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db_interface.c revision 1.1
      1 /*	$NetBSD: db_interface.c,v 1.1 2001/03/04 05:11:41 matt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1996 Scott K. Stevens
      5  *
      6  * Mach Operating System
      7  * Copyright (c) 1991,1990 Carnegie Mellon University
      8  * All Rights Reserved.
      9  *
     10  * Permission to use, copy, modify and distribute this software and its
     11  * documentation is hereby granted, provided that both the copyright
     12  * notice and this permission notice appear in all copies of the
     13  * software, derivative works or modified versions, and any portions
     14  * thereof, and that both notices appear in supporting documentation.
     15  *
     16  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
     17  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     18  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     19  *
     20  * Carnegie Mellon requests users of this software to return to
     21  *
     22  *  Software Distribution Coordinator  or  Software.Distribution (at) CS.CMU.EDU
     23  *  School of Computer Science
     24  *  Carnegie Mellon University
     25  *  Pittsburgh PA 15213-3890
     26  *
     27  * any improvements or extensions that they make and grant Carnegie the
     28  * rights to redistribute these changes.
     29  *
     30  *	From: db_interface.c,v 2.4 1991/02/05 17:11:13 mrt (CMU)
     31  */
     32 
     33 /*
     34  * Interface to new debugger.
     35  */
     36 #include "opt_ddb.h"
     37 
     38 #include <sys/param.h>
     39 #include <sys/proc.h>
     40 #include <sys/reboot.h>
     41 #include <sys/systm.h>	/* just for boothowto */
     42 #include <sys/exec.h>
     43 
     44 #include <uvm/uvm_extern.h>
     45 
     46 #include <machine/db_machdep.h>
     47 #include <machine/katelib.h>
     48 #include <machine/pte.h>
     49 #include <machine/undefined.h>
     50 #include <ddb/db_command.h>
     51 #include <ddb/db_output.h>
     52 #include <ddb/db_variables.h>
     53 #include <ddb/db_sym.h>
     54 #include <ddb/db_extern.h>
     55 #include <ddb/db_interface.h>
     56 #include <dev/cons.h>
     57 
     58 static int nil;
     59 
     60 int db_access_und_sp __P((const struct db_variable *, db_expr_t *, int));
     61 int db_access_abt_sp __P((const struct db_variable *, db_expr_t *, int));
     62 int db_access_irq_sp __P((const struct db_variable *, db_expr_t *, int));
     63 u_int db_fetch_reg __P((int, db_regs_t *));
     64 
     65 const struct db_variable db_regs[] = {
     66 	{ "spsr", (long *)&DDB_REGS->tf_spsr, FCN_NULL, },
     67 	{ "r0", (long *)&DDB_REGS->tf_r0, FCN_NULL, },
     68 	{ "r1", (long *)&DDB_REGS->tf_r1, FCN_NULL, },
     69 	{ "r2", (long *)&DDB_REGS->tf_r2, FCN_NULL, },
     70 	{ "r3", (long *)&DDB_REGS->tf_r3, FCN_NULL, },
     71 	{ "r4", (long *)&DDB_REGS->tf_r4, FCN_NULL, },
     72 	{ "r5", (long *)&DDB_REGS->tf_r5, FCN_NULL, },
     73 	{ "r6", (long *)&DDB_REGS->tf_r6, FCN_NULL, },
     74 	{ "r7", (long *)&DDB_REGS->tf_r7, FCN_NULL, },
     75 	{ "r8", (long *)&DDB_REGS->tf_r8, FCN_NULL, },
     76 	{ "r9", (long *)&DDB_REGS->tf_r9, FCN_NULL, },
     77 	{ "r10", (long *)&DDB_REGS->tf_r10, FCN_NULL, },
     78 	{ "r11", (long *)&DDB_REGS->tf_r11, FCN_NULL, },
     79 	{ "r12", (long *)&DDB_REGS->tf_r12, FCN_NULL, },
     80 	{ "usr_sp", (long *)&DDB_REGS->tf_usr_sp, FCN_NULL, },
     81 	{ "usr_lr", (long *)&DDB_REGS->tf_usr_lr, FCN_NULL, },
     82 	{ "svc_sp", (long *)&DDB_REGS->tf_svc_sp, FCN_NULL, },
     83 	{ "svc_lr", (long *)&DDB_REGS->tf_svc_lr, FCN_NULL, },
     84 	{ "pc", (long *)&DDB_REGS->tf_pc, FCN_NULL, },
     85 	{ "und_sp", (long *)&nil, db_access_und_sp, },
     86 	{ "abt_sp", (long *)&nil, db_access_abt_sp, },
     87 	{ "irq_sp", (long *)&nil, db_access_irq_sp, },
     88 };
     89 
     90 const struct db_variable * const db_eregs = db_regs + sizeof(db_regs)/sizeof(db_regs[0]);
     91 
     92 extern label_t	*db_recover;
     93 
     94 int	db_active = 0;
     95 
     96 int db_access_und_sp(vp, valp, rw)
     97 	const struct db_variable *vp;
     98 	db_expr_t *valp;
     99 	int rw;
    100 {
    101 	if (rw == DB_VAR_GET)
    102 		*valp = get_stackptr(PSR_UND32_MODE);
    103 	return(0);
    104 }
    105 
    106 int db_access_abt_sp(vp, valp, rw)
    107 	const struct db_variable *vp;
    108 	db_expr_t *valp;
    109 	int rw;
    110 {
    111 	if (rw == DB_VAR_GET)
    112 		*valp = get_stackptr(PSR_ABT32_MODE);
    113 	return(0);
    114 }
    115 
    116 int db_access_irq_sp(vp, valp, rw)
    117 	const struct db_variable *vp;
    118 	db_expr_t *valp;
    119 	int rw;
    120 {
    121 	if (rw == DB_VAR_GET)
    122 		*valp = get_stackptr(PSR_IRQ32_MODE);
    123 	return(0);
    124 }
    125 
    126 /*
    127  *  kdb_trap - field a TRACE or BPT trap
    128  */
    129 int
    130 kdb_trap(type, regs)
    131 	int type;
    132 	db_regs_t *regs;
    133 {
    134 	int s;
    135 
    136 	switch (type) {
    137 	case T_BREAKPOINT:	/* breakpoint */
    138 	case -1:		/* keyboard interrupt */
    139 		break;
    140 	default:
    141 		db_printf("kernel: trap");
    142 		if (db_recover != 0) {
    143 			db_error("Faulted in DDB; continuing...\n");
    144 			/*NOTREACHED*/
    145 		}
    146 	}
    147 
    148 	/* Should switch to kdb`s own stack here. */
    149 
    150 	ddb_regs = *regs;
    151 
    152 	s = splhigh();
    153 	db_active++;
    154 	cnpollc(TRUE);
    155 	db_trap(type, 0/*code*/);
    156 	cnpollc(FALSE);
    157 	db_active--;
    158 	splx(s);
    159 
    160 	*regs = ddb_regs;
    161 
    162 	return (1);
    163 }
    164 
    165 
    166 /*
    167  * Received keyboard interrupt sequence.
    168  */
    169 void
    170 kdb_kbd_trap(regs)
    171 	db_regs_t *regs;
    172 {
    173 	if (db_active == 0 && (boothowto & RB_KDB)) {
    174 		printf("\n\nkernel: keyboard interrupt\n");
    175 		kdb_trap(-1, regs);
    176 	}
    177 }
    178 
    179 
    180 static int
    181 db_validate_address(addr)
    182 	vm_offset_t addr;
    183 {
    184 	pt_entry_t *ptep;
    185 	pd_entry_t *pdep;
    186 	struct proc *p = curproc;
    187 
    188 	/*
    189 	 * If we have a valid pmap for curproc, use it's page directory
    190 	 * otherwise use the kernel pmap's page directory.
    191 	 */
    192 	if (!p || !p->p_vmspace || !p->p_vmspace->vm_map.pmap)
    193 		pdep = kernel_pmap->pm_pdir;
    194 	else
    195 		pdep = p->p_vmspace->vm_map.pmap->pm_pdir;
    196 
    197 	/* Make sure the address we are reading is valid */
    198 	switch ((pdep[(addr >> 20) + 0] & L1_MASK)) {
    199 	case L1_SECTION:
    200 		break;
    201 	case L1_PAGE:
    202 		/* Check the L2 page table for validity */
    203 		ptep = vtopte(addr);
    204 		if ((*ptep & L2_MASK) != L2_INVAL)
    205 			break;
    206 		/* FALLTHROUGH */
    207 	default:
    208 		return 1;
    209 	}
    210 
    211 	return 0;
    212 }
    213 
    214 /*
    215  * Read bytes from kernel address space for debugger.
    216  */
    217 void
    218 db_read_bytes(addr, size, data)
    219 	vm_offset_t	addr;
    220 	int	size;
    221 	char	*data;
    222 {
    223 	char	*src;
    224 
    225 	src = (char *)addr;
    226 	while (--size >= 0) {
    227 		if (db_validate_address((u_int)src)) {
    228 			db_printf("address %p is invalid\n", src);
    229 			return;
    230 		}
    231 		*data++ = *src++;
    232 	}
    233 }
    234 
    235 static void
    236 db_write_text(dst, ch)
    237 	unsigned char *dst;
    238 	int ch;
    239 {
    240 	pt_entry_t *ptep, pteo;
    241 	vm_offset_t va;
    242 
    243 	va = (unsigned long)dst & (~PGOFSET);
    244 	ptep = vtopte(va);
    245 
    246 	if (db_validate_address((u_int)dst)) {
    247 		db_printf(" address %p not a valid page\n", dst);
    248 		return;
    249 	}
    250 
    251 	pteo = *ptep;
    252 	*ptep = pteo | PT_AP(AP_KRW);
    253 	cpu_tlb_flushD_SE(va);
    254 
    255 	*dst = (unsigned char)ch;
    256 
    257 	/* make sure the caches and memory are in sync */
    258 	cpu_cache_syncI_rng((u_int)dst, 4);
    259 
    260 	*ptep = pteo;
    261 	cpu_tlb_flushD_SE(va);
    262 }
    263 
    264 /*
    265  * Write bytes to kernel address space for debugger.
    266  */
    267 void
    268 db_write_bytes(addr, size, data)
    269 	vm_offset_t	addr;
    270 	int	size;
    271 	char	*data;
    272 {
    273 	extern char	etext[];
    274 	char	*dst;
    275 	int	loop;
    276 
    277 	dst = (char *)addr;
    278 	loop = size;
    279 	while (--loop >= 0) {
    280 		if ((dst >= (char *)KERNEL_TEXT_BASE) && (dst < etext))
    281 			db_write_text(dst, *data);
    282 		else {
    283 			if (db_validate_address((u_int)dst)) {
    284 				db_printf("address %p is invalid\n", dst);
    285 				return;
    286 			}
    287 			*dst = *data;
    288 		}
    289 		dst++, data++;
    290 	}
    291 	/* make sure the caches and memory are in sync */
    292 	cpu_cache_syncI_rng(addr, size);
    293 
    294 	/* In case the current page tables have been modified ... */
    295 	cpu_tlb_flushID();
    296 }
    297 
    298 void
    299 cpu_Debugger()
    300 {
    301 	asm(".word	0xe7ffffff");
    302 }
    303 
    304 void db_show_vmstat_cmd __P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    305 void db_show_intrchain_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    306 void db_show_panic_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    307 void db_show_frame_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    308 #ifdef	OFW
    309 void db_of_boot_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    310 void db_of_enter_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    311 void db_of_exit_cmd	__P((db_expr_t addr, int have_addr, db_expr_t count, char *modif));
    312 #endif
    313 
    314 const struct db_command db_machine_command_table[] = {
    315 	{ "frame",	db_show_frame_cmd,	0, NULL },
    316 	{ "intrchain",	db_show_intrchain_cmd,	0, NULL },
    317 #ifdef	OFW
    318 	{ "ofboot",	db_of_boot_cmd,		0, NULL },
    319 	{ "ofenter",	db_of_enter_cmd,	0, NULL },
    320 	{ "ofexit",	db_of_exit_cmd,		0, NULL },
    321 #endif
    322 	{ "panic",	db_show_panic_cmd,	0, NULL },
    323 	{ "vmstat",	db_show_vmstat_cmd,	0, NULL },
    324 	{ NULL, 	NULL, 			0, NULL }
    325 };
    326 
    327 int
    328 db_trapper(addr, inst, frame, fault_code)
    329 	u_int		addr;
    330 	u_int		inst;
    331 	trapframe_t	*frame;
    332 	int		fault_code;
    333 {
    334 	if (fault_code == 0) {
    335 		frame->tf_pc -= INSN_SIZE;
    336 		if ((inst & ~INSN_COND_MASK) == (BKPT_INST & ~INSN_COND_MASK))
    337 			kdb_trap(T_BREAKPOINT, frame);
    338 		else
    339 			kdb_trap(-1, frame);
    340 	} else
    341 		return (1);
    342 	return (0);
    343 }
    344 
    345 extern u_int esym;
    346 extern u_int end;
    347 
    348 void
    349 db_machine_init()
    350 {
    351 	struct exec *kernexec = (struct exec *)KERNEL_TEXT_BASE;
    352 	int len;
    353 
    354 	/*
    355 	 * The boot loader currently loads the kernel with the a.out
    356 	 * header still attached.
    357 	 */
    358 
    359 	if (kernexec->a_syms == 0) {
    360 		printf("[No symbol table]\n");
    361 	} else {
    362 #if (!defined(SHARK) && !defined(OFWGENCFG)) || 1
    363 		esym = (int)&end + kernexec->a_syms + sizeof(int);
    364 #else
    365 		/* cover the symbols themselves */
    366 		esym = (int)&end + kernexec->a_syms;
    367 #endif
    368 		/*
    369 		 * and the string table.  (int containing size of string
    370 		 * table is included in string table size).
    371 		 */
    372 		len = *((u_int *)esym);
    373 		esym += (len + (sizeof(u_int) - 1)) & ~(sizeof(u_int) - 1);
    374 	}
    375 
    376 	install_coproc_handler(0, db_trapper);
    377 }
    378 
    379 u_int
    380 db_fetch_reg(reg, db_regs)
    381 	int reg;
    382 	db_regs_t *db_regs;
    383 {
    384 
    385 	switch (reg) {
    386 	case 0:
    387 		return (db_regs->tf_r0);
    388 	case 1:
    389 		return (db_regs->tf_r1);
    390 	case 2:
    391 		return (db_regs->tf_r2);
    392 	case 3:
    393 		return (db_regs->tf_r3);
    394 	case 4:
    395 		return (db_regs->tf_r4);
    396 	case 5:
    397 		return (db_regs->tf_r5);
    398 	case 6:
    399 		return (db_regs->tf_r6);
    400 	case 7:
    401 		return (db_regs->tf_r7);
    402 	case 8:
    403 		return (db_regs->tf_r8);
    404 	case 9:
    405 		return (db_regs->tf_r9);
    406 	case 10:
    407 		return (db_regs->tf_r10);
    408 	case 11:
    409 		return (db_regs->tf_r11);
    410 	case 12:
    411 		return (db_regs->tf_r12);
    412 	case 13:
    413 		return (db_regs->tf_svc_sp);
    414 	case 14:
    415 		return (db_regs->tf_svc_lr);
    416 	case 15:
    417 		return (db_regs->tf_pc);
    418 	default:
    419 		panic("db_fetch_reg: botch");
    420 	}
    421 }
    422 
    423 u_int
    424 branch_taken(insn, pc, db_regs)
    425 	u_int insn;
    426 	u_int pc;
    427 	db_regs_t *db_regs;
    428 {
    429 	u_int addr, nregs;
    430 
    431 	switch ((insn >> 24) & 0xf) {
    432 	case 0xa:	/* b ... */
    433 	case 0xb:	/* bl ... */
    434 		addr = ((insn << 2) & 0x03ffffff);
    435 		if (addr & 0x02000000)
    436 			addr |= 0xfc000000;
    437 		return (pc + 8 + addr);
    438 	case 0x7:	/* ldr pc, [pc, reg, lsl #2] */
    439 		addr = db_fetch_reg(insn & 0xf, db_regs);
    440 		addr = pc + 8 + (addr << 2);
    441 		db_read_bytes(addr, 4, (char *)&addr);
    442 		return (addr);
    443 	case 0x1:	/* mov pc, reg */
    444 		addr = db_fetch_reg(insn & 0xf, db_regs);
    445 		return (addr);
    446 	case 0x8:	/* ldmxx reg, {..., pc} */
    447 	case 0x9:
    448 		addr = db_fetch_reg((insn >> 16) & 0xf, db_regs);
    449 		nregs = (insn  & 0x5555) + ((insn  >> 1) & 0x5555);
    450 		nregs = (nregs & 0x3333) + ((nregs >> 2) & 0x3333);
    451 		nregs = (nregs + (nregs >> 4)) & 0x0f0f;
    452 		nregs = (nregs + (nregs >> 8)) & 0x001f;
    453 		switch ((insn >> 23) & 0x3) {
    454 		case 0x0:	/* ldmda */
    455 			addr = addr - 0;
    456 			break;
    457 		case 0x1:	/* ldmia */
    458 			addr = addr + 0 + ((nregs - 1) << 2);
    459 			break;
    460 		case 0x2:	/* ldmdb */
    461 			addr = addr - 4;
    462 			break;
    463 		case 0x3:	/* ldmib */
    464 			addr = addr + 4 + ((nregs - 1) << 2);
    465 			break;
    466 		}
    467 		db_read_bytes(addr, 4, (char *)&addr);
    468 		return (addr);
    469 	default:
    470 		panic("branch_taken: botch");
    471 	}
    472 }
    473