From: Peter Zijlstra <peterz@infradead.org>
To: tglx@linutronix.de, luto@amacapital.net, peterz@infradead.org
Cc: linux-kernel@vger.kernel.org, x86@kernel.org
Subject: [RFC][PATCH 4/4] x86/entry, mce: Disallow #DB during #MC
Date: Fri, 22 May 2020 22:47:42 +0200 [thread overview]
Message-ID: <20200522204943.407362690@infradead.org> (raw)
In-Reply-To: 20200522204738.645043059@infradead.org
#MC is fragile as heck, don't tempt fate.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/kernel/cpu/mce/core.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1943,22 +1943,34 @@ static __always_inline void exc_machine_
/* MCE hit kernel mode */
DEFINE_IDTENTRY_MCE(exc_machine_check)
{
+ unsigned long dr7;
+
+ local_db_save(&dr7);
exc_machine_check_kernel(regs);
+ local_db_restore(dr7);
}
/* The user mode variant. */
DEFINE_IDTENTRY_MCE_USER(exc_machine_check)
{
+ unsigned long dr7;
+
+ local_db_save(&dr7);
exc_machine_check_user(regs);
+ local_db_restore(dr7);
}
#else
/* 32bit unified entry point */
DEFINE_IDTENTRY_MCE(exc_machine_check)
{
+ unsigned long dr7;
+
+ local_db_save(&dr7);
if (user_mode(regs))
exc_machine_check_user(regs);
else
exc_machine_check_kernel(regs);
+ local_db_restore(dr7);
}
#endif
next prev parent reply other threads:[~2020-05-22 20:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 20:47 [RFC][PATCH 0/4] x86/entry: disallow #DB more Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 1/4] x86/entry: Introduce local_db_{rave,restore}() Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 2/4] x86/entry, nmi: Disable #DB Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 3/4] x86/entry: Remove debug IST frobbing Peter Zijlstra
2020-05-25 11:33 ` kbuild test robot
2020-05-25 12:33 ` kbuild test robot
2020-05-22 20:47 ` Peter Zijlstra [this message]
2020-05-22 22:13 ` [RFC][PATCH 0/4] x86/entry: disallow #DB more Andy Lutomirski
2020-05-22 22:20 ` Sean Christopherson
2020-05-22 22:43 ` Andy Lutomirski
2020-05-23 12:59 ` Peter Zijlstra
2020-05-23 21:32 ` Peter Zijlstra
2020-05-25 10:02 ` Rasmus Villemoes
2020-05-25 10:40 ` Peter Zijlstra
2020-05-25 11:01 ` Peter Zijlstra
2020-05-25 17:19 ` Andy Lutomirski
2020-05-25 18:08 ` Peter Zijlstra
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