Now that ld(1) will generate a read-only GOT for truly static binaries, we

no longer have to use mprotect(2) to take away PROT_WRITE.  This fixes ld -Z
and paves the way for the new Secure-PLT ABI.

ok miod@

1 files changed, 4 insertions, 72 deletions

diff --git a/lib/csu/powerpc/md_init.h b/lib/csu/powerpc/md_init.h
index 1a6cadec427..4a707215540 100644
--- a/lib/csu/powerpc/md_init.h
+++ b/lib/csu/powerpc/md_init.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: md_init.h,v 1.4 2015/09/01 05:40:06 guenther Exp $ */
+/* $OpenBSD: md_init.h,v 1.5 2015/09/09 09:41:42 kettenis Exp $ */
 
 /*-
  * Copyright (c) 2001 Ross Harvey
@@ -64,88 +64,20 @@
 #include <sys/syscall.h>	/* for SYS_mprotect */
 
 #define STR(x) __STRING(x)
+
 #define	MD_CRT0_START							\
 __asm(									\
 "	.text								\n" \
 "	.section	\".text\"					\n" \
 "	.align 2							\n" \
-"	.size	__got_start, 0						\n" \
-" 	.type	__got_start, @object					\n" \
-"	.size	__got_end, 0						\n" \
-" 	.type	__got_end, @object					\n" \
-"	.weak	__got_start						\n" \
-"	.weak	__got_end						\n" \
 "	.globl	_start							\n" \
 "	.type	_start, @function					\n" \
 "	.globl	__start							\n" \
 "	.type	__start, @function					\n" \
 "_start:								\n" \
 "__start:								\n" \
-"	# move argument registers to saved registers for startup flush	\n" \
-"	# ...except r6 (auxv) as ___start() doesn't need it		\n" \
-"	mr %r25, %r3							\n" \
-"	mr %r24, %r4							\n" \
-"	mr %r23, %r5							\n" \
-"	mr %r22, %r7							\n" \
-"	mflr	%r27	/* save off old link register */		\n" \
-"	bl	1f							\n" \
-"	# this instruction never gets executed but can be used		\n" \
-"	# to find the virtual address where the page is loaded.		\n" \
-"	bl _GLOBAL_OFFSET_TABLE_@local-4				\n" \
-"1:									\n" \
-"	mflr	%r6		# this stores where we are (+4)		\n" \
-"	lwz	%r18, 0(%r6)	# load the instruction at offset_sym	\n" \
-"				# it contains an offset to the location	\n" \
-"				# of the GOT.				\n" \
-"									\n" \
-"	rlwinm %r18,%r18,0,8,30 # mask off the offset portion of the instr. \n" \
-"									\n" \
-"	/*								\n" \
-"	 * these adds effectively calculate the value the		\n" \
-"	 * bl _GLOBAL_OFFSET_TABLE_@local-4				\n" \
-"	 * operation that would be below would calculate.		\n" \
-"	 */								\n" \
-"	add	%r28, %r18, %r6						\n" \
-"									\n" \
-"	addi	%r3,%r28,4		# calculate the actual got addr \n" \
-"	lwz	%r0,__got_start@got(%r3)				\n" \
-"	cmpwi	%r0,0							\n" \
-"	beq	4f							\n" \
-"	cmpw	%r0,%r28						\n" \
-"	bne	4f							\n" \
-"	lwz	%r4,__got_end@got(%r3)					\n" \
-"	cmpwi	%r4,0							\n" \
-"	beq	2f							\n" \
-"									\n" \
-"	sub	%r4, %r4, %r0						\n" \
-"	b 3f								\n" \
-"2:									\n" \
-"	li	%r4, 4							\n" \
-"3:									\n" \
-"									\n" \
-"	/* mprotect GOT to eliminate W+X regions in static binaries */	\n" \
-"	li	%r0, " STR(SYS_mprotect) "				\n" \
-"	mr	%r3, %r28						\n" \
-"	li	%r5, 5	/* (PROT_READ|PROT_EXEC) */			\n" \
-"	sc								\n" \
-"									\n" \
-"4:									\n" \
-"	li	%r0, 0							\n" \
-"	# flush the blrl instruction out of the data cache		\n" \
-"	dcbf	%r6, %r18						\n" \
-"	sync								\n" \
-"	isync								\n" \
-"	# make certain that the got table addr is not in the icache	\n" \
-"	icbi	%r6, %r18						\n" \
-"	sync								\n" \
-"	isync								\n" \
-"	mtlr %r27							\n" \
-"	# move argument registers back from saved registers		\n" \
-"	# putting cleanup in r6 instead of r7				\n" \
-"	mr %r3, %r25							\n" \
-"	mr %r4, %r24							\n" \
-"	mr %r5, %r23							\n" \
-"	mr %r6, %r22							\n" \
+"	# put cleanup in r6 instead of r7				\n" \
+"	mr %r6, %r7							\n" \
 "	b ___start							\n" \
 )