/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2006-2008 John Birrell jb@freebsd.org
 * Portions Copyright 2013 Justin Hibbits jhibbits@freebsd.org
 * Portions Copyright 2013 Howard Su howardsu@freebsd.org
 *
 */

/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/param.h>

#include <sys/dtrace.h>
#include <machine/stack.h>
#include <machine/trap.h>

#include "fbt.h"

#define FBT_PUSHM               0xe92d0000
#define FBT_POPM                0xe8bd0000
#define FBT_JUMP                0xea000000
#define FBT_SUBSP               0xe24dd000

int
fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval)
{
        solaris_cpu_t *cpu = &solaris_cpu[curcpu];
        fbt_probe_t *fbt = fbt_probetab[FBT_ADDR2NDX(addr)];
        register_t fifthparam;

        for (; fbt != NULL; fbt = fbt->fbtp_hashnext) {
                if ((uintptr_t)fbt->fbtp_patchpoint != addr)
                        continue;

                cpu->cpu_dtrace_caller = addr;

                if (fbt->fbtp_roffset == 0) {
                        /* Get 5th parameter from stack */
                        DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
                        fifthparam = *(register_t *)frame->tf_svc_sp;
                        DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT | CPU_DTRACE_BADADDR);

                        dtrace_probe(fbt->fbtp_id, frame->tf_r0,
                            frame->tf_r1, frame->tf_r2,
                            frame->tf_r3, fifthparam);
                } else {
                        dtrace_probe(fbt->fbtp_id, fbt->fbtp_roffset, rval,
                            0, 0, 0);
                }

                cpu->cpu_dtrace_caller = 0;
                return (fbt->fbtp_rval | (fbt->fbtp_savedval << DTRACE_INVOP_SHIFT));
        }

        return (0);
}

void
fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val)
{

        *fbt->fbtp_patchpoint = val;
        icache_sync((vm_offset_t)fbt->fbtp_patchpoint, sizeof(val));
}

int
fbt_provide_module_function(linker_file_t lf, int symindx,
    linker_symval_t *symval, void *opaque)
{
        char *modname = opaque;
        const char *name = symval->name;
        fbt_probe_t *fbt, *retfbt;
        uint32_t *instr, *limit;
        int popm;

        if (fbt_excluded(name))
                return (0);

        instr = (uint32_t *)symval->value;
        limit = (uint32_t *)(symval->value + symval->size);

        /*
         * va_arg functions has first instruction of
         * sub sp, sp, #?
         */
        if ((*instr & 0xfffff000) == FBT_SUBSP)
                instr++;

        /*
         * check if insn is a pushm with LR
         */
        if ((*instr & 0xffff0000) != FBT_PUSHM ||
            (*instr & (1 << LR)) == 0)
                return (0);

        fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
        fbt->fbtp_name = name;
        fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
            name, FBT_ENTRY, 2, fbt);
        fbt->fbtp_patchpoint = instr;
        fbt->fbtp_ctl = lf;
        fbt->fbtp_loadcnt = lf->loadcnt;
        fbt->fbtp_savedval = *instr;
        fbt->fbtp_patchval = FBT_BREAKPOINT;
        fbt->fbtp_rval = DTRACE_INVOP_PUSHM;
        fbt->fbtp_symindx = symindx;

        fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
        fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;

        lf->fbt_nentries++;

        popm = FBT_POPM | ((*instr) & 0x3FFF) | 0x8000;

        retfbt = NULL;
again:
        for (; instr < limit; instr++) {
                if (*instr == popm)
                        break;
                else if ((*instr & 0xff000000) == FBT_JUMP) {
                        uint32_t *target, *start;
                        int offset;

                        offset = (*instr & 0xffffff);
                        offset <<= 8;
                        offset /= 64;
                        target = instr + (2 + offset);
                        start = (uint32_t *)symval->value;
                        if (target >= limit || target < start)
                                break;
                }
        }

        if (instr >= limit)
                return (0);

        /*
         * We have a winner!
         */
        fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
        fbt->fbtp_name = name;
        if (retfbt == NULL) {
                fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
                    name, FBT_RETURN, 2, fbt);
        } else {
                retfbt->fbtp_probenext = fbt;
                fbt->fbtp_id = retfbt->fbtp_id;
        }
        retfbt = fbt;

        fbt->fbtp_patchpoint = instr;
        fbt->fbtp_ctl = lf;
        fbt->fbtp_loadcnt = lf->loadcnt;
        fbt->fbtp_symindx = symindx;
        if ((*instr & 0xff000000) == FBT_JUMP)
                fbt->fbtp_rval = DTRACE_INVOP_B;
        else
                fbt->fbtp_rval = DTRACE_INVOP_POPM;
        fbt->fbtp_roffset = (uintptr_t)instr - (uintptr_t)symval->value;
        fbt->fbtp_savedval = *instr;
        fbt->fbtp_patchval = FBT_BREAKPOINT;
        fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
        fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;

        lf->fbt_nentries++;

        instr++;
        goto again;
}