[PATCH RESEND v9 21/36] x86/fred: Add a machine check entry stub for FRED

[Xin Li <xin3.li@xxxxxxxxx>]

Add a machine check entry stub for FRED.

Tested-by: Shan Kang <shan.kang@xxxxxxxxx>
Signed-off-by: Xin Li <xin3.li@xxxxxxxxx>
---

Changes since v5:
* Disallow #DB inside #MCE for robustness sake (Peter Zijlstra).
---
 arch/x86/include/asm/fred.h    |  1 +
 arch/x86/kernel/cpu/mce/core.c | 15 +++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/arch/x86/include/asm/fred.h b/arch/x86/include/asm/fred.h
index 2a7c47dfd733..f559dd9dc4f2 100644
--- a/arch/x86/include/asm/fred.h
+++ b/arch/x86/include/asm/fred.h
@@ -115,6 +115,7 @@ typedef DECLARE_FRED_HANDLER((*fred_handler));
 DECLARE_FRED_HANDLER(fred_exc_nmi);
 DECLARE_FRED_HANDLER(fred_exc_debug);
 DECLARE_FRED_HANDLER(fred_exc_page_fault);
+DECLARE_FRED_HANDLER(fred_exc_machine_check);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index b8ad5a5b4026..98456e20f155 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -52,6 +52,7 @@
 #include <asm/mce.h>
 #include <asm/msr.h>
 #include <asm/reboot.h>
+#include <asm/fred.h>
 
 #include "internal.h"
 
@@ -2118,6 +2119,20 @@ DEFINE_IDTENTRY_MCE_USER(exc_machine_check)
        exc_machine_check_user(regs);
        local_db_restore(dr7);
 }
+
+#ifdef CONFIG_X86_FRED
+DEFINE_FRED_HANDLER(fred_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
 #else
 /* 32bit unified entry point */
 DEFINE_IDTENTRY_RAW(exc_machine_check)
-- 
2.34.1