]>
Commit | Line | Data |
---|---|---|
867e359b CM |
1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
867e359b CM |
13 | */ |
14 | ||
15 | #include <arch/chip.h> | |
16 | ||
867e359b | 17 | |
29507663 CM |
18 | /* |
19 | * This file shares the implementation of the userspace memcpy and | |
20 | * the kernel's memcpy, copy_to_user and copy_from_user. | |
21 | */ | |
22 | ||
867e359b CM |
23 | #include <linux/linkage.h> |
24 | ||
867e359b CM |
25 | #define IS_MEMCPY 0 |
26 | #define IS_COPY_FROM_USER 1 | |
867e359b CM |
27 | #define IS_COPY_TO_USER -1 |
28 | ||
29 | .section .text.memcpy_common, "ax" | |
30 | .align 64 | |
31 | ||
32 | /* Use this to preface each bundle that can cause an exception so | |
33 | * the kernel can clean up properly. The special cleanup code should | |
34 | * not use these, since it knows what it is doing. | |
35 | */ | |
36 | #define EX \ | |
37 | .pushsection __ex_table, "a"; \ | |
d4d9eab4 | 38 | .align 4; \ |
867e359b CM |
39 | .word 9f, memcpy_common_fixup; \ |
40 | .popsection; \ | |
41 | 9 | |
42 | ||
43 | ||
23504bae | 44 | /* raw_copy_from_user takes the kernel target address in r0, |
867e359b CM |
45 | * the user source in r1, and the bytes to copy in r2. |
46 | * It returns the number of uncopiable bytes (hopefully zero) in r0. | |
47 | */ | |
23504bae AV |
48 | ENTRY(raw_copy_from_user) |
49 | .type raw_copy_from_user, @function | |
50 | FEEDBACK_ENTER_EXPLICIT(raw_copy_from_user, \ | |
867e359b | 51 | .text.memcpy_common, \ |
23504bae | 52 | .Lend_memcpy_common - raw_copy_from_user) |
867e359b | 53 | { movei r29, IS_COPY_FROM_USER; j memcpy_common } |
23504bae | 54 | .size raw_copy_from_user, . - raw_copy_from_user |
867e359b | 55 | |
23504bae | 56 | /* raw_copy_to_user takes the user target address in r0, |
867e359b CM |
57 | * the kernel source in r1, and the bytes to copy in r2. |
58 | * It returns the number of uncopiable bytes (hopefully zero) in r0. | |
59 | */ | |
23504bae AV |
60 | ENTRY(raw_copy_to_user) |
61 | .type raw_copy_to_user, @function | |
62 | FEEDBACK_REENTER(raw_copy_from_user) | |
867e359b | 63 | { movei r29, IS_COPY_TO_USER; j memcpy_common } |
23504bae | 64 | .size raw_copy_to_user, . - raw_copy_to_user |
867e359b CM |
65 | |
66 | ENTRY(memcpy) | |
67 | .type memcpy, @function | |
23504bae | 68 | FEEDBACK_REENTER(raw_copy_from_user) |
867e359b CM |
69 | { movei r29, IS_MEMCPY } |
70 | .size memcpy, . - memcpy | |
71 | /* Fall through */ | |
72 | ||
73 | .type memcpy_common, @function | |
74 | memcpy_common: | |
75 | /* On entry, r29 holds one of the IS_* macro values from above. */ | |
76 | ||
77 | ||
78 | /* r0 is the dest, r1 is the source, r2 is the size. */ | |
79 | ||
80 | /* Save aside original dest so we can return it at the end. */ | |
81 | { sw sp, lr; move r23, r0; or r4, r0, r1 } | |
82 | ||
83 | /* Check for an empty size. */ | |
84 | { bz r2, .Ldone; andi r4, r4, 3 } | |
85 | ||
86 | /* Save aside original values in case of a fault. */ | |
87 | { move r24, r1; move r25, r2 } | |
88 | move r27, lr | |
89 | ||
90 | /* Check for an unaligned source or dest. */ | |
91 | { bnz r4, .Lcopy_unaligned_maybe_many; addli r4, r2, -256 } | |
92 | ||
93 | .Lcheck_aligned_copy_size: | |
94 | /* If we are copying < 256 bytes, branch to simple case. */ | |
95 | { blzt r4, .Lcopy_8_check; slti_u r8, r2, 8 } | |
96 | ||
97 | /* Copying >= 256 bytes, so jump to complex prefetching loop. */ | |
98 | { andi r6, r1, 63; j .Lcopy_many } | |
99 | ||
100 | /* | |
101 | * | |
102 | * Aligned 4 byte at a time copy loop | |
103 | * | |
104 | */ | |
105 | ||
106 | .Lcopy_8_loop: | |
107 | /* Copy two words at a time to hide load latency. */ | |
108 | EX: { lw r3, r1; addi r1, r1, 4; slti_u r8, r2, 16 } | |
109 | EX: { lw r4, r1; addi r1, r1, 4 } | |
110 | EX: { sw r0, r3; addi r0, r0, 4; addi r2, r2, -4 } | |
111 | EX: { sw r0, r4; addi r0, r0, 4; addi r2, r2, -4 } | |
112 | .Lcopy_8_check: | |
113 | { bzt r8, .Lcopy_8_loop; slti_u r4, r2, 4 } | |
114 | ||
115 | /* Copy odd leftover word, if any. */ | |
116 | { bnzt r4, .Lcheck_odd_stragglers } | |
117 | EX: { lw r3, r1; addi r1, r1, 4 } | |
118 | EX: { sw r0, r3; addi r0, r0, 4; addi r2, r2, -4 } | |
119 | ||
120 | .Lcheck_odd_stragglers: | |
121 | { bnz r2, .Lcopy_unaligned_few } | |
122 | ||
123 | .Ldone: | |
124 | /* For memcpy return original dest address, else zero. */ | |
125 | { mz r0, r29, r23; jrp lr } | |
126 | ||
127 | ||
128 | /* | |
129 | * | |
130 | * Prefetching multiple cache line copy handler (for large transfers). | |
131 | * | |
132 | */ | |
133 | ||
134 | /* Copy words until r1 is cache-line-aligned. */ | |
135 | .Lalign_loop: | |
136 | EX: { lw r3, r1; addi r1, r1, 4 } | |
137 | { andi r6, r1, 63 } | |
138 | EX: { sw r0, r3; addi r0, r0, 4; addi r2, r2, -4 } | |
139 | .Lcopy_many: | |
140 | { bnzt r6, .Lalign_loop; addi r9, r0, 63 } | |
141 | ||
142 | { addi r3, r1, 60; andi r9, r9, -64 } | |
143 | ||
29507663 CM |
144 | /* No need to prefetch dst, we'll just do the wh64 |
145 | * right before we copy a line. | |
867e359b | 146 | */ |
867e359b | 147 | EX: { lw r5, r3; addi r3, r3, 64; movei r4, 1 } |
29507663 CM |
148 | /* Intentionally stall for a few cycles to leave L2 cache alone. */ |
149 | { bnzt zero, .; move r27, lr } | |
867e359b | 150 | EX: { lw r6, r3; addi r3, r3, 64 } |
29507663 CM |
151 | /* Intentionally stall for a few cycles to leave L2 cache alone. */ |
152 | { bnzt zero, . } | |
867e359b | 153 | EX: { lw r7, r3; addi r3, r3, 64 } |
29507663 CM |
154 | /* Intentionally stall for a few cycles to leave L2 cache alone. */ |
155 | { bz zero, .Lbig_loop2 } | |
867e359b CM |
156 | |
157 | /* On entry to this loop: | |
158 | * - r0 points to the start of dst line 0 | |
159 | * - r1 points to start of src line 0 | |
160 | * - r2 >= (256 - 60), only the first time the loop trips. | |
161 | * - r3 contains r1 + 128 + 60 [pointer to end of source line 2] | |
162 | * This is our prefetch address. When we get near the end | |
163 | * rather than prefetching off the end this is changed to point | |
164 | * to some "safe" recently loaded address. | |
165 | * - r5 contains *(r1 + 60) [i.e. last word of source line 0] | |
166 | * - r6 contains *(r1 + 64 + 60) [i.e. last word of source line 1] | |
29507663 | 167 | * - r9 contains ((r0 + 63) & -64) |
867e359b CM |
168 | * [start of next dst cache line.] |
169 | */ | |
170 | ||
171 | .Lbig_loop: | |
172 | { jal .Lcopy_line2; add r15, r1, r2 } | |
173 | ||
174 | .Lbig_loop2: | |
175 | /* Copy line 0, first stalling until r5 is ready. */ | |
176 | EX: { move r12, r5; lw r16, r1 } | |
177 | { bz r4, .Lcopy_8_check; slti_u r8, r2, 8 } | |
29507663 | 178 | /* Prefetch several lines ahead. */ |
867e359b | 179 | EX: { lw r5, r3; addi r3, r3, 64 } |
29507663 | 180 | { jal .Lcopy_line } |
867e359b CM |
181 | |
182 | /* Copy line 1, first stalling until r6 is ready. */ | |
183 | EX: { move r12, r6; lw r16, r1 } | |
184 | { bz r4, .Lcopy_8_check; slti_u r8, r2, 8 } | |
29507663 | 185 | /* Prefetch several lines ahead. */ |
867e359b CM |
186 | EX: { lw r6, r3; addi r3, r3, 64 } |
187 | { jal .Lcopy_line } | |
188 | ||
189 | /* Copy line 2, first stalling until r7 is ready. */ | |
190 | EX: { move r12, r7; lw r16, r1 } | |
191 | { bz r4, .Lcopy_8_check; slti_u r8, r2, 8 } | |
29507663 | 192 | /* Prefetch several lines ahead. */ |
867e359b | 193 | EX: { lw r7, r3; addi r3, r3, 64 } |
29507663 CM |
194 | /* Use up a caches-busy cycle by jumping back to the top of the |
195 | * loop. Might as well get it out of the way now. | |
196 | */ | |
197 | { j .Lbig_loop } | |
867e359b CM |
198 | |
199 | ||
200 | /* On entry: | |
201 | * - r0 points to the destination line. | |
202 | * - r1 points to the source line. | |
29507663 | 203 | * - r3 is the next prefetch address. |
867e359b CM |
204 | * - r9 holds the last address used for wh64. |
205 | * - r12 = WORD_15 | |
29507663 CM |
206 | * - r16 = WORD_0. |
207 | * - r17 == r1 + 16. | |
208 | * - r27 holds saved lr to restore. | |
867e359b CM |
209 | * |
210 | * On exit: | |
211 | * - r0 is incremented by 64. | |
212 | * - r1 is incremented by 64, unless that would point to a word | |
29507663 CM |
213 | * beyond the end of the source array, in which case it is redirected |
214 | * to point to an arbitrary word already in the cache. | |
867e359b | 215 | * - r2 is decremented by 64. |
29507663 CM |
216 | * - r3 is unchanged, unless it points to a word beyond the |
217 | * end of the source array, in which case it is redirected | |
218 | * to point to an arbitrary word already in the cache. | |
219 | * Redirecting is OK since if we are that close to the end | |
220 | * of the array we will not come back to this subroutine | |
221 | * and use the contents of the prefetched address. | |
867e359b | 222 | * - r4 is nonzero iff r2 >= 64. |
29507663 CM |
223 | * - r9 is incremented by 64, unless it points beyond the |
224 | * end of the last full destination cache line, in which | |
225 | * case it is redirected to a "safe address" that can be | |
226 | * clobbered (sp - 64) | |
867e359b CM |
227 | * - lr contains the value in r27. |
228 | */ | |
229 | ||
230 | /* r26 unused */ | |
231 | ||
232 | .Lcopy_line: | |
29507663 CM |
233 | /* TODO: when r3 goes past the end, we would like to redirect it |
234 | * to prefetch the last partial cache line (if any) just once, for the | |
235 | * benefit of the final cleanup loop. But we don't want to | |
236 | * prefetch that line more than once, or subsequent prefetches | |
237 | * will go into the RTF. But then .Lbig_loop should unconditionally | |
238 | * branch to top of loop to execute final prefetch, and its | |
239 | * nop should become a conditional branch. | |
240 | */ | |
241 | ||
242 | /* We need two non-memory cycles here to cover the resources | |
243 | * used by the loads initiated by the caller. | |
244 | */ | |
245 | { add r15, r1, r2 } | |
867e359b | 246 | .Lcopy_line2: |
29507663 | 247 | { slt_u r13, r3, r15; addi r17, r1, 16 } |
867e359b | 248 | |
29507663 | 249 | /* NOTE: this will stall for one cycle as L1 is busy. */ |
867e359b | 250 | |
29507663 | 251 | /* Fill second L1D line. */ |
867e359b CM |
252 | EX: { lw r17, r17; addi r1, r1, 48; mvz r3, r13, r1 } /* r17 = WORD_4 */ |
253 | ||
29507663 | 254 | /* Prepare destination line for writing. */ |
867e359b | 255 | EX: { wh64 r9; addi r9, r9, 64 } |
29507663 | 256 | /* Load seven words that are L1D hits to cover wh64 L2 usage. */ |
867e359b | 257 | |
29507663 CM |
258 | /* Load the three remaining words from the last L1D line, which |
259 | * we know has already filled the L1D. | |
260 | */ | |
867e359b CM |
261 | EX: { lw r4, r1; addi r1, r1, 4; addi r20, r1, 16 } /* r4 = WORD_12 */ |
262 | EX: { lw r8, r1; addi r1, r1, 4; slt_u r13, r20, r15 }/* r8 = WORD_13 */ | |
263 | EX: { lw r11, r1; addi r1, r1, -52; mvz r20, r13, r1 } /* r11 = WORD_14 */ | |
264 | ||
29507663 CM |
265 | /* Load the three remaining words from the first L1D line, first |
266 | * stalling until it has filled by "looking at" r16. | |
267 | */ | |
867e359b CM |
268 | EX: { lw r13, r1; addi r1, r1, 4; move zero, r16 } /* r13 = WORD_1 */ |
269 | EX: { lw r14, r1; addi r1, r1, 4 } /* r14 = WORD_2 */ | |
270 | EX: { lw r15, r1; addi r1, r1, 8; addi r10, r0, 60 } /* r15 = WORD_3 */ | |
271 | ||
29507663 CM |
272 | /* Load second word from the second L1D line, first |
273 | * stalling until it has filled by "looking at" r17. | |
274 | */ | |
867e359b CM |
275 | EX: { lw r19, r1; addi r1, r1, 4; move zero, r17 } /* r19 = WORD_5 */ |
276 | ||
29507663 CM |
277 | /* Store last word to the destination line, potentially dirtying it |
278 | * for the first time, which keeps the L2 busy for two cycles. | |
279 | */ | |
867e359b CM |
280 | EX: { sw r10, r12 } /* store(WORD_15) */ |
281 | ||
29507663 | 282 | /* Use two L1D hits to cover the sw L2 access above. */ |
867e359b CM |
283 | EX: { lw r10, r1; addi r1, r1, 4 } /* r10 = WORD_6 */ |
284 | EX: { lw r12, r1; addi r1, r1, 4 } /* r12 = WORD_7 */ | |
285 | ||
29507663 | 286 | /* Fill third L1D line. */ |
867e359b CM |
287 | EX: { lw r18, r1; addi r1, r1, 4 } /* r18 = WORD_8 */ |
288 | ||
29507663 | 289 | /* Store first L1D line. */ |
867e359b CM |
290 | EX: { sw r0, r16; addi r0, r0, 4; add r16, r0, r2 } /* store(WORD_0) */ |
291 | EX: { sw r0, r13; addi r0, r0, 4; andi r16, r16, -64 } /* store(WORD_1) */ | |
292 | EX: { sw r0, r14; addi r0, r0, 4; slt_u r16, r9, r16 } /* store(WORD_2) */ | |
867e359b | 293 | EX: { sw r0, r15; addi r0, r0, 4; addi r13, sp, -64 } /* store(WORD_3) */ |
29507663 | 294 | /* Store second L1D line. */ |
867e359b CM |
295 | EX: { sw r0, r17; addi r0, r0, 4; mvz r9, r16, r13 }/* store(WORD_4) */ |
296 | EX: { sw r0, r19; addi r0, r0, 4 } /* store(WORD_5) */ | |
297 | EX: { sw r0, r10; addi r0, r0, 4 } /* store(WORD_6) */ | |
298 | EX: { sw r0, r12; addi r0, r0, 4 } /* store(WORD_7) */ | |
299 | ||
300 | EX: { lw r13, r1; addi r1, r1, 4; move zero, r18 } /* r13 = WORD_9 */ | |
301 | EX: { lw r14, r1; addi r1, r1, 4 } /* r14 = WORD_10 */ | |
302 | EX: { lw r15, r1; move r1, r20 } /* r15 = WORD_11 */ | |
303 | ||
29507663 | 304 | /* Store third L1D line. */ |
867e359b CM |
305 | EX: { sw r0, r18; addi r0, r0, 4 } /* store(WORD_8) */ |
306 | EX: { sw r0, r13; addi r0, r0, 4 } /* store(WORD_9) */ | |
307 | EX: { sw r0, r14; addi r0, r0, 4 } /* store(WORD_10) */ | |
308 | EX: { sw r0, r15; addi r0, r0, 4 } /* store(WORD_11) */ | |
309 | ||
29507663 | 310 | /* Store rest of fourth L1D line. */ |
867e359b | 311 | EX: { sw r0, r4; addi r0, r0, 4 } /* store(WORD_12) */ |
29507663 | 312 | { |
867e359b | 313 | EX: sw r0, r8 /* store(WORD_13) */ |
29507663 | 314 | addi r0, r0, 4 |
867e359b | 315 | /* Will r2 be > 64 after we subtract 64 below? */ |
29507663 CM |
316 | shri r4, r2, 7 |
317 | } | |
318 | { | |
867e359b | 319 | EX: sw r0, r11 /* store(WORD_14) */ |
29507663 CM |
320 | addi r0, r0, 8 |
321 | /* Record 64 bytes successfully copied. */ | |
322 | addi r2, r2, -64 | |
323 | } | |
867e359b CM |
324 | |
325 | { jrp lr; move lr, r27 } | |
326 | ||
29507663 | 327 | /* Convey to the backtrace library that the stack frame is size |
867e359b CM |
328 | * zero, and the real return address is on the stack rather than |
329 | * in 'lr'. | |
330 | */ | |
331 | { info 8 } | |
332 | ||
333 | .align 64 | |
334 | .Lcopy_unaligned_maybe_many: | |
335 | /* Skip the setup overhead if we aren't copying many bytes. */ | |
336 | { slti_u r8, r2, 20; sub r4, zero, r0 } | |
337 | { bnzt r8, .Lcopy_unaligned_few; andi r4, r4, 3 } | |
338 | { bz r4, .Ldest_is_word_aligned; add r18, r1, r2 } | |
339 | ||
340 | /* | |
341 | * | |
342 | * unaligned 4 byte at a time copy handler. | |
343 | * | |
344 | */ | |
345 | ||
346 | /* Copy single bytes until r0 == 0 mod 4, so we can store words. */ | |
347 | .Lalign_dest_loop: | |
348 | EX: { lb_u r3, r1; addi r1, r1, 1; addi r4, r4, -1 } | |
349 | EX: { sb r0, r3; addi r0, r0, 1; addi r2, r2, -1 } | |
350 | { bnzt r4, .Lalign_dest_loop; andi r3, r1, 3 } | |
351 | ||
352 | /* If source and dest are now *both* aligned, do an aligned copy. */ | |
353 | { bz r3, .Lcheck_aligned_copy_size; addli r4, r2, -256 } | |
354 | ||
355 | .Ldest_is_word_aligned: | |
356 | ||
867e359b CM |
357 | EX: { andi r8, r0, 63; lwadd_na r6, r1, 4} |
358 | { slti_u r9, r2, 64; bz r8, .Ldest_is_L2_line_aligned } | |
359 | ||
360 | /* This copies unaligned words until either there are fewer | |
361 | * than 4 bytes left to copy, or until the destination pointer | |
362 | * is cache-aligned, whichever comes first. | |
363 | * | |
364 | * On entry: | |
365 | * - r0 is the next store address. | |
366 | * - r1 points 4 bytes past the load address corresponding to r0. | |
367 | * - r2 >= 4 | |
368 | * - r6 is the next aligned word loaded. | |
369 | */ | |
370 | .Lcopy_unaligned_src_words: | |
371 | EX: { lwadd_na r7, r1, 4; slti_u r8, r2, 4 + 4 } | |
372 | /* stall */ | |
373 | { dword_align r6, r7, r1; slti_u r9, r2, 64 + 4 } | |
374 | EX: { swadd r0, r6, 4; addi r2, r2, -4 } | |
375 | { bnz r8, .Lcleanup_unaligned_words; andi r8, r0, 63 } | |
376 | { bnzt r8, .Lcopy_unaligned_src_words; move r6, r7 } | |
377 | ||
378 | /* On entry: | |
379 | * - r0 is the next store address. | |
380 | * - r1 points 4 bytes past the load address corresponding to r0. | |
381 | * - r2 >= 4 (# of bytes left to store). | |
382 | * - r6 is the next aligned src word value. | |
383 | * - r9 = (r2 < 64U). | |
384 | * - r18 points one byte past the end of source memory. | |
385 | */ | |
386 | .Ldest_is_L2_line_aligned: | |
387 | ||
388 | { | |
389 | /* Not a full cache line remains. */ | |
390 | bnz r9, .Lcleanup_unaligned_words | |
391 | move r7, r6 | |
392 | } | |
393 | ||
394 | /* r2 >= 64 */ | |
395 | ||
396 | /* Kick off two prefetches, but don't go past the end. */ | |
397 | { addi r3, r1, 63 - 4; addi r8, r1, 64 + 63 - 4 } | |
398 | { prefetch r3; move r3, r8; slt_u r8, r8, r18 } | |
399 | { mvz r3, r8, r1; addi r8, r3, 64 } | |
400 | { prefetch r3; move r3, r8; slt_u r8, r8, r18 } | |
401 | { mvz r3, r8, r1; movei r17, 0 } | |
402 | ||
403 | .Lcopy_unaligned_line: | |
404 | /* Prefetch another line. */ | |
405 | { prefetch r3; addi r15, r1, 60; addi r3, r3, 64 } | |
406 | /* Fire off a load of the last word we are about to copy. */ | |
407 | EX: { lw_na r15, r15; slt_u r8, r3, r18 } | |
408 | ||
409 | EX: { mvz r3, r8, r1; wh64 r0 } | |
410 | ||
411 | /* This loop runs twice. | |
412 | * | |
413 | * On entry: | |
414 | * - r17 is even before the first iteration, and odd before | |
415 | * the second. It is incremented inside the loop. Encountering | |
416 | * an even value at the end of the loop makes it stop. | |
417 | */ | |
418 | .Lcopy_half_an_unaligned_line: | |
419 | EX: { | |
420 | /* Stall until the last byte is ready. In the steady state this | |
421 | * guarantees all words to load below will be in the L2 cache, which | |
422 | * avoids shunting the loads to the RTF. | |
423 | */ | |
424 | move zero, r15 | |
425 | lwadd_na r7, r1, 16 | |
426 | } | |
427 | EX: { lwadd_na r11, r1, 12 } | |
428 | EX: { lwadd_na r14, r1, -24 } | |
429 | EX: { lwadd_na r8, r1, 4 } | |
430 | EX: { lwadd_na r9, r1, 4 } | |
431 | EX: { | |
432 | lwadd_na r10, r1, 8 | |
433 | /* r16 = (r2 < 64), after we subtract 32 from r2 below. */ | |
434 | slti_u r16, r2, 64 + 32 | |
435 | } | |
436 | EX: { lwadd_na r12, r1, 4; addi r17, r17, 1 } | |
437 | EX: { lwadd_na r13, r1, 8; dword_align r6, r7, r1 } | |
438 | EX: { swadd r0, r6, 4; dword_align r7, r8, r1 } | |
439 | EX: { swadd r0, r7, 4; dword_align r8, r9, r1 } | |
440 | EX: { swadd r0, r8, 4; dword_align r9, r10, r1 } | |
441 | EX: { swadd r0, r9, 4; dword_align r10, r11, r1 } | |
442 | EX: { swadd r0, r10, 4; dword_align r11, r12, r1 } | |
443 | EX: { swadd r0, r11, 4; dword_align r12, r13, r1 } | |
444 | EX: { swadd r0, r12, 4; dword_align r13, r14, r1 } | |
445 | EX: { swadd r0, r13, 4; addi r2, r2, -32 } | |
446 | { move r6, r14; bbst r17, .Lcopy_half_an_unaligned_line } | |
447 | ||
448 | { bzt r16, .Lcopy_unaligned_line; move r7, r6 } | |
449 | ||
450 | /* On entry: | |
451 | * - r0 is the next store address. | |
452 | * - r1 points 4 bytes past the load address corresponding to r0. | |
453 | * - r2 >= 0 (# of bytes left to store). | |
454 | * - r7 is the next aligned src word value. | |
455 | */ | |
456 | .Lcleanup_unaligned_words: | |
457 | /* Handle any trailing bytes. */ | |
458 | { bz r2, .Lcopy_unaligned_done; slti_u r8, r2, 4 } | |
459 | { bzt r8, .Lcopy_unaligned_src_words; move r6, r7 } | |
460 | ||
461 | /* Move r1 back to the point where it corresponds to r0. */ | |
462 | { addi r1, r1, -4 } | |
463 | ||
867e359b CM |
464 | /* Fall through */ |
465 | ||
466 | /* | |
467 | * | |
468 | * 1 byte at a time copy handler. | |
469 | * | |
470 | */ | |
471 | ||
472 | .Lcopy_unaligned_few: | |
473 | EX: { lb_u r3, r1; addi r1, r1, 1 } | |
474 | EX: { sb r0, r3; addi r0, r0, 1; addi r2, r2, -1 } | |
475 | { bnzt r2, .Lcopy_unaligned_few } | |
476 | ||
477 | .Lcopy_unaligned_done: | |
478 | ||
479 | /* For memcpy return original dest address, else zero. */ | |
480 | { mz r0, r29, r23; jrp lr } | |
481 | ||
482 | .Lend_memcpy_common: | |
483 | .size memcpy_common, .Lend_memcpy_common - memcpy_common | |
484 | ||
485 | .section .fixup,"ax" | |
486 | memcpy_common_fixup: | |
487 | .type memcpy_common_fixup, @function | |
488 | ||
489 | /* Skip any bytes we already successfully copied. | |
490 | * r2 (num remaining) is correct, but r0 (dst) and r1 (src) | |
491 | * may not be quite right because of unrolling and prefetching. | |
492 | * So we need to recompute their values as the address just | |
493 | * after the last byte we are sure was successfully loaded and | |
494 | * then stored. | |
495 | */ | |
496 | ||
497 | /* Determine how many bytes we successfully copied. */ | |
498 | { sub r3, r25, r2 } | |
499 | ||
500 | /* Add this to the original r0 and r1 to get their new values. */ | |
501 | { add r0, r23, r3; add r1, r24, r3 } | |
502 | ||
503 | { bzt r29, memcpy_fixup_loop } | |
504 | { blzt r29, copy_to_user_fixup_loop } | |
505 | ||
506 | copy_from_user_fixup_loop: | |
507 | /* Try copying the rest one byte at a time, expecting a load fault. */ | |
508 | .Lcfu: { lb_u r3, r1; addi r1, r1, 1 } | |
509 | { sb r0, r3; addi r0, r0, 1; addi r2, r2, -1 } | |
510 | { bnzt r2, copy_from_user_fixup_loop } | |
511 | ||
512 | .Lcopy_from_user_fixup_zero_remainder: | |
23504bae | 513 | move lr, r27 |
867e359b CM |
514 | { move r0, r2; jrp lr } |
515 | ||
516 | copy_to_user_fixup_loop: | |
517 | /* Try copying the rest one byte at a time, expecting a store fault. */ | |
518 | { lb_u r3, r1; addi r1, r1, 1 } | |
519 | .Lctu: { sb r0, r3; addi r0, r0, 1; addi r2, r2, -1 } | |
520 | { bnzt r2, copy_to_user_fixup_loop } | |
521 | .Lcopy_to_user_fixup_done: | |
522 | move lr, r27 | |
523 | { move r0, r2; jrp lr } | |
524 | ||
525 | memcpy_fixup_loop: | |
526 | /* Try copying the rest one byte at a time. We expect a disastrous | |
527 | * fault to happen since we are in fixup code, but let it happen. | |
528 | */ | |
529 | { lb_u r3, r1; addi r1, r1, 1 } | |
530 | { sb r0, r3; addi r0, r0, 1; addi r2, r2, -1 } | |
531 | { bnzt r2, memcpy_fixup_loop } | |
532 | /* This should be unreachable, we should have faulted again. | |
533 | * But be paranoid and handle it in case some interrupt changed | |
534 | * the TLB or something. | |
535 | */ | |
536 | move lr, r27 | |
537 | { move r0, r23; jrp lr } | |
538 | ||
539 | .size memcpy_common_fixup, . - memcpy_common_fixup | |
540 | ||
541 | .section __ex_table,"a" | |
d4d9eab4 | 542 | .align 4 |
867e359b CM |
543 | .word .Lcfu, .Lcopy_from_user_fixup_zero_remainder |
544 | .word .Lctu, .Lcopy_to_user_fixup_done |