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arch: remove ARCH_TASK_STRUCT_ON_STACK 

IA-64 was the only architecture which selected ARCH_TASK_STRUCT_ON_STACK.
IA-64 was removed with commit cf8e865810 ("arch: Remove Itanium (IA-64)
architecture"). Therefore remove support for ARCH_TASK_STRUCT_ON_STACK
as well.

Note: this also reveals a potential bug in powerpc code, which makes use of
__init_task_data without selecting ARCH_TASK_STRUCT_ON_STACK which makes
__init_task_data a no-op. This is broken since commit d11ed3ab31 ("Expand
INIT_TASK() in init/init_task.c and remove") from 2018 and needs to be
addressed separately.

Link: https://lkml.kernel.org/r/20231116133638.1636277-4-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Heiko Carstens 2023-11-16 14:36:38 +01:00 committed by Andrew Morton
parent 3888750e21
commit 0eb5085c38
5 changed files with 3 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/Kconfig
View File

@ -301,10 +301,6 @@ config ARCH_HAS_DMA_CLEAR_UNCACHED
config ARCH_HAS_CPU_FINALIZE_INIT
bool
# Select if arch init_task must go in the __init_task_data section
config ARCH_TASK_STRUCT_ON_STACK
bool
config HAVE_ARCH_THREAD_STRUCT_WHITELIST
bool
help

3
arch/powerpc/kexec/core_64.c
View File

@ -283,8 +283,7 @@ static void kexec_prepare_cpus(void)
* We could use a smaller stack if we don't care about anything using
* current, but that audit has not been performed.
*/
static union thread_union kexec_stack __init_task_data =
{ };
static union thread_union kexec_stack = { };
/*
* For similar reasons to the stack above, the kexecing CPU needs to be on a

7
include/linux/init_task.h
View File

@ -37,13 +37,6 @@ extern struct cred init_cred;
#define INIT_TASK_COMM "swapper"
/* Attach to the init_task data structure for proper alignment */
#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
#define __init_task_data __section(".data..init_task")
#else
#define __init_task_data /**/
#endif
/* Attach to the thread_info data structure for proper alignment */
#define __init_thread_info __section(".data..init_thread_info")

2
include/linux/sched.h
View File

@ -1955,9 +1955,7 @@ extern void ia64_set_curr_task(int cpu, struct task_struct *p);
void yield(void);
union thread_union {
#ifndef CONFIG_ARCH_TASK_STRUCT_ON_STACK
struct task_struct task;
#endif
#ifndef CONFIG_THREAD_INFO_IN_TASK
struct thread_info thread_info;
#endif

10
init/init_task.c
View File

@ -51,8 +51,7 @@ static struct sighand_struct init_sighand = {
};
#ifdef CONFIG_SHADOW_CALL_STACK
unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
__init_task_data = {
unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)] = {
[(SCS_SIZE / sizeof(long)) - 1] = SCS_END_MAGIC
};
#endif
@ -61,12 +60,7 @@ unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
* Set up the first task table, touch at your own risk!. Base=0,
* limit=0x1fffff (=2MB)
*/
struct task_struct init_task
#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
__init_task_data
#endif
__aligned(L1_CACHE_BYTES)
= {
struct task_struct init_task __aligned(L1_CACHE_BYTES) = {
#ifdef CONFIG_THREAD_INFO_IN_TASK
.thread_info = INIT_THREAD_INFO(init_task),
.stack_refcount = REFCOUNT_INIT(1),