Commit f2b8210f authored Oct 19, 2016 by Mark Rutland Committed by Zubin Mithra Aug 09, 2017

UPSTREAM: thread_info: include <current.h> for THREAD_INFO_IN_TASK



When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info()
macro relies on current having been defined prior to its use. However,
not all users of current_thread_info() include <asm/current.h>, and thus
current is not guaranteed to be defined.

When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that
get_current() / current are based upon current_thread_info(), and
<asm/current.h> includes <asm/thread_info.h>. Thus always including
<asm/current.h> would result in circular dependences on some platforms.

To ensure both cases work, this patch includes <asm/current.h>, but only
when CONFIG_THREAD_INFO_IN_TASK is selected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Bug: 38331309
Change-Id: Ia981a829798d60a54d4e3eb679d8e24b01228357
(cherry picked from commit dc3d2a679cd8631b8a570fc8ca5f4712d7d25698)
Signed-off-by: Zubin Mithra <zsm@google.com>

parent 264c551c

include/linux/thread_info.h

+6 −11

Original line number	Diff line number	Diff line
		@@ -12,17 +12,12 @@
		#include <linux/restart_block.h>

		#ifdef CONFIG_THREAD_INFO_IN_TASK
		struct thread_info {
		u32 flags; /* low level flags */
		};

		#define INIT_THREAD_INFO(tsk) \
		{ \
		.flags = 0, \
		}
		#endif

		#ifdef CONFIG_THREAD_INFO_IN_TASK
		/*
		* For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the
		* definition of current, but for !CONFIG_THREAD_INFO_IN_TASK kernels,
		* including <asm/current.h> can cause a circular dependency on some platforms.
		*/
		#include <asm/current.h>
		#define current_thread_info() ((struct thread_info *)current)
		#endif