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"
42 #include <machine/asmacros.h>
43 #include <machine/psl.h>
44 #include <machine/trap.h>
48 #define SEL_RPL_MASK 0x0003
49 #define GSEL_KPL 0x0020 /* GSEL(GCODE_SEL, SEL_KPL) */
53 .globl dtrace_invop_jump_addr
55 .type dtrace_invop_jump_addr, @object
56 .size dtrace_invop_jump_addr, 4
57 dtrace_invop_jump_addr:
59 .globl dtrace_invop_calltrap_addr
61 .type dtrace_invop_calltrap_addr, @object
62 .size dtrace_invop_calltrap_addr, 4
63 dtrace_invop_calltrap_addr:
68 ENTRY(start_exceptions)
70 /*****************************************************************************/
72 /*****************************************************************************/
74 * Trap and fault vector routines.
76 * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on
77 * the stack that mostly looks like an interrupt, but does not disable
78 * interrupts. A few of the traps we are use are interrupt gates,
79 * SDT_SYS386IGT, which are nearly the same thing except interrupts are
82 * The cpu will push a certain amount of state onto the kernel stack for
83 * the current process. The amount of state depends on the type of trap
84 * and whether the trap crossed rings or not. See i386/include/frame.h.
85 * At the very least the current EFLAGS (status register, which includes
86 * the interrupt disable state prior to the trap), the code segment register,
87 * and the return instruction pointer are pushed by the cpu. The cpu
88 * will also push an 'error' code for certain traps. We push a dummy
89 * error code for those traps where the cpu doesn't in order to maintain
90 * a consistent frame. We also push a contrived 'trap number'.
92 * The cpu does not push the general registers, we must do that, and we
93 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
94 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
95 * must load them with appropriate values for supervisor mode operation.
101 #define TRAP(a) pushl $(a) ; jmp alltraps
104 pushl $0; TRAP(T_DIVIDE)
106 pushl $0; TRAP(T_TRCTRAP)
108 pushl $0; TRAP(T_NMI)
110 pushl $0; TRAP(T_BPTFLT)
112 pushl $0; TRAP(T_DTRACE_RET)
114 pushl $0; TRAP(T_OFLOW)
116 pushl $0; TRAP(T_BOUND)
117 #ifndef KDTRACE_HOOKS
119 pushl $0; TRAP(T_PRIVINFLT)
122 pushl $0; TRAP(T_DNA)
124 pushl $0; TRAP(T_FPOPFLT)
136 pushl $0; TRAP(T_MCHK)
138 pushl $0; TRAP(T_RESERVED)
140 pushl $0; TRAP(T_ARITHTRAP)
144 pushl $0; TRAP(T_XMMFLT)
147 * All traps except ones for syscalls jump to alltraps. If
148 * interrupts were enabled when the trap occurred, then interrupts
149 * are enabled now if the trap was through a trap gate, else
150 * disabled if the trap was through an interrupt gate. Note that
151 * int0x80_syscall is a trap gate. Interrupt gates are used by
152 * page faults, non-maskable interrupts, debug and breakpoint
157 .type alltraps,@function
166 alltraps_with_regs_pushed:
169 FAKE_MCOUNT(TF_EIP(%esp))
176 * Return via doreti to handle ASTs.
182 * Privileged instruction fault.
187 /* Check if there is no DTrace hook registered. */
188 cmpl $0,dtrace_invop_jump_addr
191 /* Check if this is a user fault. */
192 cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
194 /* If so, just handle it as a normal trap. */
198 * This is a kernel instruction fault that might have been caused
199 * by a DTrace provider.
201 pushal /* Push all registers onto the stack. */
204 * Set our jump address for the jump back in the event that
205 * the exception wasn't caused by DTrace at all.
207 movl $norm_ill, dtrace_invop_calltrap_addr
209 /* Jump to the code hooked in by DTrace. */
210 jmpl *dtrace_invop_jump_addr
213 * Process the instruction fault in the normal way.
221 * Call gate entry for syscalls (lcall 7,0).
222 * This is used by FreeBSD 1.x a.out executables and "old" NetBSD executables.
224 * The intersegment call has been set up to specify one dummy parameter.
225 * This leaves a place to put eflags so that the call frame can be
226 * converted to a trap frame. Note that the eflags is (semi-)bogusly
227 * pushed into (what will be) tf_err and then copied later into the
228 * final spot. It has to be done this way because esp can't be just
229 * temporarily altered for the pushfl - an interrupt might come in
230 * and clobber the saved cs/eip.
233 IDTVEC(lcall_syscall)
234 pushfl /* save eflags */
235 popl 8(%esp) /* shuffle into tf_eflags */
236 pushl $7 /* sizeof "lcall 7,0" */
237 pushl $0 /* tf_trapno */
247 FAKE_MCOUNT(TF_EIP(%esp))
255 * Trap gate entry for syscalls (int 0x80).
256 * This is used by FreeBSD ELF executables, "new" NetBSD executables, and all
259 * Even though the name says 'int0x80', this is actually a trap gate, not an
260 * interrupt gate. Thus interrupts are enabled on entry just as they are for
264 IDTVEC(int0x80_syscall)
265 pushl $2 /* sizeof "int 0x80" */
266 pushl $0 /* tf_trapno */
276 FAKE_MCOUNT(TF_EIP(%esp))
283 ENTRY(fork_trampoline)
284 pushl %esp /* trapframe pointer */
285 pushl %ebx /* arg1 */
286 pushl %esi /* function */
289 /* cut from syscall */
292 * Return via doreti to handle ASTs.
299 * To efficiently implement classification of trap and interrupt handlers
300 * for profiling, there must be only trap handlers between the labels btrap
301 * and bintr, and only interrupt handlers between the labels bintr and
302 * eintr. This is implemented (partly) by including files that contain
303 * some of the handlers. Before including the files, set up a normal asm
304 * environment so that the included files doen't need to know that they are
315 #include <i386/i386/atpic_vector.s>
318 #if defined(DEV_APIC) && defined(DEV_ATPIC)
326 #include <i386/i386/apic_vector.s>
333 #include <i386/i386/vm86bios.s>
339 * void doreti(struct trapframe)
341 * Handle return from interrupts, traps and syscalls.
345 .type doreti,@function
348 FAKE_MCOUNT($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)