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_hwpmc_hooks.h"
39 #include "opt_kdtrace.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_OFLOW)
114 pushl $0; TRAP(T_BOUND)
115 #ifndef KDTRACE_HOOKS
117 pushl $0; TRAP(T_PRIVINFLT)
120 pushl $0; TRAP(T_DNA)
122 pushl $0; TRAP(T_FPOPFLT)
134 pushl $0; TRAP(T_MCHK)
136 pushl $0; TRAP(T_RESERVED)
138 pushl $0; TRAP(T_ARITHTRAP)
142 pushl $0; TRAP(T_XMMFLT)
145 * alltraps entry point. Interrupts are enabled if this was a trap
146 * gate (TGT), else disabled if this was an interrupt gate (IGT).
147 * Note that int0x80_syscall is a trap gate. Interrupt gates are
148 * used by page faults, non-maskable interrupts, debug and breakpoint
154 .type alltraps,@function
160 alltraps_with_regs_pushed:
162 FAKE_MCOUNT(TF_EIP(%esp))
169 * Return via doreti to handle ASTs.
175 * Privileged instruction fault.
180 /* Check if there is no DTrace hook registered. */
181 cmpl $0,dtrace_invop_jump_addr
184 /* Check if this is a user fault. */
185 cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
187 /* If so, just handle it as a normal trap. */
191 * This is a kernel instruction fault that might have been caused
192 * by a DTrace provider.
194 pushal /* Push all registers onto the stack. */
197 * Set our jump address for the jump back in the event that
198 * the exception wasn't caused by DTrace at all.
200 movl $norm_ill, dtrace_invop_calltrap_addr
202 /* Jump to the code hooked in by DTrace. */
203 jmpl *dtrace_invop_jump_addr
206 * Process the instruction fault in the normal way.
214 * SYSCALL CALL GATE (old entry point for a.out binaries)
216 * The intersegment call has been set up to specify one dummy parameter.
218 * This leaves a place to put eflags so that the call frame can be
219 * converted to a trap frame. Note that the eflags is (semi-)bogusly
220 * pushed into (what will be) tf_err and then copied later into the
221 * final spot. It has to be done this way because esp can't be just
222 * temporarily altered for the pushfl - an interrupt might come in
223 * and clobber the saved cs/eip.
226 IDTVEC(lcall_syscall)
227 pushfl /* save eflags */
228 popl 8(%esp) /* shuffle into tf_eflags */
229 pushl $7 /* sizeof "lcall 7,0" */
230 subl $4,%esp /* skip over tf_trapno */
236 FAKE_MCOUNT(TF_EIP(%esp))
244 * Call gate entry for FreeBSD ELF and Linux/NetBSD syscall (int 0x80)
246 * Even though the name says 'int0x80', this is actually a TGT (trap gate)
247 * rather then an IGT (interrupt gate). Thus interrupts are enabled on
248 * entry just as they are for a normal syscall.
251 IDTVEC(int0x80_syscall)
252 pushl $2 /* sizeof "int 0x80" */
253 subl $4,%esp /* skip over tf_trapno */
259 FAKE_MCOUNT(TF_EIP(%esp))
266 ENTRY(fork_trampoline)
267 pushl %esp /* trapframe pointer */
268 pushl %ebx /* arg1 */
269 pushl %esi /* function */
272 /* cut from syscall */
275 * Return via doreti to handle ASTs.
282 * To efficiently implement classification of trap and interrupt handlers
283 * for profiling, there must be only trap handlers between the labels btrap
284 * and bintr, and only interrupt handlers between the labels bintr and
285 * eintr. This is implemented (partly) by including files that contain
286 * some of the handlers. Before including the files, set up a normal asm
287 * environment so that the included files doen't need to know that they are
297 #include <i386/isa/atpic_vector.s>
305 #include <i386/i386/apic_vector.s>
312 #include <i386/i386/vm86bios.s>
318 * void doreti(struct trapframe)
320 * Handle return from interrupts, traps and syscalls.
324 .type doreti,@function
326 FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */
329 * Check if ASTs can be handled now. ASTs cannot be safely
330 * processed when returning from an NMI.
332 cmpb $T_NMI,TF_TRAPNO(%esp)
339 * PSL_VM must be checked first since segment registers only
340 * have an RPL in non-VM86 mode.
342 testl $PSL_VM,TF_EFLAGS(%esp) /* are we in vm86 mode? */
344 movl PCPU(CURPCB),%ecx
345 testl $PCB_VM86CALL,PCB_FLAGS(%ecx) /* are we in a vm86 call? */
346 jz doreti_ast /* can handle ASTS now if not */
350 testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
351 jz doreti_exit /* can't handle ASTs now if not */
355 * Check for ASTs atomically with returning. Disabling CPU
356 * interrupts provides sufficient locking even in the SMP case,
357 * since we will be informed of any new ASTs by an IPI.
360 movl PCPU(CURTHREAD),%eax
361 testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax)
364 pushl %esp /* pass a pointer to the trapframe */
370 * doreti_exit: pop registers, iret.
372 * The segment register pop is a special case, since it may
373 * fault if (for example) a sigreturn specifies bad segment
374 * registers. The fault is handled in trap.c.
379 .globl doreti_popl_fs
382 .globl doreti_popl_es
385 .globl doreti_popl_ds
395 * doreti_iret_fault and friends. Alternative return code for
396 * the case where we get a fault in the doreti_exit code
397 * above. trap() (i386/i386/trap.c) catches this specific
398 * case, sends the process a signal and continues in the
399 * corresponding place in the code below.
402 .globl doreti_iret_fault
407 .globl doreti_popl_ds_fault
408 doreti_popl_ds_fault:
410 .globl doreti_popl_es_fault
411 doreti_popl_es_fault:
413 .globl doreti_popl_fs_fault
414 doreti_popl_fs_fault:
415 movl $0,TF_ERR(%esp) /* XXX should be the error code */
416 movl $T_PROTFLT,TF_TRAPNO(%esp)
417 jmp alltraps_with_regs_pushed
421 * Since we are returning from an NMI, check if the current trap
422 * was from user mode and if so whether the current thread
423 * needs a user call chain capture.
425 testb $SEL_RPL_MASK,TF_CS(%esp)
427 movl PCPU(CURTHREAD),%eax /* curthread present? */
430 testl $TDP_CALLCHAIN,TD_PFLAGS(%eax) /* flagged for capture? */
433 * Take the processor out of NMI mode by executing a fake "iret".
441 * Clear interrupts and jump to AST handling code.
445 ENTRY(end_exceptions)