Commit e62a254a authored Oct 05, 2015 by Andy Lutomirski Committed by Ingo Molnar Oct 09, 2015

x86/entry/64/compat: Disable SYSENTER and SYSCALL32 entries

We've disabled the vDSO helpers to call them, so turn off the
entries entirely (temporarily) in preparation for cleaning them
up.

Signed-off-by: Andy 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: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/8d6e84bf651519289dc532dcc230adfabbd2a3eb.1444091584.git.luto@kernel.org

Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 8242c6c8

arch/x86/entry/entry_64_compat.S

+13 −0

Original line number	Diff line number	Diff line
		@@ -103,6 +103,14 @@ ENTRY(entry_SYSENTER_compat)
		jnz sysenter_fix_flags
		sysenter_flags_fixed:

		/* Temporary: SYSENTER is disabled. */
		#ifdef CONFIG_CONTEXT_TRACKING
		call enter_from_user_mode
		#endif
		ENABLE_INTERRUPTS(CLBR_NONE)
		movl $11, %edi
		call do_exit

		/*
		* Re-enable interrupts. IRQ tracing already thinks that IRQs are
		* on (since we treat user mode as having IRQs on), and the
		@@ -324,6 +332,11 @@ ENTRY(entry_SYSCALL_compat)
		* it is too small to ever cause noticeable irq latency.
		*/
		SWAPGS_UNSAFE_STACK

		/* Temporary: SYSCALL32 is disabled. */
		movl $-ENOSYS, %eax
		USERGS_SYSRET32

		movl %esp, %r8d
		movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
		ENABLE_INTERRUPTS(CLBR_NONE)