2 * Copyright (c) 1993 The Regents of the University of California.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * $FreeBSD: src/sys/i386/i386/support.s,v 1.67.2.5 2001/08/15 01:23:50 peter Exp $
34 * $DragonFly: src/sys/platform/pc32/i386/support.s,v 1.19 2007/01/08 03:33:42 dillon Exp $
39 #include <machine/asmacros.h>
40 #include <machine/cputypes.h>
41 #include <machine/pmap.h>
42 #include <machine/specialreg.h>
52 .long asm_generic_memcpy
56 .long asm_generic_bcopy
60 .long asm_generic_bcopy
64 /* fillw(pat, base, cnt) */
77 * void bcopy(const void *s, void *d, size_t count)
79 * Normal bcopy() vector, an optimized bcopy may be installed in
85 movl 4+8(%esp),%esi /* caddr_t from */
86 movl 8+8(%esp),%edi /* caddr_t to */
87 movl 12+8(%esp),%ecx /* size_t len */
94 * Generic (integer-only) bcopy() vector.
99 movl 4+8(%esp),%esi /* caddr_t from */
100 movl 8+8(%esp),%edi /* caddr_t to */
101 movl 12+8(%esp),%ecx /* size_t len */
102 call asm_generic_bcopy
110 movl 4+8(%esp),%esi /* caddr_t from */
111 movl 8+8(%esp),%edi /* caddr_t to */
112 movl 12+8(%esp),%ecx /* size_t len */
119 * void *memcpy(void *d, const void *s, size_t count)
121 * Note: memcpy does not have to support overlapping copies.
123 * Note: (d, s) arguments reversed from bcopy, and memcpy() returns d
124 * while bcopy() returns void.
139 * A stack-based on-fault routine is used for more complex PCB_ONFAULT
140 * situations (such as memcpy/bcopy/bzero). In this case the on-fault
141 * routine must be pushed on the stack.
146 /*****************************************************************************/
147 /* copyout and fubyte family */
148 /*****************************************************************************/
150 * Access user memory from inside the kernel. These routines and possibly
151 * the math- and DOS emulators should be the only places that do this.
153 * We have to access the memory with user's permissions, so use a segment
154 * selector with RPL 3. For writes to user space we have to additionally
155 * check the PTE for write permission, because the 386 does not check
156 * write permissions when we are executing with EPL 0. The 486 does check
157 * this if the WP bit is set in CR0, so we can use a simpler version here.
159 * These routines set curpcb->onfault for the time they execute. When a
160 * protection violation occurs inside the functions, the trap handler
161 * returns to *curpcb->onfault instead of the function.
165 * copyout(from_kernel, to_user, len) - MP SAFE (if not I386_CPU)
168 movl PCPU(curthread),%eax
169 movl TD_PCB(%eax),%eax
173 pushl $copyout_fault2
174 movl $stack_onfault,PCB_ONFAULT(%eax)
177 movl 12+16(%esp),%ebx
178 testl %ebx,%ebx /* anything to do? */
182 * Check explicitly for non-user addresses. If 486 write protection
183 * is being used, this check is essential because we are in kernel
184 * mode so the h/w does not provide any protection against writing
189 * First, prevent address wrapping.
195 * XXX STOP USING VM_MAX_USER_ADDRESS.
196 * It is an end address, not a max, so every time it is used correctly it
197 * looks like there is an off by one error, and of course it caused an off
198 * by one error in several places.
200 cmpl $VM_MAX_USER_ADDRESS,%eax
203 #if defined(I386_CPU)
205 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
206 cmpl $CPUCLASS_386,cpu_class
210 * We have to check each PTE for user write permission.
211 * The checking may cause a page fault, so it is important to set
212 * up everything for return via copyout_fault before here.
214 /* compute number of pages */
219 shrl $IDXSHIFT+2,%ecx
222 /* compute PTE offset for start address */
228 /* check PTE for each page */
229 leal PTmap(%edx),%eax
232 testb $PG_V,PTmap(%eax) /* PTE page must be valid */
235 andb $PG_V|PG_RW|PG_U,%al /* page must be valid and user writable */
236 cmpb $PG_V|PG_RW|PG_U,%al
240 /* simulate a trap */
245 call trapwrite /* trapwrite(addr) */
250 testl %eax,%eax /* if not ok, return EFAULT */
256 jnz 1b /* check next page */
257 #endif /* I386_CPU */
260 * Convert copyout to memcpy_vector(dest:%edi, src:%esi, conut:%ecx)
271 movl PCPU(curthread),%edx
273 movl TD_PCB(%edx),%edx
277 movl %eax,PCB_ONFAULT(%edx)
282 addl $4,%esp /* skip pushed copyout_fault vector */
287 movl PCPU(curthread),%edx
288 movl TD_PCB(%edx),%edx
289 movl $0,PCB_ONFAULT(%edx)
294 * copyin(from_user, to_kernel, len) - MP SAFE
298 movl PCPU(curthread),%eax
299 movl TD_PCB(%eax),%eax
303 movl $stack_onfault,PCB_ONFAULT(%eax)
304 movl 4+12(%esp),%esi /* caddr_t from */
305 movl 8+12(%esp),%edi /* caddr_t to */
306 movl 12+12(%esp),%ecx /* size_t len */
309 * make sure address is valid
314 cmpl $VM_MAX_USER_ADDRESS,%edx
318 * Call memcpy(destination:%edi, source:%esi, bytes:%ecx)
323 * return 0 (no error)
326 movl PCPU(curthread),%edx
328 movl TD_PCB(%edx),%edx
331 movl %eax,PCB_ONFAULT(%edx)
339 addl $4,%esp /* skip pushed copyin_fault vector */
343 movl PCPU(curthread),%edx
344 movl TD_PCB(%edx),%edx
345 movl $0,PCB_ONFAULT(%edx)
350 * fu{byte,sword,word} - MP SAFE
352 * Fetch a byte (sword, word) from user memory
355 movl PCPU(curthread),%ecx
356 movl TD_PCB(%ecx),%ecx
357 movl $fusufault,PCB_ONFAULT(%ecx)
358 movl 4(%esp),%edx /* from */
360 cmpl $VM_MAX_USER_ADDRESS-4,%edx /* verify address is valid */
364 movl $0,PCB_ONFAULT(%ecx)
371 movl PCPU(curthread),%ecx
372 movl TD_PCB(%ecx),%ecx
373 movl $fusufault,PCB_ONFAULT(%ecx)
376 cmpl $VM_MAX_USER_ADDRESS-2,%edx
380 movl $0,PCB_ONFAULT(%ecx)
387 movl PCPU(curthread),%ecx
388 movl TD_PCB(%ecx),%ecx
389 movl $fusufault,PCB_ONFAULT(%ecx)
392 cmpl $VM_MAX_USER_ADDRESS-1,%edx
396 movl $0,PCB_ONFAULT(%ecx)
401 movl PCPU(curthread),%ecx
402 movl TD_PCB(%ecx),%ecx
404 movl %eax,PCB_ONFAULT(%ecx)
409 * su{byte,sword,word} - MP SAFE (if not I386_CPU)
411 * Write a byte (word, longword) to user memory
414 movl PCPU(curthread),%ecx
415 movl TD_PCB(%ecx),%ecx
416 movl $fusufault,PCB_ONFAULT(%ecx)
419 #if defined(I386_CPU)
421 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
422 cmpl $CPUCLASS_386,cpu_class
423 jne 2f /* we only have to set the right segment selector */
424 #endif /* I486_CPU || I586_CPU || I686_CPU */
426 /* XXX - page boundary crossing is still not handled */
431 leal PTmap(%edx),%ecx
434 testb $PG_V,PTmap(%ecx) /* PTE page must be valid */
437 andb $PG_V|PG_RW|PG_U,%dl /* page must be valid and user writable */
438 cmpb $PG_V|PG_RW|PG_U,%dl
442 /* simulate a trap */
445 popl %edx /* remove junk parameter from stack */
453 cmpl $VM_MAX_USER_ADDRESS-4,%edx /* verify address validity */
459 movl PCPU(curthread),%ecx
460 movl TD_PCB(%ecx),%ecx
461 movl %eax,PCB_ONFAULT(%ecx)
465 * susword - MP SAFE (if not I386_CPU)
468 movl PCPU(curthread),%ecx
469 movl TD_PCB(%ecx),%ecx
470 movl $fusufault,PCB_ONFAULT(%ecx)
473 #if defined(I386_CPU)
475 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
476 cmpl $CPUCLASS_386,cpu_class
478 #endif /* I486_CPU || I586_CPU || I686_CPU */
480 /* XXX - page boundary crossing is still not handled */
485 leal PTmap(%edx),%ecx
488 testb $PG_V,PTmap(%ecx) /* PTE page must be valid */
491 andb $PG_V|PG_RW|PG_U,%dl /* page must be valid and user writable */
492 cmpb $PG_V|PG_RW|PG_U,%dl
496 /* simulate a trap */
499 popl %edx /* remove junk parameter from stack */
507 cmpl $VM_MAX_USER_ADDRESS-2,%edx /* verify address validity */
513 movl PCPU(curthread),%ecx /* restore trashed register */
514 movl TD_PCB(%ecx),%ecx
515 movl %eax,PCB_ONFAULT(%ecx)
519 * subyte - MP SAFE (if not I386_CPU)
522 movl PCPU(curthread),%ecx
523 movl TD_PCB(%ecx),%ecx
524 movl $fusufault,PCB_ONFAULT(%ecx)
527 #if defined(I386_CPU)
529 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU)
530 cmpl $CPUCLASS_386,cpu_class
532 #endif /* I486_CPU || I586_CPU || I686_CPU */
538 leal PTmap(%edx),%ecx
541 testb $PG_V,PTmap(%ecx) /* PTE page must be valid */
544 andb $PG_V|PG_RW|PG_U,%dl /* page must be valid and user writable */
545 cmpb $PG_V|PG_RW|PG_U,%dl
549 /* simulate a trap */
552 popl %edx /* remove junk parameter from stack */
560 cmpl $VM_MAX_USER_ADDRESS-1,%edx /* verify address validity */
566 movl PCPU(curthread),%ecx /* restore trashed register */
567 movl TD_PCB(%ecx),%ecx
568 movl %eax,PCB_ONFAULT(%ecx)
572 * copyinstr(from, to, maxlen, int *lencopied) - MP SAFE
574 * copy a string from from to to, stop when a 0 character is reached.
575 * return ENAMETOOLONG if string is longer than maxlen, and
576 * EFAULT on protection violations. If lencopied is non-zero,
577 * return the actual length in *lencopied.
582 movl PCPU(curthread),%ecx
583 movl TD_PCB(%ecx),%ecx
584 movl $cpystrflt,PCB_ONFAULT(%ecx)
586 movl 12(%esp),%esi /* %esi = from */
587 movl 16(%esp),%edi /* %edi = to */
588 movl 20(%esp),%edx /* %edx = maxlen */
590 movl $VM_MAX_USER_ADDRESS,%eax
592 /* make sure 'from' is within bounds */
596 /* restrict maxlen to <= VM_MAX_USER_ADDRESS-from */
614 /* Success -- 0 byte reached */
619 /* edx is zero - return ENAMETOOLONG or EFAULT */
620 cmpl $VM_MAX_USER_ADDRESS,%esi
623 movl $ENAMETOOLONG,%eax
630 /* set *lencopied and return %eax */
631 movl PCPU(curthread),%ecx
632 movl TD_PCB(%ecx),%ecx
633 movl $0,PCB_ONFAULT(%ecx)
647 * copystr(from, to, maxlen, int *lencopied) - MP SAFE
653 movl 12(%esp),%esi /* %esi = from */
654 movl 16(%esp),%edi /* %edi = to */
655 movl 20(%esp),%edx /* %edx = maxlen */
666 /* Success -- 0 byte reached */
671 /* edx is zero -- return ENAMETOOLONG */
672 movl $ENAMETOOLONG,%eax
675 /* set *lencopied and return %eax */
697 cld /* compare forwards */
716 * Handling of special 386 registers and descriptor tables etc
718 /* void lgdt(struct region_descriptor *rdp); */
720 /* reload the descriptor table */
724 /* flush the prefetch q */
728 /* reload "stale" selectors */
738 /* reload code selector by turning return into intersegmental return */
745 * void lidt(struct region_descriptor *rdp);
753 * void lldt(u_short sel)
760 * void ltr(u_short sel)
766 /* ssdtosd(*ssdp,*sdp) */
803 /* void load_cr3(caddr_t cr3) */
805 #if defined(SWTCH_OPTIM_STATS)
806 incl _tlb_flush_count
817 /* void load_cr4(caddr_t cr4) */
823 /* void reset_dbregs() */
826 movl %eax,%dr7 /* disable all breapoints first */
834 /*****************************************************************************/
835 /* setjump, longjump */
836 /*****************************************************************************/
840 movl %ebx,(%eax) /* save ebx */
841 movl %esp,4(%eax) /* save esp */
842 movl %ebp,8(%eax) /* save ebp */
843 movl %esi,12(%eax) /* save esi */
844 movl %edi,16(%eax) /* save edi */
845 movl (%esp),%edx /* get rta */
846 movl %edx,20(%eax) /* save eip */
847 xorl %eax,%eax /* return(0); */
852 movl (%eax),%ebx /* restore ebx */
853 movl 4(%eax),%esp /* restore esp */
854 movl 8(%eax),%ebp /* restore ebp */
855 movl 12(%eax),%esi /* restore esi */
856 movl 16(%eax),%edi /* restore edi */
857 movl 20(%eax),%edx /* get rta */
858 movl %edx,(%esp) /* put in return frame */
859 xorl %eax,%eax /* return(1); */
864 * Support for BB-profiling (gcc -a). The kernbb program will extract
865 * the data from the kernel.
875 NON_GPROF_ENTRY(__bb_init_func)
881 .byte 0xc3 /* avoid macro for `ret' */