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/net/bpf_jit32.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/net') diff --git a/arch/powerpc/net/bpf_jit32.h b/arch/powerpc/net/bpf_jit32.h index 6f4daacad296..dc50a8d4b3b9 100644 --- a/arch/powerpc/net/bpf_jit32.h +++ b/arch/powerpc/net/bpf_jit32.h @@ -106,9 +106,8 @@ DECLARE_LOAD_FUNC(sk_load_byte_msh); } while (0) #else #define PPC_BPF_LOAD_CPU(r) \ - do { BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4); \ - PPC_LHZ_OFFS(r, (1 & ~(THREAD_SIZE - 1)), \ - offsetof(struct thread_info, cpu)); \ + do { BUILD_BUG_ON(FIELD_SIZEOF(struct task_struct, cpu) != 4); \ + PPC_LHZ_OFFS(r, 2, offsetof(struct task_struct, cpu)); \ } while(0) #endif #else -- cgit v1.2.3