powerpc/32: Fix boot failure with CONFIG_STACKPROTECTOR

Commit 7c95d8893fb5 ("powerpc: Change calling convention for
create_branch() et. al.") complexified the frame of function
do_feature_fixups(), leading to GCC setting up a stack
guard when CONFIG_STACKPROTECTOR is selected.

The problem is that do_feature_fixups() is called very early
while 'current' in r2 is not set up yet and the code is still
not at the final address used at link time.

So, like other instrumentation, stack protection needs to be
deactivated for feature-fixups.c and code-patching.c

Fixes: 7c95d8893fb5 ("powerpc: Change calling convention for create_branch() et. al.")
Cc: stable@vger.kernel.org # v5.8+
Reported-by: Jonathan Neuschaefer <j.neuschaefer@gmx.net>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Jonathan Neuschaefer <j.neuschaefer@gmx.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b688fe82927b330349d9e44553363fa451ea4d95.1619715114.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index f2c690ee75d1a483fe3678172fae10970b27160d..cc1a8a0f311e7a9b2e082f5e733334b8ca34315b 100644 (file)
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -5,6 +5,9 @@
 
 ccflags-$(CONFIG_PPC64)        := $(NO_MINIMAL_TOC)
 
+CFLAGS_code-patching.o += -fno-stack-protector
+CFLAGS_feature-fixups.o += -fno-stack-protector
+
 CFLAGS_REMOVE_code-patching.o = $(CC_FLAGS_FTRACE)
 CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)