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Commit 15f4eae7 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
Browse files

x86: Move thread_info into task_struct 



Now that most of the thread_info users have been cleaned up,
this is straightforward.

Most of this code was written by Linus.

Originally-from: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a50eab40abeaec9cb9a9e3cbdeafd32190206654.1473801993.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c65eacbe

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -157,6 +157,7 @@ config X86 
	select SPARSE_IRQ

	select SRCU

	select SYSCTL_EXCEPTION_TRACE

	select THREAD_INFO_IN_TASK

	select USER_STACKTRACE_SUPPORT

	select VIRT_TO_BUS

	select X86_DEV_DMA_OPS			if X86_64

arch/x86/entry/entry_64.S

+5 −2
Original line number Diff line number Diff line
@@ -179,7 +179,8 @@ GLOBAL(entry_SYSCALL_64_after_swapgs) 
	 * If we need to do entry work or if we guess we'll need to do

	 * exit work, go straight to the slow path.

	 */

	testl	$_TIF_WORK_SYSCALL_ENTRY|_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)

	movq	PER_CPU_VAR(current_task), %r11

	testl	$_TIF_WORK_SYSCALL_ENTRY|_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)

	jnz	entry_SYSCALL64_slow_path



entry_SYSCALL_64_fastpath:
@@ -217,7 +218,8 @@ entry_SYSCALL_64_fastpath: 
	 */

	DISABLE_INTERRUPTS(CLBR_NONE)

	TRACE_IRQS_OFF

	testl	$_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)

	movq	PER_CPU_VAR(current_task), %r11

	testl	$_TIF_ALLWORK_MASK, TASK_TI_flags(%r11)

	jnz	1f



	LOCKDEP_SYS_EXIT
@@ -370,6 +372,7 @@ END(ptregs_\func) 
/*

 * %rdi: prev task

 * %rsi: next task

 * rsi: task we're switching to

 */

ENTRY(__switch_to_asm)

	/*

arch/x86/include/asm/thread_info.h

+0 −46
Original line number Diff line number Diff line
@@ -52,20 +52,6 @@ struct task_struct; 
#include <asm/cpufeature.h>

#include <linux/atomic.h>



struct thread_info {

	struct task_struct	*task;		/* main task structure */

	__u32			flags;		/* low level flags */

	__u32			cpu;		/* current CPU */

};



#define INIT_THREAD_INFO(tsk)			\

{						\

	.task		= &tsk,			\

	.flags		= 0,			\

	.cpu		= 0,			\

}



#define init_thread_info	(init_thread_union.thread_info)

#define init_stack		(init_thread_union.stack)



#else /* !__ASSEMBLY__ */
@@ -157,11 +143,6 @@ struct thread_info { 
 */

#ifndef __ASSEMBLY__



static inline struct thread_info *current_thread_info(void)

{

	return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);

}



static inline unsigned long current_stack_pointer(void)

{

	unsigned long sp;
@@ -223,33 +204,6 @@ static inline int arch_within_stack_frames(const void * const stack, 
# define cpu_current_top_of_stack (cpu_tss + TSS_sp0)

#endif



/*

 * ASM operand which evaluates to a 'thread_info' address of

 * the current task, if it is known that "reg" is exactly "off"

 * bytes below the top of the stack currently.

 *

 * ( The kernel stack's size is known at build time, it is usually

 *   2 or 4 pages, and the bottom  of the kernel stack contains

 *   the thread_info structure. So to access the thread_info very

 *   quickly from assembly code we can calculate down from the

 *   top of the kernel stack to the bottom, using constant,

 *   build-time calculations only. )

 *

 * For example, to fetch the current thread_info->flags value into %eax

 * on x86-64 defconfig kernels, in syscall entry code where RSP is

 * currently at exactly SIZEOF_PTREGS bytes away from the top of the

 * stack:

 *

 *      mov ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS), %eax

 *

 * will translate to:

 *

 *      8b 84 24 b8 c0 ff ff      mov    -0x3f48(%rsp), %eax

 *

 * which is below the current RSP by almost 16K.

 */

#define ASM_THREAD_INFO(field, reg, off) ((field)+(off)-THREAD_SIZE)(reg)



#endif



#ifdef CONFIG_COMPAT

arch/x86/kernel/asm-offsets.c

+1 −3
Original line number Diff line number Diff line
@@ -35,9 +35,7 @@ void common(void) { 
#endif



	BLANK();

	OFFSET(TI_flags, thread_info, flags);



	BLANK();

	OFFSET(TASK_TI_flags, task_struct, thread_info.flags);

	OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);



	BLANK();

arch/x86/kernel/irq_64.c

+1 −2
Original line number Diff line number Diff line
@@ -40,8 +40,7 @@ static inline void stack_overflow_check(struct pt_regs *regs) 
	if (user_mode(regs))

		return;



	if (regs->sp >= curbase + sizeof(struct thread_info) +

				  sizeof(struct pt_regs) + STACK_TOP_MARGIN &&

	if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN &&

	    regs->sp <= curbase + THREAD_SIZE)

		return;