/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Portions Copyright 2016 Ruslan Bukin <br@bsdpad.com>
 */
/*
 * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */
#include <sys/cdefs.h>

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/dtrace_impl.h>
#include <sys/kernel.h>
#include <sys/stack.h>
#include <sys/pcpu.h>

#include <machine/frame.h>
#include <machine/md_var.h>
#include <machine/encoding.h>
#include <machine/riscvreg.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>

#include <machine/atomic.h>
#include <machine/db_machdep.h>
#include <machine/md_var.h>
#include <machine/stack.h>
#include <ddb/db_sym.h>
#include <ddb/ddb.h>
#include <sys/kdb.h>

#include "regset.h"

#define MAX_USTACK_DEPTH  2048

uint8_t dtrace_fuword8_nocheck(void *);
uint16_t dtrace_fuword16_nocheck(void *);
uint32_t dtrace_fuword32_nocheck(void *);
uint64_t dtrace_fuword64_nocheck(void *);

int dtrace_match_opcode(uint32_t, int, int);
int dtrace_instr_sdsp(uint32_t **);
int dtrace_instr_ret(uint32_t **);
int dtrace_instr_c_sdsp(uint32_t **);
int dtrace_instr_c_ret(uint32_t **);

void
dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, int aframes,
    uint32_t *intrpc)
{
        struct unwind_state state;
        uintptr_t caller;
        register_t sp;
        int scp_offset;
        int depth;

        depth = 0;
        caller = solaris_cpu[curcpu].cpu_dtrace_caller;

        if (intrpc != 0) {
                pcstack[depth++] = (pc_t)intrpc;
        }

        /*
         * Construct the unwind state, starting from this function. This frame,
         * and 'aframes' others will be skipped.
         */
        __asm __volatile("mv %0, sp" : "=&r" (sp));

        state.fp = (uintptr_t)__builtin_frame_address(0);
        state.sp = (uintptr_t)sp;
        state.pc = (uintptr_t)dtrace_getpcstack;

        while (depth < pcstack_limit) {
                if (!unwind_frame(curthread, &state))
                        break;

                if (!INKERNEL(state.pc) || !kstack_contains(curthread,
                    (vm_offset_t)state.fp, sizeof(uintptr_t)))
                        break;

                if (aframes > 0) {
                        aframes--;

                        /*
                         * fbt_invop() records the return address at the time
                         * the FBT probe fires. We need to insert this into the
                         * backtrace manually, since the stack frame state at
                         * the time of the probe does not capture it.
                         */
                        if (aframes == 0 && caller != 0)
                                pcstack[depth++] = caller;
                } else {
                        pcstack[depth++] = state.pc;
                }
        }

        for (; depth < pcstack_limit; depth++) {
                pcstack[depth] = 0;
        }
}

static int
dtrace_getustack_common(uint64_t *pcstack, int pcstack_limit, uintptr_t pc,
    uintptr_t fp)
{
        volatile uint16_t *flags;
        uintptr_t oldfp;
        int ret;

        oldfp = fp;
        ret = 0;
        flags = (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;

        ASSERT(pcstack == NULL || pcstack_limit > 0);

        while (pc != 0) {
                /*
                 * We limit the number of times we can go around this
                 * loop to account for a circular stack.
                 */
                if (ret++ >= MAX_USTACK_DEPTH) {
                        *flags |= CPU_DTRACE_BADSTACK;
                        cpu_core[curcpu].cpuc_dtrace_illval = fp;
                        break;
                }

                if (pcstack != NULL) {
                        *pcstack++ = (uint64_t)pc;
                        pcstack_limit--;
                        if (pcstack_limit <= 0)
                                break;
                }

                if (fp == 0)
                        break;

                pc = dtrace_fuword64((void *)(fp - 1 * sizeof(uint64_t)));
                fp = dtrace_fuword64((void *)(fp - 2 * sizeof(uint64_t)));

                if (fp == oldfp) {
                        *flags |= CPU_DTRACE_BADSTACK;
                        cpu_core[curcpu].cpuc_dtrace_illval = fp;
                        break;
                }
                oldfp = fp;
        }

        return (ret);
}

void
dtrace_getupcstack(uint64_t *pcstack, int pcstack_limit)
{
        volatile uint16_t *flags;
        struct trapframe *tf;
        uintptr_t pc, fp;
        proc_t *p;
        int n;

        p = curproc;
        flags = (volatile uint16_t *)&cpu_core[curcpu].cpuc_dtrace_flags;

        if (*flags & CPU_DTRACE_FAULT)
                return;

        if (pcstack_limit <= 0)
                return;

        /*
         * If there's no user context we still need to zero the stack.
         */
        if (p == NULL || (tf = curthread->td_frame) == NULL)
                goto zero;

        *pcstack++ = (uint64_t)p->p_pid;
        pcstack_limit--;

        if (pcstack_limit <= 0)
                return;

        pc = tf->tf_sepc;
        fp = tf->tf_s[0];

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
                /*
                 * In an entry probe.  The frame pointer has not yet been
                 * pushed (that happens in the function prologue).  The
                 * best approach is to add the current pc as a missing top
                 * of stack and back the pc up to the caller, which is stored
                 * at the current stack pointer address since the call
                 * instruction puts it there right before the branch.
                 */
                *pcstack++ = (uint64_t)pc;
                pcstack_limit--;
                if (pcstack_limit <= 0)
                        return;

                pc = tf->tf_ra;
        }

        n = dtrace_getustack_common(pcstack, pcstack_limit, pc, fp);
        ASSERT(n >= 0);
        ASSERT(n <= pcstack_limit);

        pcstack += n;
        pcstack_limit -= n;

zero:
        while (pcstack_limit-- > 0)
                *pcstack++ = 0;
}

int
dtrace_getustackdepth(void)
{
        struct trapframe *tf;
        uintptr_t pc, fp;
        int n = 0;

        if (curproc == NULL || (tf = curthread->td_frame) == NULL)
                return (0);

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT))
                return (-1);

        pc = tf->tf_sepc;
        fp = tf->tf_s[0];

        if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_ENTRY)) {
                /*
                 * In an entry probe.  The frame pointer has not yet been
                 * pushed (that happens in the function prologue).  The
                 * best approach is to add the current pc as a missing top
                 * of stack and back the pc up to the caller, which is stored
                 * at the current stack pointer address since the call
                 * instruction puts it there right before the branch.
                 */
                pc = tf->tf_ra;
                n++;
        }

        n += dtrace_getustack_common(NULL, 0, pc, fp);

        return (0);
}

void
dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack, int pcstack_limit)
{

        printf("IMPLEMENT ME: %s\n", __func__);
}

/*ARGSUSED*/
uint64_t
dtrace_getarg(int arg, int aframes)
{

        printf("IMPLEMENT ME: %s\n", __func__);

        return (0);
}

int
dtrace_getstackdepth(int aframes)
{
        struct unwind_state state;
        int scp_offset;
        register_t sp;
        int depth;
        bool done;

        depth = 1;
        done = false;

        __asm __volatile("mv %0, sp" : "=&r" (sp));

        state.fp = (uintptr_t)__builtin_frame_address(0);
        state.sp = sp;
        state.pc = (uintptr_t)dtrace_getstackdepth;

        do {
                done = !unwind_frame(curthread, &state);
                if (!INKERNEL(state.pc) || !INKERNEL(state.fp))
                        break;
                depth++;
        } while (!done);

        if (depth < aframes)
                return (0);
        else
                return (depth - aframes);
}

ulong_t
dtrace_getreg(struct trapframe *frame, uint_t reg)
{
        switch (reg) {
        case REG_ZERO:
                return (0);
        case REG_RA:
                return (frame->tf_ra);
        case REG_SP:
                return (frame->tf_sp);
        case REG_GP:
                return (frame->tf_gp);
        case REG_TP:
                return (frame->tf_tp);
        case REG_T0 ... REG_T2:
                return (frame->tf_t[reg - REG_T0]);
        case REG_S0 ... REG_S1:
                return (frame->tf_s[reg - REG_S0]);
        case REG_A0 ... REG_A7:
                return (frame->tf_a[reg - REG_A0]);
        case REG_S2 ... REG_S11:
                return (frame->tf_s[reg - REG_S2 + 2]);
        case REG_T3 ... REG_T6:
                return (frame->tf_t[reg - REG_T3 + 3]);
        case REG_PC:
                return (frame->tf_sepc);
        default:
                DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
                return (0);
        }
        /* NOTREACHED */
}

static int
dtrace_copycheck(uintptr_t uaddr, uintptr_t kaddr, size_t size)
{

        if (uaddr + size > VM_MAXUSER_ADDRESS || uaddr + size < uaddr) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
                cpu_core[curcpu].cpuc_dtrace_illval = uaddr;
                return (0);
        }

        return (1);
}

void
dtrace_copyin(uintptr_t uaddr, uintptr_t kaddr, size_t size,
    volatile uint16_t *flags)
{

        if (dtrace_copycheck(uaddr, kaddr, size))
                dtrace_copy(uaddr, kaddr, size);
}

void
dtrace_copyout(uintptr_t kaddr, uintptr_t uaddr, size_t size,
    volatile uint16_t *flags)
{

        if (dtrace_copycheck(uaddr, kaddr, size))
                dtrace_copy(kaddr, uaddr, size);
}

void
dtrace_copyinstr(uintptr_t uaddr, uintptr_t kaddr, size_t size,
    volatile uint16_t *flags)
{

        if (dtrace_copycheck(uaddr, kaddr, size))
                dtrace_copystr(uaddr, kaddr, size, flags);
}

void
dtrace_copyoutstr(uintptr_t kaddr, uintptr_t uaddr, size_t size,
    volatile uint16_t *flags)
{

        if (dtrace_copycheck(uaddr, kaddr, size))
                dtrace_copystr(kaddr, uaddr, size, flags);
}

uint8_t
dtrace_fuword8(void *uaddr)
{

        if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
                cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
                return (0);
        }

        return (dtrace_fuword8_nocheck(uaddr));
}

uint16_t
dtrace_fuword16(void *uaddr)
{

        if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
                cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
                return (0);
        }

        return (dtrace_fuword16_nocheck(uaddr));
}

uint32_t
dtrace_fuword32(void *uaddr)
{

        if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
                cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
                return (0);
        }

        return (dtrace_fuword32_nocheck(uaddr));
}

uint64_t
dtrace_fuword64(void *uaddr)
{

        if ((uintptr_t)uaddr > VM_MAXUSER_ADDRESS) {
                DTRACE_CPUFLAG_SET(CPU_DTRACE_BADADDR);
                cpu_core[curcpu].cpuc_dtrace_illval = (uintptr_t)uaddr;
                return (0);
        }

        return (dtrace_fuword64_nocheck(uaddr));
}

int
dtrace_match_opcode(uint32_t insn, int match, int mask)
{
        if (((insn ^ match) & mask) == 0)
                return (1);

        return (0);
}

int
dtrace_instr_sdsp(uint32_t **instr)
{
        if (dtrace_match_opcode(**instr, (MATCH_SD | RS2_RA | RS1_SP),
            (MASK_SD | RS2_MASK | RS1_MASK)))
                return (1);

        return (0);
}

int
dtrace_instr_c_sdsp(uint32_t **instr)
{
        uint16_t *instr1;
        int i;

        for (i = 0; i < 2; i++) {
                instr1 = (uint16_t *)(*instr) + i;
                if (dtrace_match_opcode(*instr1, (MATCH_C_SDSP | RS2_C_RA),
                    (MASK_C_SDSP | RS2_C_MASK))) {
                        *instr = (uint32_t *)instr1;
                        return (1);
                }
        }

        return (0);
}

int
dtrace_instr_ret(uint32_t **instr)
{
        if (dtrace_match_opcode(**instr, (MATCH_JALR | (X_RA << RS1_SHIFT)),
            (MASK_JALR | RD_MASK | RS1_MASK | IMM_MASK)))
                return (1);

        return (0);
}

int
dtrace_instr_c_ret(uint32_t **instr)
{
        uint16_t *instr1;
        int i;

        for (i = 0; i < 2; i++) {
                instr1 = (uint16_t *)(*instr) + i;
                if (dtrace_match_opcode(*instr1,
                    (MATCH_C_JR | (X_RA << RD_SHIFT)), (MASK_C_JR | RD_MASK))) {
                        *instr = (uint32_t *)instr1;
                        return (1);
                }
        }

        return (0);
}