[RFC PATCH v3 13/13] objtool: arm64: Enable stack validation for arm64

[Chen Zhongjin]

From: Raphael Gault <raphael.gault@xxxxxxx>

Add build option to run stack validation at compile time.

When requiring stack validation, jump tables are disabled as it
simplifies objtool analysis (without having to introduce unreliable
artifacs). In local testing, this does not appear to significaly
affect final binary size nor system performance.

Signed-off-by: Raphael Gault <raphael.gault@xxxxxxx>
Signed-off-by: Julien Thierry <jthierry@xxxxxxxxxx>
---
 arch/arm64/Kconfig  | 1 +
 arch/arm64/Makefile | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 23048be0333b..119cfce4117f 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -201,6 +201,7 @@ config ARM64
 	select MMU_GATHER_RCU_TABLE_FREE
 	select HAVE_RSEQ
 	select HAVE_STACKPROTECTOR
+	select HAVE_STACK_VALIDATION
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 2f1de88651e6..ad2f4a5e8f6c 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -133,6 +133,10 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
   CC_FLAGS_FTRACE := -fpatchable-function-entry=2
 endif
 
+ifeq ($(CONFIG_STACK_VALIDATION),y)
+KBUILD_CFLAGS	+= -fno-jump-tables
+endif
+
 # Default value
 head-y		:= arch/arm64/kernel/head.o
 
-- 
2.17.1