From 3383642c2f9d4f5b4fa37436db4a109a1a10018c Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@kernel.org>
Date: Thu, 2 Nov 2017 00:59:17 -0700
Subject: x86/traps: Use a new on_thread_stack() helper to clean up an
 assertion

Let's keep the stack-related logic together rather than open-coding
a comparison in an assertion in the traps code.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.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/856b15bee1f55017b8f79d3758b0d51c48a08cf8.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/processor.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'arch/x86/include/asm')

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ae2ae6d80674..f10dae14f951 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -541,6 +541,12 @@ static inline unsigned long current_top_of_stack(void)
 #endif
 }
 
+static inline bool on_thread_stack(void)
+{
+	return (unsigned long)(current_top_of_stack() -
+			       current_stack_pointer) < THREAD_SIZE;
+}
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else
-- 
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