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Commit 5c39403e authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Ingo Molnar
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x86/asm/entry: Simplify task_pt_regs() macro definition 



Before this change, task_pt_regs() was using KSTK_TOP(),
and it was the only use of that macro. In turn, KSTK_TOP used
THREAD_SIZE_LONGS, and it was the only use of that macro too.

Fold these macros into task_pt_regs(). Tweak comment
about "- 8" - we now use a symbolic constant, not literal 8.

Signed-off-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
Reviewed-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1426255743-5394-1-git-send-email-dvlasenk@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 76e4c490

arch/x86/include/asm/processor.h

+6 −14
Original line number Diff line number Diff line
@@ -847,15 +847,8 @@ static inline void spin_lock_prefetch(const void *x) 


extern unsigned long thread_saved_pc(struct task_struct *tsk);



#define THREAD_SIZE_LONGS      (THREAD_SIZE/sizeof(unsigned long))

#define KSTK_TOP(info)                                                 \

({                                                                     \

       unsigned long *__ptr = (unsigned long *)(info);                 \

       (unsigned long)(&__ptr[THREAD_SIZE_LONGS]);                     \

})



/*

 * The below -8 is to reserve 8 bytes on top of the ring0 stack.

 * TOP_OF_KERNEL_STACK_PADDING reserves 8 bytes on top of the ring0 stack.

 * This is necessary to guarantee that the entire "struct pt_regs"

 * is accessible even if the CPU haven't stored the SS/ESP registers

 * on the stack (interrupt gate does not save these registers
@@ -866,10 +859,9 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk); 
 */

#define task_pt_regs(task) \

({									\

       struct pt_regs *__regs__;                                       \

       __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \

				     TOP_OF_KERNEL_STACK_PADDING);     \

       __regs__ - 1;                                                   \

	unsigned long __ptr = (unsigned long)task_stack_page(task);	\

	__ptr += THREAD_SIZE - TOP_OF_KERNEL_STACK_PADDING;		\

	((struct pt_regs *)__ptr) - 1;					\

})



#define KSTK_ESP(task)		(task_pt_regs(task)->sp)