Commit 5eca7453 authored by Wang Nan's avatar Wang Nan Committed by Ingo Molnar
Browse files

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: default avatarAndy Lutomirski <luto@amacapital.net>
Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Acked-by: default avatarAndy 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: default avatarIngo Molnar <mingo@kernel.org>
parent 1e3fbb8a

arch/x86/include/asm/desc.h

+6 −1
Original line number Diff line number Diff line
@@ -376,11 +376,16 @@ static inline void _set_gate(int gate, unsigned type, void *addr, 
 * Pentium F0 0F bugfix can have resulted in the mapped

 * IDT being write-protected.

 */

#define set_intr_gate(n, addr)						\

#define set_intr_gate_notrace(n, addr)					\

	do {								\

		BUG_ON((unsigned)n > 0xFF);				\

		_set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,	\

			  __KERNEL_CS);					\

	} while (0)



#define set_intr_gate(n, addr)						\

	do {								\

		set_intr_gate_notrace(n, addr);				\

		_trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\

				0, 0, __KERNEL_CS);			\

	} while (0)

arch/x86/kernel/traps.c

+12 −8
Original line number Diff line number Diff line
@@ -926,16 +926,20 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) 
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 @@ void __init trap_init(void) 


	/*

	 * 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);

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