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@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064958.600953282@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 51b3d480d0b62df171912fea2875849811a0e984..33aff45f58ea86ede3d5704d64f7977478593233 100644 (file)
--- 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 86e5912f2b705fd821458c83bd93791ad08bb7c9..cd4658c1e405399e4e90d7c553026018a9f29644 100644 (file)
--- 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 8c53c5d7a1bc5e9733e4b4da8ed1a760ab138dbe..00bc751c861ce8fa42c1b93d39d029694f4e328d 100644 (file)
--- 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 a56bf6051f4e3707594b1b5ddab9711da9c27117..54984b1426413879a82489c6f91b20501419e807 100644 (file)
--- 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... */