LoongArch: Improve memory ops

Message ID 20230410115734.93365-1-wangrui@loongson.cn
State New
Headers
Series LoongArch: Improve memory ops |

Commit Message

WANG Rui April 10, 2023, 11:57 a.m. UTC
  We use a jump table to dispatch cases for short data lengths, and for long data
lengths, we use unaligned memory access instruction to process the first and
last 8 bytes. The data in the middle is processed at an aligned destination
address.

We have tested micro-bench[1] on a Loongson-3C5000 16-core machine (2.2GHz):

1. memset

| length | src offset | dst offset | speed before | speed after | %       |
|--------|------------|------------|--------------|-------------|---------|
| 8      | 0          | 0          | 696.191      | 1518.785    | 118.16% |
| 8      | 0          | 1          | 696.325      | 1518.937    | 118.14% |
| 50     | 0          | 0          | 969.976      | 8053.902    | 730.32% |
| 50     | 0          | 1          | 970.034      | 8058.475    | 730.74% |
| 300    | 0          | 0          | 5876.612     | 16544.703   | 181.53% |
| 300    | 0          | 1          | 5030.849     | 16549.011   | 228.95% |
| 1200   | 0          | 0          | 11797.077    | 16752.137   | 42.00%  |
| 1200   | 0          | 1          | 5687.141     | 16645.233   | 192.68% |
| 4000   | 0          | 0          | 15723.27     | 16761.557   | 6.60%   |
| 4000   | 0          | 1          | 5906.114     | 16732.316   | 183.30% |
| 8000   | 0          | 0          | 16751.403    | 16770.002   | 0.11%   |
| 8000   | 0          | 1          | 5995.449     | 16754.07    | 179.45% |

2. memcpy

| length | src offset | dst offset | speed before | speed after | %       |
|--------|------------|------------|--------------|-------------|---------|
| 8      | 0          | 0          | 696.2        | 1670.605    | 139.96% |
| 8      | 0          | 1          | 696.325      | 1671.138    | 139.99% |
| 50     | 0          | 0          | 969.974      | 8724.999    | 799.51% |
| 50     | 0          | 1          | 970.032      | 8730.138    | 799.98% |
| 300    | 0          | 0          | 5564.662     | 16272.652   | 192.43% |
| 300    | 0          | 1          | 4670.436     | 14972.842   | 220.59% |
| 1200   | 0          | 0          | 10740.23     | 16751.728   | 55.97%  |
| 1200   | 0          | 1          | 5027.741     | 14874.564   | 195.85% |
| 4000   | 0          | 0          | 15122.367    | 16737.642   | 10.68%  |
| 4000   | 0          | 1          | 5536.918     | 14890.397   | 168.93% |
| 8000   | 0          | 0          | 16505.453    | 16553.543   | 0.29%   |
| 8000   | 0          | 1          | 5821.619     | 14841.804   | 154.94% |

3. memmove

| length | src offset | dst offset | speed before | speed after | %       |
|--------|------------|------------|--------------|-------------|---------|
| 8      | 0          | 0          | 982.693      | 1670.568    | 70.00%  |
| 8      | 0          | 1          | 983.023      | 1671.174    | 70.00%  |
| 50     | 0          | 0          | 1230.87      | 8727.625    | 609.06% |
| 50     | 0          | 1          | 1232.515     | 8730.138    | 608.32% |
| 300    | 0          | 0          | 6490.375     | 16296.993   | 151.09% |
| 300    | 0          | 1          | 4282.687     | 14972.842   | 249.61% |
| 1200   | 0          | 0          | 11742.755    | 16752.546   | 42.66%  |
| 1200   | 0          | 1          | 5039.338     | 14872.951   | 195.14% |
| 4000   | 0          | 0          | 15467.786    | 16737.09    | 8.21%   |
| 4000   | 0          | 1          | 5009.905     | 14890.542   | 197.22% |
| 8000   | 0          | 0          | 16489.664    | 16553.273   | 0.39%   |
| 8000   | 0          | 1          | 5823.786     | 14858.646   | 155.14% |

* speed: MB/s
* length: byte

[1] https://github.com/heiher/mem-bench

Signed-off-by: WANG rui <wangrui@loongson.cn>
---
 arch/loongarch/lib/clear_user.S | 137 +++++++++++++++--
 arch/loongarch/lib/copy_user.S  | 251 +++++++++++++++++++++++++-------
 arch/loongarch/lib/memcpy.S     | 147 +++++++++++++++----
 arch/loongarch/lib/memmove.S    | 120 ++++++++-------
 arch/loongarch/lib/memset.S     | 117 ++++++++++++---
 5 files changed, 605 insertions(+), 167 deletions(-)
  

Comments

Xi Ruoyao April 10, 2023, 12:20 p.m. UTC | #1
On Mon, 2023-04-10 at 19:57 +0800, WANG rui wrote:
> +       /* align up address */
> +       andi    t1, a0, 7
> +       sub.d   a0, a0, t1

bstrins.d a0, zero, 2, 0

Likewise for other aligning operations if the temporary is not used.

> +       addi.d  a0, a0, 8
  
Xi Ruoyao April 10, 2023, 12:53 p.m. UTC | #2
On Mon, 2023-04-10 at 19:57 +0800, WANG rui wrote:
> We use a jump table to dispatch cases for short data lengths, and for long data
> lengths, we use unaligned memory access instruction to process the first and
> last 8 bytes. The data in the middle is processed at an aligned destination
> address.

Regarding these functions: we have -ffreestanding which is preventing
the compiler from optimizing for e.g. "memcpy(a, b, 8);" into a simple
ld.d/st.d pair.  A explicit compiler built-in usage like

  #define memcpy(a, b, c) __builtin_memcpy(a, b, c) 

would allow the compiler to do such kind of optimization.   Will this
improve the performance?

> 
> We have tested micro-bench[1] on a Loongson-3C5000 16-core machine (2.2GHz):
> 
> 1. memset
> 
> > length | src offset | dst offset | speed before | speed after |
> > %       |
> > --------|------------|------------|--------------|-------------|----
> > -----|
> > 8      | 0          | 0          | 696.191      | 1518.785    |
> > 118.16% |
> > 8      | 0          | 1          | 696.325      | 1518.937    |
> > 118.14% |
> > 50     | 0          | 0          | 969.976      | 8053.902    |
> > 730.32% |
> > 50     | 0          | 1          | 970.034      | 8058.475    |
> > 730.74% |
> > 300    | 0          | 0          | 5876.612     | 16544.703   |
> > 181.53% |
> > 300    | 0          | 1          | 5030.849     | 16549.011   |
> > 228.95% |
> > 1200   | 0          | 0          | 11797.077    | 16752.137   |
> > 42.00%  |
> > 1200   | 0          | 1          | 5687.141     | 16645.233   |
> > 192.68% |
> > 4000   | 0          | 0          | 15723.27     | 16761.557   |
> > 6.60%   |
> > 4000   | 0          | 1          | 5906.114     | 16732.316   |
> > 183.30% |
> > 8000   | 0          | 0          | 16751.403    | 16770.002   |
> > 0.11%   |
> > 8000   | 0          | 1          | 5995.449     | 16754.07    |
> > 179.45% |
> 
> 2. memcpy
> 
> > length | src offset | dst offset | speed before | speed after |
> > %       |
> > --------|------------|------------|--------------|-------------|----
> > -----|
> > 8      | 0          | 0          | 696.2        | 1670.605    |
> > 139.96% |
> > 8      | 0          | 1          | 696.325      | 1671.138    |
> > 139.99% |
> > 50     | 0          | 0          | 969.974      | 8724.999    |
> > 799.51% |
> > 50     | 0          | 1          | 970.032      | 8730.138    |
> > 799.98% |
> > 300    | 0          | 0          | 5564.662     | 16272.652   |
> > 192.43% |
> > 300    | 0          | 1          | 4670.436     | 14972.842   |
> > 220.59% |
> > 1200   | 0          | 0          | 10740.23     | 16751.728   |
> > 55.97%  |
> > 1200   | 0          | 1          | 5027.741     | 14874.564   |
> > 195.85% |
> > 4000   | 0          | 0          | 15122.367    | 16737.642   |
> > 10.68%  |
> > 4000   | 0          | 1          | 5536.918     | 14890.397   |
> > 168.93% |
> > 8000   | 0          | 0          | 16505.453    | 16553.543   |
> > 0.29%   |
> > 8000   | 0          | 1          | 5821.619     | 14841.804   |
> > 154.94% |
> 
> 3. memmove
> 
> > length | src offset | dst offset | speed before | speed after |
> > %       |
> > --------|------------|------------|--------------|-------------|----
> > -----|
> > 8      | 0          | 0          | 982.693      | 1670.568    |
> > 70.00%  |
> > 8      | 0          | 1          | 983.023      | 1671.174    |
> > 70.00%  |
> > 50     | 0          | 0          | 1230.87      | 8727.625    |
> > 609.06% |
> > 50     | 0          | 1          | 1232.515     | 8730.138    |
> > 608.32% |
> > 300    | 0          | 0          | 6490.375     | 16296.993   |
> > 151.09% |
> > 300    | 0          | 1          | 4282.687     | 14972.842   |
> > 249.61% |
> > 1200   | 0          | 0          | 11742.755    | 16752.546   |
> > 42.66%  |
> > 1200   | 0          | 1          | 5039.338     | 14872.951   |
> > 195.14% |
> > 4000   | 0          | 0          | 15467.786    | 16737.09    |
> > 8.21%   |
> > 4000   | 0          | 1          | 5009.905     | 14890.542   |
> > 197.22% |
> > 8000   | 0          | 0          | 16489.664    | 16553.273   |
> > 0.39%   |
> > 8000   | 0          | 1          | 5823.786     | 14858.646   |
> > 155.14% |
> 
> * speed: MB/s
> * length: byte
> 
> [1] https://github.com/heiher/mem-bench
> 
> Signed-off-by: WANG rui <wangrui@loongson.cn>
> ---
>  arch/loongarch/lib/clear_user.S | 137 +++++++++++++++--
>  arch/loongarch/lib/copy_user.S  | 251 +++++++++++++++++++++++++------
> -
>  arch/loongarch/lib/memcpy.S     | 147 +++++++++++++++----
>  arch/loongarch/lib/memmove.S    | 120 ++++++++-------
>  arch/loongarch/lib/memset.S     | 117 ++++++++++++---
>  5 files changed, 605 insertions(+), 167 deletions(-)
> 
> diff --git a/arch/loongarch/lib/clear_user.S
> b/arch/loongarch/lib/clear_user.S
> index 2dc48e61a2c8..02f112b265cd 100644
> --- a/arch/loongarch/lib/clear_user.S
> +++ b/arch/loongarch/lib/clear_user.S
> @@ -13,7 +13,14 @@
>  
>  .irp to, 0, 1, 2, 3, 4, 5, 6, 7
>  .L_fixup_handle_\to\():
> -       addi.d  a0, a1, (\to) * (-8)
> +       sub.d   a0, a2, a0
> +       addi.d  a0, a0, (\to) * (-8)
> +       jr      ra
> +.endr
> +
> +.irp to, 0, 2, 4
> +.L_fixup_handle_s\to\():
> +       addi.d  a0, a1, -\to
>         jr      ra
>  .endr
>  
> @@ -44,7 +51,7 @@ SYM_FUNC_START(__clear_user_generic)
>  2:     move    a0, a1
>         jr      ra
>  
> -       _asm_extable 1b, .L_fixup_handle_0
> +       _asm_extable 1b, .L_fixup_handle_s0
>  SYM_FUNC_END(__clear_user_generic)
>  
>  /*
> @@ -54,12 +61,22 @@ SYM_FUNC_END(__clear_user_generic)
>   * a1: size
>   */
>  SYM_FUNC_START(__clear_user_fast)
> -       beqz    a1, 10f
> +       sltui   t0, a1, 9
> +       bnez    t0, .Lsmall
>  
> -       ori     a2, zero, 64
> -       blt     a1, a2, 9f
> +       add.d   a2, a0, a1
> +0:     st.d    zero, a0, 0
> +
> +       /* align up address */
> +       andi    t1, a0, 7
> +       sub.d   a0, a0, t1
> +       addi.d  a0, a0, 8
> +
> +       addi.d  a3, a2, -64
> +       bgeu    a0, a3, .Llt64
>  
>         /* set 64 bytes at a time */
> +.Lloop64:
>  1:     st.d    zero, a0, 0
>  2:     st.d    zero, a0, 8
>  3:     st.d    zero, a0, 16
> @@ -68,24 +85,95 @@ SYM_FUNC_START(__clear_user_fast)
>  6:     st.d    zero, a0, 40
>  7:     st.d    zero, a0, 48
>  8:     st.d    zero, a0, 56
> -
>         addi.d  a0, a0, 64
> -       addi.d  a1, a1, -64
> -       bge     a1, a2, 1b
> -
> -       beqz    a1, 10f
> +       bltu    a0, a3, .Lloop64
>  
>         /* set the remaining bytes */
> -9:     st.b    zero, a0, 0
> -       addi.d  a0, a0, 1
> -       addi.d  a1, a1, -1
> -       bgt     a1, zero, 9b
> +.Llt64:
> +       addi.d  a3, a2, -32
> +       bgeu    a0, a3, .Llt32
> +9:     st.d    zero, a0, 0
> +10:    st.d    zero, a0, 8
> +11:    st.d    zero, a0, 16
> +12:    st.d    zero, a0, 24
> +       addi.d  a0, a0, 32
> +
> +.Llt32:
> +       addi.d  a3, a2, -16
> +       bgeu    a0, a3, .Llt16
> +13:    st.d    zero, a0, 0
> +14:    st.d    zero, a0, 8
> +       addi.d  a0, a0, 16
> +
> +.Llt16:
> +       addi.d  a3, a2, -8
> +       bgeu    a0, a3, .Llt8
> +15:    st.d    zero, a0, 0
> +
> +.Llt8:
> +16:    st.d    zero, a2, -8
>  
>         /* return */
> -10:    move    a0, a1
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +.Lsmall:
> +       pcaddi  t0, 4
> +       slli.d  a2, a1, 4
> +       add.d   t0, t0, a2
> +       jr      t0
> +
> +       .align  4
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +17:    st.b    zero, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +18:    st.h    zero, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +19:    st.h    zero, a0, 0
> +20:    st.b    zero, a0, 2
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +21:    st.w    zero, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +22:    st.w    zero, a0, 0
> +23:    st.b    zero, a0, 4
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +24:    st.w    zero, a0, 0
> +25:    st.h    zero, a0, 4
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +26:    st.w    zero, a0, 0
> +27:    st.w    zero, a0, 3
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  4
> +28:    st.d    zero, a0, 0
> +       move    a0, zero
>         jr      ra
>  
>         /* fixup and ex_table */
> +       _asm_extable 0b, .L_fixup_handle_0
>         _asm_extable 1b, .L_fixup_handle_0
>         _asm_extable 2b, .L_fixup_handle_1
>         _asm_extable 3b, .L_fixup_handle_2
> @@ -95,4 +183,23 @@ SYM_FUNC_START(__clear_user_fast)
>         _asm_extable 7b, .L_fixup_handle_6
>         _asm_extable 8b, .L_fixup_handle_7
>         _asm_extable 9b, .L_fixup_handle_0
> +       _asm_extable 10b, .L_fixup_handle_1
> +       _asm_extable 11b, .L_fixup_handle_2
> +       _asm_extable 12b, .L_fixup_handle_3
> +       _asm_extable 13b, .L_fixup_handle_0
> +       _asm_extable 14b, .L_fixup_handle_1
> +       _asm_extable 15b, .L_fixup_handle_0
> +       _asm_extable 16b, .L_fixup_handle_1
> +       _asm_extable 17b, .L_fixup_handle_s0
> +       _asm_extable 18b, .L_fixup_handle_s0
> +       _asm_extable 19b, .L_fixup_handle_s0
> +       _asm_extable 20b, .L_fixup_handle_s2
> +       _asm_extable 21b, .L_fixup_handle_s0
> +       _asm_extable 22b, .L_fixup_handle_s0
> +       _asm_extable 23b, .L_fixup_handle_s4
> +       _asm_extable 24b, .L_fixup_handle_s0
> +       _asm_extable 25b, .L_fixup_handle_s4
> +       _asm_extable 26b, .L_fixup_handle_s0
> +       _asm_extable 27b, .L_fixup_handle_s4
> +       _asm_extable 28b, .L_fixup_handle_s0
>  SYM_FUNC_END(__clear_user_fast)
> diff --git a/arch/loongarch/lib/copy_user.S
> b/arch/loongarch/lib/copy_user.S
> index 55ac6020a1ad..b21f6d5d38f5 100644
> --- a/arch/loongarch/lib/copy_user.S
> +++ b/arch/loongarch/lib/copy_user.S
> @@ -13,7 +13,14 @@
>  
>  .irp to, 0, 1, 2, 3, 4, 5, 6, 7
>  .L_fixup_handle_\to\():
> -       addi.d  a0, a2, (\to) * (-8)
> +       sub.d   a0, a2, a0
> +       addi.d  a0, a0, (\to) * (-8)
> +       jr      ra
> +.endr
> +
> +.irp to, 0, 2, 4
> +.L_fixup_handle_s\to\():
> +       addi.d  a0, a2, -\to
>         jr      ra
>  .endr
>  
> @@ -47,8 +54,8 @@ SYM_FUNC_START(__copy_user_generic)
>  3:     move    a0, a2
>         jr      ra
>  
> -       _asm_extable 1b, .L_fixup_handle_0
> -       _asm_extable 2b, .L_fixup_handle_0
> +       _asm_extable 1b, .L_fixup_handle_s0
> +       _asm_extable 2b, .L_fixup_handle_s0
>  SYM_FUNC_END(__copy_user_generic)
>  
>  /*
> @@ -59,65 +66,209 @@ SYM_FUNC_END(__copy_user_generic)
>   * a2: n
>   */
>  SYM_FUNC_START(__copy_user_fast)
> -       beqz    a2, 19f
> +       sltui   t0, a2, 9
> +       bnez    t0, .Lsmall
>  
> -       ori     a3, zero, 64
> -       blt     a2, a3, 17f
> +       add.d   a3, a1, a2
> +       add.d   a2, a0, a2
> +0:     ld.d    t0, a1, 0
> +1:     st.d    t0, a0, 0
>  
> -       /* copy 64 bytes at a time */
> -1:     ld.d    t0, a1, 0
> -2:     ld.d    t1, a1, 8
> -3:     ld.d    t2, a1, 16
> -4:     ld.d    t3, a1, 24
> -5:     ld.d    t4, a1, 32
> -6:     ld.d    t5, a1, 40
> -7:     ld.d    t6, a1, 48
> -8:     ld.d    t7, a1, 56
> -9:     st.d    t0, a0, 0
> -10:    st.d    t1, a0, 8
> -11:    st.d    t2, a0, 16
> -12:    st.d    t3, a0, 24
> -13:    st.d    t4, a0, 32
> -14:    st.d    t5, a0, 40
> -15:    st.d    t6, a0, 48
> -16:    st.d    t7, a0, 56
> +       /* align up destination address */
> +       andi    t1, a0, 7
> +       sub.d   t0, zero, t1
> +       addi.d  t0, t0, 8
> +       add.d   a1, a1, t0
> +       add.d   a0, a0, t0
>  
> -       addi.d  a0, a0, 64
> -       addi.d  a1, a1, 64
> -       addi.d  a2, a2, -64
> -       bge     a2, a3, 1b
> +       addi.d  a4, a3, -64
> +       bgeu    a1, a4, .Llt64
>  
> -       beqz    a2, 19f
> +       /* copy 64 bytes at a time */
> +.Lloop64:
> +2:     ld.d    t0, a1, 0
> +3:     ld.d    t1, a1, 8
> +4:     ld.d    t2, a1, 16
> +5:     ld.d    t3, a1, 24
> +6:     ld.d    t4, a1, 32
> +7:     ld.d    t5, a1, 40
> +8:     ld.d    t6, a1, 48
> +9:     ld.d    t7, a1, 56
> +       addi.d  a1, a1, 64
> +10:    st.d    t0, a0, 0
> +11:    st.d    t1, a0, 8
> +12:    st.d    t2, a0, 16
> +13:    st.d    t3, a0, 24
> +14:    st.d    t4, a0, 32
> +15:    st.d    t5, a0, 40
> +16:    st.d    t6, a0, 48
> +17:    st.d    t7, a0, 56
> +       addi.d  a0, a0, 64
> +       bltu    a1, a4, .Lloop64
>  
>         /* copy the remaining bytes */
> -17:    ld.b    t0, a1, 0
> -18:    st.b    t0, a0, 0
> -       addi.d  a0, a0, 1
> -       addi.d  a1, a1, 1
> -       addi.d  a2, a2, -1
> -       bgt     a2, zero, 17b
> +.Llt64:
> +       addi.d  a4, a3, -32
> +       bgeu    a1, a4, .Llt32
> +18:    ld.d    t0, a1, 0
> +19:    ld.d    t1, a1, 8
> +20:    ld.d    t2, a1, 16
> +21:    ld.d    t3, a1, 24
> +       addi.d  a1, a1, 32
> +22:    st.d    t0, a0, 0
> +23:    st.d    t1, a0, 8
> +24:    st.d    t2, a0, 16
> +25:    st.d    t3, a0, 24
> +       addi.d  a0, a0, 32
> +
> +.Llt32:
> +       addi.d  a4, a3, -16
> +       bgeu    a1, a4, .Llt16
> +26:    ld.d    t0, a1, 0
> +27:    ld.d    t1, a1, 8
> +       addi.d  a1, a1, 16
> +28:    st.d    t0, a0, 0
> +29:    st.d    t1, a0, 8
> +       addi.d  a0, a0, 16
> +
> +.Llt16:
> +       addi.d  a4, a3, -8
> +       bgeu    a1, a4, .Llt8
> +30:    ld.d    t0, a1, 0
> +31:    st.d    t0, a0, 0
> +
> +.Llt8:
> +32:    ld.d    t0, a3, -8
> +33:    st.d    t0, a2, -8
>  
>         /* return */
> -19:    move    a0, a2
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +.Lsmall:
> +       pcaddi  t0, 8
> +       slli.d  a3, a2, 5
> +       add.d   t0, t0, a3
> +       jr      t0
> +
> +       .align  5
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +34:    ld.b    t0, a1, 0
> +35:    st.b    t0, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +36:    ld.h    t0, a1, 0
> +37:    st.h    t0, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +38:    ld.h    t0, a1, 0
> +39:    ld.b    t1, a1, 2
> +40:    st.h    t0, a0, 0
> +41:    st.b    t1, a0, 2
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +42:    ld.w    t0, a1, 0
> +43:    st.w    t0, a0, 0
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +44:    ld.w    t0, a1, 0
> +45:    ld.b    t1, a1, 4
> +46:    st.w    t0, a0, 0
> +47:    st.b    t1, a0, 4
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +48:    ld.w    t0, a1, 0
> +49:    ld.h    t1, a1, 4
> +50:    st.w    t0, a0, 0
> +51:    st.h    t1, a0, 4
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +52:    ld.w    t0, a1, 0
> +53:    ld.w    t1, a1, 3
> +54:    st.w    t0, a0, 0
> +55:    st.w    t1, a0, 3
> +       move    a0, zero
> +       jr      ra
> +
> +       .align  5
> +56:    ld.d    t0, a1, 0
> +57:    st.d    t0, a0, 0
> +       move    a0, zero
>         jr      ra
>  
>         /* fixup and ex_table */
> +       _asm_extable 0b, .L_fixup_handle_0
>         _asm_extable 1b, .L_fixup_handle_0
> -       _asm_extable 2b, .L_fixup_handle_1
> -       _asm_extable 3b, .L_fixup_handle_2
> -       _asm_extable 4b, .L_fixup_handle_3
> -       _asm_extable 5b, .L_fixup_handle_4
> -       _asm_extable 6b, .L_fixup_handle_5
> -       _asm_extable 7b, .L_fixup_handle_6
> -       _asm_extable 8b, .L_fixup_handle_7
> +       _asm_extable 2b, .L_fixup_handle_0
> +       _asm_extable 3b, .L_fixup_handle_0
> +       _asm_extable 4b, .L_fixup_handle_0
> +       _asm_extable 5b, .L_fixup_handle_0
> +       _asm_extable 6b, .L_fixup_handle_0
> +       _asm_extable 7b, .L_fixup_handle_0
> +       _asm_extable 8b, .L_fixup_handle_0
>         _asm_extable 9b, .L_fixup_handle_0
> -       _asm_extable 10b, .L_fixup_handle_1
> -       _asm_extable 11b, .L_fixup_handle_2
> -       _asm_extable 12b, .L_fixup_handle_3
> -       _asm_extable 13b, .L_fixup_handle_4
> -       _asm_extable 14b, .L_fixup_handle_5
> -       _asm_extable 15b, .L_fixup_handle_6
> -       _asm_extable 16b, .L_fixup_handle_7
> -       _asm_extable 17b, .L_fixup_handle_0
> +       _asm_extable 10b, .L_fixup_handle_0
> +       _asm_extable 11b, .L_fixup_handle_1
> +       _asm_extable 12b, .L_fixup_handle_2
> +       _asm_extable 13b, .L_fixup_handle_3
> +       _asm_extable 14b, .L_fixup_handle_4
> +       _asm_extable 15b, .L_fixup_handle_5
> +       _asm_extable 16b, .L_fixup_handle_6
> +       _asm_extable 17b, .L_fixup_handle_7
>         _asm_extable 18b, .L_fixup_handle_0
> +       _asm_extable 19b, .L_fixup_handle_0
> +       _asm_extable 20b, .L_fixup_handle_0
> +       _asm_extable 21b, .L_fixup_handle_0
> +       _asm_extable 22b, .L_fixup_handle_0
> +       _asm_extable 23b, .L_fixup_handle_1
> +       _asm_extable 24b, .L_fixup_handle_2
> +       _asm_extable 25b, .L_fixup_handle_3
> +       _asm_extable 26b, .L_fixup_handle_0
> +       _asm_extable 27b, .L_fixup_handle_0
> +       _asm_extable 28b, .L_fixup_handle_0
> +       _asm_extable 29b, .L_fixup_handle_1
> +       _asm_extable 30b, .L_fixup_handle_0
> +       _asm_extable 31b, .L_fixup_handle_0
> +       _asm_extable 32b, .L_fixup_handle_0
> +       _asm_extable 33b, .L_fixup_handle_1
> +       _asm_extable 34b, .L_fixup_handle_s0
> +       _asm_extable 35b, .L_fixup_handle_s0
> +       _asm_extable 36b, .L_fixup_handle_s0
> +       _asm_extable 37b, .L_fixup_handle_s0
> +       _asm_extable 38b, .L_fixup_handle_s0
> +       _asm_extable 39b, .L_fixup_handle_s0
> +       _asm_extable 40b, .L_fixup_handle_s0
> +       _asm_extable 41b, .L_fixup_handle_s2
> +       _asm_extable 42b, .L_fixup_handle_s0
> +       _asm_extable 43b, .L_fixup_handle_s0
> +       _asm_extable 44b, .L_fixup_handle_s0
> +       _asm_extable 45b, .L_fixup_handle_s0
> +       _asm_extable 46b, .L_fixup_handle_s0
> +       _asm_extable 47b, .L_fixup_handle_s4
> +       _asm_extable 48b, .L_fixup_handle_s0
> +       _asm_extable 49b, .L_fixup_handle_s0
> +       _asm_extable 50b, .L_fixup_handle_s0
> +       _asm_extable 51b, .L_fixup_handle_s4
> +       _asm_extable 52b, .L_fixup_handle_s0
> +       _asm_extable 53b, .L_fixup_handle_s0
> +       _asm_extable 54b, .L_fixup_handle_s0
> +       _asm_extable 55b, .L_fixup_handle_s4
> +       _asm_extable 56b, .L_fixup_handle_s0
> +       _asm_extable 57b, .L_fixup_handle_s0
>  SYM_FUNC_END(__copy_user_fast)
> diff --git a/arch/loongarch/lib/memcpy.S b/arch/loongarch/lib/memcpy.S
> index 3b7e1dec7109..39ce6621c704 100644
> --- a/arch/loongarch/lib/memcpy.S
> +++ b/arch/loongarch/lib/memcpy.S
> @@ -44,6 +44,66 @@ SYM_FUNC_START(__memcpy_generic)
>  SYM_FUNC_END(__memcpy_generic)
>  _ASM_NOKPROBE(__memcpy_generic)
>  
> +       .align  5
> +SYM_FUNC_START_NOALIGN(__memcpy_small)
> +       pcaddi  t0, 8
> +       slli.d  a2, a2, 5
> +       add.d   t0, t0, a2
> +       jr      t0
> +
> +       .align  5
> +0:     jr      ra
> +
> +       .align  5
> +1:     ld.b    t0, a1, 0
> +       st.b    t0, a0, 0
> +       jr      ra
> +
> +       .align  5
> +2:     ld.h    t0, a1, 0
> +       st.h    t0, a0, 0
> +       jr      ra
> +
> +       .align  5
> +3:     ld.h    t0, a1, 0
> +       ld.b    t1, a1, 2
> +       st.h    t0, a0, 0
> +       st.b    t1, a0, 2
> +       jr      ra
> +
> +       .align  5
> +4:     ld.w    t0, a1, 0
> +       st.w    t0, a0, 0
> +       jr      ra
> +
> +       .align  5
> +5:     ld.w    t0, a1, 0
> +       ld.b    t1, a1, 4
> +       st.w    t0, a0, 0
> +       st.b    t1, a0, 4
> +       jr      ra
> +
> +       .align  5
> +6:     ld.w    t0, a1, 0
> +       ld.h    t1, a1, 4
> +       st.w    t0, a0, 0
> +       st.h    t1, a0, 4
> +       jr      ra
> +
> +       .align  5
> +7:     ld.w    t0, a1, 0
> +       ld.w    t1, a1, 3
> +       st.w    t0, a0, 0
> +       st.w    t1, a0, 3
> +       jr      ra
> +
> +       .align  5
> +8:     ld.d    t0, a1, 0
> +       st.d    t0, a0, 0
> +       jr      ra
> +SYM_FUNC_END(__memcpy_small)
> +_ASM_NOKPROBE(__memcpy_small)
> +
>  /*
>   * void *__memcpy_fast(void *dst, const void *src, size_t n)
>   *
> @@ -52,14 +112,27 @@ _ASM_NOKPROBE(__memcpy_generic)
>   * a2: n
>   */
>  SYM_FUNC_START(__memcpy_fast)
> -       move    a3, a0
> -       beqz    a2, 3f
> +       sltui   t0, a2, 9
> +       bnez    t0, __memcpy_small
> +
> +       add.d   a3, a1, a2
> +       add.d   a2, a0, a2
> +       ld.d    a6, a1, 0
> +       ld.d    a7, a3, -8
> +
> +       /* align up destination address */
> +       andi    t1, a0, 7
> +       sub.d   t0, zero, t1
> +       addi.d  t0, t0, 8
> +       add.d   a1, a1, t0
> +       add.d   a5, a0, t0
>  
> -       ori     a4, zero, 64
> -       blt     a2, a4, 2f
> +       addi.d  a4, a3, -64
> +       bgeu    a1, a4, .Llt64
>  
>         /* copy 64 bytes at a time */
> -1:     ld.d    t0, a1, 0
> +.Lloop64:
> +       ld.d    t0, a1, 0
>         ld.d    t1, a1, 8
>         ld.d    t2, a1, 16
>         ld.d    t3, a1, 24
> @@ -67,32 +140,54 @@ SYM_FUNC_START(__memcpy_fast)
>         ld.d    t5, a1, 40
>         ld.d    t6, a1, 48
>         ld.d    t7, a1, 56
> -       st.d    t0, a0, 0
> -       st.d    t1, a0, 8
> -       st.d    t2, a0, 16
> -       st.d    t3, a0, 24
> -       st.d    t4, a0, 32
> -       st.d    t5, a0, 40
> -       st.d    t6, a0, 48
> -       st.d    t7, a0, 56
> -
> -       addi.d  a0, a0, 64
>         addi.d  a1, a1, 64
> -       addi.d  a2, a2, -64
> -       bge     a2, a4, 1b
> -
> -       beqz    a2, 3f
> +       st.d    t0, a5, 0
> +       st.d    t1, a5, 8
> +       st.d    t2, a5, 16
> +       st.d    t3, a5, 24
> +       st.d    t4, a5, 32
> +       st.d    t5, a5, 40
> +       st.d    t6, a5, 48
> +       st.d    t7, a5, 56
> +       addi.d  a5, a5, 64
> +       bltu    a1, a4, .Lloop64
>  
>         /* copy the remaining bytes */
> -2:     ld.b    t0, a1, 0
> -       st.b    t0, a0, 0
> -       addi.d  a0, a0, 1
> -       addi.d  a1, a1, 1
> -       addi.d  a2, a2, -1
> -       bgt     a2, zero, 2b
> +.Llt64:
> +       addi.d  a4, a3, -32
> +       bgeu    a1, a4, .Llt32
> +       ld.d    t0, a1, 0
> +       ld.d    t1, a1, 8
> +       ld.d    t2, a1, 16
> +       ld.d    t3, a1, 24
> +       addi.d  a1, a1, 32
> +       st.d    t0, a5, 0
> +       st.d    t1, a5, 8
> +       st.d    t2, a5, 16
> +       st.d    t3, a5, 24
> +       addi.d  a5, a5, 32
> +
> +.Llt32:
> +       addi.d  a4, a3, -16
> +       bgeu    a1, a4, .Llt16
> +       ld.d    t0, a1, 0
> +       ld.d    t1, a1, 8
> +       addi.d  a1, a1, 16
> +       st.d    t0, a5, 0
> +       st.d    t1, a5, 8
> +       addi.d  a5, a5, 16
> +
> +.Llt16:
> +       addi.d  a4, a3, -8
> +       bgeu    a1, a4, .Llt8
> +       ld.d    t0, a1, 0
> +       st.d    t0, a5, 0
> +
> +.Llt8:
> +       st.d    a6, a0, 0
> +       st.d    a7, a2, -8
>  
>         /* return */
> -3:     move    a0, a3
>         jr      ra
>  SYM_FUNC_END(__memcpy_fast)
>  _ASM_NOKPROBE(__memcpy_fast)
> diff --git a/arch/loongarch/lib/memmove.S
> b/arch/loongarch/lib/memmove.S
> index b796c3d6da05..45b725ba7867 100644
> --- a/arch/loongarch/lib/memmove.S
> +++ b/arch/loongarch/lib/memmove.S
> @@ -11,23 +11,9 @@
>  #include <asm/regdef.h>
>  
>  SYM_FUNC_START(memmove)
> -       blt     a0, a1, 1f      /* dst < src, memcpy */
> -       blt     a1, a0, 3f      /* src < dst, rmemcpy */
> +       blt     a0, a1, memcpy  /* dst < src, memcpy */
> +       blt     a1, a0, rmemcpy /* src < dst, rmemcpy */
>         jr      ra              /* dst == src, return */
> -
> -       /* if (src - dst) < 64, copy 1 byte at a time */
> -1:     ori     a3, zero, 64
> -       sub.d   t0, a1, a0
> -       blt     t0, a3, 2f
> -       b       memcpy
> -2:     b       __memcpy_generic
> -
> -       /* if (dst - src) < 64, copy 1 byte at a time */
> -3:     ori     a3, zero, 64
> -       sub.d   t0, a0, a1
> -       blt     t0, a3, 4f
> -       b       rmemcpy
> -4:     b       __rmemcpy_generic
>  SYM_FUNC_END(memmove)
>  _ASM_NOKPROBE(memmove)
>  
> @@ -76,50 +62,80 @@ _ASM_NOKPROBE(__rmemcpy_generic)
>   * a2: n
>   */
>  SYM_FUNC_START(__rmemcpy_fast)
> -       move    a3, a0
> -       beqz    a2, 3f
> +       sltui   t0, a2, 9
> +       bnez    t0, __memcpy_small
>  
> -       add.d   a0, a0, a2
> -       add.d   a1, a1, a2
> +       add.d   a3, a1, a2
> +       add.d   a2, a0, a2
> +       ld.d    a6, a1, 0
> +       ld.d    a7, a3, -8
> +
> +       /* align up destination address */
> +       andi    t1, a2, 7
> +       sub.d   a3, a3, t1
> +       sub.d   a5, a2, t1
>  
> -       ori     a4, zero, 64
> -       blt     a2, a4, 2f
> +       addi.d  a4, a1, 64
> +       bgeu    a4, a3, .Llt64
>  
>         /* copy 64 bytes at a time */
> -1:     ld.d    t0, a1, -8
> -       ld.d    t1, a1, -16
> -       ld.d    t2, a1, -24
> -       ld.d    t3, a1, -32
> -       ld.d    t4, a1, -40
> -       ld.d    t5, a1, -48
> -       ld.d    t6, a1, -56
> -       ld.d    t7, a1, -64
> -       st.d    t0, a0, -8
> -       st.d    t1, a0, -16
> -       st.d    t2, a0, -24
> -       st.d    t3, a0, -32
> -       st.d    t4, a0, -40
> -       st.d    t5, a0, -48
> -       st.d    t6, a0, -56
> -       st.d    t7, a0, -64
> -
> -       addi.d  a0, a0, -64
> -       addi.d  a1, a1, -64
> -       addi.d  a2, a2, -64
> -       bge     a2, a4, 1b
> -
> -       beqz    a2, 3f
> +.Lloop64:
> +       ld.d    t0, a3, -8
> +       ld.d    t1, a3, -16
> +       ld.d    t2, a3, -24
> +       ld.d    t3, a3, -32
> +       ld.d    t4, a3, -40
> +       ld.d    t5, a3, -48
> +       ld.d    t6, a3, -56
> +       ld.d    t7, a3, -64
> +       addi.d  a3, a3, -64
> +       st.d    t0, a5, -8
> +       st.d    t1, a5, -16
> +       st.d    t2, a5, -24
> +       st.d    t3, a5, -32
> +       st.d    t4, a5, -40
> +       st.d    t5, a5, -48
> +       st.d    t6, a5, -56
> +       st.d    t7, a5, -64
> +       addi.d  a5, a5, -64
> +       bltu    a4, a3, .Lloop64
>  
>         /* copy the remaining bytes */
> -2:     ld.b    t0, a1, -1
> -       st.b    t0, a0, -1
> -       addi.d  a0, a0, -1
> -       addi.d  a1, a1, -1
> -       addi.d  a2, a2, -1
> -       bgt     a2, zero, 2b
> +.Llt64:
> +       addi.d  a4, a1, 32
> +       bgeu    a4, a3, .Llt32
> +       ld.d    t0, a3, -8
> +       ld.d    t1, a3, -16
> +       ld.d    t2, a3, -24
> +       ld.d    t3, a3, -32
> +       addi.d  a3, a3, -32
> +       st.d    t0, a5, -8
> +       st.d    t1, a5, -16
> +       st.d    t2, a5, -24
> +       st.d    t3, a5, -32
> +       addi.d  a5, a5, -32
> +
> +.Llt32:
> +       addi.d  a4, a1, 16
> +       bgeu    a4, a3, .Llt16
> +       ld.d    t0, a3, -8
> +       ld.d    t1, a3, -16
> +       addi.d  a3, a3, -16
> +       st.d    t0, a5, -8
> +       st.d    t1, a5, -16
> +       addi.d  a5, a5, -16
> +
> +.Llt16:
> +       addi.d  a4, a1, 8
> +       bgeu    a4, a3, .Llt8
> +       ld.d    t0, a3, -8
> +       st.d    t0, a5, -8
> +
> +.Llt8:
> +       st.d    a6, a0, 0
> +       st.d    a7, a2, -8
>  
>         /* return */
> -3:     move    a0, a3
>         jr      ra
>  SYM_FUNC_END(__rmemcpy_fast)
>  _ASM_NOKPROBE(__rmemcpy_fast)
> diff --git a/arch/loongarch/lib/memset.S b/arch/loongarch/lib/memset.S
> index a9eb732ab2ad..c5836d916736 100644
> --- a/arch/loongarch/lib/memset.S
> +++ b/arch/loongarch/lib/memset.S
> @@ -56,39 +56,108 @@ _ASM_NOKPROBE(__memset_generic)
>   * a2: n
>   */
>  SYM_FUNC_START(__memset_fast)
> -       move    a3, a0
> -       beqz    a2, 3f
> -
> -       ori     a4, zero, 64
> -       blt     a2, a4, 2f
> -
>         /* fill a1 to 64 bits */
>         fill_to_64 a1
>  
> -       /* set 64 bytes at a time */
> -1:     st.d    a1, a0, 0
> -       st.d    a1, a0, 8
> -       st.d    a1, a0, 16
> -       st.d    a1, a0, 24
> -       st.d    a1, a0, 32
> -       st.d    a1, a0, 40
> -       st.d    a1, a0, 48
> -       st.d    a1, a0, 56
> +       sltui   t0, a2, 9
> +       bnez    t0, .Lsmall
>  
> -       addi.d  a0, a0, 64
> -       addi.d  a2, a2, -64
> -       bge     a2, a4, 1b
> +       add.d   a2, a0, a2
> +       st.d    a1, a0, 0
>  
> -       beqz    a2, 3f
> +       /* align up address */
> +       andi    t1, a0, 7
> +       sub.d   a3, a0, t1
> +       addi.d  a3, a3, 8
> +
> +       addi.d  a4, a2, -64
> +       bgeu    a3, a4, .Llt64
> +
> +       /* set 64 bytes at a time */
> +.Lloop64:
> +       st.d    a1, a3, 0
> +       st.d    a1, a3, 8
> +       st.d    a1, a3, 16
> +       st.d    a1, a3, 24
> +       st.d    a1, a3, 32
> +       st.d    a1, a3, 40
> +       st.d    a1, a3, 48
> +       st.d    a1, a3, 56
> +       addi.d  a3, a3, 64
> +       bltu    a3, a4, .Lloop64
>  
>         /* set the remaining bytes */
> -2:     st.b    a1, a0, 0
> -       addi.d  a0, a0, 1
> -       addi.d  a2, a2, -1
> -       bgt     a2, zero, 2b
> +.Llt64:
> +       addi.d  a4, a2, -32
> +       bgeu    a3, a4, .Llt32
> +       st.d    a1, a3, 0
> +       st.d    a1, a3, 8
> +       st.d    a1, a3, 16
> +       st.d    a1, a3, 24
> +       addi.d  a3, a3, 32
> +
> +.Llt32:
> +       addi.d  a4, a2, -16
> +       bgeu    a3, a4, .Llt16
> +       st.d    a1, a3, 0
> +       st.d    a1, a3, 8
> +       addi.d  a3, a3, 16
> +
> +.Llt16:
> +       addi.d  a4, a2, -8
> +       bgeu    a3, a4, .Llt8
> +       st.d    a1, a3, 0
> +
> +.Llt8:
> +       st.d    a1, a2, -8
>  
>         /* return */
> -3:     move    a0, a3
> +       jr      ra
> +
> +       .align  4
> +.Lsmall:
> +       pcaddi  t0, 4
> +       slli.d  a2, a2, 4
> +       add.d   t0, t0, a2
> +       jr      t0
> +
> +       .align  4
> +0:     jr      ra
> +
> +       .align  4
> +1:     st.b    a1, a0, 0
> +       jr      ra
> +
> +       .align  4
> +2:     st.h    a1, a0, 0
> +       jr      ra
> +
> +       .align  4
> +3:     st.h    a1, a0, 0
> +       st.b    a1, a0, 2
> +       jr      ra
> +
> +       .align  4
> +4:     st.w    a1, a0, 0
> +       jr      ra
> +
> +       .align  4
> +5:     st.w    a1, a0, 0
> +       st.b    a1, a0, 4
> +       jr      ra
> +
> +       .align  4
> +6:     st.w    a1, a0, 0
> +       st.h    a1, a0, 4
> +       jr      ra
> +
> +       .align  4
> +7:     st.w    a1, a0, 0
> +       st.w    a1, a0, 3
> +       jr      ra
> +
> +       .align  4
> +8:     st.d    a1, a0, 0
>         jr      ra
>  SYM_FUNC_END(__memset_fast)
>  _ASM_NOKPROBE(__memset_fast)
  
WANG Rui April 10, 2023, 2:19 p.m. UTC | #3
On Mon, Apr 10, 2023 at 8:20 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> On Mon, 2023-04-10 at 19:57 +0800, WANG rui wrote:
> > +       /* align up address */
> > +       andi    t1, a0, 7
> > +       sub.d   a0, a0, t1
>
> bstrins.d a0, zero, 2, 0
>
> Likewise for other aligning operations if the temporary is not used.

I think we're on the same page. I had previously tested this on the
user-space version[1], but it's not a performance-critical area.

[1] https://github.com/heiher/mem-bench/blob/0083d4e5a82e57939517413da3bcad81e01adbea/memset-int.S#L35-L37

Regards,
Rui
  
WANG Rui April 10, 2023, 2:22 p.m. UTC | #4
On Mon, Apr 10, 2023 at 8:54 PM Xi Ruoyao <xry111@xry111.site> wrote:
> Regarding these functions: we have -ffreestanding which is preventing
> the compiler from optimizing for e.g. "memcpy(a, b, 8);" into a simple
> ld.d/st.d pair.  A explicit compiler built-in usage like
>
>   #define memcpy(a, b, c) __builtin_memcpy(a, b, c)
>
> would allow the compiler to do such kind of optimization.   Will this
> improve the performance?

That's a good question. IIUC, the current compiler generates
inefficient code for constant-length memcpy, which may sacrifice
performance for compatibility, as not all hardware supports unaligned
memory access. We need a runtime CPU feature dispatch mechanism
similar to alternatives to improve the compiler. This is indeed a
problem that needs to be addressed.

Regards,
Rui
  
Xi Ruoyao April 10, 2023, 2:36 p.m. UTC | #5
On Mon, 2023-04-10 at 22:22 +0800, Rui Wang wrote:
> On Mon, Apr 10, 2023 at 8:54 PM Xi Ruoyao <xry111@xry111.site> wrote:
> > Regarding these functions: we have -ffreestanding which is
> > preventing
> > the compiler from optimizing for e.g. "memcpy(a, b, 8);" into a
> > simple
> > ld.d/st.d pair.  A explicit compiler built-in usage like
> > 
> >   #define memcpy(a, b, c) __builtin_memcpy(a, b, c)
> > 
> > would allow the compiler to do such kind of optimization.   Will
> > this
> > improve the performance?
> 
> That's a good question. IIUC, the current compiler generates
> inefficient code for constant-length memcpy, which may sacrifice
> performance for compatibility, as not all hardware supports unaligned
> memory access. We need a runtime CPU feature dispatch mechanism
> similar to alternatives to improve the compiler. This is indeed a
> problem that needs to be addressed.

Hmm, yep, GCC does not take the advantage of -mstrict-align expanding
memcpy etc.  I'll add it into my TODO list for GCC 14.
  
Xi Ruoyao April 10, 2023, 2:37 p.m. UTC | #6
On Mon, 2023-04-10 at 22:19 +0800, Rui Wang wrote:
> On Mon, Apr 10, 2023 at 8:20 PM Xi Ruoyao <xry111@xry111.site> wrote:
> > 
> > On Mon, 2023-04-10 at 19:57 +0800, WANG rui wrote:
> > > +       /* align up address */
> > > +       andi    t1, a0, 7
> > > +       sub.d   a0, a0, t1
> > 
> > bstrins.d a0, zero, 2, 0
> > 
> > Likewise for other aligning operations if the temporary is not used.
> 
> I think we're on the same page. I had previously tested this on the
> user-space version[1], but it's not a performance-critical area.

The point is "if you can reduce one instruction and one register usage
with no harm, why not do it?" :)

AFAIK bstrins.d should be available on all 64-bit LoongArch CPUs.
  
WANG Rui April 10, 2023, 3:52 p.m. UTC | #7
On Mon, Apr 10, 2023 at 10:36 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> Hmm, yep, GCC does not take the advantage of -mstrict-align expanding
> memcpy etc.  I'll add it into my TODO list for GCC 14.

Great! It looks like you already have some good ideas, and I look
forward to hearing your good news.

Rui
  
WANG Rui April 10, 2023, 3:53 p.m. UTC | #8
On Mon, Apr 10, 2023 at 10:38 PM Xi Ruoyao <xry111@xry111.site> wrote:
>
> The point is "if you can reduce one instruction and one register usage
> with no harm, why not do it?" :)
>
> AFAIK bstrins.d should be available on all 64-bit LoongArch CPUs.

Hmm, I will make the change in the next version. :)

Rui
  
Xi Ruoyao April 11, 2023, 6:21 a.m. UTC | #9
On Mon, 2023-04-10 at 23:52 +0800, WANG Rui wrote:
> On Mon, Apr 10, 2023 at 10:36 PM Xi Ruoyao <xry111@xry111.site> wrote:
> > 
> > Hmm, yep, GCC does not take the advantage of -mstrict-align expanding
> > memcpy etc.  I'll add it into my TODO list for GCC 14.

Technically, it takes the advantage but not very well.  It's now
https://gcc.gnu.org/PR109465.

> Great! It looks like you already have some good ideas, and I look
> forward to hearing your good news.
> 
> Rui
>
  

Patch

diff --git a/arch/loongarch/lib/clear_user.S b/arch/loongarch/lib/clear_user.S
index 2dc48e61a2c8..02f112b265cd 100644
--- a/arch/loongarch/lib/clear_user.S
+++ b/arch/loongarch/lib/clear_user.S
@@ -13,7 +13,14 @@ 
 
 .irp to, 0, 1, 2, 3, 4, 5, 6, 7
 .L_fixup_handle_\to\():
-	addi.d	a0, a1, (\to) * (-8)
+	sub.d	a0, a2, a0
+	addi.d	a0, a0, (\to) * (-8)
+	jr	ra
+.endr
+
+.irp to, 0, 2, 4
+.L_fixup_handle_s\to\():
+	addi.d	a0, a1, -\to
 	jr	ra
 .endr
 
@@ -44,7 +51,7 @@  SYM_FUNC_START(__clear_user_generic)
 2:	move	a0, a1
 	jr	ra
 
-	_asm_extable 1b, .L_fixup_handle_0
+	_asm_extable 1b, .L_fixup_handle_s0
 SYM_FUNC_END(__clear_user_generic)
 
 /*
@@ -54,12 +61,22 @@  SYM_FUNC_END(__clear_user_generic)
  * a1: size
  */
 SYM_FUNC_START(__clear_user_fast)
-	beqz	a1, 10f
+	sltui	t0, a1, 9
+	bnez	t0, .Lsmall
 
-	ori	a2, zero, 64
-	blt	a1, a2, 9f
+	add.d	a2, a0, a1
+0:	st.d	zero, a0, 0
+
+	/* align up address */
+	andi	t1, a0, 7
+	sub.d	a0, a0, t1
+	addi.d	a0, a0, 8
+
+	addi.d	a3, a2, -64
+	bgeu	a0, a3, .Llt64
 
 	/* set 64 bytes at a time */
+.Lloop64:
 1:	st.d	zero, a0, 0
 2:	st.d	zero, a0, 8
 3:	st.d	zero, a0, 16
@@ -68,24 +85,95 @@  SYM_FUNC_START(__clear_user_fast)
 6:	st.d	zero, a0, 40
 7:	st.d	zero, a0, 48
 8:	st.d	zero, a0, 56
-
 	addi.d	a0, a0, 64
-	addi.d	a1, a1, -64
-	bge	a1, a2, 1b
-
-	beqz	a1, 10f
+	bltu	a0, a3, .Lloop64
 
 	/* set the remaining bytes */
-9:	st.b	zero, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a1, a1, -1
-	bgt	a1, zero, 9b
+.Llt64:
+	addi.d	a3, a2, -32
+	bgeu	a0, a3, .Llt32
+9:	st.d	zero, a0, 0
+10:	st.d	zero, a0, 8
+11:	st.d	zero, a0, 16
+12:	st.d	zero, a0, 24
+	addi.d	a0, a0, 32
+
+.Llt32:
+	addi.d	a3, a2, -16
+	bgeu	a0, a3, .Llt16
+13:	st.d	zero, a0, 0
+14:	st.d	zero, a0, 8
+	addi.d	a0, a0, 16
+
+.Llt16:
+	addi.d	a3, a2, -8
+	bgeu	a0, a3, .Llt8
+15:	st.d	zero, a0, 0
+
+.Llt8:
+16:	st.d	zero, a2, -8
 
 	/* return */
-10:	move	a0, a1
+	move	a0, zero
+	jr	ra
+
+	.align	4
+.Lsmall:
+	pcaddi	t0, 4
+	slli.d	a2, a1, 4
+	add.d	t0, t0, a2
+	jr	t0
+
+	.align	4
+	move	a0, zero
+	jr	ra
+
+	.align	4
+17:	st.b	zero, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	4
+18:	st.h	zero, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	4
+19:	st.h	zero, a0, 0
+20:	st.b	zero, a0, 2
+	move	a0, zero
+	jr	ra
+
+	.align	4
+21:	st.w	zero, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	4
+22:	st.w	zero, a0, 0
+23:	st.b	zero, a0, 4
+	move	a0, zero
+	jr	ra
+
+	.align	4
+24:	st.w	zero, a0, 0
+25:	st.h	zero, a0, 4
+	move	a0, zero
+	jr	ra
+
+	.align	4
+26:	st.w	zero, a0, 0
+27:	st.w	zero, a0, 3
+	move	a0, zero
+	jr	ra
+
+	.align	4
+28:	st.d	zero, a0, 0
+	move	a0, zero
 	jr	ra
 
 	/* fixup and ex_table */
+	_asm_extable 0b, .L_fixup_handle_0
 	_asm_extable 1b, .L_fixup_handle_0
 	_asm_extable 2b, .L_fixup_handle_1
 	_asm_extable 3b, .L_fixup_handle_2
@@ -95,4 +183,23 @@  SYM_FUNC_START(__clear_user_fast)
 	_asm_extable 7b, .L_fixup_handle_6
 	_asm_extable 8b, .L_fixup_handle_7
 	_asm_extable 9b, .L_fixup_handle_0
+	_asm_extable 10b, .L_fixup_handle_1
+	_asm_extable 11b, .L_fixup_handle_2
+	_asm_extable 12b, .L_fixup_handle_3
+	_asm_extable 13b, .L_fixup_handle_0
+	_asm_extable 14b, .L_fixup_handle_1
+	_asm_extable 15b, .L_fixup_handle_0
+	_asm_extable 16b, .L_fixup_handle_1
+	_asm_extable 17b, .L_fixup_handle_s0
+	_asm_extable 18b, .L_fixup_handle_s0
+	_asm_extable 19b, .L_fixup_handle_s0
+	_asm_extable 20b, .L_fixup_handle_s2
+	_asm_extable 21b, .L_fixup_handle_s0
+	_asm_extable 22b, .L_fixup_handle_s0
+	_asm_extable 23b, .L_fixup_handle_s4
+	_asm_extable 24b, .L_fixup_handle_s0
+	_asm_extable 25b, .L_fixup_handle_s4
+	_asm_extable 26b, .L_fixup_handle_s0
+	_asm_extable 27b, .L_fixup_handle_s4
+	_asm_extable 28b, .L_fixup_handle_s0
 SYM_FUNC_END(__clear_user_fast)
diff --git a/arch/loongarch/lib/copy_user.S b/arch/loongarch/lib/copy_user.S
index 55ac6020a1ad..b21f6d5d38f5 100644
--- a/arch/loongarch/lib/copy_user.S
+++ b/arch/loongarch/lib/copy_user.S
@@ -13,7 +13,14 @@ 
 
 .irp to, 0, 1, 2, 3, 4, 5, 6, 7
 .L_fixup_handle_\to\():
-	addi.d	a0, a2, (\to) * (-8)
+	sub.d	a0, a2, a0
+	addi.d	a0, a0, (\to) * (-8)
+	jr	ra
+.endr
+
+.irp to, 0, 2, 4
+.L_fixup_handle_s\to\():
+	addi.d	a0, a2, -\to
 	jr	ra
 .endr
 
@@ -47,8 +54,8 @@  SYM_FUNC_START(__copy_user_generic)
 3:	move	a0, a2
 	jr	ra
 
-	_asm_extable 1b, .L_fixup_handle_0
-	_asm_extable 2b, .L_fixup_handle_0
+	_asm_extable 1b, .L_fixup_handle_s0
+	_asm_extable 2b, .L_fixup_handle_s0
 SYM_FUNC_END(__copy_user_generic)
 
 /*
@@ -59,65 +66,209 @@  SYM_FUNC_END(__copy_user_generic)
  * a2: n
  */
 SYM_FUNC_START(__copy_user_fast)
-	beqz	a2, 19f
+	sltui	t0, a2, 9
+	bnez	t0, .Lsmall
 
-	ori	a3, zero, 64
-	blt	a2, a3, 17f
+	add.d	a3, a1, a2
+	add.d	a2, a0, a2
+0:	ld.d	t0, a1, 0
+1:	st.d	t0, a0, 0
 
-	/* copy 64 bytes at a time */
-1:	ld.d	t0, a1, 0
-2:	ld.d	t1, a1, 8
-3:	ld.d	t2, a1, 16
-4:	ld.d	t3, a1, 24
-5:	ld.d	t4, a1, 32
-6:	ld.d	t5, a1, 40
-7:	ld.d	t6, a1, 48
-8:	ld.d	t7, a1, 56
-9:	st.d	t0, a0, 0
-10:	st.d	t1, a0, 8
-11:	st.d	t2, a0, 16
-12:	st.d	t3, a0, 24
-13:	st.d	t4, a0, 32
-14:	st.d	t5, a0, 40
-15:	st.d	t6, a0, 48
-16:	st.d	t7, a0, 56
+	/* align up destination address */
+	andi	t1, a0, 7
+	sub.d	t0, zero, t1
+	addi.d	t0, t0, 8
+	add.d	a1, a1, t0
+	add.d	a0, a0, t0
 
-	addi.d	a0, a0, 64
-	addi.d	a1, a1, 64
-	addi.d	a2, a2, -64
-	bge	a2, a3, 1b
+	addi.d	a4, a3, -64
+	bgeu	a1, a4, .Llt64
 
-	beqz	a2, 19f
+	/* copy 64 bytes at a time */
+.Lloop64:
+2:	ld.d	t0, a1, 0
+3:	ld.d	t1, a1, 8
+4:	ld.d	t2, a1, 16
+5:	ld.d	t3, a1, 24
+6:	ld.d	t4, a1, 32
+7:	ld.d	t5, a1, 40
+8:	ld.d	t6, a1, 48
+9:	ld.d	t7, a1, 56
+	addi.d	a1, a1, 64
+10:	st.d	t0, a0, 0
+11:	st.d	t1, a0, 8
+12:	st.d	t2, a0, 16
+13:	st.d	t3, a0, 24
+14:	st.d	t4, a0, 32
+15:	st.d	t5, a0, 40
+16:	st.d	t6, a0, 48
+17:	st.d	t7, a0, 56
+	addi.d	a0, a0, 64
+	bltu	a1, a4, .Lloop64
 
 	/* copy the remaining bytes */
-17:	ld.b	t0, a1, 0
-18:	st.b	t0, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a1, a1, 1
-	addi.d	a2, a2, -1
-	bgt	a2, zero, 17b
+.Llt64:
+	addi.d	a4, a3, -32
+	bgeu	a1, a4, .Llt32
+18:	ld.d	t0, a1, 0
+19:	ld.d	t1, a1, 8
+20:	ld.d	t2, a1, 16
+21:	ld.d	t3, a1, 24
+	addi.d	a1, a1, 32
+22:	st.d	t0, a0, 0
+23:	st.d	t1, a0, 8
+24:	st.d	t2, a0, 16
+25:	st.d	t3, a0, 24
+	addi.d	a0, a0, 32
+
+.Llt32:
+	addi.d	a4, a3, -16
+	bgeu	a1, a4, .Llt16
+26:	ld.d	t0, a1, 0
+27:	ld.d	t1, a1, 8
+	addi.d	a1, a1, 16
+28:	st.d	t0, a0, 0
+29:	st.d	t1, a0, 8
+	addi.d	a0, a0, 16
+
+.Llt16:
+	addi.d	a4, a3, -8
+	bgeu	a1, a4, .Llt8
+30:	ld.d	t0, a1, 0
+31:	st.d	t0, a0, 0
+
+.Llt8:
+32:	ld.d	t0, a3, -8
+33:	st.d	t0, a2, -8
 
 	/* return */
-19:	move	a0, a2
+	move	a0, zero
+	jr	ra
+
+	.align	5
+.Lsmall:
+	pcaddi	t0, 8
+	slli.d	a3, a2, 5
+	add.d	t0, t0, a3
+	jr	t0
+
+	.align	5
+	move	a0, zero
+	jr	ra
+
+	.align	5
+34:	ld.b	t0, a1, 0
+35:	st.b	t0, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	5
+36:	ld.h	t0, a1, 0
+37:	st.h	t0, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	5
+38:	ld.h	t0, a1, 0
+39:	ld.b	t1, a1, 2
+40:	st.h	t0, a0, 0
+41:	st.b	t1, a0, 2
+	move	a0, zero
+	jr	ra
+
+	.align	5
+42:	ld.w	t0, a1, 0
+43:	st.w	t0, a0, 0
+	move	a0, zero
+	jr	ra
+
+	.align	5
+44:	ld.w	t0, a1, 0
+45:	ld.b	t1, a1, 4
+46:	st.w	t0, a0, 0
+47:	st.b	t1, a0, 4
+	move	a0, zero
+	jr	ra
+
+	.align	5
+48:	ld.w	t0, a1, 0
+49:	ld.h	t1, a1, 4
+50:	st.w	t0, a0, 0
+51:	st.h	t1, a0, 4
+	move	a0, zero
+	jr	ra
+
+	.align	5
+52:	ld.w	t0, a1, 0
+53:	ld.w	t1, a1, 3
+54:	st.w	t0, a0, 0
+55:	st.w	t1, a0, 3
+	move	a0, zero
+	jr	ra
+
+	.align	5
+56:	ld.d	t0, a1, 0
+57:	st.d	t0, a0, 0
+	move	a0, zero
 	jr	ra
 
 	/* fixup and ex_table */
+	_asm_extable 0b, .L_fixup_handle_0
 	_asm_extable 1b, .L_fixup_handle_0
-	_asm_extable 2b, .L_fixup_handle_1
-	_asm_extable 3b, .L_fixup_handle_2
-	_asm_extable 4b, .L_fixup_handle_3
-	_asm_extable 5b, .L_fixup_handle_4
-	_asm_extable 6b, .L_fixup_handle_5
-	_asm_extable 7b, .L_fixup_handle_6
-	_asm_extable 8b, .L_fixup_handle_7
+	_asm_extable 2b, .L_fixup_handle_0
+	_asm_extable 3b, .L_fixup_handle_0
+	_asm_extable 4b, .L_fixup_handle_0
+	_asm_extable 5b, .L_fixup_handle_0
+	_asm_extable 6b, .L_fixup_handle_0
+	_asm_extable 7b, .L_fixup_handle_0
+	_asm_extable 8b, .L_fixup_handle_0
 	_asm_extable 9b, .L_fixup_handle_0
-	_asm_extable 10b, .L_fixup_handle_1
-	_asm_extable 11b, .L_fixup_handle_2
-	_asm_extable 12b, .L_fixup_handle_3
-	_asm_extable 13b, .L_fixup_handle_4
-	_asm_extable 14b, .L_fixup_handle_5
-	_asm_extable 15b, .L_fixup_handle_6
-	_asm_extable 16b, .L_fixup_handle_7
-	_asm_extable 17b, .L_fixup_handle_0
+	_asm_extable 10b, .L_fixup_handle_0
+	_asm_extable 11b, .L_fixup_handle_1
+	_asm_extable 12b, .L_fixup_handle_2
+	_asm_extable 13b, .L_fixup_handle_3
+	_asm_extable 14b, .L_fixup_handle_4
+	_asm_extable 15b, .L_fixup_handle_5
+	_asm_extable 16b, .L_fixup_handle_6
+	_asm_extable 17b, .L_fixup_handle_7
 	_asm_extable 18b, .L_fixup_handle_0
+	_asm_extable 19b, .L_fixup_handle_0
+	_asm_extable 20b, .L_fixup_handle_0
+	_asm_extable 21b, .L_fixup_handle_0
+	_asm_extable 22b, .L_fixup_handle_0
+	_asm_extable 23b, .L_fixup_handle_1
+	_asm_extable 24b, .L_fixup_handle_2
+	_asm_extable 25b, .L_fixup_handle_3
+	_asm_extable 26b, .L_fixup_handle_0
+	_asm_extable 27b, .L_fixup_handle_0
+	_asm_extable 28b, .L_fixup_handle_0
+	_asm_extable 29b, .L_fixup_handle_1
+	_asm_extable 30b, .L_fixup_handle_0
+	_asm_extable 31b, .L_fixup_handle_0
+	_asm_extable 32b, .L_fixup_handle_0
+	_asm_extable 33b, .L_fixup_handle_1
+	_asm_extable 34b, .L_fixup_handle_s0
+	_asm_extable 35b, .L_fixup_handle_s0
+	_asm_extable 36b, .L_fixup_handle_s0
+	_asm_extable 37b, .L_fixup_handle_s0
+	_asm_extable 38b, .L_fixup_handle_s0
+	_asm_extable 39b, .L_fixup_handle_s0
+	_asm_extable 40b, .L_fixup_handle_s0
+	_asm_extable 41b, .L_fixup_handle_s2
+	_asm_extable 42b, .L_fixup_handle_s0
+	_asm_extable 43b, .L_fixup_handle_s0
+	_asm_extable 44b, .L_fixup_handle_s0
+	_asm_extable 45b, .L_fixup_handle_s0
+	_asm_extable 46b, .L_fixup_handle_s0
+	_asm_extable 47b, .L_fixup_handle_s4
+	_asm_extable 48b, .L_fixup_handle_s0
+	_asm_extable 49b, .L_fixup_handle_s0
+	_asm_extable 50b, .L_fixup_handle_s0
+	_asm_extable 51b, .L_fixup_handle_s4
+	_asm_extable 52b, .L_fixup_handle_s0
+	_asm_extable 53b, .L_fixup_handle_s0
+	_asm_extable 54b, .L_fixup_handle_s0
+	_asm_extable 55b, .L_fixup_handle_s4
+	_asm_extable 56b, .L_fixup_handle_s0
+	_asm_extable 57b, .L_fixup_handle_s0
 SYM_FUNC_END(__copy_user_fast)
diff --git a/arch/loongarch/lib/memcpy.S b/arch/loongarch/lib/memcpy.S
index 3b7e1dec7109..39ce6621c704 100644
--- a/arch/loongarch/lib/memcpy.S
+++ b/arch/loongarch/lib/memcpy.S
@@ -44,6 +44,66 @@  SYM_FUNC_START(__memcpy_generic)
 SYM_FUNC_END(__memcpy_generic)
 _ASM_NOKPROBE(__memcpy_generic)
 
+	.align	5
+SYM_FUNC_START_NOALIGN(__memcpy_small)
+	pcaddi	t0, 8
+	slli.d	a2, a2, 5
+	add.d	t0, t0, a2
+	jr	t0
+
+	.align	5
+0:	jr	ra
+
+	.align	5
+1:	ld.b	t0, a1, 0
+	st.b	t0, a0, 0
+	jr	ra
+
+	.align	5
+2:	ld.h	t0, a1, 0
+	st.h	t0, a0, 0
+	jr	ra
+
+	.align	5
+3:	ld.h	t0, a1, 0
+	ld.b	t1, a1, 2
+	st.h	t0, a0, 0
+	st.b	t1, a0, 2
+	jr	ra
+
+	.align	5
+4:	ld.w	t0, a1, 0
+	st.w	t0, a0, 0
+	jr	ra
+
+	.align	5
+5:	ld.w	t0, a1, 0
+	ld.b	t1, a1, 4
+	st.w	t0, a0, 0
+	st.b	t1, a0, 4
+	jr	ra
+
+	.align	5
+6:	ld.w	t0, a1, 0
+	ld.h	t1, a1, 4
+	st.w	t0, a0, 0
+	st.h	t1, a0, 4
+	jr	ra
+
+	.align	5
+7:	ld.w	t0, a1, 0
+	ld.w	t1, a1, 3
+	st.w	t0, a0, 0
+	st.w	t1, a0, 3
+	jr	ra
+
+	.align	5
+8:	ld.d	t0, a1, 0
+	st.d	t0, a0, 0
+	jr	ra
+SYM_FUNC_END(__memcpy_small)
+_ASM_NOKPROBE(__memcpy_small)
+
 /*
  * void *__memcpy_fast(void *dst, const void *src, size_t n)
  *
@@ -52,14 +112,27 @@  _ASM_NOKPROBE(__memcpy_generic)
  * a2: n
  */
 SYM_FUNC_START(__memcpy_fast)
-	move	a3, a0
-	beqz	a2, 3f
+	sltui	t0, a2, 9
+	bnez	t0, __memcpy_small
+
+	add.d	a3, a1, a2
+	add.d	a2, a0, a2
+	ld.d	a6, a1, 0
+	ld.d	a7, a3, -8
+
+	/* align up destination address */
+	andi	t1, a0, 7
+	sub.d	t0, zero, t1
+	addi.d	t0, t0, 8
+	add.d	a1, a1, t0
+	add.d	a5, a0, t0
 
-	ori	a4, zero, 64
-	blt	a2, a4, 2f
+	addi.d	a4, a3, -64
+	bgeu	a1, a4, .Llt64
 
 	/* copy 64 bytes at a time */
-1:	ld.d	t0, a1, 0
+.Lloop64:
+	ld.d	t0, a1, 0
 	ld.d	t1, a1, 8
 	ld.d	t2, a1, 16
 	ld.d	t3, a1, 24
@@ -67,32 +140,54 @@  SYM_FUNC_START(__memcpy_fast)
 	ld.d	t5, a1, 40
 	ld.d	t6, a1, 48
 	ld.d	t7, a1, 56
-	st.d	t0, a0, 0
-	st.d	t1, a0, 8
-	st.d	t2, a0, 16
-	st.d	t3, a0, 24
-	st.d	t4, a0, 32
-	st.d	t5, a0, 40
-	st.d	t6, a0, 48
-	st.d	t7, a0, 56
-
-	addi.d	a0, a0, 64
 	addi.d	a1, a1, 64
-	addi.d	a2, a2, -64
-	bge	a2, a4, 1b
-
-	beqz	a2, 3f
+	st.d	t0, a5, 0
+	st.d	t1, a5, 8
+	st.d	t2, a5, 16
+	st.d	t3, a5, 24
+	st.d	t4, a5, 32
+	st.d	t5, a5, 40
+	st.d	t6, a5, 48
+	st.d	t7, a5, 56
+	addi.d	a5, a5, 64
+	bltu	a1, a4, .Lloop64
 
 	/* copy the remaining bytes */
-2:	ld.b	t0, a1, 0
-	st.b	t0, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a1, a1, 1
-	addi.d	a2, a2, -1
-	bgt	a2, zero, 2b
+.Llt64:
+	addi.d	a4, a3, -32
+	bgeu	a1, a4, .Llt32
+	ld.d	t0, a1, 0
+	ld.d	t1, a1, 8
+	ld.d	t2, a1, 16
+	ld.d	t3, a1, 24
+	addi.d	a1, a1, 32
+	st.d	t0, a5, 0
+	st.d	t1, a5, 8
+	st.d	t2, a5, 16
+	st.d	t3, a5, 24
+	addi.d	a5, a5, 32
+
+.Llt32:
+	addi.d	a4, a3, -16
+	bgeu	a1, a4, .Llt16
+	ld.d	t0, a1, 0
+	ld.d	t1, a1, 8
+	addi.d	a1, a1, 16
+	st.d	t0, a5, 0
+	st.d	t1, a5, 8
+	addi.d	a5, a5, 16
+
+.Llt16:
+	addi.d	a4, a3, -8
+	bgeu	a1, a4, .Llt8
+	ld.d	t0, a1, 0
+	st.d	t0, a5, 0
+
+.Llt8:
+	st.d	a6, a0, 0
+	st.d	a7, a2, -8
 
 	/* return */
-3:	move	a0, a3
 	jr	ra
 SYM_FUNC_END(__memcpy_fast)
 _ASM_NOKPROBE(__memcpy_fast)
diff --git a/arch/loongarch/lib/memmove.S b/arch/loongarch/lib/memmove.S
index b796c3d6da05..45b725ba7867 100644
--- a/arch/loongarch/lib/memmove.S
+++ b/arch/loongarch/lib/memmove.S
@@ -11,23 +11,9 @@ 
 #include <asm/regdef.h>
 
 SYM_FUNC_START(memmove)
-	blt	a0, a1, 1f	/* dst < src, memcpy */
-	blt	a1, a0, 3f	/* src < dst, rmemcpy */
+	blt	a0, a1, memcpy	/* dst < src, memcpy */
+	blt	a1, a0, rmemcpy	/* src < dst, rmemcpy */
 	jr	ra		/* dst == src, return */
-
-	/* if (src - dst) < 64, copy 1 byte at a time */
-1:	ori	a3, zero, 64
-	sub.d	t0, a1, a0
-	blt	t0, a3, 2f
-	b	memcpy
-2:	b	__memcpy_generic
-
-	/* if (dst - src) < 64, copy 1 byte at a time */
-3:	ori	a3, zero, 64
-	sub.d	t0, a0, a1
-	blt	t0, a3, 4f
-	b	rmemcpy
-4:	b	__rmemcpy_generic
 SYM_FUNC_END(memmove)
 _ASM_NOKPROBE(memmove)
 
@@ -76,50 +62,80 @@  _ASM_NOKPROBE(__rmemcpy_generic)
  * a2: n
  */
 SYM_FUNC_START(__rmemcpy_fast)
-	move	a3, a0
-	beqz	a2, 3f
+	sltui	t0, a2, 9
+	bnez	t0, __memcpy_small
 
-	add.d	a0, a0, a2
-	add.d	a1, a1, a2
+	add.d	a3, a1, a2
+	add.d	a2, a0, a2
+	ld.d	a6, a1, 0
+	ld.d	a7, a3, -8
+
+	/* align up destination address */
+	andi	t1, a2, 7
+	sub.d	a3, a3, t1
+	sub.d	a5, a2, t1
 
-	ori	a4, zero, 64
-	blt	a2, a4, 2f
+	addi.d	a4, a1, 64
+	bgeu	a4, a3, .Llt64
 
 	/* copy 64 bytes at a time */
-1:	ld.d	t0, a1, -8
-	ld.d	t1, a1, -16
-	ld.d	t2, a1, -24
-	ld.d	t3, a1, -32
-	ld.d	t4, a1, -40
-	ld.d	t5, a1, -48
-	ld.d	t6, a1, -56
-	ld.d	t7, a1, -64
-	st.d	t0, a0, -8
-	st.d	t1, a0, -16
-	st.d	t2, a0, -24
-	st.d	t3, a0, -32
-	st.d	t4, a0, -40
-	st.d	t5, a0, -48
-	st.d	t6, a0, -56
-	st.d	t7, a0, -64
-
-	addi.d	a0, a0, -64
-	addi.d	a1, a1, -64
-	addi.d	a2, a2, -64
-	bge	a2, a4, 1b
-
-	beqz	a2, 3f
+.Lloop64:
+	ld.d	t0, a3, -8
+	ld.d	t1, a3, -16
+	ld.d	t2, a3, -24
+	ld.d	t3, a3, -32
+	ld.d	t4, a3, -40
+	ld.d	t5, a3, -48
+	ld.d	t6, a3, -56
+	ld.d	t7, a3, -64
+	addi.d	a3, a3, -64
+	st.d	t0, a5, -8
+	st.d	t1, a5, -16
+	st.d	t2, a5, -24
+	st.d	t3, a5, -32
+	st.d	t4, a5, -40
+	st.d	t5, a5, -48
+	st.d	t6, a5, -56
+	st.d	t7, a5, -64
+	addi.d	a5, a5, -64
+	bltu	a4, a3, .Lloop64
 
 	/* copy the remaining bytes */
-2:	ld.b	t0, a1, -1
-	st.b	t0, a0, -1
-	addi.d	a0, a0, -1
-	addi.d	a1, a1, -1
-	addi.d	a2, a2, -1
-	bgt	a2, zero, 2b
+.Llt64:
+	addi.d	a4, a1, 32
+	bgeu	a4, a3, .Llt32
+	ld.d	t0, a3, -8
+	ld.d	t1, a3, -16
+	ld.d	t2, a3, -24
+	ld.d	t3, a3, -32
+	addi.d	a3, a3, -32
+	st.d	t0, a5, -8
+	st.d	t1, a5, -16
+	st.d	t2, a5, -24
+	st.d	t3, a5, -32
+	addi.d	a5, a5, -32
+
+.Llt32:
+	addi.d	a4, a1, 16
+	bgeu	a4, a3, .Llt16
+	ld.d	t0, a3, -8
+	ld.d	t1, a3, -16
+	addi.d	a3, a3, -16
+	st.d	t0, a5, -8
+	st.d	t1, a5, -16
+	addi.d	a5, a5, -16
+
+.Llt16:
+	addi.d	a4, a1, 8
+	bgeu	a4, a3, .Llt8
+	ld.d	t0, a3, -8
+	st.d	t0, a5, -8
+
+.Llt8:
+	st.d	a6, a0, 0
+	st.d	a7, a2, -8
 
 	/* return */
-3:	move	a0, a3
 	jr	ra
 SYM_FUNC_END(__rmemcpy_fast)
 _ASM_NOKPROBE(__rmemcpy_fast)
diff --git a/arch/loongarch/lib/memset.S b/arch/loongarch/lib/memset.S
index a9eb732ab2ad..c5836d916736 100644
--- a/arch/loongarch/lib/memset.S
+++ b/arch/loongarch/lib/memset.S
@@ -56,39 +56,108 @@  _ASM_NOKPROBE(__memset_generic)
  * a2: n
  */
 SYM_FUNC_START(__memset_fast)
-	move	a3, a0
-	beqz	a2, 3f
-
-	ori	a4, zero, 64
-	blt	a2, a4, 2f
-
 	/* fill a1 to 64 bits */
 	fill_to_64 a1
 
-	/* set 64 bytes at a time */
-1:	st.d	a1, a0, 0
-	st.d	a1, a0, 8
-	st.d	a1, a0, 16
-	st.d	a1, a0, 24
-	st.d	a1, a0, 32
-	st.d	a1, a0, 40
-	st.d	a1, a0, 48
-	st.d	a1, a0, 56
+	sltui	t0, a2, 9
+	bnez	t0, .Lsmall
 
-	addi.d	a0, a0, 64
-	addi.d	a2, a2, -64
-	bge	a2, a4, 1b
+	add.d	a2, a0, a2
+	st.d	a1, a0, 0
 
-	beqz	a2, 3f
+	/* align up address */
+	andi	t1, a0, 7
+	sub.d	a3, a0, t1
+	addi.d	a3, a3, 8
+
+	addi.d	a4, a2, -64
+	bgeu	a3, a4, .Llt64
+
+	/* set 64 bytes at a time */
+.Lloop64:
+	st.d	a1, a3, 0
+	st.d	a1, a3, 8
+	st.d	a1, a3, 16
+	st.d	a1, a3, 24
+	st.d	a1, a3, 32
+	st.d	a1, a3, 40
+	st.d	a1, a3, 48
+	st.d	a1, a3, 56
+	addi.d	a3, a3, 64
+	bltu	a3, a4, .Lloop64
 
 	/* set the remaining bytes */
-2:	st.b	a1, a0, 0
-	addi.d	a0, a0, 1
-	addi.d	a2, a2, -1
-	bgt	a2, zero, 2b
+.Llt64:
+	addi.d	a4, a2, -32
+	bgeu	a3, a4, .Llt32
+	st.d	a1, a3, 0
+	st.d	a1, a3, 8
+	st.d	a1, a3, 16
+	st.d	a1, a3, 24
+	addi.d	a3, a3, 32
+
+.Llt32:
+	addi.d	a4, a2, -16
+	bgeu	a3, a4, .Llt16
+	st.d	a1, a3, 0
+	st.d	a1, a3, 8
+	addi.d	a3, a3, 16
+
+.Llt16:
+	addi.d	a4, a2, -8
+	bgeu	a3, a4, .Llt8
+	st.d	a1, a3, 0
+
+.Llt8:
+	st.d	a1, a2, -8
 
 	/* return */
-3:	move	a0, a3
+	jr	ra
+
+	.align	4
+.Lsmall:
+	pcaddi	t0, 4
+	slli.d	a2, a2, 4
+	add.d	t0, t0, a2
+	jr	t0
+
+	.align	4
+0:	jr	ra
+
+	.align	4
+1:	st.b	a1, a0, 0
+	jr	ra
+
+	.align	4
+2:	st.h	a1, a0, 0
+	jr	ra
+
+	.align	4
+3:	st.h	a1, a0, 0
+	st.b	a1, a0, 2
+	jr	ra
+
+	.align	4
+4:	st.w	a1, a0, 0
+	jr	ra
+
+	.align	4
+5:	st.w	a1, a0, 0
+	st.b	a1, a0, 4
+	jr	ra
+
+	.align	4
+6:	st.w	a1, a0, 0
+	st.h	a1, a0, 4
+	jr	ra
+
+	.align	4
+7:	st.w	a1, a0, 0
+	st.w	a1, a0, 3
+	jr	ra
+
+	.align	4
+8:	st.d	a1, a0, 0
 	jr	ra
 SYM_FUNC_END(__memset_fast)
 _ASM_NOKPROBE(__memset_fast)