2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
16 * Carnegie Mellon requests users of this software to return to
18 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
19 * School of Computer Science
20 * Carnegie Mellon University
21 * Pittsburgh PA 15213-3890
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
26 * $FreeBSD: src/sys/i386/i386/db_interface.c,v 1.48.2.1 2000/07/07 00:38:46 obrien Exp $
27 * $DragonFly: src/sys/platform/pc32/i386/db_interface.c,v 1.14 2006/12/23 00:27:03 swildner Exp $
31 * Interface to new debugger.
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/reboot.h>
38 #include <machine/cpu.h>
39 #include <machine/smp.h>
40 #include <machine/globaldata.h>
49 static jmp_buf *db_nofault = 0;
50 extern jmp_buf db_jmpbuf;
52 extern void gdb_handle_exception (db_regs_t *, int, int);
57 static jmp_buf db_global_jmpbuf;
58 static int db_global_jmpbuf_valid;
61 #define rss() ({u_short ss; __asm __volatile("mov %%ss,%0" : "=r" (ss)); ss;})
65 * kdb_trap - field a TRACE or BPT trap
68 kdb_trap(int type, int code, struct i386_saved_state *regs)
70 volatile int ddb_mode = !(boothowto & RB_GDB);
73 * XXX try to do nothing if the console is in graphics mode.
74 * Handle trace traps (and hardware breakpoints...) by ignoring
75 * them except for forgetting about them. Return 0 for other
76 * traps to say that we haven't done anything. The trap handler
77 * will usually panic. We should handle breakpoint traps for
78 * our breakpoints by disarming our breakpoints and fixing up
81 if (cons_unavail && ddb_mode) {
82 if (type == T_TRCTRAP) {
83 regs->tf_eflags &= ~PSL_T;
90 case T_BPTFLT: /* breakpoint */
91 case T_TRCTRAP: /* debug exception */
96 * XXX this is almost useless now. In most cases,
97 * trap_fatal() has already printed a much more verbose
98 * message. However, it is dangerous to print things in
99 * trap_fatal() - kprintf() might be reentered and trap.
100 * The debugger should be given control first.
103 db_printf("kernel: type %d trap, code=%x\n", type, code);
106 jmp_buf *no_fault = db_nofault;
108 longjmp(*no_fault, 1);
113 * This handles unexpected traps in ddb commands, including calls to
114 * non-ddb functions. db_nofault only applies to memory accesses by
115 * internal ddb commands.
117 if (db_global_jmpbuf_valid)
118 longjmp(db_global_jmpbuf, 1);
121 * XXX We really should switch to a local stack here.
126 * If in kernel mode, esp and ss are not saved, so dummy them up.
128 if (ISPL(regs->tf_cs) == 0) {
129 ddb_regs.tf_esp = (int)®s->tf_esp;
130 ddb_regs.tf_ss = rss();
134 db_printf("\nCPU%d stopping CPUs: 0x%08x\n",
135 mycpu->gd_cpuid, mycpu->gd_other_cpus);
137 /* We stop all CPUs except ourselves (obviously) */
138 stop_cpus(mycpu->gd_other_cpus);
140 db_printf(" stopped\n");
143 setjmp(db_global_jmpbuf);
144 db_global_jmpbuf_valid = TRUE;
151 gdb_handle_exception(&ddb_regs, type, code);
153 db_global_jmpbuf_valid = FALSE;
156 db_printf("\nCPU%d restarting CPUs: 0x%08x\n",
157 mycpu->gd_cpuid, stopped_cpus);
159 /* Restart all the CPUs we previously stopped */
160 if (stopped_cpus != mycpu->gd_other_cpus) {
161 db_printf("whoa, other_cpus: 0x%08x, stopped_cpus: 0x%08x\n",
162 mycpu->gd_other_cpus, stopped_cpus);
163 panic("stop_cpus() failed");
165 restart_cpus(stopped_cpus);
167 db_printf(" restarted\n");
170 regs->tf_eip = ddb_regs.tf_eip;
171 regs->tf_eflags = ddb_regs.tf_eflags;
172 regs->tf_eax = ddb_regs.tf_eax;
173 regs->tf_ecx = ddb_regs.tf_ecx;
174 regs->tf_edx = ddb_regs.tf_edx;
175 regs->tf_ebx = ddb_regs.tf_ebx;
178 * If in user mode, the saved ESP and SS were valid, restore them.
180 if (ISPL(regs->tf_cs)) {
181 regs->tf_esp = ddb_regs.tf_esp;
182 regs->tf_ss = ddb_regs.tf_ss & 0xffff;
185 regs->tf_ebp = ddb_regs.tf_ebp;
186 regs->tf_esi = ddb_regs.tf_esi;
187 regs->tf_edi = ddb_regs.tf_edi;
188 regs->tf_es = ddb_regs.tf_es & 0xffff;
189 regs->tf_fs = ddb_regs.tf_fs & 0xffff;
190 regs->tf_cs = ddb_regs.tf_cs & 0xffff;
191 regs->tf_ds = ddb_regs.tf_ds & 0xffff;
196 * Read bytes from kernel address space for debugger.
199 db_read_bytes(vm_offset_t addr, size_t size, char *data)
203 db_nofault = &db_jmpbuf;
213 * Write bytes to kernel address space for debugger.
216 db_write_bytes(vm_offset_t addr, size_t size, char *data)
220 unsigned *ptep0 = NULL;
221 unsigned oldmap0 = 0;
223 unsigned *ptep1 = NULL;
224 unsigned oldmap1 = 0;
226 db_nofault = &db_jmpbuf;
228 if (addr > trunc_page((vm_offset_t)btext) - size &&
229 addr < round_page((vm_offset_t)etext)) {
231 ptep0 = pmap_pte(kernel_pmap, addr);
235 /* Map another page if the data crosses a page boundary. */
236 if ((*ptep0 & PG_PS) == 0) {
237 addr1 = trunc_page(addr + size - 1);
238 if (trunc_page(addr) != addr1) {
239 ptep1 = pmap_pte(kernel_pmap, addr1);
244 addr1 = trunc_4mpage(addr + size - 1);
245 if (trunc_4mpage(addr) != addr1) {
246 ptep1 = pmap_pte(kernel_pmap, addr1);
273 * The debugger sometimes needs to know the actual KVM address represented
274 * by the instruction pointer, stack pointer, or base pointer. Normally
275 * the actual KVM address is simply the contents of the register. However,
276 * if the debugger is entered from the BIOS or VM86 we need to figure out
277 * the offset from the segment register.
280 PC_REGS(db_regs_t *regs)
282 struct soft_segment_descriptor softseg;
284 sdtossd(&gdt[mycpu->gd_cpuid * NGDT + IDXSEL(regs->tf_cs & 0xffff)].sd, &softseg);
285 return(regs->tf_eip + softseg.ssd_base);
289 SP_REGS(db_regs_t *regs)
291 struct soft_segment_descriptor softseg;
293 sdtossd(&gdt[mycpu->gd_cpuid * NGDT + IDXSEL(regs->tf_ss & 0xffff)].sd, &softseg);
294 return(regs->tf_esp + softseg.ssd_base);
298 BP_REGS(db_regs_t *regs)
300 struct soft_segment_descriptor softseg;
302 sdtossd(&gdt[mycpu->gd_cpuid * NGDT + IDXSEL(regs->tf_ds & 0xffff)].sd, &softseg);
303 return(regs->tf_ebp + softseg.ssd_base);
308 * Move this to machdep.c and allow it to be called if any debugger is
312 Debugger(const char *msg)
314 static volatile u_char in_Debugger;
318 * Do nothing if the console is in graphics mode. This is
319 * OK if the call is for the debugger hotkey but not if the call
320 * is a weak form of panicing.
322 if (cons_unavail && !(boothowto & RB_GDB))
327 db_printf("Debugger(\"%s\")\n", msg);