[patch V2 36/44] x86/idt: Move debug stack init to table based

[Thomas Gleixner]

Add the debug_idt init table and make use of it.

Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 arch/x86/include/asm/desc.h |    2 ++
 arch/x86/kernel/idt.c       |   23 +++++++++++++++++++++++
 arch/x86/kernel/traps.c     |    6 +-----
 3 files changed, 26 insertions(+), 5 deletions(-)

--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -509,8 +509,10 @@ extern void idt_setup_early_traps(void);
 
 #ifdef CONFIG_X86_64
 extern void idt_setup_early_pf(void);
+extern void idt_setup_debugidt_traps(void);
 #else
 static inline void idt_setup_early_pf(void) { }
+static inline void idt_setup_debugidt_traps(void) { }
 #endif
 
 extern void idt_invalidate(void *addr);
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -68,6 +68,15 @@ static const __initdata struct idt_data
 static const __initdata struct idt_data early_pf_idts[] = {
        INTG(X86_TRAP_PF,               page_fault),
 };
+
+/*
+ * Override for the debug_idt. Same as the default, but with interrupt
+ * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
+ */
+static const __initdata struct idt_data dbg_idts[] = {
+       INTG(X86_TRAP_DB,       debug),
+       INTG(X86_TRAP_BP,       int3),
+};
 #endif
 
 /* Must be page-aligned because the real IDT is used in a fixmap. */
@@ -82,6 +91,10 @@ struct desc_ptr idt_descr __ro_after_ini
 /* No need to be aligned, but done to keep all IDTs defined the same way. */
 gate_desc debug_idt_table[IDT_ENTRIES] __page_aligned_bss;
 
+/*
+ * Override for the debug_idt. Same as the default, but with interrupt
+ * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
+ */
 const struct desc_ptr debug_idt_descr = {
        .size           = IDT_ENTRIES * 16 - 1,
        .address        = (unsigned long) debug_idt_table,
@@ -142,6 +155,16 @@ void __init idt_setup_early_pf(void)
        idt_setup_from_table(idt_table, early_pf_idts,
                             ARRAY_SIZE(early_pf_idts));
 }
+
+/**
+ * idt_setup_debugidt_traps - Initialize the debug idt table with debug traps
+ */
+void __init idt_setup_debugidt_traps(void)
+{
+       memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
+
+       idt_setup_from_table(debug_idt_table, dbg_idts, ARRAY_SIZE(dbg_idts));
+}
 #endif
 
 /**
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -990,9 +990,5 @@ void __init trap_init(void)
 
        x86_init.irqs.trap_init();
 
-#ifdef CONFIG_X86_64
-       memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
-       set_nmi_gate(X86_TRAP_DB, &debug);
-       set_nmi_gate(X86_TRAP_BP, &int3);
-#endif
+       idt_setup_debugidt_traps();
 }