From: Jan Beulich <jbeulich@novell.com>
Date: Thu, 12 Mar 2009 11:54:54 +0000 (+0000)
Subject: x86: fix HYPERVISOR_update_descriptor()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6a5c05f002c3e4f24887a5fe8e7df757d339d368;p=linux-beck.git

x86: fix HYPERVISOR_update_descriptor()

Impact: fix potential oops during app-initiated LDT manipulation

The underlying hypercall has differing argument requirements on 32-
and 64-bit.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
LKML-Reference: <49B9061E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index 5e79ca694326..9c371e4a9fa6 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -296,6 +296,8 @@ HYPERVISOR_get_debugreg(int reg)
 static inline int
 HYPERVISOR_update_descriptor(u64 ma, u64 desc)
 {
+	if (sizeof(u64) == sizeof(long))
+		return _hypercall2(int, update_descriptor, ma, desc);
 	return _hypercall4(int, update_descriptor, ma, ma>>32, desc, desc>>32);
 }