x86/traps: Separate set_intr_gate() and clean up early_trap_init()
As early_trap_init() doesn't use IST, replace
set_intr_gate_ist() and set_system_intr_gate_ist() with their
standard counterparts.
set_intr_gate() requires a trace_debug symbol which we don't
have and won't use. This patch separates set_intr_gate() into two
parts, and uses base version in early_trap_init().
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Cc: <dave.hansen@linux.intel.com>
Cc: <lizefan@huawei.com>
Cc: <masami.hiramatsu.pt@hitachi.com>
Cc: <oleg@redhat.com>
Cc: <rostedt@goodmis.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425010789-13714-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 4281988..9965bd1 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -926,16 +926,20 @@
void __init early_trap_init(void)
{
/*
- * Don't set ist to DEBUG_STACK as it doesn't work until TSS is
- * ready in cpu_init() <-- trap_init(). Before trap_init(), CPU
- * runs at ring 0 so it is impossible to hit an invalid stack.
- * Using the original stack works well enough at this early
- * stage. DEBUG_STACK will be equipped after cpu_init() in
+ * Don't use IST to set DEBUG_STACK as it doesn't work until TSS
+ * is ready in cpu_init() <-- trap_init(). Before trap_init(),
+ * CPU runs at ring 0 so it is impossible to hit an invalid
+ * stack. Using the original stack works well enough at this
+ * early stage. DEBUG_STACK will be equipped after cpu_init() in
* trap_init().
+ *
+ * We don't need to set trace_idt_table like set_intr_gate(),
+ * since we don't have trace_debug and it will be reset to
+ * 'debug' in trap_init() by set_intr_gate_ist().
*/
- set_intr_gate_ist(X86_TRAP_DB, &debug, 0);
+ set_intr_gate_notrace(X86_TRAP_DB, debug);
/* int3 can be called from all */
- set_system_intr_gate_ist(X86_TRAP_BP, &int3, 0);
+ set_system_intr_gate(X86_TRAP_BP, &int3);
#ifdef CONFIG_X86_32
set_intr_gate(X86_TRAP_PF, page_fault);
#endif
@@ -1015,7 +1019,7 @@
/*
* X86_TRAP_DB and X86_TRAP_BP have been set
- * in early_trap_init(). However, DEBUG_STACK works only after
+ * 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);