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Commit 02fdcd5e authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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x86/traps, context_tracking: Assert that we're in CONTEXT_KERNEL in exception entries 



Other than the super-atomic exception entries, all exception
entries are supposed to switch our context tracking state to
CONTEXT_KERNEL. Assert that they do.  These assertions appear
trivial at this point, as exception_enter() is the function
responsible for switching context, but I'm planning on reworking
x86's exception context tracking, and these assertions will help
make sure that all of this code keeps working.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20fa1ee2d943233a184aaf96ff75394d3b34dfba.1435952415.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1f484aa6

arch/x86/kernel/traps.c

+9 −0
Original line number Diff line number Diff line
@@ -292,6 +292,8 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, 
	enum ctx_state prev_state = exception_enter();

	siginfo_t info;



	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);



	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=

			NOTIFY_STOP) {

		conditional_sti(regs);
@@ -376,6 +378,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) 
	siginfo_t *info;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	if (notify_die(DIE_TRAP, "bounds", regs, error_code,

			X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)

		goto exit;
@@ -457,6 +460,7 @@ do_general_protection(struct pt_regs *regs, long error_code) 
	enum ctx_state prev_state;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	conditional_sti(regs);



	if (v8086_mode(regs)) {
@@ -514,6 +518,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) 
		return;



	prev_state = ist_enter(regs);

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP

	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,

				SIGTRAP) == NOTIFY_STOP)
@@ -750,6 +755,7 @@ dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) 
	enum ctx_state prev_state;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	math_error(regs, error_code, X86_TRAP_MF);

	exception_exit(prev_state);

}
@@ -760,6 +766,7 @@ do_simd_coprocessor_error(struct pt_regs *regs, long error_code) 
	enum ctx_state prev_state;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	math_error(regs, error_code, X86_TRAP_XF);

	exception_exit(prev_state);

}
@@ -776,6 +783,7 @@ do_device_not_available(struct pt_regs *regs, long error_code) 
	enum ctx_state prev_state;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	BUG_ON(use_eager_fpu());



#ifdef CONFIG_MATH_EMULATION
@@ -805,6 +813,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) 
	enum ctx_state prev_state;



	prev_state = exception_enter();

	CT_WARN_ON(ct_state() != CONTEXT_KERNEL);

	local_irq_enable();



	info.si_signo = SIGILL;