[tip:x86/apic] x86/idt: Move debug stack init to table based

tip-bot for Thomas Gleixner
2017-08-29T11:24:20Z

Commit-ID: 0a30908b9149b2b332ccf817261125a634765566
Gitweb: http://git.kernel.org/tip/0a30908b9149b2b332ccf817261125a634765566
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:51 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 12:07:27 +0200

x86/idt: Move debug stack init to table based

Add the debug_idt init table and make use of it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064959.006502252@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
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(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 5a3cdeb..930acd5 100644
--- 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);
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 64e2211..f5281b8 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -68,6 +68,15 @@ static const __initdata struct idt_data early_idts[] = {
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_init = {
/* 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,
@@ -143,6 +156,16 @@ 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

/**
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 835c7e8..1492bf5 100644
--- 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();
}