xref: /illumos-gate/usr/src/uts/i86pc/os/mach_kdi.c (revision 14b24e2b79293068c8e016a69ef1d872fb5e2fd5)
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  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * Copyright 2018 Joyent, Inc.
26  */
27 
28 /*
29  * Kernel/Debugger Interface (KDI) routines.  Called during debugger under
30  * various system states (boot, while running, while the debugger has control).
31  * Functions intended for use while the debugger has control may not grab any
32  * locks or perform any functions that assume the availability of other system
33  * services.
34  */
35 
36 #include <sys/systm.h>
37 #include <sys/x86_archext.h>
38 #include <sys/kdi_impl.h>
39 #include <sys/smp_impldefs.h>
40 #include <sys/psm_types.h>
41 #include <sys/segments.h>
42 #include <sys/archsystm.h>
43 #include <sys/controlregs.h>
44 #include <sys/trap.h>
45 #include <sys/kobj.h>
46 #include <sys/kobj_impl.h>
47 #include <sys/mach_mmu.h>
48 
49 void
50 kdi_idt_write(gate_desc_t *gate, uint_t vec)
51 {
52 	gate_desc_t *idt = CPU->cpu_m.mcpu_idt;
53 
54 	/*
55 	 * See kdi_idtr_set().
56 	 */
57 	if (idt == NULL) {
58 		desctbr_t idtr;
59 		rd_idtr(&idtr);
60 		idt = (gate_desc_t *)idtr.dtr_base;
61 	}
62 
63 	idt[vec] = *gate;
64 }
65 
66 ulong_t
67 kdi_dreg_get(int reg)
68 {
69 	switch (reg) {
70 	case 0:
71 		return (kdi_getdr0());
72 	case 1:
73 		return (kdi_getdr1());
74 	case 2:
75 		return (kdi_getdr2());
76 	case 3:
77 		return (kdi_getdr3());
78 	case 6:
79 		return (kdi_getdr6());
80 	case 7:
81 		return (kdi_getdr7());
82 	default:
83 		panic("invalid debug register dr%d", reg);
84 		/*NOTREACHED*/
85 	}
86 }
87 
88 void
89 kdi_dreg_set(int reg, ulong_t value)
90 {
91 	switch (reg) {
92 	case 0:
93 		kdi_setdr0(value);
94 		break;
95 	case 1:
96 		kdi_setdr1(value);
97 		break;
98 	case 2:
99 		kdi_setdr2(value);
100 		break;
101 	case 3:
102 		kdi_setdr3(value);
103 		break;
104 	case 6:
105 		kdi_setdr6(value);
106 		break;
107 	case 7:
108 		kdi_setdr7(value);
109 		break;
110 	default:
111 		panic("invalid debug register dr%d", reg);
112 		/*NOTREACHED*/
113 	}
114 }
115 
116 extern void kdi_slave_entry(void);
117 
118 void
119 kdi_stop_slaves(int cpu, int doxc)
120 {
121 	if (doxc)
122 		kdi_xc_others(cpu, kdi_slave_entry);
123 }
124 
125 /*
126  * On i86pc, slaves busy-loop, so we don't need to do anything here.
127  */
128 void
129 kdi_start_slaves(void)
130 {
131 }
132 
133 void
134 kdi_slave_wait(void)
135 {
136 }
137 
138 /*
139  * Caution.
140  * These routines are called -extremely- early, during kmdb initialization.
141  *
142  * Many common kernel functions assume that %gs has been initialized,
143  * and fail horribly if it hasn't.  At this point, the boot code has
144  * reserved a descriptor for us (KMDBGS_SEL) in it's GDT; arrange for it
145  * to point at a dummy cpu_t, temporarily at least.
146  *
147  * Note that kmdb entry relies on the fake cpu_t having zero cpu_idt/cpu_id.
148  */
149 
150 #if defined(__amd64)
151 
152 void *
153 boot_kdi_tmpinit(void)
154 {
155 	cpu_t *cpu = kobj_zalloc(sizeof (*cpu), KM_TMP);
156 	uintptr_t old;
157 
158 	cpu->cpu_self = cpu;
159 
160 	old = (uintptr_t)rdmsr(MSR_AMD_GSBASE);
161 	wrmsr(MSR_AMD_GSBASE, (uint64_t)cpu);
162 	return ((void *)old);
163 }
164 
165 void
166 boot_kdi_tmpfini(void *old)
167 {
168 	wrmsr(MSR_AMD_GSBASE, (uint64_t)old);
169 }
170 
171 #elif defined(__i386)
172 
173 void *
174 boot_kdi_tmpinit(void)
175 {
176 	cpu_t *cpu = kobj_zalloc(sizeof (*cpu), KM_TMP);
177 	uintptr_t old;
178 	desctbr_t b_gdtr;
179 	user_desc_t *bgdt;
180 
181 	cpu->cpu_self = cpu;
182 
183 	rd_gdtr(&b_gdtr);
184 	bgdt = (user_desc_t *)(b_gdtr.dtr_base);
185 
186 	set_usegd(&bgdt[GDT_BGSTMP],
187 	    cpu, sizeof (*cpu), SDT_MEMRWA, SEL_KPL, SDP_BYTES, SDP_OP32);
188 
189 	/*
190 	 * Now switch %gs to point at it.
191 	 */
192 	old = getgs();
193 	setgs(KMDBGS_SEL);
194 
195 	return ((void *)old);
196 }
197 
198 void
199 boot_kdi_tmpfini(void *old)
200 {
201 	setgs((uintptr_t)old);
202 }
203 
204 #endif	/* __i386 */
205