Second attempt at eliminating .text relocations in shared libraries

compiled with stack protector.

Use libssp_nonshared library to pull __stack_chk_fail_local symbol into
each library that needs it instead of pulling it from libc. GCC
generates local calls to this function which result in absolute
relocations put into position-independent code segment, making dynamic
loader do extra work every time given shared library is being relocated
and making affected text pages non-shareable.

Reviewed by:        kib
Approved by:        re (kib)

2 files changed, 7 insertions, 1 deletions

diff --git a/gnu/lib/libgcc/Makefile b/gnu/lib/libgcc/Makefile
index 49b96e6e3a03..399aff85bb0b 100644
--- a/gnu/lib/libgcc/Makefile
+++ b/gnu/lib/libgcc/Makefile
@@ -7,6 +7,12 @@ SHLIB_NAME=	libgcc_s.so.1
 SHLIBDIR?=	/lib
 
 .include <bsd.own.mk>
+#
+# libgcc is linked in last and thus cannot depend on ssp symbols coming
+# from earlier libraries. Disable stack protection for this library.
+#
+MK_SSP=	no
+
 .include "${.CURDIR}/../../usr.bin/cc/Makefile.tgt"
 
 .PATH: ${GCCDIR}/config/${GCC_CPU} ${GCCDIR}/config ${GCCDIR}
diff --git a/gnu/lib/libssp/libssp_nonshared/Makefile b/gnu/lib/libssp/libssp_nonshared/Makefile
index 1dcd54f6d557..94544951fdfd 100644
--- a/gnu/lib/libssp/libssp_nonshared/Makefile
+++ b/gnu/lib/libssp/libssp_nonshared/Makefile
@@ -13,6 +13,6 @@ SRCS=	ssp-local.c
 
 CFLAGS+= -DHAVE_CONFIG_H
 CFLAGS+= -I${.CURDIR}/..  -I${GCCLIB}/libssp  -I${GCCLIB}/include
-CFLAGS+= -fPIC -DPIC
+CFLAGS+= -fPIC -DPIC -fvisibility=hidden
 
 .include <bsd.lib.mk>