From dc3d2a679cd8631b8a570fc8ca5f4712d7d25698 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Wed, 19 Oct 2016 19:28:13 +0100
Subject: 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>
---
 include/linux/thread_info.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'include/linux/thread_info.h')

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index c75c6ab364ca..58373875e8ee 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -12,6 +12,12 @@
 #include <linux/restart_block.h>
 
 #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
 
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