From: Joerg Roedel <jroedel@xxxxxxx> Now that we store the task-stack in tss.sp1 we can also use it as cpu_current_top_of_stack. This unifies the handling with x86-64. Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> --- arch/x86/include/asm/processor.h | 4 ---- arch/x86/include/asm/thread_info.h | 2 -- arch/x86/kernel/cpu/common.c | 4 ---- arch/x86/kernel/process_32.c | 6 ------ 4 files changed, 16 deletions(-) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 513f960..b7c238e 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -374,12 +374,8 @@ DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw); #define __KERNEL_TSS_LIMIT \ (IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1) -#ifdef CONFIG_X86_32 -DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack); -#else /* The RO copy can't be accessed with this_cpu_xyz(), so use the RW copy. */ #define cpu_current_top_of_stack cpu_tss_rw.x86_tss.sp1 -#endif /* * Save the original ist values for checking stack pointers during debugging diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index eda3b68..ea7e118 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -207,9 +207,7 @@ static inline int arch_within_stack_frames(const void * const stack, #else /* !__ASSEMBLY__ */ -#ifdef CONFIG_X86_64 # define cpu_current_top_of_stack (cpu_tss_rw + TSS_sp1) -#endif #endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a0ed348..de1c595 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1503,10 +1503,6 @@ EXPORT_PER_CPU_SYMBOL(__preempt_count); * the top of the kernel stack. Use an extra percpu variable to track the * top of the kernel stack directly. */ -DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = - (unsigned long)&init_thread_union + THREAD_SIZE; -EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); - #ifdef CONFIG_CC_STACKPROTECTOR DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 3f3a8c6..8c29fd5 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -290,12 +290,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) update_sp0(next_p); refresh_sysenter_cs(next); this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p)); - /* - * TODO: Find a way to let cpu_current_top_of_stack point to - * cpu_tss_rw.x86_tss.sp1. Doing so now results in stack corruption with - * iret exceptions. - */ - this_cpu_write(cpu_tss_rw.x86_tss.sp1, next_p->thread.sp0); /* * Restore %gs if needed (which is common) -- 2.7.4
