[PATCH v2] mips: Do not use jal to reach __libc_start_main

[PATCH v2] mips: Do not use jal to reach __libc_start_main

[Petar Jovanovic]

Since __libc_start_main may not be in the same 256MB-aligned region as
the function __start, replace use of jal instruction with la/jalr.

This fixes linker issue reported in:
https://sourceware.org/bugzilla/show_bug.cgi?id=17601
---
 v2:
 - add ChangeLog entry.
 
 ChangeLog            |    6 ++++++
 sysdeps/mips/start.S |    8 ++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 17ec07b..af7121a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,10 @@
 
+2014-11-18  Petar Jovanovic  <petar.jovanovic@rt-rk.com>
+
+	[BZ #17601]
+	* sysdeps/mips/start.S (__start): Use indirect jump to call
+	__libc_start_main.
+
 2014-11-17  Richard Henderson  <rth@redhat.com>
 
 	* sysdeps/alpha/soft-fp/local-soft-fp.h (_FP_UNPACK_RAW_2): Remove.
diff --git a/sysdeps/mips/start.S b/sysdeps/mips/start.S
index a454941..3c012f1 100644
--- a/sysdeps/mips/start.S
+++ b/sysdeps/mips/start.S
@@ -106,7 +106,8 @@ ENTRY_POINT:
 	move $9, $2		/* rtld_fini */
 	move $10, $29		/* stack_end */
 # endif
-	jal __libc_start_main
+	PTR_LA $25, __libc_start_main
+	jalr   $25
 hlt:	b hlt			/* Crash if somehow it does return.  */
 
 #elif _MIPS_SIM == _ABIO32 /* __mips16 */
@@ -157,7 +158,9 @@ ENTRY_POINT:
 	sw	$4, 16($sp)			/* fini */
 	lw	$4, 3f				/* main */
 	sw	$2, 20($sp)			/* rtld_fini */
-	jal	__libc_start_main
+	/* Load and call __libc_start_main().  */
+	lw	$3, 4f
+	jalr	$3
 # endif
 hlt:	b	hlt		/* Crash if somehow it does return.  */
 # ifndef __PIC__
@@ -165,6 +168,7 @@ hlt:	b	hlt		/* Crash if somehow it does return.  */
 1:	.word	__libc_csu_fini
 2:	.word	__libc_csu_init
 3:	.word	main
+4:	.word	__libc_start_main
 # endif
 
 #else /* __mips16 && _MIPS_SIM != _ABIO32 */
-- 
1.7.9.5