From a9cd9c19c84c942622625865036f8171d4cc40c1 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Thu, 21 Oct 2021 16:16:47 +0200 Subject: [PATCH] ARM: stackprotector: prefer compiler for TLS based per-task protector Currently, we implement the per-task stack protector for ARM using a GCC plugin, due to lack of native compiler support. However, work is underway to get this implemented in the compiler, which means we will be able to deprecate the GCC plugin at some point. In the meantime, we will need to support both, where the native compiler implementation is obviously preferred. So let's wire this up in Kconfig and the Makefile. Signed-off-by: Ard Biesheuvel Tested-by: Marc Zyngier Tested-by: Vladimir Murzin # ARMv7M --- arch/arm/Kconfig | 8 ++++++-- arch/arm/Makefile | 9 +++++++++ 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index f0f9e8bec83ac..4e301e4d2da6b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1607,10 +1607,14 @@ config XEN help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. +config CC_HAVE_STACKPROTECTOR_TLS + def_bool $(cc-option,-mtp=cp15 -mstack-protector-guard=tls -mstack-protector-guard-offset=0) + config STACKPROTECTOR_PER_TASK bool "Use a unique stack canary value for each task" - depends on GCC_PLUGINS && STACKPROTECTOR && THREAD_INFO_IN_TASK && !XIP_DEFLATED_DATA - select GCC_PLUGIN_ARM_SSP_PER_TASK + depends on STACKPROTECTOR && THREAD_INFO_IN_TASK && !XIP_DEFLATED_DATA + depends on GCC_PLUGINS || CC_HAVE_STACKPROTECTOR_TLS + select GCC_PLUGIN_ARM_SSP_PER_TASK if !CC_HAVE_STACKPROTECTOR_TLS default y help Due to the fact that GCC uses an ordinary symbol reference from diff --git a/arch/arm/Makefile b/arch/arm/Makefile index 77172d555c7e7..e943624cbf871 100644 --- a/arch/arm/Makefile +++ b/arch/arm/Makefile @@ -275,6 +275,14 @@ endif ifeq ($(CONFIG_STACKPROTECTOR_PER_TASK),y) prepare: stack_protector_prepare +ifeq ($(CONFIG_CC_HAVE_STACKPROTECTOR_TLS),y) +stack_protector_prepare: prepare0 + $(eval KBUILD_CFLAGS += \ + -mstack-protector-guard=tls \ + -mstack-protector-guard-offset=$(shell \ + awk '{if ($$2 == "TSK_STACK_CANARY") print $$3;}'\ + include/generated/asm-offsets.h)) +else stack_protector_prepare: prepare0 $(eval SSP_PLUGIN_CFLAGS := \ -fplugin-arg-arm_ssp_per_task_plugin-offset=$(shell \ @@ -283,6 +291,7 @@ stack_protector_prepare: prepare0 $(eval KBUILD_CFLAGS += $(SSP_PLUGIN_CFLAGS)) $(eval GCC_PLUGINS_CFLAGS += $(SSP_PLUGIN_CFLAGS)) endif +endif all: $(notdir $(KBUILD_IMAGE)) -- 2.39.5