The following commit has been merged into the x86/entry branch of tip: Commit-ID: ff98610a03285516b578821549973f969118d6a3 Gitweb: https://git.kernel.org/tip/ff98610a03285516b578821549973f969118d6a3 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Fri, 29 May 2020 23:27:35 +02:00 Committer: Thomas Gleixner <t...@linutronix.de> CommitterDate: Sat, 30 May 2020 10:00:08 +02:00
x86/entry, mce: Disallow #DB during #MC #MC is fragile as heck, don't tempt fate. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Thomas Gleixner <t...@linutronix.de> Link: https://lkml.kernel.org/r/20200529213321.131187...@infradead.org --- arch/x86/kernel/cpu/mce/core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 068e6ca..be49926 100644 --- 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_check_user(struct pt_regs *regs) /* MCE hit kernel mode */ DEFINE_IDTENTRY_MCE(exc_machine_check) { + unsigned long dr7; + + dr7 = local_db_save(); exc_machine_check_kernel(regs); + local_db_restore(dr7); } /* The user mode variant. */ DEFINE_IDTENTRY_MCE_USER(exc_machine_check) { + unsigned long dr7; + + dr7 = local_db_save(); exc_machine_check_user(regs); + local_db_restore(dr7); } #else /* 32bit unified entry point */ DEFINE_IDTENTRY_MCE(exc_machine_check) { + unsigned long dr7; + + dr7 = local_db_save(); if (user_mode(regs)) exc_machine_check_user(regs); else exc_machine_check_kernel(regs); + local_db_restore(dr7); } #endif
