From dfbdcda280eb762bae2184145cc0702932d41798 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 18 Sep 2021 10:44:34 +0200 Subject: gcc-plugins: arm-ssp: Prepare for THREAD_INFO_IN_TASK support We will be enabling THREAD_INFO_IN_TASK support for ARM, which means that we can no longer load the stack canary value by masking the stack pointer and taking the copy that lives in thread_info. Instead, we will be able to load it from the task_struct directly, by using the TPIDRURO register which will hold the current task pointer when THREAD_INFO_IN_TASK is in effect. This is much more straight-forward, and allows us to declutter this code a bit while at it. Note that this means that ARMv6 (non-v6K) SMP systems can no longer use this feature, but those are quite rare to begin with, so this is a reasonable trade off. Reviewed-by: Kees Cook Signed-off-by: Ard Biesheuvel Reviewed-by: Linus Walleij Tested-by: Amit Daniel Kachhap --- arch/arm/kernel/asm-offsets.c | 4 ---- arch/arm/kernel/process.c | 4 ---- 2 files changed, 8 deletions(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index a646a3f6440f..9c864ee76107 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -63,10 +63,6 @@ int main(void) #ifdef CONFIG_IWMMXT DEFINE(TI_IWMMXT_STATE, offsetof(struct thread_info, fpstate.iwmmxt)); #endif -#ifdef CONFIG_STACKPROTECTOR_PER_TASK - DEFINE(TI_STACK_CANARY, offsetof(struct thread_info, stack_canary)); -#endif - DEFINE(THREAD_SZ_ORDER, THREAD_SIZE_ORDER); BLANK(); DEFINE(S_R0, offsetof(struct pt_regs, ARM_r0)); DEFINE(S_R1, offsetof(struct pt_regs, ARM_r1)); diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 0e2d3051741e..cd73c216b272 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -269,10 +269,6 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start, thread_notify(THREAD_NOTIFY_COPY, thread); -#ifdef CONFIG_STACKPROTECTOR_PER_TASK - thread->stack_canary = p->stack_canary; -#endif - return 0; } -- cgit v1.2.3