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>

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index bc678f0c3c9174a2d3d3599bd47d9a8aca42e453..06a8966415f90e3d8109627b4b62460832110ecf 100644 (file)
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -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)