releases/3.2.98/x86-kaiser-move-feature-detection-up.patch

From: Borislav Petkov <bp@suse.de>
Date: Mon, 25 Dec 2017 13:57:16 +0100
Subject: x86/kaiser: Move feature detection up

... before the first use of kaiser_enabled as otherwise funky
things happen:

  about to get started...
  (XEN) d0v0 Unhandled page fault fault/trap [#14, ec=0000]
  (XEN) Pagetable walk from ffff88022a449090:
  (XEN)  L4[0x110] = 0000000229e0e067 0000000000001e0e
  (XEN)  L3[0x008] = 0000000000000000 ffffffffffffffff
  (XEN) domain_crash_sync called from entry.S: fault at ffff82d08033fd08
  entry.o#create_bounce_frame+0x135/0x14d
  (XEN) Domain 0 (vcpu#0) crashed on cpu#0:
  (XEN) ----[ Xen-4.9.1_02-3.21  x86_64  debug=n   Not tainted ]----
  (XEN) CPU:    0
  (XEN) RIP:    e033:[<ffffffff81007460>]
  (XEN) RFLAGS: 0000000000000286   EM: 1   CONTEXT: pv guest (d0v0)

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 arch/x86/include/asm/kaiser.h | 2 ++
 arch/x86/kernel/setup.c       | 7 +++++++
 arch/x86/mm/kaiser.c          | 2 --
 3 files changed, 9 insertions(+), 2 deletions(-)

--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -96,8 +96,10 @@ DECLARE_PER_CPU(unsigned long, x86_cr3_p
 extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[];
 
 extern int kaiser_enabled;
+extern void __init kaiser_check_boottime_disable(void);
 #else
 #define kaiser_enabled	0
+static inline void __init kaiser_check_boottime_disable(void) {}
 #endif /* CONFIG_KAISER */
 
 /*
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -114,6 +114,7 @@
 #include <asm/mce.h>
 #include <asm/alternative.h>
 #include <asm/prom.h>
+#include <asm/kaiser.h>
 
 /*
  * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
@@ -921,6 +922,12 @@ void __init setup_arch(char **cmdline_p)
 	 */
 	init_hypervisor_platform();
 
+	/*
+	 * This needs to happen right after XENPV is set on xen and
+	 * kaiser_enabled is checked below in cleanup_highmap().
+	 */
+	kaiser_check_boottime_disable();
+
 	x86_init.resources.probe_roms();
 
 	/* after parse_early_param, so could debug it */
--- a/arch/x86/mm/kaiser.c
+++ b/arch/x86/mm/kaiser.c
@@ -318,8 +318,6 @@ void __init kaiser_init(void)
 {
 	int cpu;
 
-	kaiser_check_boottime_disable();
-
 	if (!kaiser_enabled)
 		return;