xref: /titanic_51/usr/src/cmd/mdb/intel/mdb/mdb_amd64util.c (revision 32b5e9f0cda85eef94eb578dd053e155df43fed3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 /*
27  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
28  * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
29  * Copyright (c) 2013 by Delphix. All rights reserved.
30  */
31 
32 #include <sys/types.h>
33 #include <sys/reg.h>
34 #include <sys/privregs.h>
35 #include <sys/stack.h>
36 #include <sys/frame.h>
37 
38 #include <mdb/mdb_target_impl.h>
39 #include <mdb/mdb_kreg_impl.h>
40 #include <mdb/mdb_debug.h>
41 #include <mdb/mdb_modapi.h>
42 #include <mdb/mdb_amd64util.h>
43 #include <mdb/mdb_ctf.h>
44 #include <mdb/mdb_err.h>
45 #include <mdb/mdb.h>
46 
47 #include <saveargs.h>
48 
49 /*
50  * This array is used by the getareg and putareg entry points, and also by our
51  * register variable discipline.
52  */
53 
54 const mdb_tgt_regdesc_t mdb_amd64_kregs[] = {
55 	{ "savfp", KREG_SAVFP, MDB_TGT_R_EXPORT },
56 	{ "savpc", KREG_SAVPC, MDB_TGT_R_EXPORT },
57 	{ "rdi", KREG_RDI, MDB_TGT_R_EXPORT },
58 	{ "edi", KREG_RDI, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
59 	{ "di",  KREG_RDI, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
60 	{ "dil", KREG_RDI, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
61 	{ "rsi", KREG_RSI, MDB_TGT_R_EXPORT },
62 	{ "esi", KREG_RSI, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
63 	{ "si",  KREG_RSI, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
64 	{ "sil", KREG_RSI, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
65 	{ "rdx", KREG_RDX, MDB_TGT_R_EXPORT },
66 	{ "edx", KREG_RDX, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
67 	{ "dx",  KREG_RDX, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
68 	{ "dh",  KREG_RDX, MDB_TGT_R_EXPORT | MDB_TGT_R_8H },
69 	{ "dl",  KREG_RDX, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
70 	{ "rcx", KREG_RCX, MDB_TGT_R_EXPORT },
71 	{ "ecx", KREG_RCX, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
72 	{ "cx",  KREG_RCX, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
73 	{ "ch",  KREG_RCX, MDB_TGT_R_EXPORT | MDB_TGT_R_8H },
74 	{ "cl",  KREG_RCX, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
75 	{ "r8", KREG_R8, MDB_TGT_R_EXPORT },
76 	{ "r8d", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
77 	{ "r8w", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
78 	{ "r8l", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
79 	{ "r9", KREG_R9, MDB_TGT_R_EXPORT },
80 	{ "r9d", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
81 	{ "r9w", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
82 	{ "r9l", KREG_R8,  MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
83 	{ "rax", KREG_RAX, MDB_TGT_R_EXPORT },
84 	{ "eax", KREG_RAX, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
85 	{ "ax",  KREG_RAX, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
86 	{ "ah",  KREG_RAX, MDB_TGT_R_EXPORT | MDB_TGT_R_8H },
87 	{ "al",  KREG_RAX, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
88 	{ "rbx", KREG_RBX, MDB_TGT_R_EXPORT },
89 	{ "ebx", KREG_RBX, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
90 	{ "bx",  KREG_RBX, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
91 	{ "bh",  KREG_RBX, MDB_TGT_R_EXPORT | MDB_TGT_R_8H },
92 	{ "bl",  KREG_RBX, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
93 	{ "rbp", KREG_RBP, MDB_TGT_R_EXPORT },
94 	{ "ebp", KREG_RBP, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
95 	{ "bp",  KREG_RBP, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
96 	{ "bpl", KREG_RBP, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
97 	{ "r10", KREG_R10, MDB_TGT_R_EXPORT },
98 	{ "r10d", KREG_R10, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
99 	{ "r10w", KREG_R10, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
100 	{ "r10l", KREG_R10, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
101 	{ "r11", KREG_R11, MDB_TGT_R_EXPORT },
102 	{ "r11d", KREG_R11, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
103 	{ "r11w", KREG_R11, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
104 	{ "r11l", KREG_R11, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
105 	{ "r12", KREG_R12, MDB_TGT_R_EXPORT },
106 	{ "r12d", KREG_R12, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
107 	{ "r12w", KREG_R12, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
108 	{ "r12l", KREG_R12, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
109 	{ "r13", KREG_R13, MDB_TGT_R_EXPORT },
110 	{ "r13d", KREG_R13, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
111 	{ "r13w", KREG_R13, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
112 	{ "r13l", KREG_R13, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
113 	{ "r14", KREG_R14, MDB_TGT_R_EXPORT },
114 	{ "r14d", KREG_R14, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
115 	{ "r14w", KREG_R14, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
116 	{ "r14l", KREG_R14, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
117 	{ "r15", KREG_R15, MDB_TGT_R_EXPORT },
118 	{ "r15d", KREG_R15, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
119 	{ "r15w", KREG_R15, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
120 	{ "r15l", KREG_R15, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
121 	{ "ds", KREG_DS, MDB_TGT_R_EXPORT },
122 	{ "es", KREG_ES, MDB_TGT_R_EXPORT },
123 	{ "fs", KREG_FS, MDB_TGT_R_EXPORT },
124 	{ "gs", KREG_GS, MDB_TGT_R_EXPORT },
125 	{ "trapno", KREG_TRAPNO, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV },
126 	{ "err", KREG_ERR, MDB_TGT_R_EXPORT | MDB_TGT_R_PRIV },
127 	{ "rip", KREG_RIP, MDB_TGT_R_EXPORT },
128 	{ "cs", KREG_CS, MDB_TGT_R_EXPORT },
129 	{ "rflags", KREG_RFLAGS, MDB_TGT_R_EXPORT },
130 	{ "eflags", KREG_RFLAGS, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
131 	{ "rsp", KREG_RSP, MDB_TGT_R_EXPORT },
132 	{ "esp", KREG_RSP, MDB_TGT_R_EXPORT | MDB_TGT_R_32 },
133 	{ "sp",  KREG_RSP, MDB_TGT_R_EXPORT | MDB_TGT_R_16 },
134 	{ "spl", KREG_RSP, MDB_TGT_R_EXPORT | MDB_TGT_R_8L },
135 	{ "ss", KREG_SS, MDB_TGT_R_EXPORT },
136 	{ NULL, 0, 0 }
137 };
138 
139 void
140 mdb_amd64_printregs(const mdb_tgt_gregset_t *gregs)
141 {
142 	const kreg_t *kregs = &gregs->kregs[0];
143 	kreg_t rflags = kregs[KREG_RFLAGS];
144 
145 #define	GETREG2(x) ((uintptr_t)kregs[(x)]), ((uintptr_t)kregs[(x)])
146 
147 	mdb_printf("%%rax = 0x%0?p %15A %%r9  = 0x%0?p %A\n",
148 	    GETREG2(KREG_RAX), GETREG2(KREG_R9));
149 	mdb_printf("%%rbx = 0x%0?p %15A %%r10 = 0x%0?p %A\n",
150 	    GETREG2(KREG_RBX), GETREG2(KREG_R10));
151 	mdb_printf("%%rcx = 0x%0?p %15A %%r11 = 0x%0?p %A\n",
152 	    GETREG2(KREG_RCX), GETREG2(KREG_R11));
153 	mdb_printf("%%rdx = 0x%0?p %15A %%r12 = 0x%0?p %A\n",
154 	    GETREG2(KREG_RDX), GETREG2(KREG_R12));
155 	mdb_printf("%%rsi = 0x%0?p %15A %%r13 = 0x%0?p %A\n",
156 	    GETREG2(KREG_RSI), GETREG2(KREG_R13));
157 	mdb_printf("%%rdi = 0x%0?p %15A %%r14 = 0x%0?p %A\n",
158 	    GETREG2(KREG_RDI), GETREG2(KREG_R14));
159 	mdb_printf("%%r8  = 0x%0?p %15A %%r15 = 0x%0?p %A\n\n",
160 	    GETREG2(KREG_R8), GETREG2(KREG_R15));
161 
162 	mdb_printf("%%rip = 0x%0?p %A\n", GETREG2(KREG_RIP));
163 	mdb_printf("%%rbp = 0x%0?p\n", kregs[KREG_RBP]);
164 	mdb_printf("%%rsp = 0x%0?p\n", kregs[KREG_RSP]);
165 
166 	mdb_printf("%%rflags = 0x%08x\n", rflags);
167 
168 	mdb_printf("  id=%u vip=%u vif=%u ac=%u vm=%u rf=%u nt=%u iopl=0x%x\n",
169 	    (rflags & KREG_EFLAGS_ID_MASK) >> KREG_EFLAGS_ID_SHIFT,
170 	    (rflags & KREG_EFLAGS_VIP_MASK) >> KREG_EFLAGS_VIP_SHIFT,
171 	    (rflags & KREG_EFLAGS_VIF_MASK) >> KREG_EFLAGS_VIF_SHIFT,
172 	    (rflags & KREG_EFLAGS_AC_MASK) >> KREG_EFLAGS_AC_SHIFT,
173 	    (rflags & KREG_EFLAGS_VM_MASK) >> KREG_EFLAGS_VM_SHIFT,
174 	    (rflags & KREG_EFLAGS_RF_MASK) >> KREG_EFLAGS_RF_SHIFT,
175 	    (rflags & KREG_EFLAGS_NT_MASK) >> KREG_EFLAGS_NT_SHIFT,
176 	    (rflags & KREG_EFLAGS_IOPL_MASK) >> KREG_EFLAGS_IOPL_SHIFT);
177 
178 	mdb_printf("  status=<%s,%s,%s,%s,%s,%s,%s,%s,%s>\n\n",
179 	    (rflags & KREG_EFLAGS_OF_MASK) ? "OF" : "of",
180 	    (rflags & KREG_EFLAGS_DF_MASK) ? "DF" : "df",
181 	    (rflags & KREG_EFLAGS_IF_MASK) ? "IF" : "if",
182 	    (rflags & KREG_EFLAGS_TF_MASK) ? "TF" : "tf",
183 	    (rflags & KREG_EFLAGS_SF_MASK) ? "SF" : "sf",
184 	    (rflags & KREG_EFLAGS_ZF_MASK) ? "ZF" : "zf",
185 	    (rflags & KREG_EFLAGS_AF_MASK) ? "AF" : "af",
186 	    (rflags & KREG_EFLAGS_PF_MASK) ? "PF" : "pf",
187 	    (rflags & KREG_EFLAGS_CF_MASK) ? "CF" : "cf");
188 
189 	mdb_printf("%24s%%cs = 0x%04x\t%%ds = 0x%04x\t%%es = 0x%04x\n",
190 	    " ", kregs[KREG_CS], kregs[KREG_DS], kregs[KREG_ES]);
191 
192 	mdb_printf("%%trapno = 0x%x\t\t%%fs = 0x%04x\t%%gs = 0x%04x\n",
193 	    kregs[KREG_TRAPNO], (kregs[KREG_FS] & 0xffff),
194 	    (kregs[KREG_GS] & 0xffff));
195 	mdb_printf("   %%err = 0x%x\n", kregs[KREG_ERR]);
196 }
197 
198 int
199 mdb_amd64_kvm_stack_iter(mdb_tgt_t *t, const mdb_tgt_gregset_t *gsp,
200     mdb_tgt_stack_f *func, void *arg)
201 {
202 	mdb_tgt_gregset_t gregs;
203 	kreg_t *kregs = &gregs.kregs[0];
204 	int got_pc = (gsp->kregs[KREG_RIP] != 0);
205 	uint_t argc, reg_argc;
206 	long fr_argv[32];
207 	int start_index; /* index to save_instr where to start comparison */
208 	int err;
209 	int i;
210 
211 	struct fr {
212 		uintptr_t fr_savfp;
213 		uintptr_t fr_savpc;
214 	} fr;
215 
216 	uintptr_t fp = gsp->kregs[KREG_RBP];
217 	uintptr_t pc = gsp->kregs[KREG_RIP];
218 	uintptr_t lastfp = 0;
219 
220 	ssize_t size;
221 	ssize_t insnsize;
222 	uint8_t ins[SAVEARGS_INSN_SEQ_LEN];
223 
224 	GElf_Sym s;
225 	mdb_syminfo_t sip;
226 	mdb_ctf_funcinfo_t mfp;
227 	int xpv_panic = 0;
228 	int advance_tortoise = 1;
229 	uintptr_t tortoise_fp = 0;
230 #ifndef	_KMDB
231 	int xp;
232 
233 	if ((mdb_readsym(&xp, sizeof (xp), "xpv_panicking") != -1) && (xp > 0))
234 		xpv_panic = 1;
235 #endif
236 
237 	bcopy(gsp, &gregs, sizeof (gregs));
238 
239 	while (fp != 0) {
240 		int args_style = 0;
241 
242 		if (mdb_tgt_vread(t, &fr, sizeof (fr), fp) != sizeof (fr)) {
243 			err = EMDB_NOMAP;
244 			goto badfp;
245 		}
246 
247 		if (tortoise_fp == 0) {
248 			tortoise_fp = fp;
249 		} else {
250 			/*
251 			 * Advance tortoise_fp every other frame, so we detect
252 			 * cycles with Floyd's tortoise/hare.
253 			 */
254 			if (advance_tortoise != 0) {
255 				struct fr tfr;
256 
257 				if (mdb_tgt_vread(t, &tfr, sizeof (tfr),
258 				    tortoise_fp) != sizeof (tfr)) {
259 					err = EMDB_NOMAP;
260 					goto badfp;
261 				}
262 
263 				tortoise_fp = tfr.fr_savfp;
264 			}
265 
266 			if (fp == tortoise_fp) {
267 				err = EMDB_STKFRAME;
268 				goto badfp;
269 			}
270 		}
271 
272 		advance_tortoise = !advance_tortoise;
273 
274 		if ((mdb_tgt_lookup_by_addr(t, pc, MDB_TGT_SYM_FUZZY,
275 		    NULL, 0, &s, &sip) == 0) &&
276 		    (mdb_ctf_func_info(&s, &sip, &mfp) == 0)) {
277 			int return_type = mdb_ctf_type_kind(mfp.mtf_return);
278 			mdb_ctf_id_t args_types[5];
279 
280 			argc = mfp.mtf_argc;
281 
282 			/*
283 			 * If the function returns a structure or union
284 			 * greater than 16 bytes in size %rdi contains the
285 			 * address in which to store the return value rather
286 			 * than for an argument.
287 			 */
288 			if ((return_type == CTF_K_STRUCT ||
289 			    return_type == CTF_K_UNION) &&
290 			    mdb_ctf_type_size(mfp.mtf_return) > 16)
291 				start_index = 1;
292 			else
293 				start_index = 0;
294 
295 			/*
296 			 * If any of the first 5 arguments are a structure
297 			 * less than 16 bytes in size, it will be passed
298 			 * spread across two argument registers, and we will
299 			 * not cope.
300 			 */
301 			if (mdb_ctf_func_args(&mfp, 5, args_types) == CTF_ERR)
302 				argc = 0;
303 
304 			for (i = 0; i < MIN(5, argc); i++) {
305 				int t = mdb_ctf_type_kind(args_types[i]);
306 
307 				if (((t == CTF_K_STRUCT) ||
308 				    (t == CTF_K_UNION)) &&
309 				    mdb_ctf_type_size(args_types[i]) <= 16) {
310 					argc = 0;
311 					break;
312 				}
313 			}
314 		} else {
315 			argc = 0;
316 		}
317 
318 		/*
319 		 * The number of instructions to search for argument saving is
320 		 * limited such that only instructions prior to %pc are
321 		 * considered such that we never read arguments from a
322 		 * function where the saving code has not in fact yet
323 		 * executed.
324 		 */
325 		insnsize = MIN(MIN(s.st_size, SAVEARGS_INSN_SEQ_LEN),
326 		    pc - s.st_value);
327 
328 		if (mdb_tgt_vread(t, ins, insnsize, s.st_value) != insnsize)
329 			argc = 0;
330 
331 		if ((argc != 0) &&
332 		    ((args_style = saveargs_has_args(ins, insnsize, argc,
333 		    start_index)) != SAVEARGS_NO_ARGS)) {
334 			/* Up to 6 arguments are passed via registers */
335 			reg_argc = MIN((6 - start_index), mfp.mtf_argc);
336 			size = reg_argc * sizeof (long);
337 
338 			/*
339 			 * If Studio pushed a structure return address as an
340 			 * argument, we need to read one more argument than
341 			 * actually exists (the addr) to make everything line
342 			 * up.
343 			 */
344 			if (args_style == SAVEARGS_STRUCT_ARGS)
345 				size += sizeof (long);
346 
347 			if (mdb_tgt_vread(t, fr_argv, size, (fp - size))
348 			    != size)
349 				return (-1);	/* errno has been set for us */
350 
351 			/*
352 			 * Arrange the arguments in the right order for
353 			 * printing.
354 			 */
355 			for (i = 0; i < (reg_argc / 2); i++) {
356 				long t = fr_argv[i];
357 
358 				fr_argv[i] = fr_argv[reg_argc - i - 1];
359 				fr_argv[reg_argc - i - 1] = t;
360 			}
361 
362 			if (argc > reg_argc) {
363 				size = MIN((argc - reg_argc) * sizeof (long),
364 				    sizeof (fr_argv) -
365 				    (reg_argc * sizeof (long)));
366 
367 				if (mdb_tgt_vread(t, &fr_argv[reg_argc], size,
368 				    fp + sizeof (fr)) != size)
369 					return (-1); /* errno has been set */
370 			}
371 		} else {
372 			argc = 0;
373 		}
374 
375 		if (got_pc && func(arg, pc, argc, fr_argv, &gregs) != 0)
376 			break;
377 
378 		kregs[KREG_RSP] = kregs[KREG_RBP];
379 
380 		lastfp = fp;
381 		fp = fr.fr_savfp;
382 		/*
383 		 * The Xen hypervisor marks a stack frame as belonging to
384 		 * an exception by inverting the bits of the pointer to
385 		 * that frame.  We attempt to identify these frames by
386 		 * inverting the pointer and seeing if it is within 0xfff
387 		 * bytes of the last frame.
388 		 */
389 		if (xpv_panic)
390 			if ((fp != 0) && (fp < lastfp) &&
391 			    ((lastfp ^ ~fp) < 0xfff))
392 				fp = ~fp;
393 
394 		kregs[KREG_RBP] = fp;
395 		kregs[KREG_RIP] = pc = fr.fr_savpc;
396 
397 		got_pc = (pc != 0);
398 	}
399 
400 	return (0);
401 
402 badfp:
403 	mdb_printf("%p [%s]", fp, mdb_strerror(err));
404 	return (set_errno(err));
405 }
406 
407 /*
408  * Determine the return address for the current frame.  Typically this is the
409  * fr_savpc value from the current frame, but we also perform some special
410  * handling to see if we are stopped on one of the first two instructions of
411  * a typical function prologue, in which case %rbp will not be set up yet.
412  */
413 int
414 mdb_amd64_step_out(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, kreg_t fp, kreg_t sp,
415     mdb_instr_t curinstr)
416 {
417 	struct frame fr;
418 	GElf_Sym s;
419 	char buf[1];
420 
421 	enum {
422 		M_PUSHQ_RBP	= 0x55,	/* pushq %rbp */
423 		M_REX_W		= 0x48, /* REX prefix with only W set */
424 		M_MOVL_RBP	= 0x8b	/* movq %rsp, %rbp with prefix */
425 	};
426 
427 	if (mdb_tgt_lookup_by_addr(t, pc, MDB_TGT_SYM_FUZZY,
428 	    buf, 0, &s, NULL) == 0) {
429 		if (pc == s.st_value && curinstr == M_PUSHQ_RBP)
430 			fp = sp - 8;
431 		else if (pc == s.st_value + 1 && curinstr == M_REX_W) {
432 			if (mdb_tgt_vread(t, &curinstr, sizeof (curinstr),
433 			    pc + 1) == sizeof (curinstr) && curinstr ==
434 			    M_MOVL_RBP)
435 				fp = sp;
436 		}
437 	}
438 
439 	if (mdb_tgt_vread(t, &fr, sizeof (fr), fp) == sizeof (fr)) {
440 		*p = fr.fr_savpc;
441 		return (0);
442 	}
443 
444 	return (-1); /* errno is set for us */
445 }
446 
447 /*ARGSUSED*/
448 int
449 mdb_amd64_next(mdb_tgt_t *t, uintptr_t *p, kreg_t pc, mdb_instr_t curinstr)
450 {
451 	mdb_tgt_addr_t npc;
452 	mdb_tgt_addr_t callpc;
453 
454 	enum {
455 		M_CALL_REL = 0xe8, /* call near with relative displacement */
456 		M_CALL_REG = 0xff, /* call near indirect or call far register */
457 
458 		M_REX_LO = 0x40,
459 		M_REX_HI = 0x4f
460 	};
461 
462 	/*
463 	 * If the opcode is a near call with relative displacement, assume the
464 	 * displacement is a rel32 from the next instruction.
465 	 */
466 	if (curinstr == M_CALL_REL) {
467 		*p = pc + sizeof (mdb_instr_t) + sizeof (uint32_t);
468 		return (0);
469 	}
470 
471 	/* Skip the rex prefix, if any */
472 	callpc = pc;
473 	while (curinstr >= M_REX_LO && curinstr <= M_REX_HI) {
474 		if (mdb_tgt_vread(t, &curinstr, sizeof (curinstr), ++callpc) !=
475 		    sizeof (curinstr))
476 			return (-1); /* errno is set for us */
477 	}
478 
479 	if (curinstr != M_CALL_REG) {
480 		/* It's not a call */
481 		return (set_errno(EAGAIN));
482 	}
483 
484 	if ((npc = mdb_dis_nextins(mdb.m_disasm, t, MDB_TGT_AS_VIRT, pc)) == pc)
485 		return (-1); /* errno is set for us */
486 
487 	*p = npc;
488 	return (0);
489 }
490 
491 /*ARGSUSED*/
492 int
493 mdb_amd64_kvm_frame(void *arglim, uintptr_t pc, uint_t argc, const long *argv,
494     const mdb_tgt_gregset_t *gregs)
495 {
496 	argc = MIN(argc, (uintptr_t)arglim);
497 	mdb_printf("%a(", pc);
498 
499 	if (argc != 0) {
500 		mdb_printf("%lr", *argv++);
501 		for (argc--; argc != 0; argc--)
502 			mdb_printf(", %lr", *argv++);
503 	}
504 
505 	mdb_printf(")\n");
506 	return (0);
507 }
508 
509 int
510 mdb_amd64_kvm_framev(void *arglim, uintptr_t pc, uint_t argc, const long *argv,
511     const mdb_tgt_gregset_t *gregs)
512 {
513 	/*
514 	 * Historically adb limited stack trace argument display to a fixed-
515 	 * size number of arguments since no symbolic debugging info existed.
516 	 * On amd64 we can detect the true number of saved arguments so only
517 	 * respect an arglim of zero; otherwise display the entire argv[].
518 	 */
519 	if (arglim == 0)
520 		argc = 0;
521 
522 	mdb_printf("%0?lr %a(", gregs->kregs[KREG_RBP], pc);
523 
524 	if (argc != 0) {
525 		mdb_printf("%lr", *argv++);
526 		for (argc--; argc != 0; argc--)
527 			mdb_printf(", %lr", *argv++);
528 	}
529 
530 	mdb_printf(")\n");
531 	return (0);
532 }
533