Re: [PATCH v1 1/1] x86: Rename __{start,end}_init_task to __{start,end}_init_stack

[Jürgen Groß <jgross@xxxxxxxx>]

On 13.03.24 07:05, Xin Li (Intel) wrote:
> The stack of a task has been separated from the memory of a task_struct
> struture for a long time on x86, as a result __{start,end}_init_task no
> longer mark the start and end of the init_task structure, but its stack
> only.
>
> Rename __{start,end}_init_task to __{start,end}_init_stack.
>
> Note other architectures are not affected because __{start,end}_init_task
> are used on x86 only.
>
> Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx>
> ---
>   arch/x86/include/asm/processor.h  | 4 ++--
>   arch/x86/kernel/head_64.S         | 2 +-
>   arch/x86/xen/xen-head.S           | 2 +-
>   include/asm-generic/vmlinux.lds.h | 8 ++++----
>   4 files changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 811548f131f4..8b3a3f3bb859 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -636,10 +636,10 @@ static __always_inline void prefetchw(const void *x)
>   #define KSTK_ESP(task)                (task_pt_regs(task)->sp)
>   
>   #else
> -extern unsigned long __end_init_task[];
> +extern unsigned long __end_init_stack[];
>   
>   #define INIT_THREAD {							\
> -       .sp     = (unsigned long)&__end_init_task -                 \
> +       .sp     = (unsigned long)&__end_init_stack -                        \
>                   TOP_OF_KERNEL_STACK_PADDING -                         \
>                   sizeof(struct pt_regs),                               \
>   }
> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
> index d8198fbd70e5..c7babd7ebb0f 100644
> --- a/arch/x86/kernel/head_64.S
> +++ b/arch/x86/kernel/head_64.S
> @@ -66,7 +66,7 @@ SYM_CODE_START_NOALIGN(startup_64)
>         mov     %rsi, %r15
>   
>   	/* Set up the stack for verify_cpu() */
> -       leaq    (__end_init_task - TOP_OF_KERNEL_STACK_PADDING - 
> PTREGS_SIZE)(%rip), %rsp
> +       leaq    (__end_init_stack - TOP_OF_KERNEL_STACK_PADDING - 
> PTREGS_SIZE)(%rip), %rsp
>   
>   	/* Setup GSBASE to allow stack canary access for C code */
>         movl    $MSR_GS_BASE, %ecx
> diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
> index 04101b984f24..43eadf03f46d 100644
> --- a/arch/x86/xen/xen-head.S
> +++ b/arch/x86/xen/xen-head.S
> @@ -49,7 +49,7 @@ SYM_CODE_START(startup_xen)
>         ANNOTATE_NOENDBR
>         cld
>   
> -	leaq	(__end_init_task - TOP_OF_KERNEL_STACK_PADDING - PTREGS_SIZE)(%rip), %rsp
> +       leaq    (__end_init_stack - TOP_OF_KERNEL_STACK_PADDING - 
> PTREGS_SIZE)(%rip), %rsp
>   
>   	/* Set up %gs.
>          *
> diff --git a/include/asm-generic/vmlinux.lds.h 
> b/include/asm-generic/vmlinux.lds.h
> index 5dd3a61d673d..a168be99d522 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -399,13 +399,13 @@
>   
>   #define INIT_TASK_DATA(align)						\
>         . = ALIGN(align);                                               \
> -       __start_init_task = .;                                          \
> +       __start_init_stack = .;                                         \
>         init_thread_union = .;                                          \
>         init_stack = .;                                                 \
> -       KEEP(*(.data..init_task))                                       \
> +       KEEP(*(.data..init_stack))                                      \
Is this modification really correct?

>         KEEP(*(.data..init_thread_info))                                \
> -       . = __start_init_task + THREAD_SIZE;                            \
> -       __end_init_task = .;
> +       . = __start_init_stack + THREAD_SIZE;                           \
> +       __end_init_stack = .;
>   
>   #define JUMP_TABLE_DATA							\
>         . = ALIGN(8);                                                   \
>
> base-commit: 626856ae97054963e7b8c35335d4418271c8d0c4

Juergen