[PATCH V4 2/2] arm64: Change memcpy in kernel to use the copy template file

From: Feng Kan
Date: Fri Aug 21 2015 - 18:01:03 EST


This converts the memcpy.S to use the copy template file. The copy
template file was based originally on the memcpy.S. Minor changes
was made to it to accommodate the copy to/from/in user files.

Signed-off-by: Feng Kan <fkan@xxxxxxx>
---
arch/arm64/lib/memcpy.S | 179 +++++++-----------------------------------------
1 file changed, 26 insertions(+), 153 deletions(-)

diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
index 8a9a96d..761acd7 100644
--- a/arch/arm64/lib/memcpy.S
+++ b/arch/arm64/lib/memcpy.S
@@ -36,166 +36,39 @@
* Returns:
* x0 - dest
*/
-dstin .req x0
-src .req x1
-count .req x2
-tmp1 .req x3
-tmp1w .req w3
-tmp2 .req x4
-tmp2w .req w4
-tmp3 .req x5
-tmp3w .req w5
-dst .req x6
+ .macro ldrb1 label, ptr, regB, val
+ ldrb \ptr, [\regB], \val
+ .endm

-A_l .req x7
-A_h .req x8
-B_l .req x9
-B_h .req x10
-C_l .req x11
-C_h .req x12
-D_l .req x13
-D_h .req x14
+ .macro strb1 label, ptr, regB, val
+ strb \ptr, [\regB], \val
+ .endm

-ENTRY(memcpy)
- mov dst, dstin
- cmp count, #16
- /*When memory length is less than 16, the accessed are not aligned.*/
- b.lo .Ltiny15
+ .macro ldrh1 label, ptr, regB, val
+ ldrh \ptr, [\regB], \val
+ .endm

- neg tmp2, src
- ands tmp2, tmp2, #15/* Bytes to reach alignment. */
- b.eq .LSrcAligned
- sub count, count, tmp2
- /*
- * Copy the leading memory data from src to dst in an increasing
- * address order.By this way,the risk of overwritting the source
- * memory data is eliminated when the distance between src and
- * dst is less than 16. The memory accesses here are alignment.
- */
- tbz tmp2, #0, 1f
- ldrb tmp1w, [src], #1
- strb tmp1w, [dst], #1
-1:
- tbz tmp2, #1, 2f
- ldrh tmp1w, [src], #2
- strh tmp1w, [dst], #2
-2:
- tbz tmp2, #2, 3f
- ldr tmp1w, [src], #4
- str tmp1w, [dst], #4
-3:
- tbz tmp2, #3, .LSrcAligned
- ldr tmp1, [src],#8
- str tmp1, [dst],#8
+ .macro strh1 label, ptr, regB, val
+ strh \ptr, [\regB], \val
+ .endm

-.LSrcAligned:
- cmp count, #64
- b.ge .Lcpy_over64
- /*
- * Deal with small copies quickly by dropping straight into the
- * exit block.
- */
-.Ltail63:
- /*
- * Copy up to 48 bytes of data. At this point we only need the
- * bottom 6 bits of count to be accurate.
- */
- ands tmp1, count, #0x30
- b.eq .Ltiny15
- cmp tmp1w, #0x20
- b.eq 1f
- b.lt 2f
- ldp A_l, A_h, [src], #16
- stp A_l, A_h, [dst], #16
-1:
- ldp A_l, A_h, [src], #16
- stp A_l, A_h, [dst], #16
-2:
- ldp A_l, A_h, [src], #16
- stp A_l, A_h, [dst], #16
-.Ltiny15:
- /*
- * Prefer to break one ldp/stp into several load/store to access
- * memory in an increasing address order,rather than to load/store 16
- * bytes from (src-16) to (dst-16) and to backward the src to aligned
- * address,which way is used in original cortex memcpy. If keeping
- * the original memcpy process here, memmove need to satisfy the
- * precondition that src address is at least 16 bytes bigger than dst
- * address,otherwise some source data will be overwritten when memove
- * call memcpy directly. To make memmove simpler and decouple the
- * memcpy's dependency on memmove, withdrew the original process.
- */
- tbz count, #3, 1f
- ldr tmp1, [src], #8
- str tmp1, [dst], #8
-1:
- tbz count, #2, 2f
- ldr tmp1w, [src], #4
- str tmp1w, [dst], #4
-2:
- tbz count, #1, 3f
- ldrh tmp1w, [src], #2
- strh tmp1w, [dst], #2
-3:
- tbz count, #0, .Lexitfunc
- ldrb tmp1w, [src]
- strb tmp1w, [dst]
+ .macro ldr1 label, ptr, regB, val
+ ldr \ptr, [\regB], \val
+ .endm

-.Lexitfunc:
- ret
+ .macro str1 label, ptr, regB, val
+ str \ptr, [\regB], \val
+ .endm

-.Lcpy_over64:
- subs count, count, #128
- b.ge .Lcpy_body_large
- /*
- * Less than 128 bytes to copy, so handle 64 here and then jump
- * to the tail.
- */
- ldp A_l, A_h, [src],#16
- stp A_l, A_h, [dst],#16
- ldp B_l, B_h, [src],#16
- ldp C_l, C_h, [src],#16
- stp B_l, B_h, [dst],#16
- stp C_l, C_h, [dst],#16
- ldp D_l, D_h, [src],#16
- stp D_l, D_h, [dst],#16
+ .macro ldp1 label, ptr, regB, regC, val
+ ldp \ptr, \regB, [\regC], \val
+ .endm

- tst count, #0x3f
- b.ne .Ltail63
- ret
+ .macro stp1 label, ptr, regB, regC, val
+ stp \ptr, \regB, [\regC], \val
+ .endm

- /*
- * Critical loop. Start at a new cache line boundary. Assuming
- * 64 bytes per line this ensures the entire loop is in one line.
- */
- .p2align L1_CACHE_SHIFT
-.Lcpy_body_large:
- /* pre-get 64 bytes data. */
- ldp A_l, A_h, [src],#16
- ldp B_l, B_h, [src],#16
- ldp C_l, C_h, [src],#16
- ldp D_l, D_h, [src],#16
-1:
- /*
- * interlace the load of next 64 bytes data block with store of the last
- * loaded 64 bytes data.
- */
- stp A_l, A_h, [dst],#16
- ldp A_l, A_h, [src],#16
- stp B_l, B_h, [dst],#16
- ldp B_l, B_h, [src],#16
- stp C_l, C_h, [dst],#16
- ldp C_l, C_h, [src],#16
- stp D_l, D_h, [dst],#16
- ldp D_l, D_h, [src],#16
- subs count, count, #64
- b.ge 1b
- stp A_l, A_h, [dst],#16
- stp B_l, B_h, [dst],#16
- stp C_l, C_h, [dst],#16
- stp D_l, D_h, [dst],#16
-
- tst count, #0x3f
- b.ne .Ltail63
+ENTRY(memcpy)
+#include "copy_template.S"
ret
ENDPROC(memcpy)
--
1.9.1

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