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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/x86_64/lib/copy_user.S
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/x86_64/lib/copy_user.S')
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diff --git a/arch/x86_64/lib/copy_user.S b/arch/x86_64/lib/copy_user.S
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1/* Copyright 2002 Andi Kleen, SuSE Labs.
2 * Subject to the GNU Public License v2.
3 *
4 * Functions to copy from and to user space.
5 */
6
7#define FIX_ALIGNMENT 1
8
9 #include <asm/current.h>
10 #include <asm/offset.h>
11 #include <asm/thread_info.h>
12 #include <asm/cpufeature.h>
13
14/* Standard copy_to_user with segment limit checking */
15 .globl copy_to_user
16 .p2align 4
17copy_to_user:
18 GET_THREAD_INFO(%rax)
19 movq %rdi,%rcx
20 addq %rdx,%rcx
21 jc bad_to_user
22 cmpq threadinfo_addr_limit(%rax),%rcx
23 jae bad_to_user
242:
25 .byte 0xe9 /* 32bit jump */
26 .long .Lcug-1f
271:
28
29 .section .altinstr_replacement,"ax"
303: .byte 0xe9 /* replacement jmp with 8 bit immediate */
31 .long copy_user_generic_c-1b /* offset */
32 .previous
33 .section .altinstructions,"a"
34 .align 8
35 .quad 2b
36 .quad 3b
37 .byte X86_FEATURE_K8_C
38 .byte 5
39 .byte 5
40 .previous
41
42/* Standard copy_from_user with segment limit checking */
43 .globl copy_from_user
44 .p2align 4
45copy_from_user:
46 GET_THREAD_INFO(%rax)
47 movq %rsi,%rcx
48 addq %rdx,%rcx
49 jc bad_from_user
50 cmpq threadinfo_addr_limit(%rax),%rcx
51 jae bad_from_user
52 /* FALL THROUGH to copy_user_generic */
53
54 .section .fixup,"ax"
55 /* must zero dest */
56bad_from_user:
57 movl %edx,%ecx
58 xorl %eax,%eax
59 rep
60 stosb
61bad_to_user:
62 movl %edx,%eax
63 ret
64 .previous
65
66
67/*
68 * copy_user_generic - memory copy with exception handling.
69 *
70 * Input:
71 * rdi destination
72 * rsi source
73 * rdx count
74 *
75 * Output:
76 * eax uncopied bytes or 0 if successful.
77 */
78 .globl copy_user_generic
79 .p2align 4
80copy_user_generic:
81 .byte 0x66,0x66,0x90 /* 5 byte nop for replacement jump */
82 .byte 0x66,0x90
831:
84 .section .altinstr_replacement,"ax"
852: .byte 0xe9 /* near jump with 32bit immediate */
86 .long copy_user_generic_c-1b /* offset */
87 .previous
88 .section .altinstructions,"a"
89 .align 8
90 .quad copy_user_generic
91 .quad 2b
92 .byte X86_FEATURE_K8_C
93 .byte 5
94 .byte 5
95 .previous
96.Lcug:
97 pushq %rbx
98 xorl %eax,%eax /*zero for the exception handler */
99
100#ifdef FIX_ALIGNMENT
101 /* check for bad alignment of destination */
102 movl %edi,%ecx
103 andl $7,%ecx
104 jnz .Lbad_alignment
105.Lafter_bad_alignment:
106#endif
107
108 movq %rdx,%rcx
109
110 movl $64,%ebx
111 shrq $6,%rdx
112 decq %rdx
113 js .Lhandle_tail
114
115 .p2align 4
116.Lloop:
117.Ls1: movq (%rsi),%r11
118.Ls2: movq 1*8(%rsi),%r8
119.Ls3: movq 2*8(%rsi),%r9
120.Ls4: movq 3*8(%rsi),%r10
121.Ld1: movq %r11,(%rdi)
122.Ld2: movq %r8,1*8(%rdi)
123.Ld3: movq %r9,2*8(%rdi)
124.Ld4: movq %r10,3*8(%rdi)
125
126.Ls5: movq 4*8(%rsi),%r11
127.Ls6: movq 5*8(%rsi),%r8
128.Ls7: movq 6*8(%rsi),%r9
129.Ls8: movq 7*8(%rsi),%r10
130.Ld5: movq %r11,4*8(%rdi)
131.Ld6: movq %r8,5*8(%rdi)
132.Ld7: movq %r9,6*8(%rdi)
133.Ld8: movq %r10,7*8(%rdi)
134
135 decq %rdx
136
137 leaq 64(%rsi),%rsi
138 leaq 64(%rdi),%rdi
139
140 jns .Lloop
141
142 .p2align 4
143.Lhandle_tail:
144 movl %ecx,%edx
145 andl $63,%ecx
146 shrl $3,%ecx
147 jz .Lhandle_7
148 movl $8,%ebx
149 .p2align 4
150.Lloop_8:
151.Ls9: movq (%rsi),%r8
152.Ld9: movq %r8,(%rdi)
153 decl %ecx
154 leaq 8(%rdi),%rdi
155 leaq 8(%rsi),%rsi
156 jnz .Lloop_8
157
158.Lhandle_7:
159 movl %edx,%ecx
160 andl $7,%ecx
161 jz .Lende
162 .p2align 4
163.Lloop_1:
164.Ls10: movb (%rsi),%bl
165.Ld10: movb %bl,(%rdi)
166 incq %rdi
167 incq %rsi
168 decl %ecx
169 jnz .Lloop_1
170
171.Lende:
172 popq %rbx
173 ret
174
175#ifdef FIX_ALIGNMENT
176 /* align destination */
177 .p2align 4
178.Lbad_alignment:
179 movl $8,%r9d
180 subl %ecx,%r9d
181 movl %r9d,%ecx
182 cmpq %r9,%rdx
183 jz .Lhandle_7
184 js .Lhandle_7
185.Lalign_1:
186.Ls11: movb (%rsi),%bl
187.Ld11: movb %bl,(%rdi)
188 incq %rsi
189 incq %rdi
190 decl %ecx
191 jnz .Lalign_1
192 subq %r9,%rdx
193 jmp .Lafter_bad_alignment
194#endif
195
196 /* table sorted by exception address */
197 .section __ex_table,"a"
198 .align 8
199 .quad .Ls1,.Ls1e
200 .quad .Ls2,.Ls2e
201 .quad .Ls3,.Ls3e
202 .quad .Ls4,.Ls4e
203 .quad .Ld1,.Ls1e
204 .quad .Ld2,.Ls2e
205 .quad .Ld3,.Ls3e
206 .quad .Ld4,.Ls4e
207 .quad .Ls5,.Ls5e
208 .quad .Ls6,.Ls6e
209 .quad .Ls7,.Ls7e
210 .quad .Ls8,.Ls8e
211 .quad .Ld5,.Ls5e
212 .quad .Ld6,.Ls6e
213 .quad .Ld7,.Ls7e
214 .quad .Ld8,.Ls8e
215 .quad .Ls9,.Le_quad
216 .quad .Ld9,.Le_quad
217 .quad .Ls10,.Le_byte
218 .quad .Ld10,.Le_byte
219#ifdef FIX_ALIGNMENT
220 .quad .Ls11,.Lzero_rest
221 .quad .Ld11,.Lzero_rest
222#endif
223 .quad .Le5,.Le_zero
224 .previous
225
226 /* compute 64-offset for main loop. 8 bytes accuracy with error on the
227 pessimistic side. this is gross. it would be better to fix the
228 interface. */
229 /* eax: zero, ebx: 64 */
230.Ls1e: addl $8,%eax
231.Ls2e: addl $8,%eax
232.Ls3e: addl $8,%eax
233.Ls4e: addl $8,%eax
234.Ls5e: addl $8,%eax
235.Ls6e: addl $8,%eax
236.Ls7e: addl $8,%eax
237.Ls8e: addl $8,%eax
238 addq %rbx,%rdi /* +64 */
239 subq %rax,%rdi /* correct destination with computed offset */
240
241 shlq $6,%rdx /* loop counter * 64 (stride length) */
242 addq %rax,%rdx /* add offset to loopcnt */
243 andl $63,%ecx /* remaining bytes */
244 addq %rcx,%rdx /* add them */
245 jmp .Lzero_rest
246
247 /* exception on quad word loop in tail handling */
248 /* ecx: loopcnt/8, %edx: length, rdi: correct */
249.Le_quad:
250 shll $3,%ecx
251 andl $7,%edx
252 addl %ecx,%edx
253 /* edx: bytes to zero, rdi: dest, eax:zero */
254.Lzero_rest:
255 movq %rdx,%rcx
256.Le_byte:
257 xorl %eax,%eax
258.Le5: rep
259 stosb
260 /* when there is another exception while zeroing the rest just return */
261.Le_zero:
262 movq %rdx,%rax
263 jmp .Lende
264
265 /* C stepping K8 run faster using the string copy instructions.
266 This is also a lot simpler. Use them when possible.
267 Patch in jmps to this code instead of copying it fully
268 to avoid unwanted aliasing in the exception tables. */
269
270 /* rdi destination
271 * rsi source
272 * rdx count
273 *
274 * Output:
275 * eax uncopied bytes or 0 if successfull.
276 */
277copy_user_generic_c:
278 movl %edx,%ecx
279 shrl $3,%ecx
280 andl $7,%edx
2811: rep
282 movsq
283 movl %edx,%ecx
2842: rep
285 movsb
2864: movl %ecx,%eax
287 ret
2883: lea (%rdx,%rcx,8),%rax
289 ret
290
291 .section __ex_table,"a"
292 .quad 1b,3b
293 .quad 2b,4b
294 .previous