Commit d0a0de21 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86/asm/entry: Remove INIT_TSS and fold the definitions into 'cpu_tss' 



The INIT_TSS is unnecessary.  Just define the initial TSS where
'cpu_tss' is defined.

While we're at it, merge the 32-bit and 64-bit definitions.  The
only syntactic change is that 32-bit kernels were computing sp0
as long, but now they compute it as unsigned long.

Verified by objdump: the contents and relocations of
.data..percpu..shared_aligned are unchanged on 32-bit and 64-bit
kernels.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8fc39fa3f6c5d635e93afbdd1a0fe0678a6d7913.1425611534.git.luto@amacapital.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 24933b82

arch/x86/include/asm/processor.h

+0 −20
Original line number Diff line number Diff line
@@ -818,22 +818,6 @@ static inline void spin_lock_prefetch(const void *x) 
	.io_bitmap_ptr		= NULL,					  \

}



/*

 * Note that the .io_bitmap member must be extra-big. This is because

 * the CPU will access an additional byte beyond the end of the IO

 * permission bitmap. The extra byte must be all 1 bits, and must

 * be within the limit.

 */

#define INIT_TSS  {							  \

	.x86_tss = {							  \

		.sp0		= sizeof(init_stack) + (long)&init_stack, \

		.ss0		= __KERNEL_DS,				  \

		.ss1		= __KERNEL_CS,				  \

		.io_bitmap_base	= INVALID_IO_BITMAP_OFFSET,		  \

	 },								  \

	.io_bitmap		= { [0 ... IO_BITMAP_LONGS] = ~0 },	  \

}



extern unsigned long thread_saved_pc(struct task_struct *tsk);



#define THREAD_SIZE_LONGS      (THREAD_SIZE/sizeof(unsigned long))
@@ -892,10 +876,6 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk); 
	.sp0 = (unsigned long)&init_stack + sizeof(init_stack) \

}



#define INIT_TSS  { \

	.x86_tss.sp0 = (unsigned long)&init_stack + sizeof(init_stack) \

}



/*

 * Return saved PC of a blocked thread.

 * What is this good for? it will be always the scheduler or ret_from_fork.

arch/x86/kernel/process.c

+19 −1
Original line number Diff line number Diff line
@@ -37,7 +37,25 @@ 
 * section. Since TSS's are completely CPU-local, we want them

 * on exact cacheline boundaries, to eliminate cacheline ping-pong.

 */

__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = INIT_TSS;

__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {

	.x86_tss = {

		.sp0 = (unsigned long)&init_stack + sizeof(init_stack),

#ifdef CONFIG_X86_32

		.ss0 = __KERNEL_DS,

		.ss1 = __KERNEL_CS,

		.io_bitmap_base	= INVALID_IO_BITMAP_OFFSET,

#endif

	 },

#ifdef CONFIG_X86_32

	 /*

	  * Note that the .io_bitmap member must be extra-big. This is because

	  * the CPU will access an additional byte beyond the end of the IO

	  * permission bitmap. The extra byte must be all 1 bits, and must

	  * be within the limit.

	  */

	.io_bitmap		= { [0 ... IO_BITMAP_LONGS] = ~0 },

#endif

};

EXPORT_PER_CPU_SYMBOL_GPL(cpu_tss);



#ifdef CONFIG_X86_64

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