/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_SH_PROCESSOR_64_H
#define __ASM_SH_PROCESSOR_64_H

/*
 * include/asm-sh/processor_64.h
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 * Copyright (C) 2003  Paul Mundt
 * Copyright (C) 2004  Richard Curnow
 */
#ifndef __ASSEMBLY__

#include <linux/compiler.h>
#include <asm/page.h>
#include <asm/types.h>
#include <cpu/registers.h>

#endif

/*
 * User space process size: 2GB - 4k.
 */
#define TASK_SIZE       0x7ffff000UL

#define STACK_TOP       TASK_SIZE
#define STACK_TOP_MAX   STACK_TOP

/* This decides where the kernel will search for a free chunk of vm
 * space during mmap's.
 */
#define TASK_UNMAPPED_BASE      PAGE_ALIGN(TASK_SIZE / 3)

/*
 * Bit of SR register
 *
 * FD-bit:
 *     When it's set, it means the processor doesn't have right to use FPU,
 *     and it results exception when the floating operation is executed.
 *
 * IMASK-bit:
 *     Interrupt level mask
 *
 * STEP-bit:
 *     Single step bit
 *
 */
#if defined(CONFIG_SH64_SR_WATCH)
#define SR_MMU   0x84000000
#else
#define SR_MMU   0x80000000
#endif

#define SR_IMASK 0x000000f0
#define SR_FD    0x00008000
#define SR_SSTEP 0x08000000

#ifndef __ASSEMBLY__

/*
 * FPU structure and data : require 8-byte alignment as we need to access it
   with fld.p, fst.p
 */

struct sh_fpu_hard_struct {
        unsigned long fp_regs[64];
        unsigned int fpscr;
        /* long status; * software status information */
};

/* Dummy fpu emulator  */
struct sh_fpu_soft_struct {
        unsigned long fp_regs[64];
        unsigned int fpscr;
        unsigned char lookahead;
        unsigned long entry_pc;
};

union thread_xstate {
        struct sh_fpu_hard_struct hardfpu;
        struct sh_fpu_soft_struct softfpu;
        /*
         * The structure definitions only produce 32 bit alignment, yet we need
         * to access them using 64 bit load/store as well.
         */
        unsigned long long alignment_dummy;
};

struct thread_struct {
        unsigned long sp;
        unsigned long pc;

        /* Various thread flags, see SH_THREAD_xxx */
        unsigned long flags;

        /* This stores the address of the pt_regs built during a context
           switch, or of the register save area built for a kernel mode
           exception.  It is used for backtracing the stack of a sleeping task
           or one that traps in kernel mode. */
        struct pt_regs *kregs;
        /* This stores the address of the pt_regs constructed on entry from
           user mode.  It is a fixed value over the lifetime of a process, or
           NULL for a kernel thread. */
        struct pt_regs *uregs;

        unsigned long address;
        /* Hardware debugging registers may come here */

        /* floating point info */
        union thread_xstate *xstate;

        /*
         * fpu_counter contains the number of consecutive context switches
         * that the FPU is used. If this is over a threshold, the lazy fpu
         * saving becomes unlazy to save the trap. This is an unsigned char
         * so that after 256 times the counter wraps and the behavior turns
         * lazy again; this to deal with bursty apps that only use FPU for
         * a short time
         */
        unsigned char fpu_counter;
};

#define INIT_MMAP \
{ &init_mm, 0, 0, NULL, PAGE_SHARED, VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }

#define INIT_THREAD  {                          \
        .sp             = sizeof(init_stack) +  \
                          (long) &init_stack,   \
        .pc             = 0,                    \
        .kregs          = &fake_swapper_regs,   \
        .uregs          = NULL,                 \
        .address        = 0,                    \
        .flags          = 0,                    \
}

/*
 * Do necessary setup to start up a newly executed thread.
 */
#define SR_USER (SR_MMU | SR_FD)

#define start_thread(_regs, new_pc, new_sp)                     \
        _regs->sr = SR_USER;    /* User mode. */                \
        _regs->pc = new_pc - 4; /* Compensate syscall exit */   \
        _regs->pc |= 1;         /* Set SHmedia ! */             \
        _regs->regs[18] = 0;                                    \
        _regs->regs[15] = new_sp

/* Forward declaration, a strange C thing */
struct task_struct;
struct mm_struct;

/* Free all resources held by a thread. */
extern void release_thread(struct task_struct *);

/*
 * FPU lazy state save handling.
 */

static inline void disable_fpu(void)
{
        unsigned long long __dummy;

        /* Set FD flag in SR */
        __asm__ __volatile__("getcon    " __SR ", %0\n\t"
                             "or        %0, %1, %0\n\t"
                             "putcon    %0, " __SR "\n\t"
                             : "=&r" (__dummy)
                             : "r" (SR_FD));
}

static inline void enable_fpu(void)
{
        unsigned long long __dummy;

        /* Clear out FD flag in SR */
        __asm__ __volatile__("getcon    " __SR ", %0\n\t"
                             "and       %0, %1, %0\n\t"
                             "putcon    %0, " __SR "\n\t"
                             : "=&r" (__dummy)
                             : "r" (~SR_FD));
}

/* Round to nearest, no exceptions on inexact, overflow, underflow,
   zero-divide, invalid.  Configure option for whether to flush denorms to
   zero, or except if a denorm is encountered.  */
#if defined(CONFIG_SH64_FPU_DENORM_FLUSH)
#define FPSCR_INIT  0x00040000
#else
#define FPSCR_INIT  0x00000000
#endif

#ifdef CONFIG_SH_FPU
/* Initialise the FP state of a task */
void fpinit(struct sh_fpu_hard_struct *fpregs);
#else
#define fpinit(fpregs)  do { } while (0)
#endif

extern struct task_struct *last_task_used_math;

/*
 * Return saved PC of a blocked thread.
 */
#define thread_saved_pc(tsk)    (tsk->thread.pc)

extern unsigned long get_wchan(struct task_struct *p);

#define KSTK_EIP(tsk)  ((tsk)->thread.pc)
#define KSTK_ESP(tsk)  ((tsk)->thread.sp)

#endif  /* __ASSEMBLY__ */
#endif /* __ASM_SH_PROCESSOR_64_H */