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PowerPC makecontext


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.

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S
index 95902b1..54f44c8 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/makecontext.S
@@ -47,7 +47,7 @@ ENTRY(__makecontext)
 #ifdef PIC
 	mflr	r0
 	cfi_register(lr,r0)
-	bl	1f
+	bcl	20,31,1f
 1:	mflr	r6
 	addi	r6,r6,L(exitcode)-1b
 	mtlr	r0
@@ -136,7 +136,7 @@ ENTRY(__novec_makecontext)
 #ifdef PIC
 	mflr	r0
 	cfi_register(lr,r0)
-	bl	1f
+	bcl	20,31,1f
 1:	mflr	r6
 	addi	r6,r6,L(novec_exitcode)-1b
 	mtlr	r0
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
index 4a16669..4b5550b 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/makecontext.S
@@ -125,7 +125,7 @@ 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);
+  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

-- 
Alan Modra
Australia Development Lab, IBM


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