/*-
 * 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
 * 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/param.h>
#include <sys/systm.h>
#include <sys/kdb.h>
#include <sys/proc.h>
#include <sys/reg.h>
#include <sys/smp.h>
#include <sys/stack.h>

#include <machine/cpu.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/stack.h>

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

#include <ddb/ddb.h>
#include <ddb/db_access.h>
#include <ddb/db_sym.h>
#include <ddb/db_variables.h>

static db_varfcn_t db_frame;
static db_varfcn_t db_frame_seg;

CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg));

/*
 * Machine register set.
 */
#define DB_OFFSET(x)    (db_expr_t *)offsetof(struct trapframe, x)
struct db_variable db_regs[] = {
        { "cs",         DB_OFFSET(tf_cs),       db_frame_seg },
        { "ds",         DB_OFFSET(tf_ds),       db_frame_seg },
        { "es",         DB_OFFSET(tf_es),       db_frame_seg },
        { "fs",         DB_OFFSET(tf_fs),       db_frame_seg },
        { "gs",         DB_OFFSET(tf_gs),       db_frame_seg },
        { "ss",         DB_OFFSET(tf_ss),       db_frame_seg },
        { "rax",        DB_OFFSET(tf_rax),      db_frame },
        { "rcx",        DB_OFFSET(tf_rcx),      db_frame },
        { "rdx",        DB_OFFSET(tf_rdx),      db_frame },
        { "rbx",        DB_OFFSET(tf_rbx),      db_frame },
        { "rsp",        DB_OFFSET(tf_rsp),      db_frame },
        { "rbp",        DB_OFFSET(tf_rbp),      db_frame },
        { "rsi",        DB_OFFSET(tf_rsi),      db_frame },
        { "rdi",        DB_OFFSET(tf_rdi),      db_frame },
        { "r8",         DB_OFFSET(tf_r8),       db_frame },
        { "r9",         DB_OFFSET(tf_r9),       db_frame },
        { "r10",        DB_OFFSET(tf_r10),      db_frame },
        { "r11",        DB_OFFSET(tf_r11),      db_frame },
        { "r12",        DB_OFFSET(tf_r12),      db_frame },
        { "r13",        DB_OFFSET(tf_r13),      db_frame },
        { "r14",        DB_OFFSET(tf_r14),      db_frame },
        { "r15",        DB_OFFSET(tf_r15),      db_frame },
        { "rip",        DB_OFFSET(tf_rip),      db_frame },
        { "rflags",     DB_OFFSET(tf_rflags),   db_frame },
};
struct db_variable *db_eregs = db_regs + nitems(db_regs);

static int
db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
{
        uint16_t *reg;

        if (kdb_frame == NULL)
                return (0);

        reg = (uint16_t *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
        if (op == DB_VAR_GET)
                *valuep = *reg;
        else
                *reg = *valuep;
        return (1);
}

static int
db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
{
        long *reg;

        if (kdb_frame == NULL)
                return (0);

        reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
        if (op == DB_VAR_GET)
                *valuep = *reg;
        else
                *reg = *valuep;
        return (1);
}

#define NORMAL          0
#define TRAP            1
#define INTERRUPT       2
#define SYSCALL         3

static void
db_print_stack_entry(const char *name, db_addr_t callpc, db_addr_t frame)
{

        db_printf("%s() at ", name != NULL ? name : "??");
        db_printsym(callpc, DB_STGY_PROC);
        if (frame != 0)
                db_printf("/frame %#lx", frame);
        db_printf("\n");
}

/*
 * Figure out the next frame up in the call stack.
 */
static void
db_nextframe(db_addr_t *fp, db_addr_t *ip, struct thread *td)
{
        struct trapframe *tf;
        db_addr_t tf_addr;
        int frame_type;
        long rip, rsp, rbp;
        db_expr_t offset;
        c_db_sym_t sym;
        const char *name;

        rip = db_get_value(*fp + offsetof(struct amd64_frame, f_retaddr), 8,
            false);
        rbp = db_get_value(*fp + offsetof(struct amd64_frame, f_frame), 8,
            false);

        /*
         * Figure out frame type.  We look at the address just before
         * the saved instruction pointer as the saved EIP is after the
         * call function, and if the function being called is marked as
         * dead (such as panic() at the end of dblfault_handler()), then
         * the instruction at the saved EIP will be part of a different
         * function (syscall() in this example) rather than the one that
         * actually made the call.
         */
        frame_type = NORMAL;
        sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset);
        db_symbol_values(sym, &name, NULL);
        if (name != NULL) {
                if (strcmp(name, "calltrap") == 0 ||
                    strcmp(name, "fork_trampoline") == 0 ||
                    strcmp(name, "mchk_calltrap") == 0 ||
                    strcmp(name, "nmi_calltrap") == 0 ||
                    strcmp(name, "Xdblfault") == 0)
                        frame_type = TRAP;
                else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
                    strncmp(name, "Xapic_isr", 9) == 0 ||
                    strcmp(name, "Xxen_intr_upcall") == 0 ||
                    strcmp(name, "Xtimerint") == 0 ||
                    strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
                    strcmp(name, "Xcpustop") == 0 ||
                    strcmp(name, "Xcpususpend") == 0 ||
                    strcmp(name, "Xrendezvous") == 0)
                        frame_type = INTERRUPT;
                else if (strcmp(name, "Xfast_syscall") == 0 ||
                    strcmp(name, "Xfast_syscall_pti") == 0 ||
                    strcmp(name, "fast_syscall_common") == 0)
                        frame_type = SYSCALL;
#ifdef COMPAT_FREEBSD32
                else if (strcmp(name, "Xint0x80_syscall") == 0)
                        frame_type = SYSCALL;
#endif
        }

        /*
         * Normal frames need no special processing.
         */
        if (frame_type == NORMAL) {
                *ip = rip;
                *fp = rbp;
                return;
        }

        db_print_stack_entry(name, rip, *fp);

        /*
         * Point to base of trapframe which is just above the
         * current frame.
         */
        tf_addr = *fp + 16;

        if (!__is_aligned(tf_addr, _Alignof(struct trapframe)) ||
            !INKERNEL(tf_addr)) {
                db_printf("--- invalid trapframe %p\n", (void *)tf_addr);
                *ip = 0;
                *fp = 0;
                return;
        }
        tf = (struct trapframe *)tf_addr;

        rsp = tf->tf_rsp;
        rip = tf->tf_rip;
        rbp = tf->tf_rbp;
        switch (frame_type) {
        case TRAP:
                db_printf("--- trap %#r", tf->tf_trapno);
                break;
        case SYSCALL:
                db_printf("--- syscall");
                db_decode_syscall(td, tf->tf_rax);
                break;
        case INTERRUPT:
                db_printf("--- interrupt");
                break;
        default:
                __assert_unreachable();
        }
        db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip, rsp, rbp);

        *ip = rip;
        *fp = rbp;
}

static int __nosanitizeaddress __nosanitizememory
db_backtrace(struct thread *td, struct trapframe *tf, db_addr_t frame,
    db_addr_t pc, register_t sp, int count)
{
        db_addr_t actframe;
        const char *name;
        db_expr_t offset;
        c_db_sym_t sym;
        bool first;

        if (count == -1)
                count = 1024;

        first = true;
        while (count-- && !db_pager_quit) {
                sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
                db_symbol_values(sym, &name, NULL);

                /*
                 * Attempt to determine a (possibly fake) frame that gives
                 * the caller's pc.  It may differ from `frame' if the
                 * current function never sets up a standard frame or hasn't
                 * set one up yet or has just discarded one.  The last two
                 * cases can be guessed fairly reliably for code generated
                 * by gcc.  The first case is too much trouble to handle in
                 * general because the amount of junk on the stack depends
                 * on the pc (the special handling of "calltrap", etc. in
                 * db_nextframe() works because the `next' pc is special).
                 */
                actframe = frame;
                if (first) {
                        first = false;
                        if (sym == C_DB_SYM_NULL && sp != 0) {
                                /*
                                 * If a symbol couldn't be found, we've probably
                                 * jumped to a bogus location, so try and use
                                 * the return address to find our caller.
                                 */
                                db_print_stack_entry(name, pc, 0);
                                pc = db_get_value(sp, 8, false);
                                if (db_search_symbol(pc, DB_STGY_PROC,
                                    &offset) == C_DB_SYM_NULL)
                                        break;
                                continue;
                        } else if (tf != NULL) {
                                int instr;

                                instr = db_get_value(pc, 4, false);
                                if ((instr & 0xffffffff) == 0xe5894855) {
                                        /* pushq %rbp; movq %rsp, %rbp */
                                        actframe = tf->tf_rsp - 8;
                                } else if ((instr & 0xffffff) == 0xe58948) {
                                        /* movq %rsp, %rbp */
                                        actframe = tf->tf_rsp;
                                        if (tf->tf_rbp == 0) {
                                                /* Fake frame better. */
                                                frame = actframe;
                                        }
                                } else if ((instr & 0xff) == 0xc3) {
                                        /* ret */
                                        actframe = tf->tf_rsp - 8;
                                } else if (offset == 0) {
                                        /* Probably an assembler symbol. */
                                        actframe = tf->tf_rsp - 8;
                                }
                        } else if (name != NULL &&
                            strcmp(name, "fork_trampoline") == 0) {
                                /*
                                 * Don't try to walk back on a stack for a
                                 * process that hasn't actually been run yet.
                                 */
                                db_print_stack_entry(name, pc, actframe);
                                break;
                        }
                }

                db_print_stack_entry(name, pc, actframe);

                if (actframe != frame) {
                        /* `frame' belongs to caller. */
                        pc = db_get_value(actframe +
                            offsetof(struct amd64_frame, f_retaddr), 8, false);
                        continue;
                }

                db_nextframe(&frame, &pc, td);
                if (frame == 0)
                        break;

                if (!__is_aligned(frame, _Alignof(struct amd64_frame)) ||
                    !INKERNEL(frame)) {
                        if (INKERNEL(pc)) {
                                sym = db_search_symbol(pc, DB_STGY_ANY,
                                    &offset);
                                db_symbol_values(sym, &name, NULL);
                                db_print_stack_entry(name, pc, frame);
                                break;
                        }
                        break;
                }
        }

        return (0);
}

void
db_trace_self(void)
{
        db_addr_t callpc, frame;
        register_t rbp;

        __asm __volatile("movq %%rbp,%0" : "=r" (rbp));
        callpc = db_get_value(rbp + offsetof(struct amd64_frame, f_retaddr), 8,
            false);
        frame = db_get_value(rbp + offsetof(struct amd64_frame, f_frame), 8,
            false);
        db_backtrace(curthread, NULL, frame, callpc, 0, -1);
}

int
db_trace_thread(struct thread *thr, int count)
{
        struct pcb *ctx;
        struct trapframe *tf;

        ctx = kdb_thr_ctx(thr);
        tf = thr == kdb_thread ? kdb_frame : NULL;
        return (db_backtrace(thr, tf, ctx->pcb_rbp, ctx->pcb_rip, ctx->pcb_rsp,
            count));
}

void
db_md_list_watchpoints(void)
{

        dbreg_list_watchpoints();
}