1 /*-
2 * Copyright (c) 1989, 1990 William F. Jolitz.
3 * Copyright (c) 1990 The Regents of the University of California.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 4. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 * $FreeBSD: releng/5.3/sys/i386/i386/exception.s 129742 2004-05-26 07:43:41Z bde $
31 */
32
33 #include "opt_apic.h"
34 #include "opt_npx.h"
35
36 #include <machine/asmacros.h>
37 #include <machine/psl.h>
38 #include <machine/trap.h>
39
40 #include "assym.s"
41
42 #define SEL_RPL_MASK 0x0003
43
44 .text
45
46 /*****************************************************************************/
47 /* Trap handling */
48 /*****************************************************************************/
49 /*
50 * Trap and fault vector routines.
51 *
52 * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on
53 * the stack that mostly looks like an interrupt, but does not disable
54 * interrupts. A few of the traps we are use are interrupt gates,
55 * SDT_SYS386IGT, which are nearly the same thing except interrupts are
56 * disabled on entry.
57 *
58 * The cpu will push a certain amount of state onto the kernel stack for
59 * the current process. The amount of state depends on the type of trap
60 * and whether the trap crossed rings or not. See i386/include/frame.h.
61 * At the very least the current EFLAGS (status register, which includes
62 * the interrupt disable state prior to the trap), the code segment register,
63 * and the return instruction pointer are pushed by the cpu. The cpu
64 * will also push an 'error' code for certain traps. We push a dummy
65 * error code for those traps where the cpu doesn't in order to maintain
66 * a consistent frame. We also push a contrived 'trap number'.
67 *
68 * The cpu does not push the general registers, we must do that, and we
69 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
70 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
71 * must load them with appropriate values for supervisor mode operation.
72 */
73
74 MCOUNT_LABEL(user)
75 MCOUNT_LABEL(btrap)
76
77 IDTVEC(div)
78 pushl $0; TRAP(T_DIVIDE)
79 IDTVEC(dbg)
80 pushl $0; TRAP(T_TRCTRAP)
81 IDTVEC(nmi)
82 pushl $0; TRAP(T_NMI)
83 IDTVEC(bpt)
84 pushl $0; TRAP(T_BPTFLT)
85 IDTVEC(ofl)
86 pushl $0; TRAP(T_OFLOW)
87 IDTVEC(bnd)
88 pushl $0; TRAP(T_BOUND)
89 IDTVEC(ill)
90 pushl $0; TRAP(T_PRIVINFLT)
91 IDTVEC(dna)
92 pushl $0; TRAP(T_DNA)
93 IDTVEC(fpusegm)
94 pushl $0; TRAP(T_FPOPFLT)
95 IDTVEC(tss)
96 TRAP(T_TSSFLT)
97 IDTVEC(missing)
98 TRAP(T_SEGNPFLT)
99 IDTVEC(stk)
100 TRAP(T_STKFLT)
101 IDTVEC(prot)
102 TRAP(T_PROTFLT)
103 IDTVEC(page)
104 TRAP(T_PAGEFLT)
105 IDTVEC(mchk)
106 pushl $0; TRAP(T_MCHK)
107 IDTVEC(rsvd)
108 pushl $0; TRAP(T_RESERVED)
109 IDTVEC(fpu)
110 pushl $0; TRAP(T_ARITHTRAP)
111 IDTVEC(align)
112 TRAP(T_ALIGNFLT)
113
114 IDTVEC(xmm)
115 pushl $0; TRAP(T_XMMFLT)
116
117 /*
118 * alltraps entry point. Interrupts are enabled if this was a trap
119 * gate (TGT), else disabled if this was an interrupt gate (IGT).
120 * Note that int0x80_syscall is a trap gate. Only page faults
121 * use an interrupt gate.
122 */
123
124 SUPERALIGN_TEXT
125 .globl alltraps
126 .type alltraps,@function
127 alltraps:
128 pushal
129 pushl %ds
130 pushl %es
131 pushl %fs
132 alltraps_with_regs_pushed:
133 movl $KDSEL,%eax
134 movl %eax,%ds
135 movl %eax,%es
136 movl $KPSEL,%eax
137 movl %eax,%fs
138 FAKE_MCOUNT(TF_EIP(%esp))
139 calltrap:
140 call trap
141
142 /*
143 * Return via doreti to handle ASTs.
144 */
145 MEXITCOUNT
146 jmp doreti
147
148 /*
149 * SYSCALL CALL GATE (old entry point for a.out binaries)
150 *
151 * The intersegment call has been set up to specify one dummy parameter.
152 *
153 * This leaves a place to put eflags so that the call frame can be
154 * converted to a trap frame. Note that the eflags is (semi-)bogusly
155 * pushed into (what will be) tf_err and then copied later into the
156 * final spot. It has to be done this way because esp can't be just
157 * temporarily altered for the pushfl - an interrupt might come in
158 * and clobber the saved cs/eip.
159 */
160 SUPERALIGN_TEXT
161 IDTVEC(lcall_syscall)
162 pushfl /* save eflags */
163 popl 8(%esp) /* shuffle into tf_eflags */
164 pushl $7 /* sizeof "lcall 7,0" */
165 subl $4,%esp /* skip over tf_trapno */
166 pushal
167 pushl %ds
168 pushl %es
169 pushl %fs
170 movl $KDSEL,%eax /* switch to kernel segments */
171 movl %eax,%ds
172 movl %eax,%es
173 movl $KPSEL,%eax
174 movl %eax,%fs
175 FAKE_MCOUNT(TF_EIP(%esp))
176 call syscall
177 MEXITCOUNT
178 jmp doreti
179
180 /*
181 * Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80)
182 *
183 * Even though the name says 'int0x80', this is actually a TGT (trap gate)
184 * rather then an IGT (interrupt gate). Thus interrupts are enabled on
185 * entry just as they are for a normal syscall.
186 */
187 SUPERALIGN_TEXT
188 IDTVEC(int0x80_syscall)
189 pushl $2 /* sizeof "int 0x80" */
190 subl $4,%esp /* skip over tf_trapno */
191 pushal
192 pushl %ds
193 pushl %es
194 pushl %fs
195 movl $KDSEL,%eax /* switch to kernel segments */
196 movl %eax,%ds
197 movl %eax,%es
198 movl $KPSEL,%eax
199 movl %eax,%fs
200 FAKE_MCOUNT(TF_EIP(%esp))
201 call syscall
202 MEXITCOUNT
203 jmp doreti
204
205 ENTRY(fork_trampoline)
206 pushl %esp /* trapframe pointer */
207 pushl %ebx /* arg1 */
208 pushl %esi /* function */
209 call fork_exit
210 addl $12,%esp
211 /* cut from syscall */
212
213 /*
214 * Return via doreti to handle ASTs.
215 */
216 MEXITCOUNT
217 jmp doreti
218
219
220 /*
221 * To efficiently implement classification of trap and interrupt handlers
222 * for profiling, there must be only trap handlers between the labels btrap
223 * and bintr, and only interrupt handlers between the labels bintr and
224 * eintr. This is implemented (partly) by including files that contain
225 * some of the handlers. Before including the files, set up a normal asm
226 * environment so that the included files doen't need to know that they are
227 * included.
228 */
229
230 .data
231 .p2align 4
232 .text
233 SUPERALIGN_TEXT
234 MCOUNT_LABEL(bintr)
235
236 #include <i386/isa/atpic_vector.s>
237
238 #ifdef DEV_APIC
239 .data
240 .p2align 4
241 .text
242 SUPERALIGN_TEXT
243
244 #include <i386/i386/apic_vector.s>
245 #endif
246
247 .data
248 .p2align 4
249 .text
250 SUPERALIGN_TEXT
251 #include <i386/i386/vm86bios.s>
252
253 .text
254 MCOUNT_LABEL(eintr)
255
256 /*
257 * void doreti(struct trapframe)
258 *
259 * Handle return from interrupts, traps and syscalls.
260 */
261 .text
262 SUPERALIGN_TEXT
263 .type doreti,@function
264 doreti:
265 FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */
266 doreti_next:
267 /*
268 * Check if ASTs can be handled now. PSL_VM must be checked first
269 * since segment registers only have an RPL in non-VM86 mode.
270 */
271 testl $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
272 jz doreti_notvm86
273 movl PCPU(CURPCB),%ecx
274 testl $PCB_VM86CALL,PCB_FLAGS(%ecx) /* are we in a vm86 call? */
275 jz doreti_ast /* can handle ASTS now if not */
276 jmp doreti_exit
277
278 doreti_notvm86:
279 testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
280 jz doreti_exit /* can't handle ASTs now if not */
281
282 doreti_ast:
283 /*
284 * Check for ASTs atomically with returning. Disabling CPU
285 * interrupts provides sufficient locking even in the SMP case,
286 * since we will be informed of any new ASTs by an IPI.
287 */
288 cli
289 movl PCPU(CURTHREAD),%eax
290 testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax)
291 je doreti_exit
292 sti
293 pushl %esp /* pass a pointer to the trapframe */
294 call ast
295 add $4,%esp
296 jmp doreti_ast
297
298 /*
299 * doreti_exit: pop registers, iret.
300 *
301 * The segment register pop is a special case, since it may
302 * fault if (for example) a sigreturn specifies bad segment
303 * registers. The fault is handled in trap.c.
304 */
305 doreti_exit:
306 MEXITCOUNT
307
308 .globl doreti_popl_fs
309 doreti_popl_fs:
310 popl %fs
311 .globl doreti_popl_es
312 doreti_popl_es:
313 popl %es
314 .globl doreti_popl_ds
315 doreti_popl_ds:
316 popl %ds
317 popal
318 addl $8,%esp
319 .globl doreti_iret
320 doreti_iret:
321 iret
322
323 /*
324 * doreti_iret_fault and friends. Alternative return code for
325 * the case where we get a fault in the doreti_exit code
326 * above. trap() (i386/i386/trap.c) catches this specific
327 * case, sends the process a signal and continues in the
328 * corresponding place in the code below.
329 */
330 ALIGN_TEXT
331 .globl doreti_iret_fault
332 doreti_iret_fault:
333 subl $8,%esp
334 pushal
335 pushl %ds
336 .globl doreti_popl_ds_fault
337 doreti_popl_ds_fault:
338 pushl %es
339 .globl doreti_popl_es_fault
340 doreti_popl_es_fault:
341 pushl %fs
342 .globl doreti_popl_fs_fault
343 doreti_popl_fs_fault:
344 movl $0,TF_ERR(%esp) /* XXX should be the error code */
345 movl $T_PROTFLT,TF_TRAPNO(%esp)
346 jmp alltraps_with_regs_pushed
Cache object: 3df7232f8284a7a5367b91c68cd1e522
|