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Re: PowerPC SecurePLT - stepping into library function
On 01/06/2012 12:56 PM, Mark Kettenis wrote:
Date: Fri, 06 Jan 2012 12:24:38 -0800
From: Michael Eager<eager@eagerm.com>
https://www.power.org/resources/downloads/Power-Arch-32-bit-ABI-supp-1.0-Linux.pdf
Thanks!
I guess you'll have to do some sort of instruction pattern matching.
The ABI document suggests specific code sequences for them, which is
probably what everybody uses to implement them. You might want to
have a look at what is done in mips-linux-tdep.c, since it seems to
have linkage stubs outside of the PLT as well. Actually closer to
home the 64-bit PowerPC stuff seems to do somethings similar.
mips and ppc64 seem to do the similar tests, but in different places.
mips adds instruction pattern matching to the in_solib_dynsym_resolve()
test at infrun.c:4755 so that it succeeds, entering a block of code
which skips the symbol resolver.
ppc64 does instruction pattern matching to skip over trampoline code,
called at infrun.c:4902 but since it calls the same failing
in_solib_dynsym_resolve() a couple lines later, I don't think that it
has any effect.
Looks like doing the same as mips is the best approach.
Thanks for the pointer.
--
Michael Eager eager@eagercon.com
1960 Park Blvd., Palo Alto, CA 94306 650-325-8077