linux-kernel - [tip:x86/apic] x86/idt: Consolidate IDT invalidation

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Date:   Tue, 29 Aug 2017 04:16:25 -0700
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     brgerst@...il.com, mingo@...nel.org, torvalds@...ux-foundation.org,
        hpa@...or.com, tglx@...utronix.de, bp@...en8.de,
        linux-kernel@...r.kernel.org, rostedt@...dmis.org, luto@...nel.org,
        dvlasenk@...hat.com, peterz@...radead.org, jpoimboe@...hat.com
Subject: [tip:x86/apic] x86/idt: Consolidate IDT invalidation

Commit-ID:  e802a51ede91350438c051da2f238f5e8c918ead
Gitweb:     http://git.kernel.org/tip/e802a51ede91350438c051da2f238f5e8c918ead
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:46 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 29 Aug 2017 12:07:26 +0200

x86/idt: Consolidate IDT invalidation

kexec and reboot have both code to invalidate IDT. Create a common function
and use 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/20170828064958.600953282@linutronix.de
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/desc.h        |  3 +++
 arch/x86/kernel/idt.c              | 11 +++++++++++
 arch/x86/kernel/machine_kexec_32.c | 14 +-------------
 arch/x86/kernel/reboot.c           |  4 +---
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 51b3d48..33aff45 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -503,4 +503,7 @@ static inline void load_current_idt(void)
 	else
 		load_idt((const struct desc_ptr *)&idt_descr);
 }
+
+extern void idt_invalidate(void *addr);
+
 #endif /* _ASM_X86_DESC_H */
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 86e5912..cd4658c 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -24,3 +24,14 @@ const struct desc_ptr debug_idt_descr = {
 	.address	= (unsigned long) debug_idt_table,
 };
 #endif
+
+/**
+ * idt_invalidate - Invalidate interrupt descriptor table
+ * @addr:	The virtual address of the 'invalid' IDT
+ */
+void idt_invalidate(void *addr)
+{
+	struct desc_ptr idt = { .address = (unsigned long) addr, .size = 0 };
+
+	load_idt(&idt);
+}
diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
index 8c53c5d..00bc751 100644
--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -26,18 +26,6 @@
 #include <asm/set_memory.h>
 #include <asm/debugreg.h>
 
-static void set_idt(void *newidt, __u16 limit)
-{
-	struct desc_ptr curidt;
-
-	/* ia32 supports unaliged loads & stores */
-	curidt.size    = limit;
-	curidt.address = (unsigned long)newidt;
-
-	load_idt(&curidt);
-}
-
-
 static void set_gdt(void *newgdt, __u16 limit)
 {
 	struct desc_ptr curgdt;
@@ -245,7 +233,7 @@ void machine_kexec(struct kimage *image)
 	 * If you want to load them you must set up your own idt & gdt.
 	 */
 	set_gdt(phys_to_virt(0), 0);
-	set_idt(phys_to_virt(0), 0);
+	idt_invalidate(phys_to_virt(0));
 
 	/* now call it */
 	image->start = relocate_kernel_ptr((unsigned long)image->head,
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index a56bf60..54984b1 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -38,8 +38,6 @@
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
-static const struct desc_ptr no_idt = {};
-
 /*
  * This is set if we need to go through the 'emergency' path.
  * When machine_emergency_restart() is called, we may be on
@@ -638,7 +636,7 @@ static void native_machine_emergency_restart(void)
 			break;
 
 		case BOOT_TRIPLE:
-			load_idt(&no_idt);
+			idt_invalidate(NULL);
 			__asm__ __volatile__("int3");
 
 			/* We're probably dead after this, but... */