[PATCH/RFC] powerpc: avoid generating .eh_frame sections with gcc-4.4

Sam Ravnborg sam at ravnborg.org
Wed Feb 25 16:47:07 EST 2009


On Tue, Feb 24, 2009 at 01:51:12AM -0500, Kyle McMartin wrote:
> From: Kyle McMartin <kyle at redhat.com>
> 
> On ppc64 (at least) gcc-4.4 is defaulting to generating .eh_frame
> sections, which are, for the kernel, fairly pointless. Additionally, on
> ppc64 this generates a relocation format which the kernel module loader
> does not currently support (R_PPC64_REL32.)
> 
> Alexandre Oliva verifies that -fno-dwarf2-cfi-asm prevents this
> .eh_frame section from being generated.
> 
> These seem to be used for unwinding, but it doesn't look like we
> currently use them anywhere. (In fact, we explicitly dump them in the
> x86_64 linker script.)
> 
> If these .eh_frame sections are eventually used, adding a per-arch
> CONFIG_WANT_UNWIND check would be trivial.
> 
> (This was reported against Fedora, which appears to be the only distro
> doing any building against gcc-4.4 at present: RH bz#486545.)
> 
> Signed-off-by: Kyle McMartin <kyle at redhat.com>
> Cc: roland at redhat.com
> Cc: aoliva at redhat.com

Kyle - can you resend wit an updated changelog reflecting the comments
from Roland and Alexandre.

I got it wrong when reading the above - so chances are others does too.

Thanks,
	Sam



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