Messages in this thread |  | | From | Michael Ellerman <> | Subject | Re: [PATCH v4 0/9] powerpc: Switch to CONFIG_THREAD_INFO_IN_TASK | Date | Sat, 06 Oct 2018 22:21:30 +1000 |
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Christophe Leroy <christophe.leroy@c-s.fr> writes:
> The purpose of this serie is to activate 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.
We need to fixup bpf_jit32.h:
#ifdef CONFIG_SMP #ifdef CONFIG_PPC64 #define PPC_BPF_LOAD_CPU(r) \ do { BUILD_BUG_ON(FIELD_SIZEOF(struct paca_struct, paca_index) != 2); \ PPC_LHZ_OFFS(r, 13, offsetof(struct paca_struct, paca_index)); \ } 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)); \ } while(0) #endif #else #define PPC_BPF_LOAD_CPU(r) do { PPC_LI(r, 0); } while(0) #endif
cheers
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