* [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections'
@ 2021-10-19 2:14 Ye Weihua
2021-10-20 2:59 ` Ye Weihua
2021-10-20 16:55 ` Kees Cook
0 siblings, 2 replies; 4+ messages in thread
From: Ye Weihua @ 2021-10-19 2:14 UTC (permalink / raw)
To: masahiroy, michal.lkml, keescook, daniel, andriin; +Cc: linux-kbuild
Hi,
When I was compiling the ppc32 kernel with the compilation option
'-fdata-sections', a compilation error occurred and the message was as
follows:
"Inconsistent kallsyms data
Try make KALLSYMS_EXTRA_PASS=1 as a workaround"
After comparing the symbol tables, I found that the "_end" and
"__bss_stop" positions in Symtem.map and tmp_System.map are different:
in Symtem.map they are in the middle of the symbol table. In
tmp_System.map, they are at the end of the symbol table.
commit af73d78bd384aa9b add "strip-debug" to improve performance.
However, the addition takes effect only for tmp_vmlinux but not for
vmlinux. As a result, the symbol tables are different after the
"-fdata-sections" compilation option is enabled.
How the "strip-debug" compilation option affects symbol table order?
Can "strip-debug" be added during vmlinux generation?
Kind regards,
Weihua
.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections'
2021-10-19 2:14 [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections' Ye Weihua
@ 2021-10-20 2:59 ` Ye Weihua
2021-10-20 16:55 ` Kees Cook
1 sibling, 0 replies; 4+ messages in thread
From: Ye Weihua @ 2021-10-20 2:59 UTC (permalink / raw)
To: masahiroy, michal.lkml, keescook, daniel, andriin; +Cc: linux-kbuild
Hi,
I did additional testing on other architectures and found that only the
ppc32 had this problem. Is there a difference between the compiler's
support for the ppc32 architecture and other architectures?
I hope you'll take the time to reply. Thanks.
Kind regards,
Weihua
.
On 2021/10/19 10:14, Ye Weihua wrote:
> Hi,
>
>
> When I was compiling the ppc32 kernel with the compilation option
> '-fdata-sections', a compilation error occurred and the message was as
> follows:
>
>
> "Inconsistent kallsyms data
>
> Try make KALLSYMS_EXTRA_PASS=1 as a workaround"
>
>
> After comparing the symbol tables, I found that the "_end" and
> "__bss_stop" positions in Symtem.map and tmp_System.map are different:
> in Symtem.map they are in the middle of the symbol table. In
> tmp_System.map, they are at the end of the symbol table.
>
>
> commit af73d78bd384aa9b add "strip-debug" to improve performance.
> However, the addition takes effect only for tmp_vmlinux but not for
> vmlinux. As a result, the symbol tables are different after the
> "-fdata-sections" compilation option is enabled.
>
>
> How the "strip-debug" compilation option affects symbol table order?
>
> Can "strip-debug" be added during vmlinux generation?
>
>
> Kind regards,
>
> Weihua
>
> .
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections'
2021-10-19 2:14 [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections' Ye Weihua
2021-10-20 2:59 ` Ye Weihua
@ 2021-10-20 16:55 ` Kees Cook
2021-10-21 1:46 ` Ye Weihua
1 sibling, 1 reply; 4+ messages in thread
From: Kees Cook @ 2021-10-20 16:55 UTC (permalink / raw)
To: Ye Weihua; +Cc: masahiroy, michal.lkml, daniel, andriin, linux-kbuild
On Tue, Oct 19, 2021 at 10:14:34AM +0800, Ye Weihua wrote:
> Hi,
>
>
> When I was compiling the ppc32 kernel with the compilation option
> '-fdata-sections', a compilation error occurred and the message was as
> follows:
>
>
> "Inconsistent kallsyms data
>
> Try make KALLSYMS_EXTRA_PASS=1 as a workaround"
>
>
> After comparing the symbol tables, I found that the "_end" and "__bss_stop"
> positions in Symtem.map and tmp_System.map are different: in Symtem.map they
> are in the middle of the symbol table. In tmp_System.map, they are at the
> end of the symbol table.
>
>
> commit af73d78bd384aa9b add "strip-debug" to improve performance. However,
> the addition takes effect only for tmp_vmlinux but not for vmlinux. As a
> result, the symbol tables are different after the "-fdata-sections"
> compilation option is enabled.
>
>
> How the "strip-debug" compilation option affects symbol table order?
>
> Can "strip-debug" be added during vmlinux generation?
How did you add -fdata-sections? There needs to be a lot of special
handling to use that option...
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections'
2021-10-20 16:55 ` Kees Cook
@ 2021-10-21 1:46 ` Ye Weihua
0 siblings, 0 replies; 4+ messages in thread
From: Ye Weihua @ 2021-10-21 1:46 UTC (permalink / raw)
To: Kees Cook; +Cc: masahiroy, michal.lkml, daniel, andriin, linux-kbuild
On 2021/10/21 0:55, Kees Cook wrote:
> On Tue, Oct 19, 2021 at 10:14:34AM +0800, Ye Weihua wrote:
>> Hi,
>>
>>
>> When I was compiling the ppc32 kernel with the compilation option
>> '-fdata-sections', a compilation error occurred and the message was as
>> follows:
>>
>>
>> "Inconsistent kallsyms data
>>
>> Try make KALLSYMS_EXTRA_PASS=1 as a workaround"
>>
>>
>> After comparing the symbol tables, I found that the "_end" and "__bss_stop"
>> positions in Symtem.map and tmp_System.map are different: in Symtem.map they
>> are in the middle of the symbol table. In tmp_System.map, they are at the
>> end of the symbol table.
>>
>>
>> commit af73d78bd384aa9b add "strip-debug" to improve performance. However,
>> the addition takes effect only for tmp_vmlinux but not for vmlinux. As a
>> result, the symbol tables are different after the "-fdata-sections"
>> compilation option is enabled.
>>
>>
>> How the "strip-debug" compilation option affects symbol table order?
>>
>> Can "strip-debug" be added during vmlinux generation?
> How did you add -fdata-sections? There needs to be a lot of special
> handling to use that option...
I added "-fdata-sections" to the "CFLAGS_KERNEL" field and "-Wl,--gc-sections" to "LDFLAGS_VMLINUX" in Makefile. I've configured it this way on other architectures, but I haven't had the same problem with the exception of ppc32. Are there any other configurations or steps required?
Thanks.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-10-21 1:46 UTC | newest]
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2021-10-19 2:14 [QUESTION] Compile error on ppc32 with compilation option '-fdata-sections' Ye Weihua
2021-10-20 2:59 ` Ye Weihua
2021-10-20 16:55 ` Kees Cook
2021-10-21 1:46 ` Ye Weihua
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