linux-kernel - [PATCH 5.15 145/201] x86/extable: Provide EX_TYPE_DEFAULT_MCE_SAFE and EX_TYPE_FAULT_MCE

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Date:   Wed, 27 Jul 2022 18:10:49 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...e.de>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 145/201] x86/extable: Provide EX_TYPE_DEFAULT_MCE_SAFE and EX_TYPE_FAULT_MCE_SAFE

From: Thomas Gleixner <tglx@...utronix.de>

[ Upstream commit 2cadf5248b9316d3c8af876e795d61c55476f6e9 ]

Provide exception fixup types which can be used to identify fixups which
allow in kernel #MC recovery and make them invoke the existing handlers.

These will be used at places where #MC recovery is handled correctly by the
caller.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lkml.kernel.org/r/20210908132525.269689153@linutronix.de
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/include/asm/extable_fixup_types.h | 3 +++
 arch/x86/kernel/cpu/mce/severity.c         | 2 ++
 arch/x86/mm/extable.c                      | 2 ++
 3 files changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/extable_fixup_types.h b/arch/x86/include/asm/extable_fixup_types.h
index 0adc117618e6..409524d5d2eb 100644
--- a/arch/x86/include/asm/extable_fixup_types.h
+++ b/arch/x86/include/asm/extable_fixup_types.h
@@ -16,4 +16,7 @@
 #define	EX_TYPE_WRMSR_IN_MCE		10
 #define	EX_TYPE_RDMSR_IN_MCE		11
 
+#define	EX_TYPE_DEFAULT_MCE_SAFE	12
+#define	EX_TYPE_FAULT_MCE_SAFE		13
+
 #endif
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
index 74fe763bffda..d9b77a74f8d2 100644
--- a/arch/x86/kernel/cpu/mce/severity.c
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -278,6 +278,8 @@ static int error_context(struct mce *m, struct pt_regs *regs)
 		m->kflags |= MCE_IN_KERNEL_COPYIN;
 		fallthrough;
 	case EX_TYPE_FAULT:
+	case EX_TYPE_FAULT_MCE_SAFE:
+	case EX_TYPE_DEFAULT_MCE_SAFE:
 		m->kflags |= MCE_IN_KERNEL_RECOV;
 		return IN_KERNEL_RECOV;
 	default:
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 5db46df409b5..f37e290e6d0a 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -131,8 +131,10 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code,
 
 	switch (e->type) {
 	case EX_TYPE_DEFAULT:
+	case EX_TYPE_DEFAULT_MCE_SAFE:
 		return ex_handler_default(e, regs);
 	case EX_TYPE_FAULT:
+	case EX_TYPE_FAULT_MCE_SAFE:
 		return ex_handler_fault(e, regs, trapnr);
 	case EX_TYPE_UACCESS:
 		return ex_handler_uaccess(e, regs, trapnr);
-- 
2.35.1