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/kernel/setup-common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/setup-common.c') diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index 9a6a0859c1ef..e7534f306c8e 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -937,7 +937,7 @@ void __init setup_arch(char **cmdline_p) /* Reserve large chunks of memory for use by CMA for KVM. */ kvm_cma_reserve(); - klp_init_thread_info(&init_thread_info); + klp_init_thread_info(&init_task); init_mm.start_code = (unsigned long)_stext; init_mm.end_code = (unsigned long) _etext; -- cgit v1.2.3