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 * $FreeBSD$
31 */
32
33 #include "opt_apic.h"
34 #include "opt_kdtrace.h"
35 #include "opt_npx.h"
36
37 #include <machine/asmacros.h>
38 #include <machine/psl.h>
39 #include <machine/trap.h>
40
41 #include "assym.s"
42
43 #define SEL_RPL_MASK 0x0003
44 #define GSEL_KPL 0x0020 /* GSEL(GCODE_SEL, SEL_KPL) */
45
46
47 #ifdef KDTRACE_HOOKS
48 .bss
49 .globl dtrace_invop_jump_addr
50 .align 4
51 .type dtrace_invop_jump_addr, @object
52 .size dtrace_invop_jump_addr, 4
53 dtrace_invop_jump_addr:
54 .zero 4
55 .globl dtrace_invop_calltrap_addr
56 .align 4
57 .type dtrace_invop_calltrap_addr, @object
58 .size dtrace_invop_calltrap_addr, 4
59 dtrace_invop_calltrap_addr:
60 .zero 8
61 #endif
62 .text
63
64 /*****************************************************************************/
65 /* Trap handling */
66 /*****************************************************************************/
67 /*
68 * Trap and fault vector routines.
69 *
70 * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on
71 * the stack that mostly looks like an interrupt, but does not disable
72 * interrupts. A few of the traps we are use are interrupt gates,
73 * SDT_SYS386IGT, which are nearly the same thing except interrupts are
74 * disabled on entry.
75 *
76 * The cpu will push a certain amount of state onto the kernel stack for
77 * the current process. The amount of state depends on the type of trap
78 * and whether the trap crossed rings or not. See i386/include/frame.h.
79 * At the very least the current EFLAGS (status register, which includes
80 * the interrupt disable state prior to the trap), the code segment register,
81 * and the return instruction pointer are pushed by the cpu. The cpu
82 * will also push an 'error' code for certain traps. We push a dummy
83 * error code for those traps where the cpu doesn't in order to maintain
84 * a consistent frame. We also push a contrived 'trap number'.
85 *
86 * The cpu does not push the general registers, we must do that, and we
87 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
88 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
89 * must load them with appropriate values for supervisor mode operation.
90 */
91
92 MCOUNT_LABEL(user)
93 MCOUNT_LABEL(btrap)
94
95 #define TRAP(a) pushl $(a) ; jmp alltraps
96
97 IDTVEC(div)
98 pushl $0; TRAP(T_DIVIDE)
99 IDTVEC(dbg)
100 pushl $0; TRAP(T_TRCTRAP)
101 IDTVEC(nmi)
102 pushl $0; TRAP(T_NMI)
103 IDTVEC(bpt)
104 pushl $0; TRAP(T_BPTFLT)
105 IDTVEC(ofl)
106 pushl $0; TRAP(T_OFLOW)
107 IDTVEC(bnd)
108 pushl $0; TRAP(T_BOUND)
109 #ifndef KDTRACE_HOOKS
110 IDTVEC(ill)
111 pushl $0; TRAP(T_PRIVINFLT)
112 #endif
113 IDTVEC(dna)
114 pushl $0; TRAP(T_DNA)
115 IDTVEC(fpusegm)
116 pushl $0; TRAP(T_FPOPFLT)
117 IDTVEC(tss)
118 TRAP(T_TSSFLT)
119 IDTVEC(missing)
120 TRAP(T_SEGNPFLT)
121 IDTVEC(stk)
122 TRAP(T_STKFLT)
123 IDTVEC(prot)
124 TRAP(T_PROTFLT)
125 IDTVEC(page)
126 TRAP(T_PAGEFLT)
127 IDTVEC(mchk)
128 pushl $0; TRAP(T_MCHK)
129 IDTVEC(rsvd)
130 pushl $0; TRAP(T_RESERVED)
131 IDTVEC(fpu)
132 pushl $0; TRAP(T_ARITHTRAP)
133 IDTVEC(align)
134 TRAP(T_ALIGNFLT)
135 IDTVEC(xmm)
136 pushl $0; TRAP(T_XMMFLT)
137
138 /*
139 * alltraps entry point. Interrupts are enabled if this was a trap
140 * gate (TGT), else disabled if this was an interrupt gate (IGT).
141 * Note that int0x80_syscall is a trap gate. Interrupt gates are
142 * used by page faults, non-maskable interrupts, debug and breakpoint
143 * exceptions.
144 */
145
146 SUPERALIGN_TEXT
147 .globl alltraps
148 .type alltraps,@function
149 alltraps:
150 pushal
151 pushl %ds
152 pushl %es
153 pushl %fs
154 alltraps_with_regs_pushed:
155 SET_KERNEL_SREGS
156 FAKE_MCOUNT(TF_EIP(%esp))
157 calltrap:
158 pushl %esp
159 call trap
160 add $4, %esp
161
162 /*
163 * Return via doreti to handle ASTs.
164 */
165 MEXITCOUNT
166 jmp doreti
167
168 /*
169 * Privileged instruction fault.
170 */
171 #ifdef KDTRACE_HOOKS
172 SUPERALIGN_TEXT
173 IDTVEC(ill)
174 /* Check if there is no DTrace hook registered. */
175 cmpl $0,dtrace_invop_jump_addr
176 je norm_ill
177
178 /* Check if this is a user fault. */
179 cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
180
181 /* If so, just handle it as a normal trap. */
182 jne norm_ill
183
184 /*
185 * This is a kernel instruction fault that might have been caused
186 * by a DTrace provider.
187 */
188 pushal /* Push all registers onto the stack. */
189
190 /*
191 * Set our jump address for the jump back in the event that
192 * the exception wasn't caused by DTrace at all.
193 */
194 movl $norm_ill, dtrace_invop_calltrap_addr
195
196 /* Jump to the code hooked in by DTrace. */
197 jmpl *dtrace_invop_jump_addr
198
199 /*
200 * Process the instruction fault in the normal way.
201 */
202 norm_ill:
203 pushl $0
204 TRAP(T_PRIVINFLT)
205 #endif
206
207 /*
208 * SYSCALL CALL GATE (old entry point for a.out binaries)
209 *
210 * The intersegment call has been set up to specify one dummy parameter.
211 *
212 * This leaves a place to put eflags so that the call frame can be
213 * converted to a trap frame. Note that the eflags is (semi-)bogusly
214 * pushed into (what will be) tf_err and then copied later into the
215 * final spot. It has to be done this way because esp can't be just
216 * temporarily altered for the pushfl - an interrupt might come in
217 * and clobber the saved cs/eip.
218 */
219 SUPERALIGN_TEXT
220 IDTVEC(lcall_syscall)
221 pushfl /* save eflags */
222 popl 8(%esp) /* shuffle into tf_eflags */
223 pushl $7 /* sizeof "lcall 7,0" */
224 subl $4,%esp /* skip over tf_trapno */
225 pushal
226 pushl %ds
227 pushl %es
228 pushl %fs
229 SET_KERNEL_SREGS
230 FAKE_MCOUNT(TF_EIP(%esp))
231 pushl %esp
232 call syscall
233 add $4, %esp
234 MEXITCOUNT
235 jmp doreti
236
237 /*
238 * Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80)
239 *
240 * Even though the name says 'int0x80', this is actually a TGT (trap gate)
241 * rather then an IGT (interrupt gate). Thus interrupts are enabled on
242 * entry just as they are for a normal syscall.
243 */
244 SUPERALIGN_TEXT
245 IDTVEC(int0x80_syscall)
246 pushl $2 /* sizeof "int 0x80" */
247 subl $4,%esp /* skip over tf_trapno */
248 pushal
249 pushl %ds
250 pushl %es
251 pushl %fs
252 SET_KERNEL_SREGS
253 FAKE_MCOUNT(TF_EIP(%esp))
254 pushl %esp
255 call syscall
256 add $4, %esp
257 MEXITCOUNT
258 jmp doreti
259
260 ENTRY(fork_trampoline)
261 pushl %esp /* trapframe pointer */
262 pushl %ebx /* arg1 */
263 pushl %esi /* function */
264 call fork_exit
265 addl $12,%esp
266 /* cut from syscall */
267
268 /*
269 * Return via doreti to handle ASTs.
270 */
271 MEXITCOUNT
272 jmp doreti
273
274
275 /*
276 * To efficiently implement classification of trap and interrupt handlers
277 * for profiling, there must be only trap handlers between the labels btrap
278 * and bintr, and only interrupt handlers between the labels bintr and
279 * eintr. This is implemented (partly) by including files that contain
280 * some of the handlers. Before including the files, set up a normal asm
281 * environment so that the included files doen't need to know that they are
282 * included.
283 */
284
285 .data
286 .p2align 4
287 .text
288 SUPERALIGN_TEXT
289 MCOUNT_LABEL(bintr)
290
291 #include <i386/isa/atpic_vector.s>
292
293 #ifdef DEV_APIC
294 .data
295 .p2align 4
296 .text
297 SUPERALIGN_TEXT
298
299 #include <i386/i386/apic_vector.s>
300 #endif
301
302 .data
303 .p2align 4
304 .text
305 SUPERALIGN_TEXT
306 #include <i386/i386/vm86bios.s>
307
308 .text
309 MCOUNT_LABEL(eintr)
310
311 /*
312 * void doreti(struct trapframe)
313 *
314 * Handle return from interrupts, traps and syscalls.
315 */
316 .text
317 SUPERALIGN_TEXT
318 .type doreti,@function
319 doreti:
320 FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */
321 doreti_next:
322 /*
323 * Check if ASTs can be handled now. PSL_VM must be checked first
324 * since segment registers only have an RPL in non-VM86 mode.
325 */
326 testl $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
327 jz doreti_notvm86
328 movl PCPU(CURPCB),%ecx
329 testl $PCB_VM86CALL,PCB_FLAGS(%ecx) /* are we in a vm86 call? */
330 jz doreti_ast /* can handle ASTS now if not */
331 jmp doreti_exit
332
333 doreti_notvm86:
334 testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
335 jz doreti_exit /* can't handle ASTs now if not */
336
337 doreti_ast:
338 /*
339 * Check for ASTs atomically with returning. Disabling CPU
340 * interrupts provides sufficient locking even in the SMP case,
341 * since we will be informed of any new ASTs by an IPI.
342 */
343 cli
344 movl PCPU(CURTHREAD),%eax
345 testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax)
346 je doreti_exit
347 sti
348 pushl %esp /* pass a pointer to the trapframe */
349 call ast
350 add $4,%esp
351 jmp doreti_ast
352
353 /*
354 * doreti_exit: pop registers, iret.
355 *
356 * The segment register pop is a special case, since it may
357 * fault if (for example) a sigreturn specifies bad segment
358 * registers. The fault is handled in trap.c.
359 */
360 doreti_exit:
361 MEXITCOUNT
362
363 .globl doreti_popl_fs
364 doreti_popl_fs:
365 popl %fs
366 .globl doreti_popl_es
367 doreti_popl_es:
368 popl %es
369 .globl doreti_popl_ds
370 doreti_popl_ds:
371 popl %ds
372 popal
373 addl $8,%esp
374 .globl doreti_iret
375 doreti_iret:
376 iret
377
378 /*
379 * doreti_iret_fault and friends. Alternative return code for
380 * the case where we get a fault in the doreti_exit code
381 * above. trap() (i386/i386/trap.c) catches this specific
382 * case, sends the process a signal and continues in the
383 * corresponding place in the code below.
384 */
385 ALIGN_TEXT
386 .globl doreti_iret_fault
387 doreti_iret_fault:
388 subl $8,%esp
389 pushal
390 pushl %ds
391 .globl doreti_popl_ds_fault
392 doreti_popl_ds_fault:
393 pushl %es
394 .globl doreti_popl_es_fault
395 doreti_popl_es_fault:
396 pushl %fs
397 .globl doreti_popl_fs_fault
398 doreti_popl_fs_fault:
399 movl $0,TF_ERR(%esp) /* XXX should be the error code */
400 movl $T_PROTFLT,TF_TRAPNO(%esp)
401 jmp alltraps_with_regs_pushed
Cache object: fe460a2ebc60a82a485ee2abd6f224fb
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