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authorH.J. Lu <hjl.tools@gmail.com>2017-08-04 12:59:35 -0700
committerH.J. Lu <hjl.tools@gmail.com>2017-08-04 12:59:51 -0700
commit1e8e527dd9718eaebe8417b73befb0c821b7b327 (patch)
tree408997f8dd08bcb0d541baf1ce39ff31d3a490bf
parente13daad7ac81968e9aaa4a87497f898bb15f4ef8 (diff)
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i386: Support static PIE in start.S
Since start.o may be compiled as PIC, we should check PIC instead of
SHARED.  Also avoid dynamic relocation against main in static PIE since
_start is the entry point before the executable is relocated.

	* sysdeps/i386/start.S (_start): Check Check PIC instead of
	SHARED.  Avoid dynamic relocation against main in static PIE.
-rw-r--r--ChangeLog5
-rw-r--r--sysdeps/i386/start.S11
2 files changed, 14 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog
index 8291f6e05b..acfcdcc2ee 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2017-08-04  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* sysdeps/i386/start.S (_start): Check Check PIC instead of
+	SHARED.  Avoid dynamic relocation against main in static PIE.
+
+2017-08-04  H.J. Lu  <hongjiu.lu@intel.com>
+
 	[BZ #21815]
 	* elf/Makefile (CFLAGS-tst-prelink.c): New.
 	(LDFLAGS-tst-prelink): Likewise.
diff --git a/sysdeps/i386/start.S b/sysdeps/i386/start.S
index ccb1e2b38f..375a93c15a 100644
--- a/sysdeps/i386/start.S
+++ b/sysdeps/i386/start.S
@@ -81,7 +81,7 @@ _start:
 	pushl %edx		/* Push address of the shared library
 				   termination function.  */
 
-#ifdef SHARED
+#ifdef PIC
 	/* Load PIC register.  */
 	call 1f
 	addl $_GLOBAL_OFFSET_TABLE_, %ebx
@@ -95,7 +95,14 @@ _start:
 	pushl %ecx		/* Push second argument: argv.  */
 	pushl %esi		/* Push first argument: argc.  */
 
+# ifdef SHARED
 	pushl main@GOT(%ebx)
+# else
+	/* Avoid relocation in static PIE since _start is called before
+	   it is relocated.  */
+	leal main@GOTOFF(%ebx), %eax
+	pushl %eax
+# endif
 
 	/* Call the user's main function, and exit with its value.
 	   But let the libc call main.    */
@@ -117,7 +124,7 @@ _start:
 
 	hlt			/* Crash if somehow `exit' does return.  */
 
-#ifdef SHARED
+#ifdef PIC
 1:	movl	(%esp), %ebx
 	ret
 #endif