Commit 0eb5085c authored by Heiko Carstens's avatar Heiko Carstens Committed by Andrew Morton
Browse files

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 cf8e8658 ("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 d11ed3ab ("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: default avatarHeiko Carstens <hca@linux.ibm.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3888750e

arch/Kconfig

+0 −4
Original line number Diff line number Diff line
@@ -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

arch/powerpc/kexec/core_64.c

+1 −2
Original line number Diff line number Diff line
@@ -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

include/linux/init_task.h

+0 −7
Original line number Diff line number Diff line
@@ -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")

include/linux/sched.h

+0 −2
Original line number Diff line number Diff line
@@ -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

init/init_task.c

+2 −8
Original line number Diff line number Diff line
@@ -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),