2 * Copyright (c) 1989, 1990 William F. Jolitz.
3 * Copyright (c) 1990 The Regents of the University of California.
4 * Copyright (c) 2007 The FreeBSD Foundation
7 * Portions of this software were developed by A. Joseph Koshy under
8 * sponsorship from the FreeBSD Foundation and Google, Inc.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 #include "opt_atpic.h"
39 #include "opt_hwpmc_hooks.h"
40 #include "opt_kdtrace.h"
43 #include <machine/asmacros.h>
44 #include <machine/psl.h>
45 #include <machine/trap.h>
49 #define SEL_RPL_MASK 0x0003
50 #define GSEL_KPL 0x0020 /* GSEL(GCODE_SEL, SEL_KPL) */
54 .globl dtrace_invop_jump_addr
56 .type dtrace_invop_jump_addr, @object
57 .size dtrace_invop_jump_addr, 4
58 dtrace_invop_jump_addr:
60 .globl dtrace_invop_calltrap_addr
62 .type dtrace_invop_calltrap_addr, @object
63 .size dtrace_invop_calltrap_addr, 4
64 dtrace_invop_calltrap_addr:
69 ENTRY(start_exceptions)
71 /*****************************************************************************/
73 /*****************************************************************************/
75 * Trap and fault vector routines.
77 * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on
78 * the stack that mostly looks like an interrupt, but does not disable
79 * interrupts. A few of the traps we are use are interrupt gates,
80 * SDT_SYS386IGT, which are nearly the same thing except interrupts are
83 * The cpu will push a certain amount of state onto the kernel stack for
84 * the current process. The amount of state depends on the type of trap
85 * and whether the trap crossed rings or not. See i386/include/frame.h.
86 * At the very least the current EFLAGS (status register, which includes
87 * the interrupt disable state prior to the trap), the code segment register,
88 * and the return instruction pointer are pushed by the cpu. The cpu
89 * will also push an 'error' code for certain traps. We push a dummy
90 * error code for those traps where the cpu doesn't in order to maintain
91 * a consistent frame. We also push a contrived 'trap number'.
93 * The cpu does not push the general registers, we must do that, and we
94 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
95 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
96 * must load them with appropriate values for supervisor mode operation.
102 #define TRAP(a) pushl $(a) ; jmp alltraps
105 pushl $0; TRAP(T_DIVIDE)
107 pushl $0; TRAP(T_TRCTRAP)
109 pushl $0; TRAP(T_NMI)
111 pushl $0; TRAP(T_BPTFLT)
113 pushl $0; TRAP(T_DTRACE_RET)
115 pushl $0; TRAP(T_OFLOW)
117 pushl $0; TRAP(T_BOUND)
118 #ifndef KDTRACE_HOOKS
120 pushl $0; TRAP(T_PRIVINFLT)
123 pushl $0; TRAP(T_DNA)
125 pushl $0; TRAP(T_FPOPFLT)
137 pushl $0; TRAP(T_MCHK)
139 pushl $0; TRAP(T_RESERVED)
141 pushl $0; TRAP(T_ARITHTRAP)
145 pushl $0; TRAP(T_XMMFLT)
148 * All traps except ones for syscalls jump to alltraps. If
149 * interrupts were enabled when the trap occurred, then interrupts
150 * are enabled now if the trap was through a trap gate, else
151 * disabled if the trap was through an interrupt gate. Note that
152 * int0x80_syscall is a trap gate. Interrupt gates are used by
153 * page faults, non-maskable interrupts, debug and breakpoint
158 .type alltraps,@function
167 alltraps_with_regs_pushed:
170 FAKE_MCOUNT(TF_EIP(%esp))
177 * Return via doreti to handle ASTs.
183 * Privileged instruction fault.
188 /* Check if there is no DTrace hook registered. */
189 cmpl $0,dtrace_invop_jump_addr
192 /* Check if this is a user fault. */
193 cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
195 /* If so, just handle it as a normal trap. */
199 * This is a kernel instruction fault that might have been caused
200 * by a DTrace provider.
202 pushal /* Push all registers onto the stack. */
205 * Set our jump address for the jump back in the event that
206 * the exception wasn't caused by DTrace at all.
208 movl $norm_ill, dtrace_invop_calltrap_addr
210 /* Jump to the code hooked in by DTrace. */
211 jmpl *dtrace_invop_jump_addr
214 * Process the instruction fault in the normal way.
222 * Call gate entry for syscalls (lcall 7,0).
223 * This is used by FreeBSD 1.x a.out executables and "old" NetBSD executables.
225 * The intersegment call has been set up to specify one dummy parameter.
226 * This leaves a place to put eflags so that the call frame can be
227 * converted to a trap frame. Note that the eflags is (semi-)bogusly
228 * pushed into (what will be) tf_err and then copied later into the
229 * final spot. It has to be done this way because esp can't be just
230 * temporarily altered for the pushfl - an interrupt might come in
231 * and clobber the saved cs/eip.
234 IDTVEC(lcall_syscall)
235 pushfl /* save eflags */
236 popl 8(%esp) /* shuffle into tf_eflags */
237 pushl $7 /* sizeof "lcall 7,0" */
238 subl $4,%esp /* skip over tf_trapno */
248 FAKE_MCOUNT(TF_EIP(%esp))
256 * Trap gate entry for syscalls (int 0x80).
257 * This is used by FreeBSD ELF executables, "new" NetBSD executables, and all
260 * Even though the name says 'int0x80', this is actually a trap gate, not an
261 * interrupt gate. Thus interrupts are enabled on entry just as they are for
265 IDTVEC(int0x80_syscall)
266 pushl $2 /* sizeof "int 0x80" */
267 subl $4,%esp /* skip over tf_trapno */
277 FAKE_MCOUNT(TF_EIP(%esp))
284 ENTRY(fork_trampoline)
285 pushl %esp /* trapframe pointer */
286 pushl %ebx /* arg1 */
287 pushl %esi /* function */
290 /* cut from syscall */
293 * Return via doreti to handle ASTs.
300 * To efficiently implement classification of trap and interrupt handlers
301 * for profiling, there must be only trap handlers between the labels btrap
302 * and bintr, and only interrupt handlers between the labels bintr and
303 * eintr. This is implemented (partly) by including files that contain
304 * some of the handlers. Before including the files, set up a normal asm
305 * environment so that the included files doen't need to know that they are
316 #include <i386/i386/atpic_vector.s>
319 #if defined(DEV_APIC) && defined(DEV_ATPIC)
327 #include <i386/i386/apic_vector.s>
334 #include <i386/i386/vm86bios.s>
340 * void doreti(struct trapframe)
342 * Handle return from interrupts, traps and syscalls.
346 .type doreti,@function
348 FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */
351 * Check if ASTs can be handled now. ASTs cannot be safely
352 * processed when returning from an NMI.
354 cmpb $T_NMI,TF_TRAPNO(%esp)
361 * PSL_VM must be checked first since segment registers only
362 * have an RPL in non-VM86 mode.
363 * ASTs can not be handled now if we are in a vm86 call.
365 testl $PSL_VM,TF_EFLAGS(%esp)
367 movl PCPU(CURPCB),%ecx
368 testl $PCB_VM86CALL,PCB_FLAGS(%ecx)
373 testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
374 jz doreti_exit /* can't handle ASTs now if not */
378 * Check for ASTs atomically with returning. Disabling CPU
379 * interrupts provides sufficient locking even in the SMP case,
380 * since we will be informed of any new ASTs by an IPI.
383 movl PCPU(CURTHREAD),%eax
384 testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax)
387 pushl %esp /* pass a pointer to the trapframe */
393 * doreti_exit: pop registers, iret.
395 * The segment register pop is a special case, since it may
396 * fault if (for example) a sigreturn specifies bad segment
397 * registers. The fault is handled in trap.c.
402 .globl doreti_popl_fs
405 .globl doreti_popl_es
408 .globl doreti_popl_ds
418 * doreti_iret_fault and friends. Alternative return code for
419 * the case where we get a fault in the doreti_exit code
420 * above. trap() (i386/i386/trap.c) catches this specific
421 * case, sends the process a signal and continues in the
422 * corresponding place in the code below.
425 .globl doreti_iret_fault
431 .globl doreti_popl_ds_fault
432 doreti_popl_ds_fault:
435 .globl doreti_popl_es_fault
436 doreti_popl_es_fault:
439 .globl doreti_popl_fs_fault
440 doreti_popl_fs_fault:
442 movl $0,TF_ERR(%esp) /* XXX should be the error code */
443 movl $T_PROTFLT,TF_TRAPNO(%esp)
444 jmp alltraps_with_regs_pushed
448 * Since we are returning from an NMI, check if the current trap
449 * was from user mode and if so whether the current thread
450 * needs a user call chain capture.
452 testb $SEL_RPL_MASK,TF_CS(%esp)
454 movl PCPU(CURTHREAD),%eax /* curthread present? */
457 testl $TDP_CALLCHAIN,TD_PFLAGS(%eax) /* flagged for capture? */
460 * Take the processor out of NMI mode by executing a fake "iret".
468 * Call the callchain capture hook after turning interrupts back on.
473 pushl %esp /* frame pointer */
474 pushl $PMC_FN_USER_CALLCHAIN /* command */
475 movl PCPU(CURTHREAD),%eax
476 pushl %eax /* curthread */
481 ENTRY(end_exceptions)