x86/idt: Remove the tracing IDT completely

No more users of the tracing IDT. All exception tracepoints have been moved
into the regular handlers. Get rid of the mess which shouldn't have been
created in the first place.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
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/20170828064957.378851687@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 1 insertions, 48 deletions

diff --git a/arch/x86/kernel/tracepoint.c b/arch/x86/kernel/tracepoint.c
index dd4aa04bb95c..4cae92f15495 100644
--- a/arch/x86/kernel/tracepoint.c
+++ b/arch/x86/kernel/tracepoint.c
@@ -10,58 +10,15 @@
 #include <asm/hw_irq.h>
 #include <asm/desc.h>
 
-atomic_t trace_idt_ctr = ATOMIC_INIT(0);
-struct desc_ptr trace_idt_descr = { NR_VECTORS * 16 - 1,
-				(unsigned long) trace_idt_table };
-
-/* No need to be aligned, but done to keep all IDTs defined the same way. */
-gate_desc trace_idt_table[NR_VECTORS] __page_aligned_bss;
-
 DEFINE_STATIC_KEY_FALSE(trace_irqvectors_key);
-static int trace_irq_vector_refcount;
-static DEFINE_MUTEX(irq_vector_mutex);
-
-static void set_trace_idt_ctr(int val)
-{
-	atomic_set(&trace_idt_ctr, val);
-	/* Ensure the trace_idt_ctr is set before sending IPI */
-	wmb();
-}
-
-static void switch_idt(void *arg)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	load_current_idt();
-	local_irq_restore(flags);
-}
 
 int trace_irq_vector_regfunc(void)
 {
 	static_branch_inc(&trace_irqvectors_key);
-
-	mutex_lock(&irq_vector_mutex);
-	if (!trace_irq_vector_refcount) {
-		set_trace_idt_ctr(1);
-		smp_call_function(switch_idt, NULL, 0);
-		switch_idt(NULL);
-	}
-	trace_irq_vector_refcount++;
-	mutex_unlock(&irq_vector_mutex);
 	return 0;
 }
 
 void trace_irq_vector_unregfunc(void)
 {
 	static_branch_dec(&trace_irqvectors_key);
-
-	mutex_lock(&irq_vector_mutex);
-	trace_irq_vector_refcount--;
-	if (!trace_irq_vector_refcount) {
-		set_trace_idt_ctr(0);
-		smp_call_function(switch_idt, NULL, 0);
-		switch_idt(NULL);
-	}
-	mutex_unlock(&irq_vector_mutex);
 }
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 309532451d94..36c583625328 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -939,12 +939,8 @@ void __init early_trap_init(void)
 	 * stack.  Using the original stack works well enough at this
 	 * early stage. DEBUG_STACK will be equipped after cpu_init() in
 	 * trap_init().
-	 *
-	 * We don't need to set trace_idt_table like set_intr_gate(),
-	 * since we don't have trace_debug and it will be reset to
-	 * 'debug' in trap_init() by set_intr_gate_ist().
 	 */
-	set_intr_gate_notrace(X86_TRAP_DB, debug);
+	set_intr_gate(X86_TRAP_DB, debug);
 	/* int3 can be called from all */
 	set_system_intr_gate(X86_TRAP_BP, &int3);
 #ifdef CONFIG_X86_32