/*
 * Copyright (c) 2010-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @brief IA-32 specific kernel interface header
 * This header contains the IA-32 specific kernel interface.  It is included
 * by the generic kernel interface header (include/arch/cpu.h)
 */

#ifndef _ARCH_IFACE_H
#define _ARCH_IFACE_H

#include <irq.h>
#include <arch/x86/irq_controller.h>
#include <kernel_arch_thread.h>
#include <generated_dts_board.h>
#include <mmustructs.h>

#ifndef _ASMLANGUAGE
#include <arch/x86/asm_inline.h>
#include <arch/x86/addr_types.h>
#include <arch/x86/segmentation.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* APIs need to support non-byte addressable architectures */

#define OCTET_TO_SIZEOFUNIT(X) (X)
#define SIZEOFUNIT_TO_OCTET(X) (X)

/* GDT layout */
#define CODE_SEG	0x08
#define DATA_SEG	0x10
#define MAIN_TSS	0x18
#define DF_TSS		0x20
#define USER_CODE_SEG	0x2b /* at dpl=3 */
#define USER_DATA_SEG	0x33 /* at dpl=3 */

/**
 * Macro used internally by NANO_CPU_INT_REGISTER and NANO_CPU_INT_REGISTER_ASM.
 * Not meant to be used explicitly by platform, driver or application code.
 */
#define MK_ISR_NAME(x) __isr__##x

#ifndef _ASMLANGUAGE

#ifdef CONFIG_INT_LATENCY_BENCHMARK
void _int_latency_start(void);
void _int_latency_stop(void);
#else
#define _int_latency_start()  do { } while (0)
#define _int_latency_stop()   do { } while (0)
#endif

/* interrupt/exception/error related definitions */

/*
 * The TCS must be aligned to the same boundary as that used by the floating
 * point register set.  This applies even for threads that don't initially
 * use floating point, since it is possible to enable floating point support
 * later on.
 */

#define STACK_ALIGN  FP_REG_SET_ALIGN

typedef struct s_isrList {
	/** Address of ISR/stub */
	void		*fnc;
	/** IRQ associated with the ISR/stub, or -1 if this is not
	 * associated with a real interrupt; in this case vec must
	 * not be -1
	 */
	unsigned int    irq;
	/** Priority associated with the IRQ. Ignored if vec is not -1 */
	unsigned int    priority;
	/** Vector number associated with ISR/stub, or -1 to assign based
	 * on priority
	 */
	unsigned int    vec;
	/** Privilege level associated with ISR/stub */
	unsigned int    dpl;

	/** If nonzero, specifies a TSS segment selector. Will configure
	 * a task gate instead of an interrupt gate. fnc parameter will be
	 * ignored
	 */
	unsigned int	tss;
} ISR_LIST;


/**
 * @brief Connect a routine to an interrupt vector
 *
 * This macro "connects" the specified routine, @a r, to the specified interrupt
 * vector, @a v using the descriptor privilege level @a d. On the IA-32
 * architecture, an interrupt vector is a value from 0 to 255. This macro
 * populates the special intList section with the address of the routine, the
 * vector number and the descriptor privilege level. The genIdt tool then picks
 * up this information and generates an actual IDT entry with this information
 * properly encoded.
 *
 * The @a d argument specifies the privilege level for the interrupt-gate
 * descriptor; (hardware) interrupts and exceptions should specify a level of 0,
 * whereas handlers for user-mode software generated interrupts should specify 3.
 * @param r Routine to be connected
 * @param n IRQ number
 * @param p IRQ priority
 * @param v Interrupt Vector
 * @param d Descriptor Privilege Level
 *
 * @return N/A
 *
 */

#define NANO_CPU_INT_REGISTER(r, n, p, v, d) \
	 static ISR_LIST __attribute__((section(".intList"))) \
			 __attribute__((used)) MK_ISR_NAME(r) = \
			{ \
				.fnc = &(r), \
				.irq = (n), \
				.priority = (p), \
				.vec = (v), \
				.dpl = (d), \
				.tss = 0 \
			}

/**
 * @brief Connect an IA hardware task to an interrupt vector
 *
 * This is very similar to NANO_CPU_INT_REGISTER but instead of connecting
 * a handler function, the interrupt will induce an IA hardware task
 * switch to another hardware task instead.
 *
 * @param tss_p GDT/LDT segment selector for the TSS representing the task
 * @param irq_p IRQ number
 * @param priority_p IRQ priority
 * @param vec_p Interrupt vector
 * @param dpl_p Descriptor privilege level
 */
#define _X86_IDT_TSS_REGISTER(tss_p, irq_p, priority_p, vec_p, dpl_p) \
	static ISR_LIST __attribute__((section(".intList"))) \
			__attribute__((used)) MK_ISR_NAME(r) = \
			{ \
				.fnc = NULL, \
				.irq = (irq_p), \
				.priority = (priority_p), \
				.vec = (vec_p), \
				.dpl = (dpl_p), \
				.tss = (tss_p) \
			}

/**
 * Code snippets for populating the vector ID and priority into the intList
 *
 * The 'magic' of static interrupts is accomplished by building up an array
 * 'intList' at compile time, and the gen_idt tool uses this to create the
 * actual IDT data structure.
 *
 * For controllers like APIC, the vectors in the IDT are not normally assigned
 * at build time; instead the sentinel value -1 is saved, and gen_idt figures
 * out the right vector to use based on our priority scheme. Groups of 16
 * vectors starting at 32 correspond to each priority level.
 *
 * On MVIC, the mapping is fixed; the vector to use is just the irq line
 * number plus 0x20. The priority argument supplied by the user is discarded.
 *
 * These macros are only intended to be used by IRQ_CONNECT() macro.
 */
#if CONFIG_X86_FIXED_IRQ_MAPPING
#define _VECTOR_ARG(irq_p)	_IRQ_CONTROLLER_VECTOR_MAPPING(irq_p)
#else
#define _VECTOR_ARG(irq_p)	(-1)
#endif /* CONFIG_X86_FIXED_IRQ_MAPPING */

/**
 * Configure a static interrupt.
 *
 * All arguments must be computable by the compiler at build time.
 *
 * Internally this function does a few things:
 *
 * 1. There is a declaration of the interrupt parameters in the .intList
 * section, used by gen_idt to create the IDT. This does the same thing
 * as the NANO_CPU_INT_REGISTER() macro, but is done in assembly as we
 * need to populate the .fnc member with the address of the assembly
 * IRQ stub that we generate immediately afterwards.
 *
 * 2. The IRQ stub itself is declared. The code will go in its own named
 * section .text.irqstubs section (which eventually gets linked into 'text')
 * and the stub shall be named (isr_name)_irq(irq_line)_stub
 *
 * 3. The IRQ stub pushes the ISR routine and its argument onto the stack
 * and then jumps to the common interrupt handling code in _interrupt_enter().
 *
 * 4. _irq_controller_irq_config() is called at runtime to set the mapping
 * between the vector and the IRQ line as well as triggering flags
 *
 * @param irq_p IRQ line number
 * @param priority_p Interrupt priority
 * @param isr_p Interrupt service routine
 * @param isr_param_p ISR parameter
 * @param flags_p IRQ triggering options, as defined in irq_controller.h
 *
 * @return The vector assigned to this interrupt
 */
#define _ARCH_IRQ_CONNECT(irq_p, priority_p, isr_p, isr_param_p, flags_p) \
({ \
	__asm__ __volatile__(							\
		".pushsection .intList\n\t" \
		".long %c[isr]_irq%c[irq]_stub\n\t"	/* ISR_LIST.fnc */ \
		".long %c[irq]\n\t"		/* ISR_LIST.irq */ \
		".long %c[priority]\n\t"	/* ISR_LIST.priority */ \
		".long %c[vector]\n\t"		/* ISR_LIST.vec */ \
		".long 0\n\t"			/* ISR_LIST.dpl */ \
		".long 0\n\t"			/* ISR_LIST.tss */ \
		".popsection\n\t" \
		".pushsection .text.irqstubs\n\t" \
		".global %c[isr]_irq%c[irq]_stub\n\t" \
		"%c[isr]_irq%c[irq]_stub:\n\t" \
		"pushl %[isr_param]\n\t" \
		"pushl %[isr]\n\t" \
		"jmp _interrupt_enter\n\t" \
		".popsection\n\t" \
		: \
		: [isr] "i" (isr_p), \
		  [isr_param] "i" (isr_param_p), \
		  [priority] "i" (priority_p), \
		  [vector] "i" _VECTOR_ARG(irq_p), \
		  [irq] "i" (irq_p)); \
	_irq_controller_irq_config(_IRQ_TO_INTERRUPT_VECTOR(irq_p), (irq_p), \
				   (flags_p)); \
	_IRQ_TO_INTERRUPT_VECTOR(irq_p); \
})

/** Configure a 'direct' static interrupt
 *
 * All arguments must be computable by the compiler at build time
 *
 */
#define _ARCH_IRQ_DIRECT_CONNECT(irq_p, priority_p, isr_p, flags_p) \
({ \
	NANO_CPU_INT_REGISTER(isr_p, irq_p, priority_p, -1, 0); \
	_irq_controller_irq_config(_IRQ_TO_INTERRUPT_VECTOR(irq_p), (irq_p), \
				   (flags_p)); \
	_IRQ_TO_INTERRUPT_VECTOR(irq_p); \
})


#ifdef CONFIG_X86_FIXED_IRQ_MAPPING
/* Fixed vector-to-irq association mapping.
 * No need for the table at all.
 */
#define _IRQ_TO_INTERRUPT_VECTOR(irq) _IRQ_CONTROLLER_VECTOR_MAPPING(irq)
#else
/**
 * @brief Convert a statically connected IRQ to its interrupt vector number
 *
 * @param irq IRQ number
 */
extern unsigned char _irq_to_interrupt_vector[];
#define _IRQ_TO_INTERRUPT_VECTOR(irq)                       \
			((unsigned int) _irq_to_interrupt_vector[irq])
#endif

#ifdef CONFIG_SYS_POWER_MANAGEMENT
extern void _arch_irq_direct_pm(void);
#define _ARCH_ISR_DIRECT_PM() _arch_irq_direct_pm()
#else
#define _ARCH_ISR_DIRECT_PM() do { } while (0)
#endif

#define _ARCH_ISR_DIRECT_HEADER() _arch_isr_direct_header()
#define _ARCH_ISR_DIRECT_FOOTER(swap) _arch_isr_direct_footer(swap)

/* FIXME prefer these inline, but see GH-3056 */
extern void _arch_isr_direct_header(void);
extern void _arch_isr_direct_footer(int maybe_swap);

#define _ARCH_ISR_DIRECT_DECLARE(name) \
	static inline int name##_body(void); \
	__attribute__ ((interrupt)) void name(void *stack_frame) \
	{ \
		ARG_UNUSED(stack_frame); \
		int check_reschedule; \
		ISR_DIRECT_HEADER(); \
		check_reschedule = name##_body(); \
		ISR_DIRECT_FOOTER(check_reschedule); \
	} \
	static inline int name##_body(void)

/**
 * @brief Exception Stack Frame
 *
 * A pointer to an "exception stack frame" (ESF) is passed as an argument
 * to exception handlers registered via nanoCpuExcConnect().  As the system
 * always operates at ring 0, only the EIP, CS and EFLAGS registers are pushed
 * onto the stack when an exception occurs.
 *
 * The exception stack frame includes the volatile registers (EAX, ECX, and
 * EDX) as well as the 5 non-volatile registers (EDI, ESI, EBX, EBP and ESP).
 * Those registers are pushed onto the stack by _ExcEnt().
 */

typedef struct nanoEsf {
	unsigned int esp;
	unsigned int ebp;
	unsigned int ebx;
	unsigned int esi;
	unsigned int edi;
	unsigned int edx;
	unsigned int eax;
	unsigned int ecx;
	unsigned int errorCode;
	unsigned int eip;
	unsigned int cs;
	unsigned int eflags;
} NANO_ESF;


struct _x86_syscall_stack_frame {
	u32_t eip;
	u32_t cs;
	u32_t eflags;

	/* These are only present if cs = USER_CODE_SEG */
	u32_t esp;
	u32_t ss;
};

/**
 * @brief "interrupt stack frame" (ISF)
 *
 * An "interrupt stack frame" (ISF) as constructed by the processor and the
 * interrupt wrapper function _interrupt_enter().  As the system always
 * operates at ring 0, only the EIP, CS and EFLAGS registers are pushed onto
 * the stack when an interrupt occurs.
 *
 * The interrupt stack frame includes the volatile registers EAX, ECX, and EDX
 * plus nonvolatile EDI pushed on the stack by _interrupt_enter().
 *
 * Only target-based debug tools such as GDB require the other non-volatile
 * registers (ESI, EBX, EBP and ESP) to be preserved during an interrupt.
 */

typedef struct nanoIsf {
	unsigned int edi;
	unsigned int ecx;
	unsigned int edx;
	unsigned int eax;
	unsigned int eip;
	unsigned int cs;
	unsigned int eflags;
} NANO_ISF;

#endif /* !_ASMLANGUAGE */

/*
 * Reason codes passed to both _NanoFatalErrorHandler()
 * and _SysFatalErrorHandler().
 */

/** Unhandled exception/interrupt */
#define _NANO_ERR_SPURIOUS_INT		 (0)
/** Page fault */
#define _NANO_ERR_PAGE_FAULT		 (1)
/** General protection fault */
#define _NANO_ERR_GEN_PROT_FAULT	 (2)
/** Stack corruption detected */
#define _NANO_ERR_STACK_CHK_FAIL	 (4)
/** Kernel Allocation Failure */
#define _NANO_ERR_ALLOCATION_FAIL    (5)
/** Unhandled exception */
#define _NANO_ERR_CPU_EXCEPTION		(6)
/** Kernel oops (fatal to thread) */
#define _NANO_ERR_KERNEL_OOPS		(7)
/** Kernel panic (fatal to system) */
#define _NANO_ERR_KERNEL_PANIC		(8)

#ifndef _ASMLANGUAGE

/**
 * @brief Disable all interrupts on the CPU (inline)
 *
 * This routine disables interrupts.  It can be called from either interrupt
 * or thread level.  This routine returns an architecture-dependent
 * lock-out key representing the "interrupt disable state" prior to the call;
 * this key can be passed to irq_unlock() to re-enable interrupts.
 *
 * The lock-out key should only be used as the argument to the irq_unlock()
 * API.  It should never be used to manually re-enable interrupts or to inspect
 * or manipulate the contents of the source register.
 *
 * This function can be called recursively: it will return a key to return the
 * state of interrupt locking to the previous level.
 *
 * WARNINGS
 * Invoking a kernel routine with interrupts locked may result in
 * interrupts being re-enabled for an unspecified period of time.  If the
 * called routine blocks, interrupts will be re-enabled while another
 * thread executes, or while the system is idle.
 *
 * The "interrupt disable state" is an attribute of a thread.  Thus, if a
 * thread disables interrupts and subsequently invokes a kernel
 * routine that causes the calling thread to block, the interrupt
 * disable state will be restored when the thread is later rescheduled
 * for execution.
 *
 * @return An architecture-dependent lock-out key representing the
 * "interrupt disable state" prior to the call.
 *
 */

static ALWAYS_INLINE unsigned int _arch_irq_lock(void)
{
	unsigned int key = _do_irq_lock();

	_int_latency_start();

	return key;
}


/**
 *
 * @brief Enable all interrupts on the CPU (inline)
 *
 * This routine re-enables interrupts on the CPU.  The @a key parameter
 * is an architecture-dependent lock-out key that is returned by a previous
 * invocation of irq_lock().
 *
 * This routine can be called from either interrupt or thread level.
 *
 * @return N/A
 *
 */

static ALWAYS_INLINE void _arch_irq_unlock(unsigned int key)
{
	if (!(key & 0x200)) {
		return;
	}

	_int_latency_stop();

	_do_irq_unlock();
}

/**
 * The NANO_SOFT_IRQ macro must be used as the value for the @a irq parameter
 * to NANO_CPU_INT_REGISTER when connecting to an interrupt that does not
 * correspond to any IRQ line (such as spurious vector or SW IRQ)
 */
#define NANO_SOFT_IRQ	((unsigned int) (-1))

/**
 * @brief Enable a specific IRQ
 * @param irq IRQ
 */
extern void	_arch_irq_enable(unsigned int irq);
/**
 * @brief Disable a specific IRQ
 * @param irq IRQ
 */
extern void	_arch_irq_disable(unsigned int irq);

/**
 * @defgroup float_apis Floating Point APIs
 * @ingroup kernel_apis
 * @{
 */

struct k_thread;
typedef struct k_thread *k_tid_t;

/**
 * @brief Enable preservation of floating point context information.
 *
 * This routine informs the kernel that the specified thread (which may be
 * the current thread) will be using the floating point registers.
 * The @a options parameter indicates which floating point register sets
 * will be used by the specified thread:
 *
 *  a) K_FP_REGS  indicates x87 FPU and MMX registers only
 *  b) K_SSE_REGS indicates SSE registers (and also x87 FPU and MMX registers)
 *
 * Invoking this routine initializes the thread's floating point context info
 * to that of an FPU that has been reset. The next time the thread is scheduled
 * by _Swap() it will either inherit an FPU that is guaranteed to be in a "sane"
 * state (if the most recent user of the FPU was cooperatively swapped out)
 * or the thread's own floating point context will be loaded (if the most
 * recent user of the FPU was preempted, or if this thread is the first user
 * of the FPU). Thereafter, the kernel will protect the thread's FP context
 * so that it is not altered during a preemptive context switch.
 *
 * @warning
 * This routine should only be used to enable floating point support for a
 * thread that does not currently have such support enabled already.
 *
 * @param thread ID of thread.
 * @param options Registers to be preserved (K_FP_REGS or K_SSE_REGS).
 *
 * @return N/A
 */
extern void k_float_enable(k_tid_t thread, unsigned int options);

/**
 * @brief Disable preservation of floating point context information.
 *
 * This routine informs the kernel that the specified thread (which may be
 * the current thread) will no longer be using the floating point registers.
 *
 * @warning
 * This routine should only be used to disable floating point support for
 * a thread that currently has such support enabled.
 *
 * @param thread ID of thread.
 *
 * @return N/A
 */
extern void k_float_disable(k_tid_t thread);

/**
 * @}
 */

#include <stddef.h>	/* for size_t */

extern void	k_cpu_idle(void);

extern u32_t _timer_cycle_get_32(void);
#define _arch_k_cycle_get_32()	_timer_cycle_get_32()

/** kernel provided routine to report any detected fatal error. */
extern FUNC_NORETURN void _NanoFatalErrorHandler(unsigned int reason,
						 const NANO_ESF * pEsf);

/** User provided routine to handle any detected fatal error post reporting. */
extern FUNC_NORETURN void _SysFatalErrorHandler(unsigned int reason,
						const NANO_ESF * pEsf);


#ifdef CONFIG_X86_ENABLE_TSS
extern struct task_state_segment _main_tss;
#endif

#ifdef CONFIG_USERSPACE
/* Syscall invocation macros. x86-specific machine constraints used to ensure
 * args land in the proper registers, see implementation of
 * _x86_syscall_entry_stub in userspace.S
 *
 * the entry stub clobbers EDX and ECX on IAMCU systems
 */

static inline u32_t _arch_syscall_invoke6(u32_t arg1, u32_t arg2, u32_t arg3,
					  u32_t arg4, u32_t arg5, u32_t arg6,
					  u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("push %%ebp\n\t"
			 "mov %[arg6], %%ebp\n\t"
			 "int $0x80\n\t"
			 "pop %%ebp\n\t"
			 : "=a" (ret)
#ifdef CONFIG_X86_IAMCU
			   , "=d" (arg2), "=c" (arg3)
#endif
			 : "S" (call_id), "a" (arg1), "d" (arg2),
			   "c" (arg3), "b" (arg4), "D" (arg5),
			   [arg6] "m" (arg6)
			 : "memory", "esp");
	return ret;
}

static inline u32_t _arch_syscall_invoke5(u32_t arg1, u32_t arg2, u32_t arg3,
					  u32_t arg4, u32_t arg5, u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
#ifdef CONFIG_X86_IAMCU
			   , "=d" (arg2), "=c" (arg3)
#endif
			 : "S" (call_id), "a" (arg1), "d" (arg2),
			   "c" (arg3), "b" (arg4), "D" (arg5)
			 : "memory");
	return ret;
}

static inline u32_t _arch_syscall_invoke4(u32_t arg1, u32_t arg2, u32_t arg3,
					  u32_t arg4, u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
#ifdef CONFIG_X86_IAMCU
			   , "=d" (arg2), "=c" (arg3)
#endif
			 : "S" (call_id), "a" (arg1), "d" (arg2), "c" (arg3),
			   "b" (arg4)
			 : "memory");
	return ret;
}

static inline u32_t _arch_syscall_invoke3(u32_t arg1, u32_t arg2, u32_t arg3,
					  u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
#ifdef CONFIG_X86_IAMCU
			   , "=d" (arg2), "=c" (arg3)
#endif
			 : "S" (call_id), "a" (arg1), "d" (arg2), "c" (arg3)
			 : "memory");
	return ret;
}

static inline u32_t _arch_syscall_invoke2(u32_t arg1, u32_t arg2, u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
#ifdef CONFIG_X86_IAMCU
			   , "=d" (arg2)
#endif
			 : "S" (call_id), "a" (arg1), "d" (arg2)
			 : "memory"
#ifdef CONFIG_X86_IAMCU
			 , "ecx"
#endif
			 );
	return ret;
}

static inline u32_t _arch_syscall_invoke1(u32_t arg1, u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
			 : "S" (call_id), "a" (arg1)
			 : "memory"
#ifdef CONFIG_X86_IAMCU
			 , "edx", "ecx"
#endif
			 );
	return ret;
}

static inline u32_t _arch_syscall_invoke0(u32_t call_id)
{
	u32_t ret;

	__asm__ volatile("int $0x80"
			 : "=a" (ret)
			 : "S" (call_id)
			 : "memory"
#ifdef CONFIG_X86_IAMCU
			 , "edx", "ecx"
#endif
			 );
	return ret;
}

static inline int _arch_is_user_context(void)
{
	int cs;

	/* On x86, read the CS register (which cannot be manually set) */
	__asm__ volatile ("mov %%cs, %[cs_val]" : [cs_val] "=r" (cs));

	return cs == USER_CODE_SEG;
}
#endif /* CONFIG_USERSPACE */


#if defined(CONFIG_HW_STACK_PROTECTION) && defined(CONFIG_USERSPACE)
/* With both hardware stack protection and userspace enabled, stacks are
 * arranged as follows:
 *
 * High memory addresses
 * +---------------+
 * | Thread stack  |
 * +---------------+
 * | Kernel stack  |
 * +---------------+
 * | Guard page    |
 * +---------------+
 * Low Memory addresses
 *
 * Kernel stacks are fixed at 4K. All the pages containing the thread stack
 * are marked as user-accessible.
 * All threads start in supervisor mode, and the kernel stack/guard page
 * are both marked non-present in the MMU.
 * If a thread drops down to user mode, the kernel stack page will be marked
 * as present, supervior-only, and the _main_tss.esp0 field updated to point
 * to the top of it.
 * All context switches will save/restore the esp0 field in the TSS.
 */
#define _STACK_GUARD_SIZE	(MMU_PAGE_SIZE * 2)
#define _STACK_BASE_ALIGN	MMU_PAGE_SIZE
#elif defined(CONFIG_HW_STACK_PROTECTION) || defined(CONFIG_USERSPACE)
/* If only one of HW stack protection or userspace is enabled, then the
 * stack will be preceded by one page which is a guard page or a kernel mode
 * stack, respectively.
 */
#define _STACK_GUARD_SIZE	MMU_PAGE_SIZE
#define _STACK_BASE_ALIGN	MMU_PAGE_SIZE
#else /* Neither feature */
#define _STACK_GUARD_SIZE	0
#define _STACK_BASE_ALIGN	STACK_ALIGN
#endif

#define _ARCH_THREAD_STACK_DEFINE(sym, size) \
	struct _k_thread_stack_element __kernel_noinit \
		__aligned(_STACK_BASE_ALIGN) \
		sym[(size) + _STACK_GUARD_SIZE]

#define _ARCH_THREAD_STACK_ARRAY_DEFINE(sym, nmemb, size) \
	struct _k_thread_stack_element __kernel_noinit \
		__aligned(_STACK_BASE_ALIGN) \
		sym[nmemb][ROUND_UP(size, _STACK_BASE_ALIGN) + \
			   _STACK_GUARD_SIZE]

#define _ARCH_THREAD_STACK_MEMBER(sym, size) \
	struct _k_thread_stack_element __aligned(_STACK_BASE_ALIGN) \
		sym[(size) + _STACK_GUARD_SIZE]

#define _ARCH_THREAD_STACK_SIZEOF(sym) \
	(sizeof(sym) - _STACK_GUARD_SIZE)

#define _ARCH_THREAD_STACK_BUFFER(sym) \
	((char *)((sym) + _STACK_GUARD_SIZE))

#if CONFIG_X86_KERNEL_OOPS
#define _ARCH_EXCEPT(reason_p) do { \
	__asm__ volatile( \
		"push %[reason]\n\t" \
		"int %[vector]\n\t" \
		: \
		: [vector] "i" (CONFIG_X86_KERNEL_OOPS_VECTOR), \
		  [reason] "i" (reason_p)); \
	CODE_UNREACHABLE; \
} while (0)
#endif

/** Dummy ESF for fatal errors that would otherwise not have an ESF */
extern const NANO_ESF _default_esf;

#ifdef CONFIG_X86_MMU
/* Linker variable. It is needed to access the start of the Page directory */


#ifdef CONFIG_X86_PAE_MODE
extern u64_t __mmu_tables_start;
#define X86_MMU_PDPT ((struct x86_mmu_page_directory_pointer *)\
		      (u32_t *)(void *)&__mmu_tables_start)
#else
extern u32_t __mmu_tables_start;
#define X86_MMU_PD ((struct x86_mmu_page_directory *)\
		    (void *)&__mmu_tables_start)
#endif


/**
 * @brief Fetch page table flags for a particular page
 *
 * Given a memory address, return the flags for the containing page's
 * PDE and PTE entries. Intended for debugging.
 *
 * @param addr Memory address to example
 * @param pde_flags Output parameter for page directory entry flags
 * @param pte_flags Output parameter for page table entry flags
 */
void _x86_mmu_get_flags(void *addr,
			x86_page_entry_data_t *pde_flags,
			x86_page_entry_data_t *pte_flags);


/**
 * @brief set flags in the MMU page tables
 *
 * Modify bits in the existing page tables for a particular memory
 * range, which must be page-aligned
 *
 * @param ptr Starting memory address which must be page-aligned
 * @param size Size of the region, must be page size multiple
 * @param flags Value of bits to set in the page table entries
 * @param mask Mask indicating which particular bits in the page table entries to
 *	 modify
 */

void _x86_mmu_set_flags(void *ptr,
			size_t size,
			x86_page_entry_data_t flags,
			x86_page_entry_data_t mask);

#endif /* CONFIG_X86_MMU */

#endif /* !_ASMLANGUAGE */

/* reboot through Reset Control Register (I/O port 0xcf9) */

#define SYS_X86_RST_CNT_REG 0xcf9
#define SYS_X86_RST_CNT_SYS_RST 0x02
#define SYS_X86_RST_CNT_CPU_RST 0x4
#define SYS_X86_RST_CNT_FULL_RST 0x08

#ifdef __cplusplus
}
#endif

#endif /* _ARCH_IFACE_H */