/*      $NetBSD: db_machdep.c,v 1.15 2022/12/24 14:47:47 uwe Exp $      */

/*
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: db_machdep.c,v 1.15 2022/12/24 14:47:47 uwe Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/syscall.h>

#include <machine/frame.h>
#include <machine/trap.h>
#include <machine/intrdefs.h>

#include <machine/db_machdep.h>
#include <ddb/db_sym.h>
#include <ddb/db_access.h>
#include <ddb/db_variables.h>
#include <ddb/db_output.h>
#include <ddb/db_interface.h>
#include <ddb/db_user.h>
#include <ddb/db_proc.h>
#include <ddb/db_command.h>
#include <x86/db_machdep.h>

#define dbreg(xx) (long *)offsetof(db_regs_t, tf_ ## xx)

/*
 * Machine register set.
 */
const struct db_variable db_regs[] = {
        { "ds",         dbreg(ds),     db_x86_regop, NULL },
        { "es",         dbreg(es),     db_x86_regop, NULL },
        { "fs",         dbreg(fs),     db_x86_regop, NULL },
        { "gs",         dbreg(gs),     db_x86_regop, NULL },
        { "rdi",        dbreg(rdi),    db_x86_regop, NULL },
        { "rsi",        dbreg(rsi),    db_x86_regop, NULL },
        { "rbp",        dbreg(rbp),    db_x86_regop, NULL },
        { "rbx",        dbreg(rbx),    db_x86_regop, NULL },
        { "rdx",        dbreg(rdx),    db_x86_regop, NULL },
        { "rcx",        dbreg(rcx),    db_x86_regop, NULL },
        { "rax",        dbreg(rax),    db_x86_regop, NULL },
        { "r8",         dbreg(r8),     db_x86_regop, NULL },
        { "r9",         dbreg(r9),     db_x86_regop, NULL },
        { "r10",        dbreg(r10),    db_x86_regop, NULL },
        { "r11",        dbreg(r11),    db_x86_regop, NULL },
        { "r12",        dbreg(r12),    db_x86_regop, NULL },
        { "r13",        dbreg(r13),    db_x86_regop, NULL },
        { "r14",        dbreg(r14),    db_x86_regop, NULL },
        { "r15",        dbreg(r15),    db_x86_regop, NULL },
        { "rip",        dbreg(rip),    db_x86_regop, NULL },
        { "cs",         dbreg(cs),     db_x86_regop, NULL },
        { "rflags",     dbreg(rflags), db_x86_regop, NULL },
        { "rsp",        dbreg(rsp),    db_x86_regop, NULL },
        { "ss",         dbreg(ss),     db_x86_regop, NULL },
};
const struct db_variable * const db_eregs =
    db_regs + sizeof(db_regs)/sizeof(db_regs[0]);

/*
 * Figure out how many arguments were passed into the frame at "fp".
 * We can probably figure out how many arguments where passed above
 * the first 6 (which are in registers), but since we can't
 * reliably determine the values currently, just return 0.
 */
int
db_numargs(long *retaddrp)
{
        return 0;
}

/*
 * Figure out the next frame up in the call stack.
 * For trap(), we print the address of the faulting instruction and
 *   proceed with the calling frame.  We return the ip that faulted.
 *   If the trap was caused by jumping through a bogus pointer, then
 *   the next line in the backtrace will list some random function as
 *   being called.  It should get the argument list correct, though.
 *   It might be possible to dig out from the next frame up the name
 *   of the function that faulted, but that could get hairy.
 */
int
db_nextframe(long **nextframe, long **retaddr, long **arg0, db_addr_t *ip,
    long *argp, int is_trap, void (*pr)(const char *, ...))
{
        struct trapframe *tf;
        struct x86_64_frame *fp;
        struct intrframe *ifp;
        int trapno, err, i;
        db_expr_t syscallno;

        switch (is_trap) {
            case NONE:
                *ip = (db_addr_t)
                        db_get_value((long)*retaddr, 8, false);
                fp = (struct x86_64_frame *)
                        db_get_value((long)*nextframe, 8, false);
                if (fp == NULL)
                        return 0;
                *nextframe = (long *)&fp->f_frame;
                *retaddr = (long *)&fp->f_retaddr;
                *arg0 = (long *)&fp->f_arg0;
                break;

            case SYSCALL:
                tf = (struct trapframe *)argp;
                syscallno = db_get_value((long)&tf->tf_rax, 8, false);
                if (syscallno == SYS_syscall || syscallno == SYS___syscall) {
                        syscallno = db_get_value((long)&tf->tf_rdi, 8, false);
                        (*pr)("--- syscall (number %"DDB_EXPR_FMT"u"
                            " via SYS_syscall) ---\n",
                            syscallno);
                } else {
                        (*pr)("--- syscall (number %"DDB_EXPR_FMT"u) ---\n",
                            syscallno);
                }
                return 0;

            case TRAP:
            case INTERRUPT:
            default:

                /* The only argument to trap() is the trapframe. */
                tf = (struct trapframe *)argp;
                switch (is_trap) {
                case TRAP:
                        (*pr)("--- trap (number %"DDB_EXPR_FMT"u) ---\n",
                                db_get_value((long)&tf->tf_trapno, 8, false));
                        break;
                case INTERRUPT:
                        (*pr)("--- interrupt ---\n");
                        break;
                }
                *ip = (db_addr_t)db_get_value((long)&tf->tf_rip, 8, false);
                fp = (struct x86_64_frame *)
                        db_get_value((long)&tf->tf_rbp, 8, false);
                if (fp == NULL)
                        return 0;
                if (((uintptr_t)fp & 7) != 0)
                        return 0;
                *nextframe = (long *)&fp->f_frame;
                *retaddr = (long *)&fp->f_retaddr;
                *arg0 = (long *)&fp->f_arg0;
                break;
        }

        /*
         * A bit of a hack. Since %rbp may be used in the stub code,
         * walk the stack looking for a valid interrupt frame. Such
         * a frame can be recognized by always having
         * err 0 or IREENT_MAGIC and trapno T_ASTFLT.
         */
        int traptype = NONE;
        db_sym_t sym = db_frame_info(*nextframe, (db_addr_t)*ip,
                                     NULL, NULL, &traptype, NULL);
        if (sym != DB_SYM_NULL && traptype == INTERRUPT) {
                for (i = 0; i < 4; i++) {
                        ifp = (struct intrframe *)(argp + i);
                        err = db_get_value((long)&ifp->if_tf.tf_err,
                            sizeof(long), false);
                        trapno = db_get_value((long)&ifp->if_tf.tf_trapno,
                            sizeof(long), false);
                        if ((err == 0 || err == IREENT_MAGIC)
                            && trapno == T_ASTFLT) {
                                *nextframe = (long *)ifp - 1;
                                break;
                        }
                }
                if (i == 4) {
                        (*pr)("DDB lost frame for ");
                        db_printsym(*ip, DB_STGY_ANY, pr);
                        (*pr)(", trying %p\n",argp);
                        *nextframe = argp;
                }
        }
        return 1;
}

db_sym_t
db_frame_info(long *frame, db_addr_t callpc, const char **namep,
    db_expr_t *offp, int *is_trap, int *nargp)
{
        db_expr_t offset;
        db_sym_t sym;
        int narg;
        const char *name;

        sym = db_search_symbol(callpc, DB_STGY_ANY, &offset);
        if (sym != DB_SYM_NULL && offset == 0) {
                sym = db_search_symbol(callpc - 1, DB_STGY_ANY, &offset);
                offset++;
        }
        db_symbol_values(sym, &name, NULL);
        if (sym == DB_SYM_NULL)
                return DB_SYM_NULL;

        *is_trap = NONE;
        narg = 0;

        if (INKERNEL((long)frame) && name) {
                /*
                 * XXX traps should be based off of the Xtrap*
                 * locations rather than on trap, since some traps
                 * (e.g., npxdna) don't go through trap()
                 */
                if (!strcmp(name, "trap")) {
                        *is_trap = TRAP;
                        narg = 0;
                } else if (!strcmp(name, "syscall") ||
                    !strcmp(name, "handle_syscall")) {
                        *is_trap = SYSCALL;
                        narg = 0;
                } else if (name[0] == 'X') {
                        if (!strncmp(name, "Xintr", 5) ||
                            !strncmp(name, "Xhandle", 7) ||
                            !strncmp(name, "Xresume", 7) ||
                            !strncmp(name, "Xstray", 6) ||
                            !strncmp(name, "Xhold", 5) ||
                            !strncmp(name, "Xrecurse", 8) ||
                            !strcmp(name, "Xdoreti") ||
                            !strncmp(name, "Xsoft", 5)) {
                                *is_trap = INTERRUPT;
                                narg = 0;
                        }
                }
        }

        if (offp != NULL)
                *offp = offset;
        if (nargp != NULL)
                *nargp = narg;
        if (namep != NULL)
                *namep = name;
        return sym;
}