Re: Fwd: [PATCH] arm: ensure symbol is a thumb symbol in new binutils

[Christophe PRIOUZEAU <christophe dot priouzeau at st dot com>]

Hi Nick,
On 06/05/2018 01:37 PM, Nick Clifton wrote:
> Hi Christophe, Hi Romain,
>
>> I have made several test, with or without the define
>> "DEFAULT_THUMB_ADR_SETS_INTERWORKING",
>> but my test are always fails (no boot of my kernel).
> OK - now I am confused.  If changing the behaviour of the ADR and ADRL
> pseudo-ops is not working, then what is causing the boot failure ?
>
> Hmm, or is it that my patch is not working (at all) and not changing
> anything.
>
> Christophe - are you able to supply an assembler source file that
> I can try assembling to see what changes, if anything, when I use
> the new options ?
>
> Cheers
>    Nick
>
>
I'm not able to provide a simplest code which generate a bad assembler.
I have only the source code of kernel 4.11 use on my configuration of 
buildroot.
On code generated we see the issue on entry-common.o 
(arch/arm/kernel/entry-common.o):
code ok: f2af 1e3b     subw    lr, pc, #315    ; 0x13b
code KO: f2af 1e3a     subw    lr, pc, #314    ; 0x13a
(see assembler code obtained by objdump)

Info:
AFLAGS=-Wp,-MD,arch/arm/kernel/.entry-common.o.d  -nostdinc -isystem 
/mnt/internal_storage/stm32f7/buildroot_to_test_02/output/host/lib/gcc/arm-buildroot-uclinux-uclibcgnueabi/6.4.0/include 
-I./arch/arm/include -I./arch/arm/include/generated/uapi 
-I./arch/arm/include/generated  -I./include -I./arch/arm/include/uapi 
-I./include/uapi -I./include/generated/uapi -include 
./include/linux/kconfig.h -D__KERNEL__ -mlittle-endian -D__ASSEMBLY__ 
-fno-PIE -mabi=aapcs-linux -mno-thumb-interwork -mfpu=vfp 
-funwind-tables -mthumb -Wa,-mimplicit-it=always 
-Wa,-mno-warn-deprecated -Wa,-mthumb -D__LINUX_ARM_ARCH__=7 
-march=armv7-m -Wa,-march=armv7-m -include asm/unified.h -msoft-float 
-DCC_HAVE_ASM_GOTO -Wa,-gdwarf-2

/mnt/internal_storage/stm32f7/buildroot_to_test_02/output/host/bin/arm-buildroot-uclinux-uclibcgnueabi-gcc 
-Wp,-MD,arch/arm/kernel/.entry-common.o.d  -nostdinc -isystem 
/mnt/internal_storage/stm32f7/buildroot_to_test_02/output/host/lib/gcc/arm-buildroot-uclinux-uclibcgnueabi/6.4.0/include 
-I./arch/arm/include -I./arch/arm/include/generated/uapi 
-I./arch/arm/include/generated  -I./include -I./arch/arm/include/uapi 
-I./include/uapi -I./include/generated/uapi -include 
./include/linux/kconfig.h -D__KERNEL__ -mlittle-endian -D__ASSEMBLY__ 
-fno-PIE -mabi=aapcs-linux -mno-thumb-interwork -mfpu=vfp 
-funwind-tables -mthumb -Wa,-mimplicit-it=always 
-Wa,-mno-warn-deprecated -Wa,-mthumb -D__LINUX_ARM_ARCH__=7 
-march=armv7-m -Wa,-march=armv7-m -include asm/unified.h -msoft-float 
-DCC_HAVE_ASM_GOTO -Wa,-gdwarf-2   -c -o arch/arm/kernel/entry-common.o 
arch/arm/kernel/entry-common.S

PS: More I made test and more I don't understand what are generating the 
issue.
With the test provided on mail thread: 
https://patchwork.kernel.org/patch/10072631/ , I obtain the same code 
with the two version of binutils (2.28.1 and 2.30).

I Hope this kind of information can help you.
Thanks for yours time.
Regards
Christophe

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Attachment: entry-common_disassembled_kernel_4.11_ko.objdump
Description: entry-common_disassembled_kernel_4.11_ko.objdump