1 files changed, 112 insertions, 5 deletions

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 8bf1c06070d5..b90e5dfeee46 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -36,8 +36,8 @@ static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *in
 
 extern struct desc_ptr idt_descr;
 extern gate_desc idt_table[];
-extern struct desc_ptr nmi_idt_descr;
-extern gate_desc nmi_idt_table[];
+extern struct desc_ptr debug_idt_descr;
+extern gate_desc debug_idt_table[];
 
 struct gdt_page {
 	struct desc_struct gdt[GDT_ENTRIES];
@@ -316,7 +316,20 @@ static inline void set_nmi_gate(int gate, void *addr)
 	gate_desc s;
 
 	pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
-	write_idt_entry(nmi_idt_table, gate, &s);
+	write_idt_entry(debug_idt_table, gate, &s);
+}
+#endif
+
+#ifdef CONFIG_TRACING
+extern struct desc_ptr trace_idt_descr;
+extern gate_desc trace_idt_table[];
+static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
+{
+	write_idt_entry(trace_idt_table, entry, gate);
+}
+#else
+static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
+{
 }
 #endif
 
@@ -331,6 +344,7 @@ static inline void _set_gate(int gate, unsigned type, void *addr,
 	 * setup time
 	 */
 	write_idt_entry(idt_table, gate, &s);
+	write_trace_idt_entry(gate, &s);
 }
 
 /*
@@ -360,12 +374,39 @@ static inline void alloc_system_vector(int vector)
 	}
 }
 
-static inline void alloc_intr_gate(unsigned int n, void *addr)
+#ifdef CONFIG_TRACING
+static inline void trace_set_intr_gate(unsigned int gate, void *addr)
+{
+	gate_desc s;
+
+	pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
+	write_idt_entry(trace_idt_table, gate, &s);
+}
+
+static inline void __trace_alloc_intr_gate(unsigned int n, void *addr)
+{
+	trace_set_intr_gate(n, addr);
+}
+#else
+static inline void trace_set_intr_gate(unsigned int gate, void *addr)
+{
+}
+
+#define __trace_alloc_intr_gate(n, addr)
+#endif
+
+static inline void __alloc_intr_gate(unsigned int n, void *addr)
 {
-	alloc_system_vector(n);
 	set_intr_gate(n, addr);
 }
 
+#define alloc_intr_gate(n, addr)				\
+	do {							\
+		alloc_system_vector(n);				\
+		__alloc_intr_gate(n, addr);			\
+		__trace_alloc_intr_gate(n, trace_##addr);	\
+	} while (0)
+
 /*
  * This routine sets up an interrupt gate at directory privilege level 3.
  */
@@ -405,4 +446,70 @@ static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 	_set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 }
 
+#ifdef CONFIG_X86_64
+DECLARE_PER_CPU(u32, debug_idt_ctr);
+static inline bool is_debug_idt_enabled(void)
+{
+	if (this_cpu_read(debug_idt_ctr))
+		return true;
+
+	return false;
+}
+
+static inline void load_debug_idt(void)
+{
+	load_idt((const struct desc_ptr *)&debug_idt_descr);
+}
+#else
+static inline bool is_debug_idt_enabled(void)
+{
+	return false;
+}
+
+static inline void load_debug_idt(void)
+{
+}
+#endif
+
+#ifdef CONFIG_TRACING
+extern atomic_t trace_idt_ctr;
+static inline bool is_trace_idt_enabled(void)
+{
+	if (atomic_read(&trace_idt_ctr))
+		return true;
+
+	return false;
+}
+
+static inline void load_trace_idt(void)
+{
+	load_idt((const struct desc_ptr *)&trace_idt_descr);
+}
+#else
+static inline bool is_trace_idt_enabled(void)
+{
+	return false;
+}
+
+static inline void load_trace_idt(void)
+{
+}
+#endif
+
+/*
+ * The load_current_idt() must be called with interrupts disabled
+ * to avoid races. That way the IDT will always be set back to the expected
+ * descriptor. It's also called when a CPU is being initialized, and
+ * that doesn't need to disable interrupts, as nothing should be
+ * bothering the CPU then.
+ */
+static inline void load_current_idt(void)
+{
+	if (is_debug_idt_enabled())
+		load_debug_idt();
+	else if (is_trace_idt_enabled())
+		load_trace_idt();
+	else
+		load_idt((const struct desc_ptr *)&idt_descr);
+}
 #endif /* _ASM_X86_DESC_H */