/*      $NetBSD: db_trace.c,v 1.33 2018/01/24 09:04:44 skrll Exp $      */

/*
 * Copyright (c) 2000, 2001 Ben Harris
 * Copyright (c) 1996 Scott K. Stevens
 *
 * 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/param.h>

__KERNEL_RCSID(0, "$NetBSD: db_trace.c,v 1.33 2018/01/24 09:04:44 skrll Exp $");

#include <sys/proc.h>
#include <arm/armreg.h>
#include <arm/cpufunc.h>
#include <arm/pcb.h>
#include <machine/db_machdep.h>
#include <machine/vmparam.h>

#include <ddb/db_access.h>
#include <ddb/db_interface.h>
#include <ddb/db_sym.h>
#include <ddb/db_proc.h>
#include <ddb/db_output.h>

#define INKERNEL(va)    (((vaddr_t)(va)) >= VM_MIN_KERNEL_ADDRESS)

/*
 * APCS stack frames are awkward beasts, so I don't think even trying to use
 * a structure to represent them is a good idea.
 *
 * Here's the diagram from the APCS.  Increasing address is _up_ the page.
 *
 *          save code pointer       [fp]        <- fp points to here
 *          return link value       [fp, #-4]
 *          return sp value         [fp, #-8]
 *          return fp value         [fp, #-12]
 *          [saved v7 value]
 *          [saved v6 value]
 *          [saved v5 value]
 *          [saved v4 value]
 *          [saved v3 value]
 *          [saved v2 value]
 *          [saved v1 value]
 *          [saved a4 value]
 *          [saved a3 value]
 *          [saved a2 value]
 *          [saved a1 value]
 *
 * The save code pointer points twelve bytes beyond the start of the
 * code sequence (usually a single STM) that created the stack frame.
 * We have to disassemble it if we want to know which of the optional
 * fields are actually present.
 */

#define FR_SCP  (0)
#define FR_RLV  (-1)
#define FR_RSP  (-2)
#define FR_RFP  (-3)

void
db_stack_trace_print(db_expr_t addr, bool have_addr,
                db_expr_t count, const char *modif,
                void (*pr)(const char *, ...))
{
        struct trapframe *tf = NULL;
        uint32_t        *frame, *lastframe;
        const char      *cp = modif;
        char c;
        bool            kernel_only = true;
        bool            trace_thread = false;
        bool            trace_full = false;
        bool            lwpaddr = false;
        db_addr_t       scp, pc;
        int             scp_offset;

        while ((c = *cp++) != 0) {
                if (c == 'a') {
                        lwpaddr = true;
                        trace_thread = true;
                }
                if (c == 'u')
                        kernel_only = false;
                if (c == 't')
                        trace_thread = true;
                if (c == 'f')
                        trace_full = true;
        }

#ifdef _KERNEL
        if (!have_addr)
                frame = (uint32_t *)(DDB_REGS->tf_r11);
        else
#endif
        {
                if (trace_thread) {
                        struct pcb *pcb;
                        proc_t p;
                        lwp_t l;

                        if (lwpaddr) {
                                db_read_bytes(addr, sizeof(l),
                                    (char *)&l);
                                db_read_bytes((db_addr_t)l.l_proc,
                                    sizeof(p), (char *)&p);
                                (*pr)("trace: pid %d ", p.p_pid);
                        } else {
                                proc_t  *pp;

                                (*pr)("trace: pid %d ", (int)addr);
                                if ((pp = db_proc_find((pid_t)addr)) == 0) {
                                        (*pr)("not found\n");
                                        return;
                                }
                                db_read_bytes((db_addr_t)pp, sizeof(p), (char *)&p);
                                addr = (db_addr_t)p.p_lwps.lh_first;
                                db_read_bytes(addr, sizeof(l), (char *)&l);
                        }
                        (*pr)("lid %d ", l.l_lid);
                        pcb = lwp_getpcb(&l);
                        tf = lwp_trapframe(&l);
#ifndef _KERNEL
                        struct pcb pcbb;
                        db_read_bytes((db_addr_t)pcb, sizeof(*pcb),
                            (char *)&pcbb);
                        pcb = &pcbb;
#endif
                        frame = (uint32_t *)(pcb->pcb_r11);
                        (*pr)("at %p\n", frame);
                } else
                        frame = (uint32_t *)(addr);
        }
        scp_offset = -(get_pc_str_offset() >> 2);

        if (frame == NULL)
                return;

        lastframe = frame;
#ifndef _KERNEL
        uint32_t frameb[4];
        db_read_bytes((db_addr_t)(frame - 3), sizeof(frameb),
            (char *)frameb);
        frame = frameb + 3;
#endif

        /*
         * In theory, the SCP isn't guaranteed to be in the function
         * that generated the stack frame.  We hope for the best.
         */
        scp = frame[FR_SCP];
        pc = scp;

        while (count--) {
                uint32_t        savecode;
                int             r;
                uint32_t        *rp;
                const char      *sep;

                scp = frame[FR_SCP];
                (*pr)("%p: ", lastframe);

                db_printsym(pc, DB_STGY_PROC, pr);
                if (trace_full) {
                        (*pr)("\n\t");
                        (*pr)("pc =0x%08x rlv=0x%08x (", pc, frame[FR_RLV]);
                        db_printsym(frame[FR_RLV], DB_STGY_PROC, pr);
                        (*pr)(")\n");
                        (*pr)("\trsp=0x%08x rfp=0x%08x", frame[FR_RSP],
                             frame[FR_RFP]);
                }

#ifndef _KERNEL
                db_read_bytes((db_addr_t)((uint32_t *)scp + scp_offset),
                    sizeof(savecode), (void *)&savecode);
#else
                if ((scp & 3) == 0) {
                        savecode = ((uint32_t *)scp)[scp_offset];
                } else {
                        savecode = 0;
                }
#endif
                if (trace_full &&
                    (savecode & 0x0e100000) == 0x08000000) {
                        /* Looks like an STM */
                        rp = frame - 4;
                        sep = "\n\t";
                        for (r = 10; r >= 0; r--) {
                                if (savecode & (1 << r)) {
                                        (*pr)("%sr%d=0x%08x",
                                            sep, r, *rp--);
                                        sep = (frame - rp) % 4 == 2 ?
                                            "\n\t" : " ";
                                }
                        }
                }

                (*pr)("\n");
                /*
                 * Switch to next frame up
                 */
                if (frame[FR_RFP] == 0)
                        break; /* Top of stack */
                pc = frame[FR_RLV];

                frame = (uint32_t *)(frame[FR_RFP]);

                if (frame == NULL)
                        break;

                if (INKERNEL((int)frame)) {
                        /* staying in kernel */
                        if (frame <= lastframe) {
                                (*pr)("Bad frame pointer: %p\n", frame);
                                break;
                        }
                } else if (INKERNEL((int)lastframe)) {
                        if (trace_thread) {
                                (*pr)("--- tf %p ---\n", tf);
                        }
                        /* switch from user to kernel */
                        if (kernel_only)
                                break;  /* kernel stack only */
                } else {
                        /* in user */
                        if (frame <= lastframe) {
                                (*pr)("Bad user frame pointer: %p\n",
                                          frame);
                                break;
                        }
                }
                lastframe = frame;
#ifndef _KERNEL
                db_read_bytes((db_addr_t)(frame - 3), sizeof(frameb),
                    (char *)frameb);
                frame = frameb + 3;
#endif
        }
}