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

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Date:   Tue, 29 Aug 2017 04:18:51 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     luto@...nel.org, tglx@...utronix.de, mingo@...nel.org,
        peterz@...radead.org, rostedt@...dmis.org,
        linux-kernel@...r.kernel.org, hpa@...or.com, brgerst@...il.com,
        jpoimboe@...hat.com, bp@...en8.de, torvalds@...ux-foundation.org,
        dvlasenk@...hat.com
Subject: [tip:x86/apic] x86/idt: Move IST stack based traps to table init

Commit-ID:  90f6225fba0c732f3f5f9f5e265bdefa021ff12d
Gitweb:     http://git.kernel.org/tip/90f6225fba0c732f3f5f9f5e265bdefa021ff12d
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:52 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 29 Aug 2017 12:07:27 +0200

x86/idt: Move IST stack based traps to table init

Initialize the IST based traps via a table.

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/20170828064959.091328949@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/desc.h |  2 ++
 arch/x86/kernel/idt.c       | 22 ++++++++++++++++++++++
 arch/x86/kernel/traps.c     |  9 +--------
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 930acd5..e624527 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -509,9 +509,11 @@ extern void idt_setup_early_traps(void);
 
 #ifdef CONFIG_X86_64
 extern void idt_setup_early_pf(void);
+extern void idt_setup_ist_traps(void);
 extern void idt_setup_debugidt_traps(void);
 #else
 static inline void idt_setup_early_pf(void) { }
+static inline void idt_setup_ist_traps(void) { }
 static inline void idt_setup_debugidt_traps(void) { }
 #endif
 
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index f5281b8..a6326fd 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -92,6 +92,20 @@ struct desc_ptr idt_descr __ro_after_init = {
 gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
 
 /*
+ * The exceptions which use Interrupt stacks. They are setup after
+ * cpu_init() when the TSS has been initialized.
+ */
+static const __initdata struct idt_data ist_idts[] = {
+	ISTG(X86_TRAP_DB,	debug,		DEBUG_STACK),
+	ISTG(X86_TRAP_NMI,	nmi,		NMI_STACK),
+	ISTG(X86_TRAP_BP,	int3,		DEBUG_STACK),
+	ISTG(X86_TRAP_DF,	double_fault,	DOUBLEFAULT_STACK),
+#ifdef CONFIG_X86_MCE
+	ISTG(X86_TRAP_MC,	&machine_check,	MCE_STACK),
+#endif
+};
+
+/*
  * Override for the debug_idt. Same as the default, but with interrupt
  * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
  */
@@ -158,6 +172,14 @@ void __init idt_setup_early_pf(void)
 }
 
 /**
+ * idt_setup_ist_traps - Initialize the idt table with traps using IST
+ */
+void __init idt_setup_ist_traps(void)
+{
+	idt_setup_from_table(idt_table, ist_idts, ARRAY_SIZE(ist_idts));
+}
+
+/**
  * idt_setup_debugidt_traps - Initialize the debug idt table with debug traps
  */
 void __init idt_setup_debugidt_traps(void)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 1492bf5..293f5bd 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -979,14 +979,7 @@ void __init trap_init(void)
 	 */
 	cpu_init();
 
-	/*
-	 * X86_TRAP_DB and X86_TRAP_BP have been set
-	 * in early_trap_init(). However, ITS works only after
-	 * cpu_init() loads TSS. See comments in early_trap_init().
-	 */
-	set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
-	/* int3 can be called from all */
-	set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
+	idt_setup_ist_traps();
 
 	x86_init.irqs.trap_init();