/*  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
  ",

  	       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);
  }

  struct jump_label_key paravirt_steal_enabled;
  struct jump_label_key paravirt_steal_rq_enabled;
  
  static u64 native_steal_clock(int cpu)
  {
  	return 0;
  }

  /* 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 */

  
  #ifdef CONFIG_X86_64
  	.extra_user_64bit_cs = __USER_CS,
  #endif

  };

  struct pv_init_ops pv_init_ops = {
  	.patch = native_patch,

  };
  
  struct pv_time_ops pv_time_ops = {

  	.sched_clock = native_sched_clock,

  	.steal_clock = native_steal_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,

  	.set_pmd_at = native_set_pmd_at,

  	.pte_update = paravirt_nop,
  	.pte_update_defer = paravirt_nop,

  	.pmd_update = paravirt_nop,
  	.pmd_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);