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

[liweihao]

Hi, Huacai,

Thanks for the advices.
I'll fix these issues and create a new patch version.

Weihao

On 2023/8/30 下午11:40, Huacai Chen wrote:
> 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