From: Ard Biesheuvel <ardb@kernel.org> mainline inclusion from mainline-v5.16-rc1 commit 336868afbaae2d153fc20268a21747c31e5071b8 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4Q94A CVE: NA ------------------------------ Instead of relying on awful hacks to obtain the offset of the cpu field in struct task_struct, move it back into struct thread_info, which does not create the same level of circular dependency hell when trying to include the header file that defines it. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Guan Jing <guanjing6@huawei.com> Conflicts: arch/powerpc/Makefile Reviewed-by: Chen Hui <judy.chenhui@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/powerpc/Makefile | 8 -------- arch/powerpc/include/asm/smp.h | 17 +---------------- arch/powerpc/kernel/asm-offsets.c | 2 -- 3 files changed, 1 insertion(+), 26 deletions(-) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 5c8c06215dd4..35bf7634e095 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -434,14 +434,6 @@ else endif endif -ifdef CONFIG_SMP -prepare: task_cpu_prepare - -PHONY += task_cpu_prepare -task_cpu_prepare: prepare0 - $(eval KBUILD_CFLAGS += -D_TASK_CPU=$(shell awk '{if ($$2 == "TASK_CPU") print $$3;}' include/generated/asm-offsets.h)) -endif - PHONY += checkbin # Check toolchain versions: # - gcc-4.6 is the minimum kernel-wide version so nothing required. diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index 635bdf947105..25825d597709 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -82,22 +82,7 @@ int is_cpu_dead(unsigned int cpu); /* 32-bit */ extern int smp_hw_index[]; -/* - * This is particularly ugly: it appears we can't actually get the definition - * of task_struct here, but we need access to the CPU this task is running on. - * Instead of using task_struct we're using _TASK_CPU which is extracted from - * asm-offsets.h by kbuild to get the current processor ID. - * - * This also needs to be safeguarded when building asm-offsets.s because at - * that time _TASK_CPU is not defined yet. It could have been guarded by - * _TASK_CPU itself, but we want the build to fail if _TASK_CPU is missing - * when building something else than asm-offsets.s - */ -#ifdef GENERATING_ASM_OFFSETS -#define raw_smp_processor_id() (0) -#else -#define raw_smp_processor_id() (*(unsigned int *)((void *)current + _TASK_CPU)) -#endif +#define raw_smp_processor_id() (current_thread_info()->cpu) #define hard_smp_processor_id() (smp_hw_index[smp_processor_id()]) static inline int get_hard_smp_processor_id(int cpu) diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index 5c125255571c..c5fe4be1c68a 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -9,8 +9,6 @@ * #defines from the assembly-language output. */ -#define GENERATING_ASM_OFFSETS /* asm/smp.h */ - #include <linux/compat.h> #include <linux/signal.h> #include <linux/sched.h> -- 2.20.1