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

Thomas Gleixner
2017-08-25T22:00:05Z

[-- Attachment #1: x86-idt--Move-debug-stack-init-to-table-based.patch --]
[-- Type: text/plain, Size: 2502 bytes --]

Add the debug_idt init table and make use of it.

Signed-off-by: Thomas Gleixner <tglx@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();
}