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authorAlan Modra <amodra@gmail.com>2013-08-17 18:36:45 +0930
committerAlan Modra <amodra@gmail.com>2013-10-04 10:38:59 +0930
commit0b2c2ace3601d5d59cf89130b16840e7f132f7a6 (patch)
tree0a96e682a1ff8f61773d41e00ba55485ee7d4c86 /sysdeps/unix/sysv/linux/powerpc/powerpc64
parent02f04a6c7fea2b474b026bbce721d8c658d71fda (diff)
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PowerPC makecontext
http://sourceware.org/ml/libc-alpha/2013-08/msg00092.html

Use conditional form of branch and link to avoid destroying the cpu
link stack used to predict blr return addresses.

	* sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S: Use
	conditional form of branch and link when obtaining pc.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S: Likewise.
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/powerpc64')
-rw-r--r--sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S6
1 files changed, 4 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
index 4a16669383..32fc47c3f3 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
@@ -124,8 +124,10 @@ L(noparms):
 
   /* If the target function returns we need to do some cleanup.  We use a
      code trick to get the address of our cleanup function into the link
-     register.  Do not add any code between here and L(exitcode).  */
-  bl  L(gotexitcodeaddr);
+     register.  Do not add any code between here and L(exitcode).
+     Use this conditional form of branch and link to avoid destroying
+     the cpu link stack used to predict blr return addresses.  */
+  bcl	20,31,L(gotexitcodeaddr);
 
 	/* This is the helper code which gets called if a function which
 	   is registered with 'makecontext' returns.  In this case we