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linux
riscv: __asm_copy_to-from_user: Fix: Typos in comments
Fixing typos and grammar mistakes and using more intuitive label
name.
Signed-off-by: Akira Tsukamoto <akira.tsukamoto@gmail.com>
Fixes: ca6eaaa210de ("riscv: __asm_copy_to-from_user: Optimize unaligned memory access and pipeline stall")
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
authored by Akira Tsukamoto and committed by Palmer Dabbelt ea196c54 d4b3e010
+9
-9
arch/riscv/lib/uaccess.S
+9
-9
arch/riscv/lib/uaccess.S
···
33
34
/*
35
* Use byte copy only if too small.
36
*/
37
li a3, 9*SZREG /* size must be larger than size in word_copy */
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bltu a2, a3, .Lbyte_copy_tail
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/*
41
-
* Copy first bytes until dst is align to word boundary.
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* a0 - start of dst
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* t1 - start of aligned dst
44
*/
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addi t1, a0, SZREG-1
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andi t1, t1, ~(SZREG-1)
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/* dst is already aligned, skip */
48
-
beq a0, t1, .Lskip_first_bytes
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1:
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/* a5 - one byte for copying data */
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fixup lb a5, 0(a1), 10f
···
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addi a0, a0, 1 /* dst */
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bltu a0, t1, 1b /* t1 - start of aligned dst */
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58
-
.Lskip_first_bytes:
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/*
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* Now dst is aligned.
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* Use shift-copy if src is misaligned.
···
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*
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* a0 - start of aligned dst
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* a1 - start of aligned src
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-
* a3 - a1 & mask:(SZREG-1)
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* t0 - end of aligned dst
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*/
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addi t0, t0, -(8*SZREG) /* not to over run */
···
106
* For misaligned copy we still perform aligned word copy, but
107
* we need to use the value fetched from the previous iteration and
108
* do some shifts.
109
-
* This is safe because reading less than a word size.
110
*
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* a0 - start of aligned dst
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* a1 - start of src
···
116
*/
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/* calculating aligned word boundary for dst */
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andi t1, t0, ~(SZREG-1)
119
-
/* Converting unaligned src to aligned arc */
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andi a1, a1, ~(SZREG-1)
121
122
/*
···
128
li a5, SZREG*8
129
sub t4, a5, t3
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-
/* Load the first word to combine with seceond word */
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fixup REG_L a5, 0(a1), 10f
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3:
···
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* a1 - start of remaining src
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* t0 - end of remaining dst
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*/
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-
bgeu a0, t0, 5f
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4:
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fixup lb a5, 0(a1), 10f
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addi a1, a1, 1 /* src */
···
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addi a0, a0, 1 /* dst */
169
bltu a0, t0, 4b /* t0 - end of dst */
170
171
-
5:
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/* Disable access to user memory */
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csrc CSR_STATUS, t6
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li a0, 0
···
33
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/*
35
* Use byte copy only if too small.
36
+
* SZREG holds 4 for RV32 and 8 for RV64
37
*/
38
li a3, 9*SZREG /* size must be larger than size in word_copy */
39
bltu a2, a3, .Lbyte_copy_tail
40
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/*
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+
* Copy first bytes until dst is aligned to word boundary.
43
* a0 - start of dst
44
* t1 - start of aligned dst
45
*/
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addi t1, a0, SZREG-1
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andi t1, t1, ~(SZREG-1)
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/* dst is already aligned, skip */
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+
beq a0, t1, .Lskip_align_dst
50
1:
51
/* a5 - one byte for copying data */
52
fixup lb a5, 0(a1), 10f
···
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addi a0, a0, 1 /* dst */
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bltu a0, t1, 1b /* t1 - start of aligned dst */
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57
+
.Lskip_align_dst:
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/*
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* Now dst is aligned.
60
* Use shift-copy if src is misaligned.
···
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*
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* a0 - start of aligned dst
73
* a1 - start of aligned src
74
* t0 - end of aligned dst
75
*/
76
addi t0, t0, -(8*SZREG) /* not to over run */
···
106
* For misaligned copy we still perform aligned word copy, but
107
* we need to use the value fetched from the previous iteration and
108
* do some shifts.
109
+
* This is safe because reading is less than a word size.
110
*
111
* a0 - start of aligned dst
112
* a1 - start of src
···
116
*/
117
/* calculating aligned word boundary for dst */
118
andi t1, t0, ~(SZREG-1)
119
+
/* Converting unaligned src to aligned src */
120
andi a1, a1, ~(SZREG-1)
121
122
/*
···
128
li a5, SZREG*8
129
sub t4, a5, t3
130
131
+
/* Load the first word to combine with second word */
132
fixup REG_L a5, 0(a1), 10f
133
134
3:
···
160
* a1 - start of remaining src
161
* t0 - end of remaining dst
162
*/
163
+
bgeu a0, t0, .Lout_copy_user /* check if end of copy */
164
4:
165
fixup lb a5, 0(a1), 10f
166
addi a1, a1, 1 /* src */
···
168
addi a0, a0, 1 /* dst */
169
bltu a0, t0, 4b /* t0 - end of dst */
170
171
+
.Lout_copy_user:
172
/* Disable access to user memory */
173
csrc CSR_STATUS, t6
174
li a0, 0