Messages in this thread | | | From | WANG Rui <> | Date | Wed, 30 Aug 2023 10:24:51 +0800 | Subject | Re: [PATCH 1/1] LoongArch: adjust copy/clear_user exception handler behavior |
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Hello weihao,
On Wed, Aug 30, 2023 at 9:04 AM liweihao <liweihao@loongson.cn> 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@loongson.cn> > --- > 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
I'm sure the jump target here is 29b.
-- WANG Rui
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