From: Ard Biesheuvel ardb@kernel.org
mainline inclusion from mainline-v5.16-rc1 commit bcf9033e5449bdcaa9bed46467a7141a8049dadb category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4Q94A CVE: NA
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THREAD_INFO_IN_TASK moved the CPU field out of thread_info, but this causes some issues on architectures that define raw_smp_processor_id() in terms of this field, due to the fact that #include'ing linux/sched.h to get at struct task_struct is problematic in terms of circular dependencies.
Given that thread_info and task_struct are the same data structure anyway when THREAD_INFO_IN_TASK=y, let's move it back so that having access to the type definition of struct thread_info is sufficient to reference the CPU number of the current task.
Note that this requires THREAD_INFO_IN_TASK's definition of the task_thread_info() helper to be updated, as task_cpu() takes a pointer-to-const, whereas task_thread_info() (which is used to generate lvalues as well), needs a non-const pointer. So make it a macro instead.
Signed-off-by: Ard Biesheuvel ardb@kernel.org Acked-by: Catalin Marinas catalin.marinas@arm.com 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/arm64/kernel/head.S Reviewed-by: Chen Hui judy.chenhui@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/powerpc/kernel/asm-offsets.c | 2 +- arch/powerpc/kernel/smp.c | 2 +- include/linux/sched.h | 13 +------------ kernel/sched/sched.h | 4 ---- 4 files changed, 3 insertions(+), 18 deletions(-)
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index c5fe4be1c68a..760f656efcf6 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -96,7 +96,7 @@ int main(void) #endif /* CONFIG_PPC64 */ OFFSET(TASK_STACK, task_struct, stack); #ifdef CONFIG_SMP - OFFSET(TASK_CPU, task_struct, cpu); + OFFSET(TASK_CPU, task_struct, thread_info.cpu); #endif
#ifdef CONFIG_LIVEPATCH diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index b7bed52a5a73..ab2d3446e628 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1103,7 +1103,7 @@ static void cpu_idle_thread_init(unsigned int cpu, struct task_struct *idle) paca_ptrs[cpu]->kstack = (unsigned long)task_stack_page(idle) + THREAD_SIZE - STACK_FRAME_OVERHEAD; #endif - idle->cpu = cpu; + task_thread_info(idle)->cpu = cpu; secondary_current = current_set[cpu] = idle; }
diff --git a/include/linux/sched.h b/include/linux/sched.h index 3bc2f15df252..5cd59c883522 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -694,10 +694,6 @@ struct task_struct { #ifdef CONFIG_SMP int on_cpu; struct __call_single_node wake_entry; -#ifdef CONFIG_THREAD_INFO_IN_TASK - /* Current CPU: */ - unsigned int cpu; -#endif unsigned int wakee_flips; unsigned long wakee_flip_decay_ts; struct task_struct *last_wakee; @@ -1771,10 +1767,7 @@ extern struct thread_info init_thread_info; extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
#ifdef CONFIG_THREAD_INFO_IN_TASK -static inline struct thread_info *task_thread_info(struct task_struct *task) -{ - return &task->thread_info; -} +# define task_thread_info(task) (&(task)->thread_info) #elif !defined(__HAVE_THREAD_FUNCTIONS) # define task_thread_info(task) ((struct thread_info *)(task)->stack) #endif @@ -1970,11 +1963,7 @@ static __always_inline bool need_resched(void)
static inline unsigned int task_cpu(const struct task_struct *p) { -#ifdef CONFIG_THREAD_INFO_IN_TASK - return READ_ONCE(p->cpu); -#else return READ_ONCE(task_thread_info(p)->cpu); -#endif }
extern void set_task_cpu(struct task_struct *p, unsigned int cpu); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 451440e36318..66be40862d99 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1652,11 +1652,7 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) * per-task data have been completed by this moment. */ smp_wmb(); -#ifdef CONFIG_THREAD_INFO_IN_TASK - WRITE_ONCE(p->cpu, cpu); -#else WRITE_ONCE(task_thread_info(p)->cpu, cpu); -#endif p->wake_cpu = cpu; #endif }