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 * 3. 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"
41 #include <machine/asmacros.h>
42 #include <machine/psl.h>
43 #include <machine/trap.h>
47 #define SEL_RPL_MASK 0x0003
48 #define GSEL_KPL 0x0020 /* GSEL(GCODE_SEL, SEL_KPL) */
52 .globl dtrace_invop_jump_addr
54 .type dtrace_invop_jump_addr, @object
55 .size dtrace_invop_jump_addr, 4
56 dtrace_invop_jump_addr:
58 .globl dtrace_invop_calltrap_addr
60 .type dtrace_invop_calltrap_addr, @object
61 .size dtrace_invop_calltrap_addr, 4
62 dtrace_invop_calltrap_addr:
67 ENTRY(start_exceptions)
69 /*****************************************************************************/
71 /*****************************************************************************/
73 * Trap and fault vector routines.
75 * Most traps are 'trap gates', SDT_SYS386TGT. A trap gate pushes state on
76 * the stack that mostly looks like an interrupt, but does not disable
77 * interrupts. A few of the traps we are use are interrupt gates,
78 * SDT_SYS386IGT, which are nearly the same thing except interrupts are
81 * The cpu will push a certain amount of state onto the kernel stack for
82 * the current process. The amount of state depends on the type of trap
83 * and whether the trap crossed rings or not. See i386/include/frame.h.
84 * At the very least the current EFLAGS (status register, which includes
85 * the interrupt disable state prior to the trap), the code segment register,
86 * and the return instruction pointer are pushed by the cpu. The cpu
87 * will also push an 'error' code for certain traps. We push a dummy
88 * error code for those traps where the cpu doesn't in order to maintain
89 * a consistent frame. We also push a contrived 'trap number'.
91 * The cpu does not push the general registers, we must do that, and we
92 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
93 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
94 * must load them with appropriate values for supervisor mode operation.
100 #define TRAP(a) pushl $(a) ; jmp alltraps
103 pushl $0; TRAP(T_DIVIDE)
105 pushl $0; TRAP(T_TRCTRAP)
107 pushl $0; TRAP(T_NMI)
109 pushl $0; TRAP(T_BPTFLT)
111 pushl $0; TRAP(T_DTRACE_RET)
113 pushl $0; TRAP(T_OFLOW)
115 pushl $0; TRAP(T_BOUND)
116 #ifndef KDTRACE_HOOKS
118 pushl $0; TRAP(T_PRIVINFLT)
121 pushl $0; TRAP(T_DNA)
123 pushl $0; TRAP(T_FPOPFLT)
135 pushl $0; TRAP(T_MCHK)
137 pushl $0; TRAP(T_RESERVED)
139 pushl $0; TRAP(T_ARITHTRAP)
143 pushl $0; TRAP(T_XMMFLT)
146 * All traps except ones for syscalls jump to alltraps. If
147 * interrupts were enabled when the trap occurred, then interrupts
148 * are enabled now if the trap was through a trap gate, else
149 * disabled if the trap was through an interrupt gate. Note that
150 * int0x80_syscall is a trap gate. Interrupt gates are used by
151 * page faults, non-maskable interrupts, debug and breakpoint
156 .type alltraps,@function
165 alltraps_with_regs_pushed:
168 FAKE_MCOUNT(TF_EIP(%esp))
175 * Return via doreti to handle ASTs.
181 * Privileged instruction fault.
187 * Check if a DTrace hook is registered. The default (data) segment
188 * cannot be used for this since %ds is not known good until we
189 * verify that the entry was from kernel mode.
191 cmpl $0,%ss:dtrace_invop_jump_addr
195 * Check if this is a user fault. If so, just handle it as a normal
198 cmpl $GSEL_KPL, 4(%esp) /* Check the code segment */
200 testl $PSL_VM, 8(%esp) /* and vm86 mode. */
204 * This is a kernel instruction fault that might have been caused
205 * by a DTrace provider.
211 * Set our jump address for the jump back in the event that
212 * the exception wasn't caused by DTrace at all.
214 movl $norm_ill, dtrace_invop_calltrap_addr
216 /* Jump to the code hooked in by DTrace. */
217 jmpl *dtrace_invop_jump_addr
220 * Process the instruction fault in the normal way.
228 * Call gate entry for syscalls (lcall 7,0).
229 * This is used by FreeBSD 1.x a.out executables and "old" NetBSD executables.
231 * The intersegment call has been set up to specify one dummy parameter.
232 * This leaves a place to put eflags so that the call frame can be
233 * converted to a trap frame. Note that the eflags is (semi-)bogusly
234 * pushed into (what will be) tf_err and then copied later into the
235 * final spot. It has to be done this way because esp can't be just
236 * temporarily altered for the pushfl - an interrupt might come in
237 * and clobber the saved cs/eip.
240 IDTVEC(lcall_syscall)
241 pushfl /* save eflags */
242 popl 8(%esp) /* shuffle into tf_eflags */
243 pushl $7 /* sizeof "lcall 7,0" */
244 pushl $0 /* tf_trapno */
254 FAKE_MCOUNT(TF_EIP(%esp))
262 * Trap gate entry for syscalls (int 0x80).
263 * This is used by FreeBSD ELF executables, "new" NetBSD executables, and all
266 * Even though the name says 'int0x80', this is actually a trap gate, not an
267 * interrupt gate. Thus interrupts are enabled on entry just as they are for
271 IDTVEC(int0x80_syscall)
272 pushl $2 /* sizeof "int 0x80" */
273 pushl $0 /* tf_trapno */
283 FAKE_MCOUNT(TF_EIP(%esp))
290 ENTRY(fork_trampoline)
291 pushl %esp /* trapframe pointer */
292 pushl %ebx /* arg1 */
293 pushl %esi /* function */
296 /* cut from syscall */
299 * Return via doreti to handle ASTs.
306 * To efficiently implement classification of trap and interrupt handlers
307 * for profiling, there must be only trap handlers between the labels btrap
308 * and bintr, and only interrupt handlers between the labels bintr and
309 * eintr. This is implemented (partly) by including files that contain
310 * some of the handlers. Before including the files, set up a normal asm
311 * environment so that the included files doen't need to know that they are
322 #include <i386/i386/atpic_vector.s>
325 #if defined(DEV_APIC) && defined(DEV_ATPIC)
333 #include <i386/i386/apic_vector.s>
340 #include <i386/i386/vm86bios.s>
346 * void doreti(struct trapframe)
348 * Handle return from interrupts, traps and syscalls.
352 .type doreti,@function
355 FAKE_MCOUNT($bintr) /* init "from" bintr -> doreti */
358 * Check if ASTs can be handled now. ASTs cannot be safely
359 * processed when returning from an NMI.
361 cmpb $T_NMI,TF_TRAPNO(%esp)
368 * PSL_VM must be checked first since segment registers only
369 * have an RPL in non-VM86 mode.
370 * ASTs can not be handled now if we are in a vm86 call.
372 testl $PSL_VM,TF_EFLAGS(%esp)
374 movl PCPU(CURPCB),%ecx
375 testl $PCB_VM86CALL,PCB_FLAGS(%ecx)
380 testb $SEL_RPL_MASK,TF_CS(%esp) /* are we returning to user mode? */
381 jz doreti_exit /* can't handle ASTs now if not */
385 * Check for ASTs atomically with returning. Disabling CPU
386 * interrupts provides sufficient locking even in the SMP case,
387 * since we will be informed of any new ASTs by an IPI.
390 movl PCPU(CURTHREAD),%eax
391 testl $TDF_ASTPENDING | TDF_NEEDRESCHED,TD_FLAGS(%eax)
394 pushl %esp /* pass a pointer to the trapframe */
400 * doreti_exit: pop registers, iret.
402 * The segment register pop is a special case, since it may
403 * fault if (for example) a sigreturn specifies bad segment
404 * registers. The fault is handled in trap.c.
409 .globl doreti_popl_fs
412 .globl doreti_popl_es
415 .globl doreti_popl_ds
425 * doreti_iret_fault and friends. Alternative return code for
426 * the case where we get a fault in the doreti_exit code
427 * above. trap() (i386/i386/trap.c) catches this specific
428 * case, and continues in the corresponding place in the code
431 * If the fault occured during return to usermode, we recreate
432 * the trap frame and call trap() to send a signal. Otherwise
433 * the kernel was tricked into fault by attempt to restore invalid
434 * usermode segment selectors on return from nested fault or
435 * interrupt, where interrupted kernel entry code not yet loaded
436 * kernel selectors. In the latter case, emulate iret and zero
437 * the invalid selector.
440 .globl doreti_iret_fault
446 .globl doreti_popl_ds_fault
447 doreti_popl_ds_fault:
448 testb $SEL_RPL_MASK,TF_CS-TF_DS(%esp)
449 jz doreti_popl_ds_kfault
452 .globl doreti_popl_es_fault
453 doreti_popl_es_fault:
454 testb $SEL_RPL_MASK,TF_CS-TF_ES(%esp)
455 jz doreti_popl_es_kfault
458 .globl doreti_popl_fs_fault
459 doreti_popl_fs_fault:
460 testb $SEL_RPL_MASK,TF_CS-TF_FS(%esp)
461 jz doreti_popl_fs_kfault
463 movl $0,TF_ERR(%esp) /* XXX should be the error code */
464 movl $T_PROTFLT,TF_TRAPNO(%esp)
465 jmp alltraps_with_regs_pushed
467 doreti_popl_ds_kfault:
470 doreti_popl_es_kfault:
473 doreti_popl_fs_kfault:
480 * Since we are returning from an NMI, check if the current trap
481 * was from user mode and if so whether the current thread
482 * needs a user call chain capture.
484 testb $SEL_RPL_MASK,TF_CS(%esp)
486 movl PCPU(CURTHREAD),%eax /* curthread present? */
489 testl $TDP_CALLCHAIN,TD_PFLAGS(%eax) /* flagged for capture? */
492 * Take the processor out of NMI mode by executing a fake "iret".
500 * Call the callchain capture hook after turning interrupts back on.
505 pushl %esp /* frame pointer */
506 pushl $PMC_FN_USER_CALLCHAIN /* command */
507 movl PCPU(CURTHREAD),%eax
508 pushl %eax /* curthread */
513 ENTRY(end_exceptions)