xref: /freebsd/sys/i386/i386/copyout_fast.S (revision 95ee2897e98f5d444f26ed2334cc7c439f9c16c6)
1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2018 The FreeBSD Foundation
5 *
6 * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
7 * under sponsorship from the FreeBSD Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <machine/asmacros.h>
32#include <machine/cputypes.h>
33#include <machine/pmap.h>
34#include <machine/specialreg.h>
35
36#include "assym.inc"
37
38/*
39 * Fast path for copyout code.  We switch to user space %cr3 and perform
40 * move operation between user memory and copyout buffer, located in the
41 * trampoline area.  We must switch to trampoline stack, because both
42 * user and kernel buffer accesses might cause page fault.
43 *
44 * Page fault handler expects %edx to point to the onfault routine.
45 * Handler switches to idlePTD and calls the routine.
46 * The routine must restore the stack, enable interrupts, and
47 * return to the caller, informing it about failure.
48 */
49	.text
50
51ENTRY(copyout_fast)
52	pushl	%ebp
53	movl	%esp, %ebp
54	pushl	%esi
55	pushl	%edi
56	pushl	%ebx
57
58	movl	20(%ebp),%ebx		/* KCR3 */
59	/* bcopy(%esi = kaddr, %edi = PCPU(copyout_buf), %ecx = len) */
60	movl	16(%ebp),%ecx
61	movl	8(%ebp),%esi
62	movl	%esp,%eax
63	movl	$copyout_fault,%edx
64
65	cli
66	movl	PCPU(COPYOUT_BUF),%edi
67pf_y1:	rep; movsb
68
69	movl	16(%ebp),%ecx		/* len */
70	movl	PCPU(COPYOUT_BUF),%esi	/* kaddr */
71	movl	12(%ebp),%edi		/* uaddr */
72	movl	PCPU(TRAMPSTK),%esp
73	movl	PCPU(CURPCB),%edx
74	movl	PCB_CR3(%edx),%edx	/* UCR3 */
75	movl	%edx,%cr3
76	movl	$copyout_fault,%edx
77	/* bcopy(%esi = PCPU(copyout_buf), %edi = udaddr, %ecx = len) */
78pf_x1:	rep; movsb
79
80	movl	%ebx,%cr3
81	movl	%eax,%esp
82	sti
83	xorl	%eax,%eax
84	popl	%ebx
85	popl	%edi
86	popl	%esi
87	leave
88	ret
89END(copyout_fast)
90
91ENTRY(copyin_fast)
92	pushl	%ebp
93	movl	%esp, %ebp
94	pushl	%esi
95	pushl	%edi
96	pushl	%ebx
97
98	movl	20(%ebp),%ebx		/* KCR3 */
99	movl	PCPU(CURPCB),%eax
100	movl	PCB_CR3(%eax),%edx	/* UCR3 */
101	movl	16(%ebp),%ecx		/* len */
102	movl	8(%ebp),%esi		/* udaddr */
103	movl	%esp,%eax
104
105	cli
106	movl	PCPU(COPYOUT_BUF),%edi	/* kaddr */
107	movl	PCPU(TRAMPSTK),%esp
108	movl	%edx,%cr3
109	movl	$copyout_fault,%edx
110	/* bcopy(%esi = udaddr, %edi = PCPU(copyout_buf), %ecx = len) */
111pf_x2:	rep; movsb
112
113	movl	%ebx,%cr3
114	movl	%eax,%esp
115
116	/* bcopy(%esi = PCPU(copyout_buf), %edi = kaddr, %ecx = len) */
117	movl	16(%ebp),%ecx
118	movl	12(%ebp),%edi
119	movl	PCPU(COPYOUT_BUF),%esi
120pf_y2:	rep; movsb
121
122	sti
123	xorl	%eax,%eax
124	popl	%ebx
125	popl	%edi
126	popl	%esi
127	leave
128	ret
129END(copyin_fast)
130
131	ALIGN_TEXT
132copyout_fault:
133	movl	%eax,%esp
134	sti
135	movl	$EFAULT,%eax
136	popl	%ebx
137	popl	%edi
138	popl	%esi
139	leave
140	ret
141
142ENTRY(fueword_fast)
143	pushl	%ebp
144	movl	%esp,%ebp
145	pushl	%ebx
146	pushl	%esi
147	pushl	%edi
148	movl	8(%ebp),%ecx			/* from */
149	movl	PCPU(CURPCB),%eax
150	movl	PCB_CR3(%eax),%eax
151	movl	$fusufault,%edx
152	movl	16(%ebp),%ebx
153	movl	%esp,%esi
154	cli
155	movl	PCPU(TRAMPSTK),%esp
156	movl	%eax,%cr3
157pf_x3:	movl	(%ecx),%eax
158	movl	%ebx,%cr3
159	movl	%esi,%esp
160	sti
161	movl	12(%ebp),%edx
162	movl	%eax,(%edx)
163	xorl	%eax,%eax
164	popl	%edi
165	popl	%esi
166	popl	%ebx
167	leave
168	ret
169END(fueword_fast)
170
171ENTRY(fuword16_fast)
172	pushl	%ebp
173	movl	%esp,%ebp
174	pushl	%ebx
175	pushl	%esi
176	pushl	%edi
177	movl	8(%ebp),%ecx			/* from */
178	movl	PCPU(CURPCB),%eax
179	movl	PCB_CR3(%eax),%eax
180	movl	$fusufault,%edx
181	movl	12(%ebp),%ebx
182	movl	%esp,%esi
183	cli
184	movl	PCPU(TRAMPSTK),%esp
185	movl	%eax,%cr3
186pf_x4:	movzwl	(%ecx),%eax
187	movl	%ebx,%cr3
188	movl	%esi,%esp
189	sti
190	popl	%edi
191	popl	%esi
192	popl	%ebx
193	leave
194	ret
195END(fuword16_fast)
196
197ENTRY(fubyte_fast)
198	pushl	%ebp
199	movl	%esp,%ebp
200	pushl	%ebx
201	pushl	%esi
202	pushl	%edi
203	movl	8(%ebp),%ecx			/* from */
204	movl	PCPU(CURPCB),%eax
205	movl	PCB_CR3(%eax),%eax
206	movl	$fusufault,%edx
207	movl	12(%ebp),%ebx
208	movl	%esp,%esi
209	cli
210	movl	PCPU(TRAMPSTK),%esp
211	movl	%eax,%cr3
212pf_x5:	movzbl	(%ecx),%eax
213	movl	%ebx,%cr3
214	movl	%esi,%esp
215	sti
216	popl	%edi
217	popl	%esi
218	popl	%ebx
219	leave
220	ret
221END(fubyte_fast)
222
223	ALIGN_TEXT
224fusufault:
225	movl	%esi,%esp
226	sti
227	xorl	%eax,%eax
228	decl	%eax
229	popl	%edi
230	popl	%esi
231	popl	%ebx
232	leave
233	ret
234
235ENTRY(suword_fast)
236	pushl	%ebp
237	movl	%esp,%ebp
238	pushl	%ebx
239	pushl	%esi
240	pushl	%edi
241	movl	PCPU(CURPCB),%eax
242	movl	PCB_CR3(%eax),%eax
243	movl	$fusufault,%edx
244	movl	8(%ebp),%ecx			/* to */
245	movl	12(%ebp),%edi			/* val */
246	movl	16(%ebp),%ebx
247	movl	%esp,%esi
248	cli
249	movl	PCPU(TRAMPSTK),%esp
250	movl	%eax,%cr3
251pf_x6:	movl	%edi,(%ecx)
252	movl	%ebx,%cr3
253	movl	%esi,%esp
254	sti
255	xorl	%eax,%eax
256	popl	%edi
257	popl	%esi
258	popl	%ebx
259	leave
260	ret
261END(suword_fast)
262
263ENTRY(suword16_fast)
264	pushl	%ebp
265	movl	%esp,%ebp
266	pushl	%ebx
267	pushl	%esi
268	pushl	%edi
269	movl	PCPU(CURPCB),%eax
270	movl	PCB_CR3(%eax),%eax
271	movl	$fusufault,%edx
272	movl	8(%ebp),%ecx			/* to */
273	movl	12(%ebp),%edi			/* val */
274	movl	16(%ebp),%ebx
275	movl	%esp,%esi
276	cli
277	movl	PCPU(TRAMPSTK),%esp
278	movl	%eax,%cr3
279pf_x7:	movw	%di,(%ecx)
280	movl	%ebx,%cr3
281	movl	%esi,%esp
282	sti
283	xorl	%eax,%eax
284	popl	%edi
285	popl	%esi
286	popl	%ebx
287	leave
288	ret
289END(suword16_fast)
290
291ENTRY(subyte_fast)
292	pushl	%ebp
293	movl	%esp,%ebp
294	pushl	%ebx
295	pushl	%esi
296	pushl	%edi
297	movl	PCPU(CURPCB),%eax
298	movl	PCB_CR3(%eax),%eax
299	movl	$fusufault,%edx
300	movl	8(%ebp),%ecx			/* to */
301	movl	12(%ebp),%edi			/* val */
302	movl	16(%ebp),%ebx
303	movl	%esp,%esi
304	cli
305	movl	PCPU(TRAMPSTK),%esp
306	movl	%eax,%cr3
307	movl	%edi,%eax
308pf_x8:	movb	%al,(%ecx)
309	movl	%ebx,%cr3
310	movl	%esi,%esp
311	sti
312	xorl	%eax,%eax
313	popl	%edi
314	popl	%esi
315	popl	%ebx
316	leave
317	ret
318END(subyte_fast)
319