From ed1cd6deb013a11959d17a94e35ce159197632da Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 31 Jan 2019 10:08:58 +0000 Subject: powerpc: Activate CONFIG_THREAD_INFO_IN_TASK This patch activates CONFIG_THREAD_INFO_IN_TASK which moves the thread_info into task_struct. Moving thread_info into task_struct has the following advantages: - It protects thread_info from corruption in the case of stack overflows. - Its address is harder to determine if stack addresses are leaked, making a number of attacks more difficult. This has the following consequences: - thread_info is now located at the beginning of task_struct. - The 'cpu' field is now in task_struct, and only exists when CONFIG_SMP is active. - thread_info doesn't have anymore the 'task' field. This patch: - Removes all recopy of thread_info struct when the stack changes. - Changes the CURRENT_THREAD_INFO() macro to point to current. - Selects CONFIG_THREAD_INFO_IN_TASK. - Modifies raw_smp_processor_id() to get ->cpu from current without including linux/sched.h to avoid circular inclusion and without including asm/asm-offsets.h to avoid symbol names duplication between ASM constants and C constants. - Modifies klp_init_thread_info() to take a task_struct pointer argument. Signed-off-by: Christophe Leroy Reviewed-by: Nicholas Piggin [mpe: Add task_stack.h to livepatch.h to fix build fails] Signed-off-by: Michael Ellerman --- arch/powerpc/Makefile | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/powerpc/Makefile') diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index ac033341ed55..53ffe935f3b0 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -427,6 +427,13 @@ else endif endif +ifdef CONFIG_SMP +prepare: task_cpu_prepare + +task_cpu_prepare: prepare0 + $(eval KBUILD_CFLAGS += -D_TASK_CPU=$(shell awk '{if ($$2 == "TI_CPU") print $$3;}' include/generated/asm-offsets.h)) +endif + # Check toolchain versions: # - gcc-4.6 is the minimum kernel-wide version so nothing required. checkbin: -- cgit v1.2.3