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Re-initialize gp after a jsr.

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When rtld runs the .fini section in a shared lib (C++), the code in
question from .../contrib/gdb/config/alpha/crtbegin.asm first calls
__do_globals_dtors_aux and then __do_frame_takedown.  Unfortunately, the
value of gp after a jsr is undefined and in this case had changed from before
the call, probably as a result of calling code in some other shared library.
The normal calling convention for alpha is to re-initialize gp using
'ldgp gp,0(ra)' after a jsr instruction but in this case no such
re-initialization is done. This leads to a bogus value being read for the
address of __do_frame_takedown and a quick segfault.

Submitted by:   dfr
Obtained from:  GCC 3.0
This commit is contained in:
David E. O'Brien 2001-08-17 22:54:26 +00:00
parent db695db7f0
commit a6d80351b7
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=81867
1 changed files with 4 additions and 0 deletions
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4
contrib/gcc/config/alpha/crtbegin.asm
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@ -68,6 +68,7 @@ __EH_FRAME_BEGIN__:
br $29,1f
1: ldgp $29,0($29)
jsr $26,__do_global_dtors_aux
ldgp $29,0($26)
# Ideally this call would go in crtend.o, except that we can't
# get hold of __EH_FRAME_BEGIN__ there.
@ -190,3 +191,6 @@ __do_frame_takedown:
.weak __register_frame_info
.weak __deregister_frame_info
.section .rodata
.ascii "$FreeBSD$\0"