Commit-ID: 3383642c2f9d4f5b4fa37436db4a109a1a10018c
Gitweb: https://git.kernel.org/tip/3383642c2f9d4f5b4fa37436db4a109a1a10018c
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Thu, 2 Nov 2017 00:59:17 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 2 Nov 2017 11:04:49 +0100
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@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Cc: Borislav Petkov <bpetkov@xxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/856b15bee1f55017b8f79d3758b0d51c48a08cf8.1509609304.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 6 ++++++
arch/x86/kernel/traps.c | 3 +--
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index ae2ae6d..f10dae1 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
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 67db4f4..42a9c44 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -141,8 +141,7 @@ void ist_begin_non_atomic(struct pt_regs *regs)
* will catch asm bugs and any attempt to use ist_preempt_enable
* from double_fault.
*/
- BUG_ON((unsigned long)(current_top_of_stack() -
- current_stack_pointer) >= THREAD_SIZE);
+ BUG_ON(!on_thread_stack());
preempt_enable_no_resched();
}
--
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