[PATCH v2 14/36] x86/entry/64/compat: Disable SYSENTER and SYSCALL32 entries

From: Andy Lutomirski
Date: Mon Oct 05 2015 - 20:56:09 EST


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@xxxxxxxxxx>
---
arch/x86/entry/entry_64_compat.S | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 1432d60a1f4a..e11aa38696fe 100644
--- 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)
--
2.4.3

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