Re: [PATCH 1/1] LoongArch: adjust copy/clear_user exception handler behavior

From: Huacai Chen
Date: Wed Aug 30 2023 - 14:45:48 EST


Hi, Weihao,

The title should be "LoongArch: Adjust {copy, clear}_user exception
handler behavior" and 1/1 is unnecessary. Commit logs also need
similar adjustments.

On Wed, Aug 30, 2023 at 9:04 AM liweihao <liweihao@xxxxxxxxxxx> wrote:
>
> The copy/clear_user function should returns number of bytes that could
> not be copied/cleared. So, try to copy/clear byte by byte when ld.d/w/h
> and st.d/w/h trapped into an exception.
>
> Signed-off-by: liweihao <liweihao@xxxxxxxxxxx>
Your email format should be "Weihao Li <liweihao@xxxxxxxxxxx>"

Huacai
> ---
> arch/loongarch/lib/clear_user.S | 87 ++++++++---------
> arch/loongarch/lib/copy_user.S | 161 ++++++++++++++++----------------
> 2 files changed, 127 insertions(+), 121 deletions(-)
>
> diff --git a/arch/loongarch/lib/clear_user.S b/arch/loongarch/lib/clear_user.S
> index 0790eadce166..9b6eef569f89 100644
> --- a/arch/loongarch/lib/clear_user.S
> +++ b/arch/loongarch/lib/clear_user.S
> @@ -11,19 +11,6 @@
> #include <asm/cpu.h>
> #include <asm/regdef.h>
>
> -.irp to, 0, 1, 2, 3, 4, 5, 6, 7
> -.L_fixup_handle_\to\():
> - 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
> -
> SYM_FUNC_START(__clear_user)
> /*
> * Some CPUs support hardware unaligned access
> @@ -51,7 +38,7 @@ SYM_FUNC_START(__clear_user_generic)
> 2: move a0, a1
> jr ra
>
> - _asm_extable 1b, .L_fixup_handle_s0
> + _asm_extable 1b, 2b
> SYM_FUNC_END(__clear_user_generic)
>
> /*
> @@ -173,33 +160,47 @@ SYM_FUNC_START(__clear_user_fast)
> 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 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_0
> - _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
> +.Llarge_fixup:
> + sub.d a1, a2, a0
> +
> +.Lsmall_fixup:
> +29: st.b zero, a0, 0
> + addi.d a0, a0, 1
> + addi.d a1, a1, -1
> + bgt a1, zero, 1b
> +
> +.Lexit:
> + move a0, a1
> + jr ra
> +
> + _asm_extable 0b, .Lsmall_fixup
> + _asm_extable 1b, .Llarge_fixup
> + _asm_extable 2b, .Llarge_fixup
> + _asm_extable 3b, .Llarge_fixup
> + _asm_extable 4b, .Llarge_fixup
> + _asm_extable 5b, .Llarge_fixup
> + _asm_extable 6b, .Llarge_fixup
> + _asm_extable 7b, .Llarge_fixup
> + _asm_extable 8b, .Llarge_fixup
> + _asm_extable 9b, .Llarge_fixup
> + _asm_extable 10b, .Llarge_fixup
> + _asm_extable 11b, .Llarge_fixup
> + _asm_extable 12b, .Llarge_fixup
> + _asm_extable 13b, .Llarge_fixup
> + _asm_extable 14b, .Llarge_fixup
> + _asm_extable 15b, .Llarge_fixup
> + _asm_extable 16b, .Llarge_fixup
> + _asm_extable 17b, .Lexit
> + _asm_extable 18b, .Lsmall_fixup
> + _asm_extable 19b, .Lsmall_fixup
> + _asm_extable 20b, .Lsmall_fixup
> + _asm_extable 21b, .Lsmall_fixup
> + _asm_extable 22b, .Lsmall_fixup
> + _asm_extable 23b, .Lsmall_fixup
> + _asm_extable 24b, .Lsmall_fixup
> + _asm_extable 25b, .Lsmall_fixup
> + _asm_extable 26b, .Lsmall_fixup
> + _asm_extable 27b, .Lsmall_fixup
> + _asm_extable 28b, .Lsmall_fixup
> + _asm_extable 29b, .Lexit
> SYM_FUNC_END(__clear_user_fast)
> diff --git a/arch/loongarch/lib/copy_user.S b/arch/loongarch/lib/copy_user.S
> index bfe3d2793d00..feec3d362803 100644
> --- a/arch/loongarch/lib/copy_user.S
> +++ b/arch/loongarch/lib/copy_user.S
> @@ -11,19 +11,6 @@
> #include <asm/cpu.h>
> #include <asm/regdef.h>
>
> -.irp to, 0, 1, 2, 3, 4, 5, 6, 7
> -.L_fixup_handle_\to\():
> - 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
> -
> SYM_FUNC_START(__copy_user)
> /*
> * Some CPUs support hardware unaligned access
> @@ -54,8 +41,8 @@ SYM_FUNC_START(__copy_user_generic)
> 3: move a0, a2
> jr ra
>
> - _asm_extable 1b, .L_fixup_handle_s0
> - _asm_extable 2b, .L_fixup_handle_s0
> + _asm_extable 1b, 3b
> + _asm_extable 2b, 3b
> SYM_FUNC_END(__copy_user_generic)
>
> /*
> @@ -69,10 +56,10 @@ SYM_FUNC_START(__copy_user_fast)
> sltui t0, a2, 9
> bnez t0, .Lsmall
>
> - add.d a3, a1, a2
> - add.d a2, a0, a2
> 0: ld.d t0, a1, 0
> 1: st.d t0, a0, 0
> + add.d a3, a1, a2
> + add.d a2, a0, a2
>
> /* align up destination address */
> andi t1, a0, 7
> @@ -94,7 +81,6 @@ SYM_FUNC_START(__copy_user_fast)
> 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
> @@ -103,6 +89,7 @@ SYM_FUNC_START(__copy_user_fast)
> 15: st.d t5, a0, 40
> 16: st.d t6, a0, 48
> 17: st.d t7, a0, 56
> + addi.d a1, a1, 64
> addi.d a0, a0, 64
> bltu a1, a4, .Lloop64
>
> @@ -114,11 +101,11 @@ SYM_FUNC_START(__copy_user_fast)
> 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 a1, a1, 32
> addi.d a0, a0, 32
>
> .Llt32:
> @@ -126,9 +113,9 @@ SYM_FUNC_START(__copy_user_fast)
> 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 a1, a1, 16
> addi.d a0, a0, 16
>
> .Llt16:
> @@ -136,6 +123,7 @@ SYM_FUNC_START(__copy_user_fast)
> bgeu a1, a4, .Llt8
> 30: ld.d t0, a1, 0
> 31: st.d t0, a0, 0
> + addi.d a1, a1, 8
> addi.d a0, a0, 8
>
> .Llt8:
> @@ -214,62 +202,79 @@ SYM_FUNC_START(__copy_user_fast)
> 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_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_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_0
> - _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
> +.Llarge_fixup:
> + sub.d a2, a2, a0
> +
> +.Lsmall_fixup:
> +58: ld.b t0, a1, 0
> +59: st.b t0, a0, 0
> + addi.d a0, a0, 1
> + addi.d a1, a1, 1
> + addi.d a2, a2, -1
> + bgt a2, zero, 58b
> +
> +.Lexit:
> + move a0, a2
> + jr ra
> +
> + _asm_extable 0b, .Lsmall_fixup
> + _asm_extable 1b, .Lsmall_fixup
> + _asm_extable 2b, .Llarge_fixup
> + _asm_extable 3b, .Llarge_fixup
> + _asm_extable 4b, .Llarge_fixup
> + _asm_extable 5b, .Llarge_fixup
> + _asm_extable 6b, .Llarge_fixup
> + _asm_extable 7b, .Llarge_fixup
> + _asm_extable 8b, .Llarge_fixup
> + _asm_extable 9b, .Llarge_fixup
> + _asm_extable 10b, .Llarge_fixup
> + _asm_extable 11b, .Llarge_fixup
> + _asm_extable 12b, .Llarge_fixup
> + _asm_extable 13b, .Llarge_fixup
> + _asm_extable 14b, .Llarge_fixup
> + _asm_extable 15b, .Llarge_fixup
> + _asm_extable 16b, .Llarge_fixup
> + _asm_extable 17b, .Llarge_fixup
> + _asm_extable 18b, .Llarge_fixup
> + _asm_extable 19b, .Llarge_fixup
> + _asm_extable 20b, .Llarge_fixup
> + _asm_extable 21b, .Llarge_fixup
> + _asm_extable 22b, .Llarge_fixup
> + _asm_extable 23b, .Llarge_fixup
> + _asm_extable 24b, .Llarge_fixup
> + _asm_extable 25b, .Llarge_fixup
> + _asm_extable 26b, .Llarge_fixup
> + _asm_extable 27b, .Llarge_fixup
> + _asm_extable 28b, .Llarge_fixup
> + _asm_extable 29b, .Llarge_fixup
> + _asm_extable 30b, .Llarge_fixup
> + _asm_extable 31b, .Llarge_fixup
> + _asm_extable 32b, .Llarge_fixup
> + _asm_extable 33b, .Llarge_fixup
> + _asm_extable 34b, .Lexit
> + _asm_extable 35b, .Lexit
> + _asm_extable 36b, .Lsmall_fixup
> + _asm_extable 37b, .Lsmall_fixup
> + _asm_extable 38b, .Lsmall_fixup
> + _asm_extable 39b, .Lsmall_fixup
> + _asm_extable 40b, .Lsmall_fixup
> + _asm_extable 41b, .Lsmall_fixup
> + _asm_extable 42b, .Lsmall_fixup
> + _asm_extable 43b, .Lsmall_fixup
> + _asm_extable 44b, .Lsmall_fixup
> + _asm_extable 45b, .Lsmall_fixup
> + _asm_extable 46b, .Lsmall_fixup
> + _asm_extable 47b, .Lsmall_fixup
> + _asm_extable 48b, .Lsmall_fixup
> + _asm_extable 49b, .Lsmall_fixup
> + _asm_extable 50b, .Lsmall_fixup
> + _asm_extable 51b, .Lsmall_fixup
> + _asm_extable 52b, .Lsmall_fixup
> + _asm_extable 53b, .Lsmall_fixup
> + _asm_extable 54b, .Lsmall_fixup
> + _asm_extable 55b, .Lsmall_fixup
> + _asm_extable 56b, .Lsmall_fixup
> + _asm_extable 57b, .Lsmall_fixup
> + _asm_extable 58b, .Lexit
> + _asm_extable 59b, .Lexit
> SYM_FUNC_END(__copy_user_fast)
> --
> 2.39.2
>
>