linux-kernel - [tip:x86/apic] x86/idt: Move debug stack init to table based

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Message-ID: <tip-0a30908b9149b2b332ccf817261125a634765566@git.kernel.org>
Date:   Tue, 29 Aug 2017 04:18:28 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, luto@...nel.org, torvalds@...ux-foundation.org,
        bp@...en8.de, rostedt@...dmis.org, hpa@...or.com, mingo@...nel.org,
        brgerst@...il.com, linux-kernel@...r.kernel.org,
        peterz@...radead.org, jpoimboe@...hat.com, dvlasenk@...hat.com
Subject: [tip:x86/apic] x86/idt: Move debug stack init to table based

Commit-ID:  0a30908b9149b2b332ccf817261125a634765566
Gitweb:     http://git.kernel.org/tip/0a30908b9149b2b332ccf817261125a634765566
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:51 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 29 Aug 2017 12:07:27 +0200

x86/idt: Move debug stack init to table based

Add the debug_idt init table and make use of it.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Josh Poimboeuf <jpoimboe@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Link: http://lkml.kernel.org/r/20170828064959.006502252@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/desc.h |  2 ++
 arch/x86/kernel/idt.c       | 23 +++++++++++++++++++++++
 arch/x86/kernel/traps.c     |  6 +-----
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 5a3cdeb..930acd5 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -509,8 +509,10 @@ extern void idt_setup_early_traps(void);
 
 #ifdef CONFIG_X86_64
 extern void idt_setup_early_pf(void);
+extern void idt_setup_debugidt_traps(void);
 #else
 static inline void idt_setup_early_pf(void) { }
+static inline void idt_setup_debugidt_traps(void) { }
 #endif
 
 extern void idt_invalidate(void *addr);
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 64e2211..f5281b8 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -68,6 +68,15 @@ static const __initdata struct idt_data early_idts[] = {
 static const __initdata struct idt_data early_pf_idts[] = {
 	INTG(X86_TRAP_PF,		page_fault),
 };
+
+/*
+ * Override for the debug_idt. Same as the default, but with interrupt
+ * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
+ */
+static const __initdata struct idt_data dbg_idts[] = {
+	INTG(X86_TRAP_DB,	debug),
+	INTG(X86_TRAP_BP,	int3),
+};
 #endif
 
 /* Must be page-aligned because the real IDT is used in a fixmap. */
@@ -82,6 +91,10 @@ struct desc_ptr idt_descr __ro_after_init = {
 /* No need to be aligned, but done to keep all IDTs defined the same way. */
 gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
 
+/*
+ * Override for the debug_idt. Same as the default, but with interrupt
+ * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
+ */
 const struct desc_ptr debug_idt_descr = {
 	.size		= IDT_ENTRIES * 16 - 1,
 	.address	= (unsigned long) debug_idt_table,
@@ -143,6 +156,16 @@ void __init idt_setup_early_pf(void)
 	idt_setup_from_table(idt_table, early_pf_idts,
 			     ARRAY_SIZE(early_pf_idts));
 }
+
+/**
+ * idt_setup_debugidt_traps - Initialize the debug idt table with debug traps
+ */
+void __init idt_setup_debugidt_traps(void)
+{
+	memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
+
+	idt_setup_from_table(debug_idt_table, dbg_idts, ARRAY_SIZE(dbg_idts));
+}
 #endif
 
 /**
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 835c7e8..1492bf5 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -990,9 +990,5 @@ void __init trap_init(void)
 
 	x86_init.irqs.trap_init();
 
-#ifdef CONFIG_X86_64
-	memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
-	set_nmi_gate(X86_TRAP_DB, &debug);
-	set_nmi_gate(X86_TRAP_BP, &int3);
-#endif
+	idt_setup_debugidt_traps();
 }