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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-12-12 13:08:44 +0100
committerWill Deacon <will.deacon@arm.com>2018-12-12 18:45:31 +0000
commit0a1213fa7432778b71a1c0166bf56660a3aab030 (patch)
treeddf7b68d14a504fe97fbdefe00bf8a3296590cc5 /arch/arm64/Makefile
parent4ab215061554ae2a4b78744a5dd3b3c6639f16a7 (diff)
downloadlinux-0a1213fa7432778b71a1c0166bf56660a3aab030.tar.gz
arm64: enable per-task stack canaries
This enables the use of per-task stack canary values if GCC has
support for emitting the stack canary reference relative to the
value of sp_el0, which holds the task struct pointer in the arm64
kernel.

The $(eval) extends KBUILD_CFLAGS at the moment the make rule is
applied, which means asm-offsets.o (which we rely on for the offset
value) is built without the arguments, and everything built afterwards
has the options set.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'arch/arm64/Makefile')
-rw-r--r--arch/arm64/Makefile10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 8978f60779c4..398bdb81a900 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -56,6 +56,16 @@ KBUILD_AFLAGS	+= $(lseinstr) $(brokengasinst)
 KBUILD_CFLAGS	+= $(call cc-option,-mabi=lp64)
 KBUILD_AFLAGS	+= $(call cc-option,-mabi=lp64)
 
+ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y)
+prepare: stack_protector_prepare
+stack_protector_prepare: prepare0
+	$(eval KBUILD_CFLAGS += -mstack-protector-guard=sysreg		  \
+				-mstack-protector-guard-reg=sp_el0	  \
+				-mstack-protector-guard-offset=$(shell	  \
+			awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}' \
+					include/generated/asm-offsets.h))
+endif
+
 ifeq ($(CONFIG_CPU_BIG_ENDIAN), y)
 KBUILD_CPPFLAGS	+= -mbig-endian
 CHECKFLAGS	+= -D__AARCH64EB__