The following commit has been merged into the x86/entry branch of tip:
Commit-ID: 71ed49d8fb33023f242419a77ecb1141c029cac4
Gitweb: https://git.kernel.org/tip/71ed49d8fb33023f242419a77ecb1141c029cac4
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri, 12 Jun 2020 14:02:27 +02:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Fri, 12 Jun 2020 14:15:48 +02:00
x86/entry: Make NMI use IDTENTRY_RAW
For no reason other than beginning brainmelt, IDTENTRY_NMI was mapped to
IDTENTRY_IST.
This is not a problem on 64bit because the IST default entry point maps to
IDTENTRY_RAW which does not any entry handling. The surplus function
declaration for the noist C entry point is unused and as there is no ASM
code emitted for NMI this went unnoticed.
On 32bit IDTENTRY_IST maps to a regular IDTENTRY which does the normal
entry handling. That is clearly the wrong thing to do for NMI.
Map it to IDTENTRY_RAW to unbreak it. The IDTENTRY_NMI mapping needs to
stay to avoid emitting ASM code.
Fixes: 6271fef00b34 ("x86/entry: Convert NMI to IDTENTRY_NMI")
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Debugged-by: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/CA+G9fYvF3cyrY+-iw_SZtpN-i2qA2BruHg4M=QYECU2-dNdsMw@xxxxxxxxxxxxxx
---
arch/x86/include/asm/idtentry.h | 4 ++--
arch/x86/kernel/nmi.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 2fc6b0c..cf51c50 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -391,8 +391,8 @@ __visible noinstr void func(struct pt_regs *regs, \
#define DEFINE_IDTENTRY_MCE DEFINE_IDTENTRY_IST
#define DEFINE_IDTENTRY_MCE_USER DEFINE_IDTENTRY_NOIST
-#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_IST
-#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_IST
+#define DECLARE_IDTENTRY_NMI DECLARE_IDTENTRY_RAW
+#define DEFINE_IDTENTRY_NMI DEFINE_IDTENTRY_RAW
#define DECLARE_IDTENTRY_DEBUG DECLARE_IDTENTRY_IST
#define DEFINE_IDTENTRY_DEBUG DEFINE_IDTENTRY_IST
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 3a98ff3..2de365f 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -476,7 +476,7 @@ static DEFINE_PER_CPU(enum nmi_states, nmi_state);
static DEFINE_PER_CPU(unsigned long, nmi_cr2);
static DEFINE_PER_CPU(unsigned long, nmi_dr7);
-DEFINE_IDTENTRY_NMI(exc_nmi)
+DEFINE_IDTENTRY_RAW(exc_nmi)
{
if (IS_ENABLED(CONFIG_SMP) && cpu_is_offline(smp_processor_id()))
return;
|