 			     unsigned long addr, u16 site_clobbers,
 			     unsigned len)
 {
 	struct branch *b = insnbuf;
 	unsigned long delta = (unsigned long)target - (addr+5);

 	if (tgt_clobbers & ~site_clobbers)
 		return len;	/* target would clobber too much for this site */
 	if (len < 5)
 		return len;	/* call too long for patch site */

 	b->opcode = 0xe8; /* call */
 	b->delta = delta;
 	BUILD_BUG_ON(sizeof(*b) != 5);

 	return 5;
 }

 unsigned paravirt_patch_jmp(void *insnbuf, const void *target,
 			    unsigned long addr, unsigned len)
 {
 	struct branch *b = insnbuf;
 	unsigned long delta = (unsigned long)target - (addr+5);

 	if (len < 5)
 		return len;	/* call too long for patch site */

 	b->opcode = 0xe9;	/* jmp */
 	b->delta = delta;

 	return 5;
 }

 /* Neat trick to map patch type back to the call within the
  * corresponding structure. */
 static void *get_call_destination(u8 type)
 {
 	struct paravirt_patch_template tmpl = {
 		.pv_init_ops = pv_init_ops,
 		.pv_time_ops = pv_time_ops,
 		.pv_cpu_ops = pv_cpu_ops,
 		.pv_irq_ops = pv_irq_ops,
 		.pv_apic_ops = pv_apic_ops,
 		.pv_mmu_ops = pv_mmu_ops,
 #ifdef CONFIG_PARAVIRT_SPINLOCKS
 		.pv_lock_ops = pv_lock_ops,
 #endif
 	};
 	return *((void **)&tmpl + type);
 }

 unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
 				unsigned long addr, unsigned len)
 {
 	void *opfunc = get_call_destination(type);
 	unsigned ret;

 	if (opfunc == NULL)
 		/* If there's no function, patch it with a ud2a (BUG) */
 		ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
 	else if (opfunc == _paravirt_nop)
 		/* If the operation is a nop, then nop the callsite */
 		ret = paravirt_patch_nop();

 	/* identity functions just return their single argument */
 	else if (opfunc == _paravirt_ident_32)
 		ret = paravirt_patch_ident_32(insnbuf, len);
 	else if (opfunc == _paravirt_ident_64)
 		ret = paravirt_patch_ident_64(insnbuf, len);

 	else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) ||
 		 type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) ||
 		 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) ||
 		 type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
 		/* If operation requires a jmp, then jmp */
 		ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
 	else
 		/* Otherwise call the function; assume target could
 		   clobber any caller-save reg */
 		ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
 					  addr, clobbers, len);

 	return ret;
 }

 unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
 			      const char *start, const char *end)
 {
 	unsigned insn_len = end - start;

 	if (insn_len > len || start == NULL)
 		insn_len = len;
 	else
 		memcpy(insnbuf, start, insn_len);

 	return insn_len;
 }

 static void native_flush_tlb(void)
 {
 	__native_flush_tlb();
 }

 /*
  * Global pages have to be flushed a bit differently. Not a real
  * performance problem because this does not happen often.
  */
 static void native_flush_tlb_global(void)
 {
 	__native_flush_tlb_global();
 }

 static void native_flush_tlb_single(unsigned long addr)
 {
 	__native_flush_tlb_single(addr);
 }

 /* These are in entry.S */
 extern void native_iret(void);
 extern void native_irq_enable_sysexit(void);
 extern void native_usergs_sysret32(void);
 extern void native_usergs_sysret64(void);

 static struct resource reserve_ioports = {
 	.start = 0,
 	.end = IO_SPACE_LIMIT,
 	.name = "paravirt-ioport",
 	.flags = IORESOURCE_IO | IORESOURCE_BUSY,
 };

 /*
  * Reserve the whole legacy IO space to prevent any legacy drivers
  * from wasting time probing for their hardware.  This is a fairly
  * brute-force approach to disabling all non-virtual drivers.
  *
  * Note that this must be called very early to have any effect.
  */
 int paravirt_disable_iospace(void)
 {
 	return request_resource(&ioport_resource, &reserve_ioports);
 }

 static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;

 static inline void enter_lazy(enum paravirt_lazy_mode mode)
 {
 	BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);

 	percpu_write(paravirt_lazy_mode, mode);
 }

 static void leave_lazy(enum paravirt_lazy_mode mode)
 {
 	BUG_ON(percpu_read(paravirt_lazy_mode) != mode);

 	percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
 }

 void paravirt_enter_lazy_mmu(void)
 {
 	enter_lazy(PARAVIRT_LAZY_MMU);
 }

 void paravirt_leave_lazy_mmu(void)
 {
 	leave_lazy(PARAVIRT_LAZY_MMU);
 }

 void paravirt_start_context_switch(struct task_struct *prev)
 {
 	BUG_ON(preemptible());

 	if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
 		arch_leave_lazy_mmu_mode();
 		set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
 	}
 	enter_lazy(PARAVIRT_LAZY_CPU);
 }

 void paravirt_end_context_switch(struct task_struct *next)
 {
 	BUG_ON(preemptible());

 	leave_lazy(PARAVIRT_LAZY_CPU);

 	if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
 		arch_enter_lazy_mmu_mode();
 }

 enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
 {
 	if (in_interrupt())
 		return PARAVIRT_LAZY_NONE;

 	return percpu_read(paravirt_lazy_mode);
 }

 void arch_flush_lazy_mmu_mode(void)
 {
 	preempt_disable();

 	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
 		arch_leave_lazy_mmu_mode();
 		arch_enter_lazy_mmu_mode();
 	}

 	preempt_enable();
 }

 struct pv_info pv_info = {
 	.name = "bare hardware",
 	.paravirt_enabled = 0,
 	.kernel_rpl = 0,
 	.shared_kernel_pmd = 1,	/* Only used when CONFIG_X86_PAE is set */
 };

 struct pv_init_ops pv_init_ops = {
 	.patch = native_patch,
 };

 struct pv_time_ops pv_time_ops = {
 	.sched_clock = native_sched_clock,
 };

 struct pv_irq_ops pv_irq_ops = {
 	.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
 	.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
 	.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
 	.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
 	.safe_halt = native_safe_halt,
 	.halt = native_halt,
 #ifdef CONFIG_X86_64
 	.adjust_exception_frame = paravirt_nop,
 #endif
 };

 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,
 	.read_cr4_safe = native_read_cr4_safe,
 	.write_cr4 = native_write_cr4,
 #ifdef CONFIG_X86_64
 	.read_cr8 = native_read_cr8,
 	.write_cr8 = native_write_cr8,
 #endif
 	.wbinvd = native_wbinvd,
 	.read_msr = native_read_msr_safe,
 	.rdmsr_regs = native_rdmsr_safe_regs,
 	.write_msr = native_write_msr_safe,
 	.wrmsr_regs = native_wrmsr_safe_regs,
 	.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,
 	.load_idt = native_load_idt,
 	.store_gdt = native_store_gdt,
 	.store_idt = native_store_idt,
 	.store_tr = native_store_tr,
 	.load_tls = native_load_tls,
 #ifdef CONFIG_X86_64
 	.load_gs_index = native_load_gs_index,
 #endif
 	.write_ldt_entry = native_write_ldt_entry,
 	.write_gdt_entry = native_write_gdt_entry,
 	.write_idt_entry = native_write_idt_entry,

 	.alloc_ldt = paravirt_nop,
 	.free_ldt = paravirt_nop,

 	.load_sp0 = native_load_sp0,

 #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 	.irq_enable_sysexit = native_irq_enable_sysexit,
 #endif
 #ifdef CONFIG_X86_64
 #ifdef CONFIG_IA32_EMULATION
 	.usergs_sysret32 = native_usergs_sysret32,
 #endif
 	.usergs_sysret64 = native_usergs_sysret64,
 #endif
 	.iret = native_iret,
 	.swapgs = native_swapgs,

 	.set_iopl_mask = native_set_iopl_mask,
 	.io_delay = native_io_delay,

 	.start_context_switch = paravirt_nop,
 	.end_context_switch = paravirt_nop,
 };

 struct pv_apic_ops pv_apic_ops = {
 #ifdef CONFIG_X86_LOCAL_APIC
 	.startup_ipi_hook = paravirt_nop,
 #endif
 };

 #if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
 /* 32-bit pagetable entries */
 #define PTE_IDENT	__PV_IS_CALLEE_SAVE(_paravirt_ident_32)
 #else
 /* 64-bit pagetable entries */
 #define PTE_IDENT	__PV_IS_CALLEE_SAVE(_paravirt_ident_64)
 #endif

 struct pv_mmu_ops pv_mmu_ops = {

 	.read_cr2 = native_read_cr2,
 	.write_cr2 = native_write_cr2,
 	.read_cr3 = native_read_cr3,
 	.write_cr3 = native_write_cr3,

 	.flush_tlb_user = native_flush_tlb,
 	.flush_tlb_kernel = native_flush_tlb_global,
 	.flush_tlb_single = native_flush_tlb_single,
 	.flush_tlb_others = native_flush_tlb_others,

 	.pgd_alloc = __paravirt_pgd_alloc,
 	.pgd_free = paravirt_nop,

 	.alloc_pte = paravirt_nop,
 	.alloc_pmd = paravirt_nop,
 	.alloc_pud = paravirt_nop,
 	.release_pte = paravirt_nop,
 	.release_pmd = paravirt_nop,
 	.release_pud = paravirt_nop,

 	.set_pte = native_set_pte,
 	.set_pte_at = native_set_pte_at,
 	.set_pmd = native_set_pmd,
 	.pte_update = paravirt_nop,
 	.pte_update_defer = paravirt_nop,

 	.ptep_modify_prot_start = __ptep_modify_prot_start,
 	.ptep_modify_prot_commit = __ptep_modify_prot_commit,

 #if PAGETABLE_LEVELS >= 3
 #ifdef CONFIG_X86_PAE
 	.set_pte_atomic = native_set_pte_atomic,
 	.pte_clear = native_pte_clear,
 	.pmd_clear = native_pmd_clear,
 #endif
 	.set_pud = native_set_pud,

 	.pmd_val = PTE_IDENT,
 	.make_pmd = PTE_IDENT,

 #if PAGETABLE_LEVELS == 4
 	.pud_val = PTE_IDENT,
 	.make_pud = PTE_IDENT,

 	.set_pgd = native_set_pgd,
 #endif
 #endif /* PAGETABLE_LEVELS >= 3 */

 	.pte_val = PTE_IDENT,
 	.pgd_val = PTE_IDENT,

 	.make_pte = PTE_IDENT,
 	.make_pgd = PTE_IDENT,

 	.dup_mmap = paravirt_nop,
 	.exit_mmap = paravirt_nop,
 	.activate_mm = paravirt_nop,

 	.lazy_mode = {
 		.enter = paravirt_nop,
 		.leave = paravirt_nop,
 	},

 	.set_fixmap = native_set_fixmap,
 };

 EXPORT_SYMBOL_GPL(pv_time_ops);
 EXPORT_SYMBOL    (pv_cpu_ops);
 EXPORT_SYMBOL    (pv_mmu_ops);
 EXPORT_SYMBOL_GPL(pv_apic_ops);
 EXPORT_SYMBOL_GPL(pv_info);
 EXPORT_SYMBOL    (pv_irq_ops);
	/* Paravirtualization interfaces
	Copyright (C) 2006 Rusty Russell IBM Corporation

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

	2007 - x86_64 support added by Glauber de Oliveira Costa, Red Hat Inc
	*/

	#include <linux/errno.h>
	#include <linux/module.h>
	#include <linux/efi.h>
	#include <linux/bcd.h>
	#include <linux/highmem.h>

	#include <asm/bug.h>
	#include <asm/paravirt.h>
	#include <asm/desc.h>
	#include <asm/setup.h>
	#include <asm/pgtable.h>
	#include <asm/time.h>
	#include <asm/pgalloc.h>
	#include <asm/irq.h>
	#include <asm/delay.h>
	#include <asm/fixmap.h>
	#include <asm/apic.h>
	#include <asm/tlbflush.h>
	#include <asm/timer.h>

	/* nop stub */
	void _paravirt_nop(void)
	{
	}

	/* identity function, which can be inlined */
	u32 _paravirt_ident_32(u32 x)
	{
	return x;
	}

	u64 _paravirt_ident_64(u64 x)
	{
	return x;
	}

	void __init default_banner(void)
	{
	printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
	pv_info.name);
	}

	/* Simple instruction patching code. */
	#define DEF_NATIVE(ops, name, code) \
	extern const char start_##ops##_##name[], end_##ops##_##name[]; \
	asm("start_" #ops "_" #name ": " code "; end_" #ops "_" #name ":")

	/* Undefined instruction for dealing with missing ops pointers. */
	static const unsigned char ud2a[] = { 0x0f, 0x0b };

	unsigned paravirt_patch_nop(void)
	{
	return 0;
	}

	unsigned paravirt_patch_ignore(unsigned len)
	{
	return len;
	}

	struct branch {
	unsigned char opcode;
	u32 delta;
	} __attribute__((packed));

	unsigned paravirt_patch_call(void *insnbuf,
	const void *target, u16 tgt_clobbers,
	unsigned long addr, u16 site_clobbers,
	unsigned len)
	{
	struct branch *b = insnbuf;
	unsigned long delta = (unsigned long)target - (addr+5);

	if (tgt_clobbers & ~site_clobbers)
	return len; /* target would clobber too much for this site */
	if (len < 5)
	return len; /* call too long for patch site */

	b->opcode = 0xe8; /* call */
	b->delta = delta;
	BUILD_BUG_ON(sizeof(*b) != 5);

	return 5;
	}

	unsigned paravirt_patch_jmp(void insnbuf, const void target,
	unsigned long addr, unsigned len)
	{
	struct branch *b = insnbuf;
	unsigned long delta = (unsigned long)target - (addr+5);

	if (len < 5)
	return len; /* call too long for patch site */

	b->opcode = 0xe9; /* jmp */
	b->delta = delta;

	return 5;
	}

	/* Neat trick to map patch type back to the call within the
	* corresponding structure. */
	static void *get_call_destination(u8 type)
	{
	struct paravirt_patch_template tmpl = {
	.pv_init_ops = pv_init_ops,
	.pv_time_ops = pv_time_ops,
	.pv_cpu_ops = pv_cpu_ops,
	.pv_irq_ops = pv_irq_ops,
	.pv_apic_ops = pv_apic_ops,
	.pv_mmu_ops = pv_mmu_ops,
	#ifdef CONFIG_PARAVIRT_SPINLOCKS
	.pv_lock_ops = pv_lock_ops,
	#endif
	};
	return ((void *)&tmpl + type);
	}

	unsigned paravirt_patch_default(u8 type, u16 clobbers, void *insnbuf,
	unsigned long addr, unsigned len)
	{
	void *opfunc = get_call_destination(type);
	unsigned ret;

	if (opfunc == NULL)
	/* If there's no function, patch it with a ud2a (BUG) */
	ret = paravirt_patch_insns(insnbuf, len, ud2a, ud2a+sizeof(ud2a));
	else if (opfunc == _paravirt_nop)
	/* If the operation is a nop, then nop the callsite */
	ret = paravirt_patch_nop();

	/* identity functions just return their single argument */
	else if (opfunc == _paravirt_ident_32)
	ret = paravirt_patch_ident_32(insnbuf, len);
	else if (opfunc == _paravirt_ident_64)
	ret = paravirt_patch_ident_64(insnbuf, len);

	else if (type == PARAVIRT_PATCH(pv_cpu_ops.iret) \|\|
	type == PARAVIRT_PATCH(pv_cpu_ops.irq_enable_sysexit) \|\|
	type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret32) \|\|
	type == PARAVIRT_PATCH(pv_cpu_ops.usergs_sysret64))
	/* If operation requires a jmp, then jmp */
	ret = paravirt_patch_jmp(insnbuf, opfunc, addr, len);
	else
	/* Otherwise call the function; assume target could
	clobber any caller-save reg */
	ret = paravirt_patch_call(insnbuf, opfunc, CLBR_ANY,
	addr, clobbers, len);

	return ret;
	}

	unsigned paravirt_patch_insns(void *insnbuf, unsigned len,
	const char start, const char end)
	{
	unsigned insn_len = end - start;

	if (insn_len > len \|\| start == NULL)
	insn_len = len;
	else
	memcpy(insnbuf, start, insn_len);

	return insn_len;
	}

	static void native_flush_tlb(void)
	{
	__native_flush_tlb();
	}

	/*
	* Global pages have to be flushed a bit differently. Not a real
	* performance problem because this does not happen often.
	*/
	static void native_flush_tlb_global(void)
	{
	__native_flush_tlb_global();
	}

	static void native_flush_tlb_single(unsigned long addr)
	{
	__native_flush_tlb_single(addr);
	}

	/* These are in entry.S */
	extern void native_iret(void);
	extern void native_irq_enable_sysexit(void);
	extern void native_usergs_sysret32(void);
	extern void native_usergs_sysret64(void);

	static struct resource reserve_ioports = {
	.start = 0,
	.end = IO_SPACE_LIMIT,
	.name = "paravirt-ioport",
	.flags = IORESOURCE_IO \| IORESOURCE_BUSY,
	};

	/*
	* Reserve the whole legacy IO space to prevent any legacy drivers
	* from wasting time probing for their hardware. This is a fairly
	* brute-force approach to disabling all non-virtual drivers.
	*
	* Note that this must be called very early to have any effect.
	*/
	int paravirt_disable_iospace(void)
	{
	return request_resource(&ioport_resource, &reserve_ioports);
	}

	static DEFINE_PER_CPU(enum paravirt_lazy_mode, paravirt_lazy_mode) = PARAVIRT_LAZY_NONE;

	static inline void enter_lazy(enum paravirt_lazy_mode mode)
	{
	BUG_ON(percpu_read(paravirt_lazy_mode) != PARAVIRT_LAZY_NONE);

	percpu_write(paravirt_lazy_mode, mode);
	}

	static void leave_lazy(enum paravirt_lazy_mode mode)
	{
	BUG_ON(percpu_read(paravirt_lazy_mode) != mode);

	percpu_write(paravirt_lazy_mode, PARAVIRT_LAZY_NONE);
	}

	void paravirt_enter_lazy_mmu(void)
	{
	enter_lazy(PARAVIRT_LAZY_MMU);
	}

	void paravirt_leave_lazy_mmu(void)
	{
	leave_lazy(PARAVIRT_LAZY_MMU);
	}

	void paravirt_start_context_switch(struct task_struct *prev)
	{
	BUG_ON(preemptible());

	if (percpu_read(paravirt_lazy_mode) == PARAVIRT_LAZY_MMU) {
	arch_leave_lazy_mmu_mode();
	set_ti_thread_flag(task_thread_info(prev), TIF_LAZY_MMU_UPDATES);
	}
	enter_lazy(PARAVIRT_LAZY_CPU);
	}

	void paravirt_end_context_switch(struct task_struct *next)
	{
	BUG_ON(preemptible());

	leave_lazy(PARAVIRT_LAZY_CPU);

	if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))
	arch_enter_lazy_mmu_mode();
	}

	enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
	{
	if (in_interrupt())
	return PARAVIRT_LAZY_NONE;

	return percpu_read(paravirt_lazy_mode);
	}

	void arch_flush_lazy_mmu_mode(void)
	{
	preempt_disable();

	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_MMU) {
	arch_leave_lazy_mmu_mode();
	arch_enter_lazy_mmu_mode();
	}

	preempt_enable();
	}

	struct pv_info pv_info = {
	.name = "bare hardware",
	.paravirt_enabled = 0,
	.kernel_rpl = 0,
	.shared_kernel_pmd = 1, /* Only used when CONFIG_X86_PAE is set */
	};

	struct pv_init_ops pv_init_ops = {
	.patch = native_patch,
	};

	struct pv_time_ops pv_time_ops = {
	.sched_clock = native_sched_clock,
	};

	struct pv_irq_ops pv_irq_ops = {
	.save_fl = __PV_IS_CALLEE_SAVE(native_save_fl),
	.restore_fl = __PV_IS_CALLEE_SAVE(native_restore_fl),
	.irq_disable = __PV_IS_CALLEE_SAVE(native_irq_disable),
	.irq_enable = __PV_IS_CALLEE_SAVE(native_irq_enable),
	.safe_halt = native_safe_halt,
	.halt = native_halt,
	#ifdef CONFIG_X86_64
	.adjust_exception_frame = paravirt_nop,
	#endif
	};

	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,
	.read_cr4_safe = native_read_cr4_safe,
	.write_cr4 = native_write_cr4,
	#ifdef CONFIG_X86_64
	.read_cr8 = native_read_cr8,
	.write_cr8 = native_write_cr8,
	#endif
	.wbinvd = native_wbinvd,
	.read_msr = native_read_msr_safe,
	.rdmsr_regs = native_rdmsr_safe_regs,
	.write_msr = native_write_msr_safe,
	.wrmsr_regs = native_wrmsr_safe_regs,
	.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,
	.load_idt = native_load_idt,
	.store_gdt = native_store_gdt,
	.store_idt = native_store_idt,
	.store_tr = native_store_tr,
	.load_tls = native_load_tls,
	#ifdef CONFIG_X86_64
	.load_gs_index = native_load_gs_index,
	#endif
	.write_ldt_entry = native_write_ldt_entry,
	.write_gdt_entry = native_write_gdt_entry,
	.write_idt_entry = native_write_idt_entry,

	.alloc_ldt = paravirt_nop,
	.free_ldt = paravirt_nop,

	.load_sp0 = native_load_sp0,

	#if defined(CONFIG_X86_32) \|\| defined(CONFIG_IA32_EMULATION)
	.irq_enable_sysexit = native_irq_enable_sysexit,
	#endif
	#ifdef CONFIG_X86_64
	#ifdef CONFIG_IA32_EMULATION
	.usergs_sysret32 = native_usergs_sysret32,
	#endif
	.usergs_sysret64 = native_usergs_sysret64,
	#endif
	.iret = native_iret,
	.swapgs = native_swapgs,

	.set_iopl_mask = native_set_iopl_mask,
	.io_delay = native_io_delay,

	.start_context_switch = paravirt_nop,
	.end_context_switch = paravirt_nop,
	};

	struct pv_apic_ops pv_apic_ops = {
	#ifdef CONFIG_X86_LOCAL_APIC
	.startup_ipi_hook = paravirt_nop,
	#endif
	};

	#if defined(CONFIG_X86_32) && !defined(CONFIG_X86_PAE)
	/* 32-bit pagetable entries */
	#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_32)
	#else
	/* 64-bit pagetable entries */
	#define PTE_IDENT __PV_IS_CALLEE_SAVE(_paravirt_ident_64)
	#endif

	struct pv_mmu_ops pv_mmu_ops = {

	.read_cr2 = native_read_cr2,
	.write_cr2 = native_write_cr2,
	.read_cr3 = native_read_cr3,
	.write_cr3 = native_write_cr3,

	.flush_tlb_user = native_flush_tlb,
	.flush_tlb_kernel = native_flush_tlb_global,
	.flush_tlb_single = native_flush_tlb_single,
	.flush_tlb_others = native_flush_tlb_others,

	.pgd_alloc = __paravirt_pgd_alloc,
	.pgd_free = paravirt_nop,

	.alloc_pte = paravirt_nop,
	.alloc_pmd = paravirt_nop,
	.alloc_pud = paravirt_nop,
	.release_pte = paravirt_nop,
	.release_pmd = paravirt_nop,
	.release_pud = paravirt_nop,

	.set_pte = native_set_pte,
	.set_pte_at = native_set_pte_at,
	.set_pmd = native_set_pmd,
	.pte_update = paravirt_nop,
	.pte_update_defer = paravirt_nop,

	.ptep_modify_prot_start = __ptep_modify_prot_start,
	.ptep_modify_prot_commit = __ptep_modify_prot_commit,

	#if PAGETABLE_LEVELS >= 3
	#ifdef CONFIG_X86_PAE
	.set_pte_atomic = native_set_pte_atomic,
	.pte_clear = native_pte_clear,
	.pmd_clear = native_pmd_clear,
	#endif
	.set_pud = native_set_pud,

	.pmd_val = PTE_IDENT,
	.make_pmd = PTE_IDENT,

	#if PAGETABLE_LEVELS == 4
	.pud_val = PTE_IDENT,
	.make_pud = PTE_IDENT,

	.set_pgd = native_set_pgd,
	#endif
	#endif /* PAGETABLE_LEVELS >= 3 */

	.pte_val = PTE_IDENT,
	.pgd_val = PTE_IDENT,

	.make_pte = PTE_IDENT,
	.make_pgd = PTE_IDENT,

	.dup_mmap = paravirt_nop,
	.exit_mmap = paravirt_nop,
	.activate_mm = paravirt_nop,

	.lazy_mode = {
	.enter = paravirt_nop,
	.leave = paravirt_nop,
	},

	.set_fixmap = native_set_fixmap,
	};

	EXPORT_SYMBOL_GPL(pv_time_ops);
	EXPORT_SYMBOL (pv_cpu_ops);
	EXPORT_SYMBOL (pv_mmu_ops);
	EXPORT_SYMBOL_GPL(pv_apic_ops);
	EXPORT_SYMBOL_GPL(pv_info);
	EXPORT_SYMBOL (pv_irq_ops);