[patch V2 37/44] x86/idt: Move ist stack based traps to table init

[Thomas Gleixner]

Initialize the IST based traps via a table

Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 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(-)

--- 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
 
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -92,6 +92,20 @@ struct desc_ptr idt_descr __ro_after_ini
 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.
  */
@@ -157,6 +171,14 @@ 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)
--- 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();