[OpenAFS-devel] subtle change needed for s390x
Carsten Jacobi
jacobi@de.ibm.com
Mon, 13 Sep 2010 15:09:51 +0200
Hello,
I've tried to build OpenAFS-1.4.12 last week for Linux on s390x and
the build failed with this error:
`savecontext' referenced in section `.text'
of /usr/src/packages/BUILD/openafs-1.4.12/lib/liblwp.a(lwp.o): defined =
in
discarded section `.note.GNU-stack'
of /usr/src/packages/BUILD/openafs-1.4.12/lib/liblwp.a(process.o)
After some investigations I've found out that the ELF-Section
'.note.GNU-stack'
must not contain anything (size=3D0) but is meant as a notification to
activate
some special memory protection mechanisms against stack overflows or
something (I've found some details here:
http://www.gentoo.org/proj/en/hardened/gnu-stack.xml).
At the moment, the 'savecontext' label is placed into the '.note.GNU-st=
ack'
section (in the readelf output the section has a length of 0x90 bytes) =
and
it seems this section is removed somewhere with its contents thus causi=
ng
the above error.
Could you change the file src/lwp/process.s390x.s such that the marker
for the '.note.GNU-stack' is at the very end of that assembly source? I=
t
should be made sure that the symbol 'savecontext' won't be part of the
'.note.GNU-stack' sections as this is a notifier only and it seems some=
other "intelligent" tools just remove the section.
And it stroke me that the C-Compiler generates the .section statement
with the keyword @progbits instead of %progbits. After moving the .sect=
ion
statement to the bottom of the file and replacing the '%' character wit=
h
'@'
the code compiles through on Novell-SLES11.
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Mit freundlichen Gr=FC=DFen / Kind regards =
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Carsten Jacobi =
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Millicode Developer =
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IBM Systems &Technology Group, Systems Software Development / FW Proce=
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