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

Thomas Gleixner
2017-08-25T22:00:04Z

[-- Attachment #1: x86-idt--Move-ist-stack-based-traps-to-table-init.patch --]
[-- Type: text/plain, Size: 2426 bytes --]

Initialize the IST based traps via a table

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