[04/12] Compile the entire dynamic linker with -fno-stack-protector.
Commit Message
From: Nick Alcock <nick.alcock@oracle.com>
Also compile corresponding routines in the static libc.a with the same
flag.
v3: Use $(no-stack-protector).
Introduce $(elide-stack-protector) and use it to reduce redundancy.
Bring all the elisions together textually.
v9: Adapt to no-sse adjustments in sysdeps/i386/Makefile.
* elf/Makefile (elide-stack-protector): New.
(CFLAGS-.os): Use it, eliding $(all-rtld-routines).
(CFLAGS-.oX): Likewise, eliding $(elide-routines.os).
(rtld-CFLAGS): Likewise.
sysdeps/i386/Makefile (rtld-CFLAGS): Use +=, not =.
---
elf/Makefile | 13 +++++++++++++
elf/rtld-Rules | 2 ++
sysdeps/i386/Makefile | 2 +-
3 files changed, 16 insertions(+), 1 deletion(-)
@@ -50,6 +50,19 @@ CFLAGS-dl-runtime.c = -fexceptions -fasynchronous-unwind-tables
CFLAGS-dl-lookup.c = -fexceptions -fasynchronous-unwind-tables
CFLAGS-dl-iterate-phdr.c = $(uses-callbacks)
+# Compile rtld itself without stack protection.
+# Also compile all routines in the static library that are elided from
+# the shared libc because they are in ld.so the same way.
+
+define elide-stack-protector
+$(if $(filter $(@F),$(patsubst %,%$(1),$(2))), $(no-stack-protector))
+endef
+
+CFLAGS-.o += $(call elide-stack-protector,.o,$(elide-routines.os))
+CFLAGS-.op += $(call elide-stack-protector,.op,$(elide-routines.os))
+CFLAGS-.og += $(call elide-stack-protector,.og,$(elide-routines.os))
+CFLAGS-.os += $(call elide-stack-protector,.os,$(all-rtld-routines))
+
ifeq ($(unwind-find-fde),yes)
routines += unwind-dw2-fde-glibc
shared-only-routines += unwind-dw2-fde-glibc
@@ -144,4 +144,6 @@ cpp-srcs-left := $(rtld-modules:%.os=%)
lib := rtld
include $(patsubst %,$(..)cppflags-iterator.mk,$(cpp-srcs-left))
+rtld-CFLAGS += $(no-stack-protector)
+
endif
@@ -88,7 +88,7 @@ endif
# the first 3 mm/xmm/ymm/zmm registers are used to pass vector parameters
# which must be preserved.
# With SSE disabled, ensure -fpmath is not set to use sse either.
-rtld-CFLAGS = -mno-sse -mno-mmx -mfpmath=387
+rtld-CFLAGS += -mno-sse -mno-mmx -mfpmath=387
ifeq ($(subdir),elf)
CFLAGS-.os += $(if $(filter $(@F),$(patsubst %,%.os,$(all-rtld-routines))),\
$(rtld-CFLAGS))