xref: /illumos-gate/usr/src/uts/i86xpv/os/mach_kdi.c (revision 8b80e8cb6855118d46f605e91b5ed4ce83417395)
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 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
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/hypervisor.h>
48 #include <sys/bootconf.h>
49 #include <sys/bootinfo.h>
50 #include <sys/promif.h>
51 #include <sys/evtchn_impl.h>
52 #include <sys/cpu.h>
53 #include <vm/kboot_mmu.h>
54 #include <vm/hat_pte.h>
55 
56 static volatile int kdi_slaves_go;
57 
58 /*
59  * These are not safe against dropping into kmdb when fbt::: is active. This is
60  * also broken on i86pc...
61  */
62 
63 void
64 kdi_idtr_write(desctbr_t *idtr)
65 {
66 	gate_desc_t *idt = (gate_desc_t *)idtr->dtr_base;
67 	uint_t nidt = (idtr->dtr_limit + 1) / sizeof (*idt);
68 	uint_t vec;
69 
70 	for (vec = 0; vec < nidt; vec++, idt++)
71 		xen_idt_write(idt, vec);
72 }
73 
74 void
75 kdi_idt_write(gate_desc_t *gate, uint_t vec)
76 {
77 	gate_desc_t *idt = CPU->cpu_m.mcpu_idt;
78 
79 	/*
80 	 * See kdi_idtr_set().
81 	 */
82 	if (idt != NULL)
83 		idt[vec] = *gate;
84 
85 	xen_idt_write(gate, vec);
86 }
87 
88 ulong_t
89 kdi_dreg_get(int reg)
90 {
91 	return (__hypercall1(__HYPERVISOR_get_debugreg, (long)reg));
92 }
93 
94 void
95 kdi_dreg_set(int reg, ulong_t value)
96 {
97 	(void) __hypercall2(__HYPERVISOR_set_debugreg, (long)reg, value);
98 }
99 
100 void
101 kdi_flush_caches(void)
102 {
103 }
104 
105 /*
106  * To avoid domains sucking up CPU while sitting in kmdb, we make all the slave
107  * CPUs wait for a wake-up evtchn.  The master CPU, meanwhile, sleeps for
108  * console activity.
109  */
110 
111 extern void kdi_slave_entry(void);
112 
113 void
114 kdi_stop_slaves(int cpu, int doxc)
115 {
116 	if (doxc)
117 		kdi_xc_others(cpu, kdi_slave_entry);
118 	kdi_slaves_go = 0;
119 }
120 
121 void
122 kdi_start_slaves(void)
123 {
124 	int c;
125 
126 	kdi_slaves_go = 1;
127 
128 	for (c = 0; c < NCPU; c++) {
129 		if (cpu[c] == NULL || !(cpu[c]->cpu_flags & CPU_READY))
130 			continue;
131 		ec_try_ipi(XC_CPUPOKE_PIL, c);
132 	}
133 }
134 
135 /*ARGSUSED*/
136 static int
137 check_slave(void *arg)
138 {
139 	return (kdi_slaves_go == 1);
140 }
141 
142 void
143 kdi_slave_wait(void)
144 {
145 	if (!(cpu[CPU->cpu_id]->cpu_flags & CPU_READY))
146 		return;
147 
148 	ec_wait_on_ipi(XC_CPUPOKE_PIL, check_slave, NULL);
149 }
150 
151 /*
152  * Caution.
153  * These routines are called -extremely- early, during kmdb initialization.
154  *
155  * Many common kernel functions assume that %gs has been initialized,
156  * and fail horribly if it hasn't.  At this point, the boot code has
157  * reserved a descriptor for us (KMDBGS_SEL) in it's GDT; arrange for it
158  * to point at a dummy cpu_t, temporarily at least.
159  *
160  * Note that kmdb entry relies on the fake cpu_t having zero cpu_idt/cpu_id.
161  */
162 
163 #if defined(__amd64)
164 
165 void *
166 boot_kdi_tmpinit(void)
167 {
168 	cpu_t *cpu = kobj_zalloc(sizeof (*cpu), KM_TMP);
169 	user_desc_t *bgdt;
170 	uint64_t gdtpa;
171 	ulong_t ma[1];
172 
173 	cpu->cpu_self = cpu;
174 
175 	/*
176 	 * (Note that we had better switch to a -new- GDT before
177 	 * we discard the KM_TMP mappings, or disaster will ensue.)
178 	 */
179 	bgdt = kobj_zalloc(PAGESIZE, KM_TMP);
180 	ASSERT(((uintptr_t)bgdt & PAGEOFFSET) == 0);
181 
182 	init_boot_gdt(bgdt);
183 
184 	gdtpa = pfn_to_pa(va_to_pfn(bgdt));
185 	ma[0] = (ulong_t)(pa_to_ma(gdtpa) >> PAGESHIFT);
186 	kbm_read_only((uintptr_t)bgdt, gdtpa);
187 	if (HYPERVISOR_set_gdt(ma, PAGESIZE / sizeof (user_desc_t)))
188 		panic("boot_kdi_tmpinit:HYPERVISOR_set_gdt() failed");
189 
190 	load_segment_registers(B64CODE_SEL, 0, 0, B32DATA_SEL);
191 
192 	/*
193 	 * Now point %gsbase to our temp cpu structure.
194 	 */
195 	xen_set_segment_base(SEGBASE_GS_KERNEL, (ulong_t)cpu);
196 	return (0);
197 }
198 
199 /*ARGSUSED*/
200 void
201 boot_kdi_tmpfini(void *old)
202 {
203 	/*
204 	 * This breaks, why do we need it anyway?
205 	 */
206 #if 0	/* XXPV */
207 	load_segment_registers(B64CODE_SEL, 0, KMDBGS_SEL, B32DATA_SEL);
208 #endif
209 }
210 
211 #elif defined(__i386)
212 
213 /*
214  * Sigh.  We're called before we've initialized the kernels GDT, living
215  * off the hypervisor's default GDT.  For kmdb's sake, we switch now to
216  * a GDT that looks like dboot's GDT; very shortly we'll initialize and
217  * switch to the kernel's GDT.
218  */
219 
220 void *
221 boot_kdi_tmpinit(void)
222 {
223 	cpu_t *cpu = kobj_zalloc(sizeof (*cpu), KM_TMP);
224 	user_desc_t *bgdt;
225 	uint64_t gdtpa;
226 	ulong_t ma[1];
227 
228 	cpu->cpu_self = cpu;
229 
230 	/*
231 	 * (Note that we had better switch to a -new- GDT before
232 	 * we discard the KM_TMP mappings, or disaster will ensue.)
233 	 */
234 	bgdt = kobj_zalloc(PAGESIZE, KM_TMP);
235 
236 	ASSERT(((uintptr_t)bgdt & PAGEOFFSET) == 0);
237 	gdtpa = pfn_to_pa(va_to_pfn(bgdt));
238 
239 	init_boot_gdt(bgdt);
240 
241 	set_usegd(&bgdt[GDT_BGSTMP],
242 	    cpu, sizeof (*cpu), SDT_MEMRWA, SEL_KPL, SDP_BYTES, SDP_OP32);
243 
244 	ma[0] = (ulong_t)(pa_to_ma(gdtpa) >> PAGESHIFT);
245 	kbm_read_only((uintptr_t)bgdt, gdtpa);
246 	if (HYPERVISOR_set_gdt(ma, PAGESIZE / sizeof (user_desc_t)))
247 		panic("boot_kdi_tmpinit:HYPERVISOR_set_gdt() failed");
248 
249 	load_segment_registers(B32CODE_SEL, B32DATA_SEL, B32DATA_SEL, 0,
250 	    KMDBGS_SEL, B32DATA_SEL);
251 	return (0);
252 }
253 
254 /*ARGSUSED*/
255 void
256 boot_kdi_tmpfini(void *old)
257 {
258 	load_segment_registers(B32CODE_SEL, B32DATA_SEL, B32DATA_SEL, 0,
259 	    0, B32DATA_SEL);
260 }
261 
262 #endif	/* __i386 */
263