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
5 * Copyright (c) 2008 The DragonFly Project.
6 * Copyright (c) 2008 Jordan Gordeev.
9 * Portions of this software were developed by A. Joseph Koshy under
10 * sponsorship from the FreeBSD Foundation and Google, Inc.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
38 #include "opt_atpic.h"
40 #include "opt_compat.h"
42 #include <machine/asmacros.h>
43 #include <machine/psl.h>
44 #include <machine/trap.h>
45 #include <machine/segments.h>
51 .globl lwkt_switch_return
53 /*****************************************************************************/
55 /*****************************************************************************/
57 * Trap and fault vector routines.
59 * All traps are 'interrupt gates', SDT_SYSIGT. An interrupt gate pushes
60 * state on the stack but also disables interrupts. This is important for
61 * us for the use of the swapgs instruction. We cannot be interrupted
62 * until the GS.base value is correct. For most traps, we automatically
63 * then enable interrupts if the interrupted context had them enabled.
64 * This is equivalent to the i386 port's use of SDT_SYS386TGT.
66 * The cpu will push a certain amount of state onto the kernel stack for
67 * the current process. See x86_64/include/frame.h.
68 * This includes the current RFLAGS (status register, which includes
69 * the interrupt disable state prior to the trap), the code segment register,
70 * and the return instruction pointer are pushed by the cpu. The cpu
71 * will also push an 'error' code for certain traps. We push a dummy
72 * error code for those traps where the cpu doesn't in order to maintain
73 * a consistent frame. We also push a contrived 'trap number'.
75 * The cpu does not push the general registers, we must do that, and we
76 * must restore them prior to calling 'iret'. The cpu adjusts the %cs and
77 * %ss segment registers, but does not mess with %ds, %es, or %fs. Thus we
78 * must load them with appropriate values for supervisor mode operation.
85 * Interrupts are enabled for all traps, otherwise horrible livelocks
86 * can occur with the smp_invltlb and cpusync ode.
89 #define TRAP_NOEN(a) \
91 movq $0,TF_XFLAGS(%rsp) ; \
92 movq $(a),TF_TRAPNO(%rsp) ; \
93 movq $0,TF_ADDR(%rsp) ; \
94 movq $0,TF_ERR(%rsp) ; \
98 /* Regular traps; The cpu does not supply tf_err for these. */
101 movq $0,TF_XFLAGS(%rsp) ; \
102 movq $(a),TF_TRAPNO(%rsp) ; \
103 movq $0,TF_ADDR(%rsp) ; \
104 movq $0,TF_ERR(%rsp) ; \
131 /* This group of traps have tf_err already pushed by the cpu */
132 #define TRAP_ERR(a) \
134 movq $(a),TF_TRAPNO(%rsp) ; \
135 movq $0,TF_ADDR(%rsp) ; \
136 movq $0,TF_XFLAGS(%rsp) ; \
148 * alltraps entry point. Use swapgs if this is the first time in the
149 * kernel from userland. Reenable interrupts if they were enabled
150 * before the trap. This approximates SDT_SYS386TGT on the i386 port.
155 .type alltraps,@function
157 /* Fixup %gs if coming from userland */
158 testb $SEL_RPL_MASK,TF_CS(%rsp)
162 testq $PSL_I,TF_RFLAGS(%rsp)
166 movq %rdi,TF_RDI(%rsp)
167 alltraps_pushregs_no_rdi:
168 movq %rsi,TF_RSI(%rsp)
169 movq %rdx,TF_RDX(%rsp)
170 movq %rcx,TF_RCX(%rsp)
173 movq %rax,TF_RAX(%rsp)
174 movq %rbx,TF_RBX(%rsp)
175 movq %rbp,TF_RBP(%rsp)
176 movq %r10,TF_R10(%rsp)
177 movq %r11,TF_R11(%rsp)
178 movq %r12,TF_R12(%rsp)
179 movq %r13,TF_R13(%rsp)
180 movq %r14,TF_R14(%rsp)
181 movq %r15,TF_R15(%rsp)
182 FAKE_MCOUNT(TF_RIP(%rsp))
184 .type calltrap,@function
190 jmp doreti /* Handle any pending ASTs */
193 * alltraps_noen entry point. Unlike alltraps above, we want to
194 * leave the interrupts disabled. This corresponds to
195 * SDT_SYS386IGT on the i386 port.
199 .type alltraps_noen,@function
201 /* Fixup %gs if coming from userland */
202 testb $SEL_RPL_MASK,TF_CS(%rsp)
205 jmp alltraps_pushregs
209 movq $T_DOUBLEFLT,TF_TRAPNO(%rsp)
210 movq $0,TF_ADDR(%rsp)
212 movq $0,TF_XFLAGS(%rsp)
213 movq %rdi,TF_RDI(%rsp)
214 movq %rsi,TF_RSI(%rsp)
215 movq %rdx,TF_RDX(%rsp)
216 movq %rcx,TF_RCX(%rsp)
219 movq %rax,TF_RAX(%rsp)
220 movq %rbx,TF_RBX(%rsp)
221 movq %rbp,TF_RBP(%rsp)
222 movq %r10,TF_R10(%rsp)
223 movq %r11,TF_R11(%rsp)
224 movq %r12,TF_R12(%rsp)
225 movq %r13,TF_R13(%rsp)
226 movq %r14,TF_R14(%rsp)
227 movq %r15,TF_R15(%rsp)
228 testb $SEL_RPL_MASK,TF_CS(%rsp)
233 call dblfault_handler
239 movq $T_PAGEFLT,TF_TRAPNO(%rsp)
240 /* Fixup %gs if coming from userland */
241 testb $SEL_RPL_MASK,TF_CS(%rsp)
245 movq %rdi,TF_RDI(%rsp) /* free up a GP register */
246 movq %cr2,%rdi /* preserve %cr2 before .. */
247 movq %rdi,TF_ADDR(%rsp) /* enabling interrupts. */
248 movq $0,TF_XFLAGS(%rsp)
249 testq $PSL_I,TF_RFLAGS(%rsp)
250 jz alltraps_pushregs_no_rdi
252 jmp alltraps_pushregs_no_rdi
255 * We have to special-case this one. If we get a trap in doreti() at
256 * the iretq stage, we'll reenter with the wrong gs state. We'll have
257 * to do a special the swapgs in this case even coming from the kernel.
258 * XXX linux has a trap handler for their equivalent of load_gs().
262 movq $T_PROTFLT,TF_TRAPNO(%rsp)
263 movq $0,TF_ADDR(%rsp)
264 movq $0,TF_XFLAGS(%rsp)
265 movq %rdi,TF_RDI(%rsp) /* free up a GP register */
268 * Fixup %gs if coming from userland. Handle the special case where
269 * %fs faults in doreti at the iretq instruction itself.
271 leaq doreti_iret(%rip),%rdi
272 cmpq %rdi,TF_RIP(%rsp) /* special iretq fault case */
274 testb $SEL_RPL_MASK,TF_CS(%rsp) /* check if from userland */
279 testq $PSL_I,TF_RFLAGS(%rsp)
280 jz alltraps_pushregs_no_rdi
282 jmp alltraps_pushregs_no_rdi
285 * Fast syscall entry point. We enter here with just our new %cs/%ss set,
286 * and the new privilige level. We are still running on the old user stack
287 * pointer. We have to juggle a few things around to find our stack etc.
288 * swapgs gives us access to our PCPU space only.
292 movq %rsp,PCPU(scratch_rsp)
293 movq PCPU(common_tss) + TSS_RSP0, %rsp
294 /* Now emulate a trapframe. Make the 8 byte alignment odd for call. */
296 /* defer TF_RSP till we have a spare register */
297 movq %r11,TF_RFLAGS(%rsp)
298 movq %rcx,TF_RIP(%rsp) /* %rcx original value is in %r10 */
299 movq PCPU(scratch_rsp),%r11 /* %r11 already saved */
300 movq %r11,TF_RSP(%rsp) /* user stack pointer */
301 orl $RQF_QUICKRET,PCPU(reqflags)
303 movq $KUDSEL,TF_SS(%rsp)
304 movq $KUCSEL,TF_CS(%rsp)
306 movq $T_FAST_SYSCALL,TF_TRAPNO(%rsp) /* for the vkernel */
307 movq $0,TF_XFLAGS(%rsp) /* note: used in signal frame */
308 movq %rdi,TF_RDI(%rsp) /* arg 1 */
309 movq %rsi,TF_RSI(%rsp) /* arg 2 */
310 movq %rdx,TF_RDX(%rsp) /* arg 3 */
311 movq %r10,TF_RCX(%rsp) /* arg 4 */
312 movq %r8,TF_R8(%rsp) /* arg 5 */
313 movq %r9,TF_R9(%rsp) /* arg 6 */
314 movq %rax,TF_RAX(%rsp) /* syscall number */
315 movq %rbx,TF_RBX(%rsp) /* C preserved */
316 movq %rbp,TF_RBP(%rsp) /* C preserved */
317 movq %r12,TF_R12(%rsp) /* C preserved */
318 movq %r13,TF_R13(%rsp) /* C preserved */
319 movq %r14,TF_R14(%rsp) /* C preserved */
320 movq %r15,TF_R15(%rsp) /* C preserved */
321 FAKE_MCOUNT(TF_RIP(%rsp))
326 * Fast return from system call
329 testl $RQF_IPIQ|RQF_TIMER|RQF_INTPEND|RQF_AST_MASK,PCPU(reqflags)
331 testl $RQF_QUICKRET,PCPU(reqflags)
334 movq TF_RDI(%rsp),%rdi
335 movq TF_RSI(%rsp),%rsi
336 movq TF_RDX(%rsp),%rdx
337 movq TF_RAX(%rsp),%rax
338 movq TF_RFLAGS(%rsp),%r11
339 movq TF_RIP(%rsp),%rcx
340 movq TF_RSP(%rsp),%rsp
344 * Normal slow / full iret
351 * Here for CYA insurance, in case a "syscall" instruction gets
352 * issued from 32 bit compatability mode. MSR_CSTAR has to point
353 * to *something* if EFER_SCE is enabled.
355 IDTVEC(fast_syscall32)
359 * NMI handling is special.
361 * First, NMIs do not respect the state of the processor's RFLAGS.IF
362 * bit and the NMI handler may be invoked at any time, including when
363 * the processor is in a critical section with RFLAGS.IF == 0. In
364 * particular, this means that the processor's GS.base values could be
365 * inconsistent on entry to the handler, and so we need to read
366 * MSR_GSBASE to determine if a 'swapgs' is needed. We use '%ebx', a
367 * C-preserved register, to remember whether to swap GS back on the
370 * Second, the processor treats NMIs specially, blocking further NMIs
371 * until an 'iretq' instruction is executed. We therefore need to
372 * execute the NMI handler with interrupts disabled to prevent a
373 * nested interrupt from executing an 'iretq' instruction and
374 * inadvertently taking the processor out of NMI mode.
376 * Third, the NMI handler runs on its own stack (tss_ist1), shared
377 * with the double fault handler.
382 movq $(T_NMI),TF_TRAPNO(%rsp)
383 movq $0,TF_ADDR(%rsp)
385 movq $0,TF_XFLAGS(%rsp)
386 movq %rdi,TF_RDI(%rsp)
387 movq %rsi,TF_RSI(%rsp)
388 movq %rdx,TF_RDX(%rsp)
389 movq %rcx,TF_RCX(%rsp)
392 movq %rax,TF_RAX(%rsp)
393 movq %rbx,TF_RBX(%rsp)
394 movq %rbp,TF_RBP(%rsp)
395 movq %r10,TF_R10(%rsp)
396 movq %r11,TF_R11(%rsp)
397 movq %r12,TF_R12(%rsp)
398 movq %r13,TF_R13(%rsp)
399 movq %r14,TF_R14(%rsp)
400 movq %r15,TF_R15(%rsp)
402 testb $SEL_RPL_MASK,TF_CS(%rsp)
403 jnz nmi_needswapgs /* we came from userland */
404 movl $MSR_GSBASE,%ecx
406 cmpl $VM_MAX_USER_ADDRESS >> 32,%edx
407 jae nmi_calltrap /* GS.base holds a kernel VA */
411 /* Note: this label is also used by ddb and gdb: */
413 FAKE_MCOUNT(TF_RIP(%rsp))
422 movq TF_RDI(%rsp),%rdi
423 movq TF_RSI(%rsp),%rsi
424 movq TF_RDX(%rsp),%rdx
425 movq TF_RCX(%rsp),%rcx
428 movq TF_RAX(%rsp),%rax
429 movq TF_RBX(%rsp),%rbx
430 movq TF_RBP(%rsp),%rbp
431 movq TF_R10(%rsp),%r10
432 movq TF_R11(%rsp),%r11
433 movq TF_R12(%rsp),%r12
434 movq TF_R13(%rsp),%r13
435 movq TF_R14(%rsp),%r14
436 movq TF_R15(%rsp),%r15
441 * This function is what cpu_heavy_restore jumps to after a new process
442 * is created. The LWKT subsystem switches while holding a critical
443 * section and we maintain that abstraction here (e.g. because
444 * cpu_heavy_restore needs it due to PCB_*() manipulation), then get out of
445 * it before calling the initial function (typically fork_return()) and/or
446 * returning to user mode.
448 * The MP lock is not held at any point but the critcount is bumped
449 * on entry to prevent interruption of the trampoline at a bad point.
451 * This is effectively what td->td_switch() returns to. It 'returns' the
452 * old thread in %rax and since this is not returning to a td->td_switch()
453 * call from lwkt_switch() we must handle the cleanup for the old thread
454 * by calling lwkt_switch_return().
456 * fork_trampoline(%rax:otd, %rbx:func, %r12:arg)
458 ENTRY(fork_trampoline)
460 call lwkt_switch_return
461 movq PCPU(curthread),%rax
462 decl TD_CRITCOUNT(%rax)
465 * cpu_set_fork_handler intercepts this function call to
466 * have this call a non-return function to stay in kernel mode.
468 * initproc has its own fork handler, start_init(), which DOES
471 * %rbx - chaining function (typically fork_return)
472 * %r12 -> %rdi (argument)
473 * frame-> %rsi (trap frame)
475 * void (func:rbx)(arg:rdi, trapframe:rsi)
477 movq %rsp, %rsi /* pass trapframe by reference */
478 movq %r12, %rdi /* arg1 */
479 call *%rbx /* function */
481 /* cut from syscall */
487 * Return via doreti to handle ASTs.
489 * trapframe is at the top of the stack.
495 * To efficiently implement classification of trap and interrupt handlers
496 * for profiling, there must be only trap handlers between the labels btrap
497 * and bintr, and only interrupt handlers between the labels bintr and
498 * eintr. This is implemented (partly) by including files that contain
499 * some of the handlers. Before including the files, set up a normal asm
500 * environment so that the included files doen't need to know that they are
510 #include <x86_64/ia32/ia32_exception.S>
520 #include <x86_64/x86_64/apic_vector.S>
529 #include <x86_64/isa/atpic_vector.S>