I will check with fresh Yocto build later or tomorrow.

-- 
With best wishes
Dmitry

вс, 23 февр. 2020 г., 19:08 Dmitry Baryshkov <[email protected]>:

> If I remember correctly, ARMv5 be was BE-32
>
> --
> With best wishes
> Dmitry
>
> вс, 23 февр. 2020 г., 18:45 Michael Weiser <[email protected]>:
>
>> Hi all,
>>
>> On Sat, Feb 22, 2020 at 07:43:18PM +0100, Michael Weiser wrote:
>>
>> > > 2. Eliminate use of rev in the armbe code.
>> > ... I've been looking at the revs and they now strike me as taking the
>> > easy way out anyway. They work around the implicit LE order in which
>>
>> Updated code is now at
>> https://git.lysator.liu.se/michaelweiser/nettle/-/tree/arm-memxor-generic
>> and inline below for comments.
>>
>> It now compiles and runs the testsuite fine on my native armv7veb when
>> configurd with:
>>
>> CFLAGS="-march=armv6" LDFLAGS="-march=armv6" \
>>         ../configure --disable-documentation \
>>                 --host=armv6b-unknown-linux-gnueabihf
>> [...]
>>   Assembly files:    arm/neon arm/v6 arm
>>
>> and:
>>
>> CFLAGS="-march=armv5te" LDFLAGS="-march=armv5te -Wl,--be8" \
>>         ../configure --disable-documentation \
>>                 --host=armv5b-unknown-linux-gnueabihf
>> [...]
>>   Assembly files:    arm
>>
>> LDFLAGS "-Wl,--be8" is necessary for armv5teb to work on my system
>> because it is BE8 which the gcc linker driver defaults to when run with
>> -march=armv6 but not for armv5 which causes the resuling binaries to be
>> BE32 and segfault or bus error in ld-linux.so.3 on startup. For a
>> (likely wrong) explanation of BE8 vs. BE32 see
>> https://lists.lysator.liu.se/pipermail/nettle-bugs/2018/007059.html.
>>
>> A quick check can be done with file:
>>
>> $ echo "int main(void) {}" > t.c
>> $ gcc -march=armv5te -o t t.c
>> $ ./t
>> Segmentation fault
>> $ file t
>> t: ELF 32-bit MSB shared object, ARM, EABI5 version 1 (SYSV),
>> dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux
>> 3.2.0, not stripped
>> $ gcc -march=armv5te -Wl,--be8 -o t t.c
>> $ ./t
>> $ file t
>> t: ELF 32-bit MSB shared object, ARM, EABI5 BE8 version 1 (SYSV),
>> dynamically linked, interpreter /lib/ld-linux-armhf.so.3, for GNU/Linux
>> 3.2.0, not stripped
>>
>> The qemu environment is churning along in compilation currently.
>>
>> Previous assembler error for reference:
>>
>> $ make -j4
>> [...]
>> /usr/bin/m4 ../asm.m4 machine.m4 config.m4 memxor.asm >memxor.s
>> /usr/bin/m4 ../asm.m4 machine.m4 config.m4 memxor3.asm >memxor3.s
>> gcc -I.  -DHAVE_CONFIG_H -march=armv5te -ggdb3 -Wall -W
>> -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes
>> -Wpointer-arith -Wbad-function-cast -Wnested-externs -fpic -MT memxor.o
>> -MD -MP -MF memxor.o.d -c memxor.s
>> gcc -I.  -DHAVE_CONFIG_H -march=armv5te -ggdb3 -Wall -W
>> -Wmissing-prototypes -Wmissing-declarations -Wstrict-prototypes
>> -Wpointer-arith -Wbad-function-cast -Wnested-externs -fpic -MT memxor3.o
>> -MD -MP -MF memxor3.o.d -c memxor3.s
>> memxor.s: memxor3.s: Assembler messages:
>> memxor3.s:146: Error: selected processor does not support `rev r4,r4' in
>> ARM mode
>> Assembler messages:
>> memxor3.s:256: Error: selected processor does not support `rev r4,r4' in
>> ARM mode
>> memxor.s:126: Error: selected processor does not support `rev r3,r3' in
>> ARM mode
>> --
>> Thanks,
>> Michael
>>
>> From 3e2118d41472842c368bb5bb56d71023b861b59d Mon Sep 17 00:00:00 2001
>> From: Michael Weiser <[email protected]>
>> Date: Sun, 23 Feb 2020 15:22:51 +0100
>> Subject: [PATCH] arm: Fix memxor for non-armv6+ big-endian systems
>>
>> ARM assembly adjustments for big-endian systems contained armv6+-only
>> instructions (rev) in generic arm memxor code. Replace those with an
>> actual conversion of the leftover byte store routines for big-endian
>> systems. This also provides a slight optimisation by removing the
>> additional instruction as well as increased symmetry between little- and
>> big-endian implementations.
>>
>> Signed-off-by: Michael Weiser <[email protected]>
>> ---
>>  arm/memxor.asm  | 12 ++++++------
>>  arm/memxor3.asm | 27 ++++++++++++++-------------
>>  2 files changed, 20 insertions(+), 19 deletions(-)
>>
>> diff --git a/arm/memxor.asm b/arm/memxor.asm
>> index 239a4034..b802e95c 100644
>> --- a/arm/memxor.asm
>> +++ b/arm/memxor.asm
>> @@ -138,24 +138,24 @@ PROLOGUE(nettle_memxor)
>>         adds    N, #8
>>         beq     .Lmemxor_odd_done
>>
>> -       C We have TNC/8 left-over bytes in r4, high end
>> +       C We have TNC/8 left-over bytes in r4, (since working upwards) low
>> +       C end on LE and high end on BE
>>         S0ADJ   r4, CNT
>>         ldr     r3, [DST]
>>         eor     r3, r4
>>
>> -       C memxor_leftover does an LSB store
>> -       C so we need to reverse if actually BE
>> -IF_BE(<        rev     r3, r3>)
>> -
>>         pop     {r4,r5,r6}
>>
>>         C Store bytes, one by one.
>>  .Lmemxor_leftover:
>> +       C bring uppermost byte down for saving while preserving lower ones
>> +IF_BE(<        ror     r3, #24>)
>>         strb    r3, [DST], #+1
>>         subs    N, #1
>>         beq     .Lmemxor_done
>>         subs    TNC, #8
>> -       lsr     r3, #8
>> +       C bring down next byte, no need to preserve
>> +IF_LE(<        lsr     r3, #8>)
>>         bne     .Lmemxor_leftover
>>         b       .Lmemxor_bytes
>>  .Lmemxor_odd_done:
>> diff --git a/arm/memxor3.asm b/arm/memxor3.asm
>> index 69598e1c..76b8aae6 100644
>> --- a/arm/memxor3.asm
>> +++ b/arm/memxor3.asm
>> @@ -159,21 +159,21 @@ PROLOGUE(nettle_memxor3)
>>         adds    N, #8
>>         beq     .Lmemxor3_done
>>
>> -       C Leftover bytes in r4, low end
>> +       C Leftover bytes in r4, (since working downwards) in high end on
>> LE and
>> +       C low end on BE
>>         ldr     r5, [AP, #-4]
>>         eor     r4, r5, r4, S1ADJ ATNC
>>
>> -       C leftover does an LSB store
>> -       C so we need to reverse if actually BE
>> -IF_BE(<        rev     r4, r4>)
>> -
>>  .Lmemxor3_au_leftover:
>>         C Store a byte at a time
>> -       ror     r4, #24
>> +       C bring uppermost byte down for saving while preserving lower ones
>> +IF_LE(<        ror     r4, #24>)
>>         strb    r4, [DST, #-1]!
>>         subs    N, #1
>>         beq     .Lmemxor3_done
>>         subs    ACNT, #8
>> +       C bring down next byte, no need to preserve
>> +IF_BE(<        lsr     r4, #8>)
>>         sub     AP, #1
>>         bne     .Lmemxor3_au_leftover
>>         b       .Lmemxor3_bytes
>> @@ -273,18 +273,19 @@ IF_BE(<   rev     r4, r4>)
>>         adds    N, #8
>>         beq     .Lmemxor3_done
>>
>> -       C leftover does an LSB store
>> -       C so we need to reverse if actually BE
>> -IF_BE(<        rev     r4, r4>)
>> -
>> -       C Leftover bytes in a4, low end
>> -       ror     r4, ACNT
>> +       C Leftover bytes in r4, (since working downwards) in high end on
>> LE and
>> +       C low end on BE after preparatory alignment correction
>> +IF_LE(<        ror     r4, ACNT>)
>> +IF_BE(<        ror     r4, ATNC>)
>>  .Lmemxor3_uu_leftover:
>> -       ror     r4, #24
>> +       C bring uppermost byte down for saving while preserving lower ones
>> +IF_LE(<        ror     r4, #24>)
>>         strb    r4, [DST, #-1]!
>>         subs    N, #1
>>         beq     .Lmemxor3_done
>>         subs    ACNT, #8
>> +       C bring down next byte, no need to preserve
>> +IF_BE(<        lsr     r4, #8>)
>>         bne     .Lmemxor3_uu_leftover
>>         b       .Lmemxor3_bytes
>>
>> --
>> 2.25.0
>>
>> _______________________________________________
>> nettle-bugs mailing list
>> [email protected]
>> http://lists.lysator.liu.se/mailman/listinfo/nettle-bugs
>>
>
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