pve-edge-kernel/patches/kernel/0099-x86-entry-Add-task_top_of_stack-to-find-the-top-of-a.patch

From 181d224dabca9a9061a6955cf3d49a4eba7294bf Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <[email protected]>
Date: Thu, 2 Nov 2017 00:59:11 -0700
Subject: [PATCH 099/242] x86/entry: Add task_top_of_stack() to find the top of
 a task's stack
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CVE-2017-5754

This will let us get rid of a few places that hardcode accesses to
thread.sp0.

Signed-off-by: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/b49b3f95a8ff858c40c9b0f5b32be0355324327d.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
(cherry picked from commit 3500130b84a3cdc5b6796eba1daf178944935efe)
Signed-off-by: Andy Whitcroft <[email protected]>
Signed-off-by: Kleber Sacilotto de Souza <[email protected]>
(cherry picked from commit f1078e10e361afaeb22ee72c54d5ad397e19728d)
Signed-off-by: Fabian Grünbichler <[email protected]>
---
 arch/x86/include/asm/processor.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 85ddfc1a9bb5..f83fbf1b6dd9 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -788,6 +788,8 @@ static inline void spin_lock_prefetch(const void *x)
 #define TOP_OF_INIT_STACK ((unsigned long)&init_stack + sizeof(init_stack) - \
 			   TOP_OF_KERNEL_STACK_PADDING)
 
+#define task_top_of_stack(task) ((unsigned long)(task_pt_regs(task) + 1))
+
 #ifdef CONFIG_X86_32
 /*
  * User space process size: 3GB (default).
-- 
2.14.2