xref: /freebsd/sys/i386/i386/copyout_fast.S (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
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 * $FreeBSD$
31 */
32
33#include <machine/asmacros.h>
34#include <machine/cputypes.h>
35#include <machine/pmap.h>
36#include <machine/specialreg.h>
37
38#include "assym.inc"
39
40/*
41 * Fast path for copyout code.  We switch to user space %cr3 and perform
42 * move operation between user memory and copyout buffer, located in the
43 * trampoline area.  We must switch to trampoline stack, because both
44 * user and kernel buffer accesses might cause page fault.
45 *
46 * Page fault handler expects %edx to point to the onfault routine.
47 * Handler switches to idlePTD and calls the routine.
48 * The routine must restore the stack, enable interrupts, and
49 * return to the caller, informing it about failure.
50 */
51	.text
52
53ENTRY(copyout_fast)
54	pushl	%ebp
55	movl	%esp, %ebp
56	pushl	%esi
57	pushl	%edi
58	pushl	%ebx
59
60	movl	20(%ebp),%ebx		/* KCR3 */
61	/* bcopy(%esi = kaddr, %edi = PCPU(copyout_buf), %ecx = len) */
62	movl	16(%ebp),%ecx
63	movl	8(%ebp),%esi
64	movl	%esp,%eax
65	movl	$copyout_fault,%edx
66
67	cli
68	movl	PCPU(COPYOUT_BUF),%edi
69pf_y1:	rep; movsb
70
71	movl	16(%ebp),%ecx		/* len */
72	movl	PCPU(COPYOUT_BUF),%esi	/* kaddr */
73	movl	12(%ebp),%edi		/* uaddr */
74	movl	PCPU(TRAMPSTK),%esp
75	movl	PCPU(CURPCB),%edx
76	movl	PCB_CR3(%edx),%edx	/* UCR3 */
77	movl	%edx,%cr3
78	movl	$copyout_fault,%edx
79	/* bcopy(%esi = PCPU(copyout_buf), %edi = udaddr, %ecx = len) */
80pf_x1:	rep; movsb
81
82	movl	%ebx,%cr3
83	movl	%eax,%esp
84	sti
85	xorl	%eax,%eax
86	popl	%ebx
87	popl	%edi
88	popl	%esi
89	leave
90	ret
91END(copyout_fast)
92
93ENTRY(copyin_fast)
94	pushl	%ebp
95	movl	%esp, %ebp
96	pushl	%esi
97	pushl	%edi
98	pushl	%ebx
99
100	movl	20(%ebp),%ebx		/* KCR3 */
101	movl	PCPU(CURPCB),%eax
102	movl	PCB_CR3(%eax),%edx	/* UCR3 */
103	movl	16(%ebp),%ecx		/* len */
104	movl	8(%ebp),%esi		/* udaddr */
105	movl	%esp,%eax
106
107	cli
108	movl	PCPU(COPYOUT_BUF),%edi	/* kaddr */
109	movl	PCPU(TRAMPSTK),%esp
110	movl	%edx,%cr3
111	movl	$copyout_fault,%edx
112	/* bcopy(%esi = udaddr, %edi = PCPU(copyout_buf), %ecx = len) */
113pf_x2:	rep; movsb
114
115	movl	%ebx,%cr3
116	movl	%eax,%esp
117
118	/* bcopy(%esi = PCPU(copyout_buf), %edi = kaddr, %ecx = len) */
119	movl	16(%ebp),%ecx
120	movl	12(%ebp),%edi
121	movl	PCPU(COPYOUT_BUF),%esi
122pf_y2:	rep; movsb
123
124	sti
125	xorl	%eax,%eax
126	popl	%ebx
127	popl	%edi
128	popl	%esi
129	leave
130	ret
131END(copyin_fast)
132
133	ALIGN_TEXT
134copyout_fault:
135	movl	%eax,%esp
136	sti
137	movl	$EFAULT,%eax
138	popl	%ebx
139	popl	%edi
140	popl	%esi
141	leave
142	ret
143
144ENTRY(fueword_fast)
145	pushl	%ebp
146	movl	%esp,%ebp
147	pushl	%ebx
148	pushl	%esi
149	pushl	%edi
150	movl	8(%ebp),%ecx			/* from */
151	movl	PCPU(CURPCB),%eax
152	movl	PCB_CR3(%eax),%eax
153	movl	$fusufault,%edx
154	movl	16(%ebp),%ebx
155	movl	%esp,%esi
156	cli
157	movl	PCPU(TRAMPSTK),%esp
158	movl	%eax,%cr3
159pf_x3:	movl	(%ecx),%eax
160	movl	%ebx,%cr3
161	movl	%esi,%esp
162	sti
163	movl	12(%ebp),%edx
164	movl	%eax,(%edx)
165	xorl	%eax,%eax
166	popl	%edi
167	popl	%esi
168	popl	%ebx
169	leave
170	ret
171END(fueword_fast)
172
173ENTRY(fuword16_fast)
174	pushl	%ebp
175	movl	%esp,%ebp
176	pushl	%ebx
177	pushl	%esi
178	pushl	%edi
179	movl	8(%ebp),%ecx			/* from */
180	movl	PCPU(CURPCB),%eax
181	movl	PCB_CR3(%eax),%eax
182	movl	$fusufault,%edx
183	movl	12(%ebp),%ebx
184	movl	%esp,%esi
185	cli
186	movl	PCPU(TRAMPSTK),%esp
187	movl	%eax,%cr3
188pf_x4:	movzwl	(%ecx),%eax
189	movl	%ebx,%cr3
190	movl	%esi,%esp
191	sti
192	popl	%edi
193	popl	%esi
194	popl	%ebx
195	leave
196	ret
197END(fuword16_fast)
198
199ENTRY(fubyte_fast)
200	pushl	%ebp
201	movl	%esp,%ebp
202	pushl	%ebx
203	pushl	%esi
204	pushl	%edi
205	movl	8(%ebp),%ecx			/* from */
206	movl	PCPU(CURPCB),%eax
207	movl	PCB_CR3(%eax),%eax
208	movl	$fusufault,%edx
209	movl	12(%ebp),%ebx
210	movl	%esp,%esi
211	cli
212	movl	PCPU(TRAMPSTK),%esp
213	movl	%eax,%cr3
214pf_x5:	movzbl	(%ecx),%eax
215	movl	%ebx,%cr3
216	movl	%esi,%esp
217	sti
218	popl	%edi
219	popl	%esi
220	popl	%ebx
221	leave
222	ret
223END(fubyte_fast)
224
225	ALIGN_TEXT
226fusufault:
227	movl	%esi,%esp
228	sti
229	xorl	%eax,%eax
230	decl	%eax
231	popl	%edi
232	popl	%esi
233	popl	%ebx
234	leave
235	ret
236
237ENTRY(suword_fast)
238	pushl	%ebp
239	movl	%esp,%ebp
240	pushl	%ebx
241	pushl	%esi
242	pushl	%edi
243	movl	PCPU(CURPCB),%eax
244	movl	PCB_CR3(%eax),%eax
245	movl	$fusufault,%edx
246	movl	8(%ebp),%ecx			/* to */
247	movl	12(%ebp),%edi			/* val */
248	movl	16(%ebp),%ebx
249	movl	%esp,%esi
250	cli
251	movl	PCPU(TRAMPSTK),%esp
252	movl	%eax,%cr3
253pf_x6:	movl	%edi,(%ecx)
254	movl	%ebx,%cr3
255	movl	%esi,%esp
256	sti
257	xorl	%eax,%eax
258	popl	%edi
259	popl	%esi
260	popl	%ebx
261	leave
262	ret
263END(suword_fast)
264
265ENTRY(suword16_fast)
266	pushl	%ebp
267	movl	%esp,%ebp
268	pushl	%ebx
269	pushl	%esi
270	pushl	%edi
271	movl	PCPU(CURPCB),%eax
272	movl	PCB_CR3(%eax),%eax
273	movl	$fusufault,%edx
274	movl	8(%ebp),%ecx			/* to */
275	movl	12(%ebp),%edi			/* val */
276	movl	16(%ebp),%ebx
277	movl	%esp,%esi
278	cli
279	movl	PCPU(TRAMPSTK),%esp
280	movl	%eax,%cr3
281pf_x7:	movw	%di,(%ecx)
282	movl	%ebx,%cr3
283	movl	%esi,%esp
284	sti
285	xorl	%eax,%eax
286	popl	%edi
287	popl	%esi
288	popl	%ebx
289	leave
290	ret
291END(suword16_fast)
292
293ENTRY(subyte_fast)
294	pushl	%ebp
295	movl	%esp,%ebp
296	pushl	%ebx
297	pushl	%esi
298	pushl	%edi
299	movl	PCPU(CURPCB),%eax
300	movl	PCB_CR3(%eax),%eax
301	movl	$fusufault,%edx
302	movl	8(%ebp),%ecx			/* to */
303	movl	12(%ebp),%edi			/* val */
304	movl	16(%ebp),%ebx
305	movl	%esp,%esi
306	cli
307	movl	PCPU(TRAMPSTK),%esp
308	movl	%eax,%cr3
309	movl	%edi,%eax
310pf_x8:	movb	%al,(%ecx)
311	movl	%ebx,%cr3
312	movl	%esi,%esp
313	sti
314	xorl	%eax,%eax
315	popl	%edi
316	popl	%esi
317	popl	%ebx
318	leave
319	ret
320END(subyte_fast)
321