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) <[email protected]>
---
Change since v1:
* Revert an accident insane change, init_task to init_stack (Jürgen Groß).
---
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 | 6 +++---
4 files changed, 7 insertions(+), 7 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 514d3002ad8a..cdfdcca23045 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_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: 7e19a79344df2ed5e106091c29338962261b0290
--
2.44.0
On 18.03.24 08:14, 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) <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Juergen
* Xin Li (Intel) <[email protected]> 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) <[email protected]>
> ---
>
> Change since v1:
> * Revert an accident insane change, init_task to init_stack (J?rgen Gro?).
> ---
> 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 | 6 +++---
> 4 files changed, 7 insertions(+), 7 deletions(-)
Note that this is now in conflict with this cleanup by Brian Gerst:
2cb16181a1d1 x86/boot: Simplify boot stack setup
.. which removed __end_init_task[] entirely.
Thanks,
Ingo
On 3/21/2024 12:54 PM, Ingo Molnar wrote:
>
> * Xin Li (Intel) <[email protected]> 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) <[email protected]>
>> ---
>>
>> Change since v1:
>> * Revert an accident insane change, init_task to init_stack (Jürgen Groß).
>> ---
>> 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 | 6 +++---
>> 4 files changed, 7 insertions(+), 7 deletions(-)
>
> Note that this is now in conflict with this cleanup by Brian Gerst:
>
> 2cb16181a1d1 x86/boot: Simplify boot stack setup
I like this patch, which does something that I'm also doing, further
x86_64 doesn't have the concept of TOP_OF_KERNEL_STACK_PADDING, and
I guess it was extended from x86_32 but defined to 0 just for code
consistency.
Yes, FRED code uses TOP_OF_KERNEL_STACK_PADDING, but a FRED event frame
could contain different amount of information for different event types,
e.g., #MCE could push extra bytes of information, or perhaps even for
different instances of the same event type. Thus the size of an event
frame pushed by a FRED CPU is not fixed and the address of the pt_regs
structure that is used to save the user level context of current task is
not at a fixed offset from the top of current task kernel stack.
>
> .. which removed __end_init_task[] entirely.
Not really, but __end_init_task[] is only used to initialize
__top_init_kernel_stack.
I will rebase and send v3.
Thanks!
Xin