[GIT PULL] update paravirt after f443ff42 "x86: Sync 32/64-bit kernel_thread" and related

[GIT PULL] update paravirt after f443ff42 "x86: Sync 32/64-bit kernel_thread" and related

[Ian Campbell]

The following changes since commit 7284ce6c9f6153d1777df5f310c959724d1bd446:
  Linus Torvalds (1):
        Linux 2.6.33-rc4

are available in the git repository at:

  git://xenbits.xensource.com/people/ianc/linux-2.6.git for-x86/bugfixes

Cyrill Gorcunov (1):
      x86: kernel_thread -- initialize SS to a known state

Ian Campbell (1):
      xen: 64 bit kernel RPL should be 0.

 arch/x86/kernel/process.c |    2 ++
 arch/x86/xen/enlighten.c  |    4 ++++
 2 files changed, 6 insertions(+), 0 deletions(-)

[PATCH] x86: kernel_thread -- initialize SS to a known state

[Ian Campbell]

From: Cyrill Gorcunov <gorcunov@openvz.org>

Before the kernel_thread was converted into "C" we had
pt_regs::ss set to __KERNEL_DS (by SAVE_ALL asm macro).

Though I must admit I didn't find any *explicit* load of
%ss from this structure the better to be on a safe side
and set it to a known value.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
 arch/x86/kernel/process.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c6ee241..02c3ee0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -288,6 +288,8 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 	regs.es = __USER_DS;
 	regs.fs = __KERNEL_PERCPU;
 	regs.gs = __KERNEL_STACK_CANARY;
+#else
+	regs.ss = __KERNEL_DS;
 #endif
 
 	regs.orig_ax = -1;
-- 
1.5.6.5

[tip:x86/urgent] x86: kernel_thread() -- initialize SS to a known state

[tip-bot for Cyrill Gorcunov]

Commit-ID:  864a0922dd128392467611d9857e5138c6a91999
Gitweb:     http://git.kernel.org/tip/864a0922dd128392467611d9857e5138c6a91999
Author:     Cyrill Gorcunov <gorcunov@openvz.org>
AuthorDate: Wed, 13 Jan 2010 10:16:07 +0000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 13 Jan 2010 11:23:45 +0100

x86: kernel_thread() -- initialize SS to a known state

Before the kernel_thread was converted into "C" we had
pt_regs::ss set to __KERNEL_DS (by SAVE_ALL asm macro).

Though I must admit I didn't find any *explicit* load of
%ss from this structure the better to be on a safe side
and set it to a known value.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1263377768-19600-1-git-send-email-ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/process.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c6ee241..02c3ee0 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -288,6 +288,8 @@ int kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
 	regs.es = __USER_DS;
 	regs.fs = __KERNEL_PERCPU;
 	regs.gs = __KERNEL_STACK_CANARY;
+#else
+	regs.ss = __KERNEL_DS;
 #endif
 
 	regs.orig_ax = -1;

[PATCH] xen: 64 bit kernel RPL should be 0.

[Ian Campbell]

Under Xen 64 bit guests actually run their kernel in ring 3, however the
hypervisor takes care of squashing descriptor the RPLs transparently (in
order to allow them to continue to differentiate between user and kernel
space CS using the RPL). Therefore the Xen paravirt backend should use
RPL==0 instead of 1 (or 3). Using RPL==1 causes generic arch code to
take incorrect code paths because it uses "testl $3, <CS>, je foo" type
tests for a userspace CS and this considers 1==userspace.

This issue was previously masked because get_kernel_rpl() was omitted
when setting CS in kernel_thread(). This was fixed when kernel_thread()
was unified with 32 bit in f443ff4201dd25cd4dec183f9919ecba90c8edc2.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
---
 arch/x86/xen/enlighten.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 2b26dd5..36daccb 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1151,9 +1151,13 @@ asmlinkage void __init xen_start_kernel(void)
 
 	/* keep using Xen gdt for now; no urgent need to change it */
 
+#ifdef CONFIG_X86_32
 	pv_info.kernel_rpl = 1;
 	if (xen_feature(XENFEAT_supervisor_mode_kernel))
 		pv_info.kernel_rpl = 0;
+#else
+	pv_info.kernel_rpl = 0;
+#endif
 
 	/* set the limit of our address space */
 	xen_reserve_top();
-- 
1.5.6.5

[tip:x86/urgent] x86: xen: 64-bit kernel RPL should be 0

[tip-bot for Ian Campbell]

Commit-ID:  e68266b7001a4e29af083716f0c36c0d6dbb1b39
Gitweb:     http://git.kernel.org/tip/e68266b7001a4e29af083716f0c36c0d6dbb1b39
Author:     Ian Campbell <ian.campbell@citrix.com>
AuthorDate: Wed, 13 Jan 2010 10:16:08 +0000
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 13 Jan 2010 11:23:54 +0100

x86: xen: 64-bit kernel RPL should be 0

Under Xen 64 bit guests actually run their kernel in ring 3,
however the hypervisor takes care of squashing descriptor the
RPLs transparently (in order to allow them to continue to
differentiate between user and kernel space CS using the RPL).
Therefore the Xen paravirt backend should use RPL==0 instead of
1 (or 3). Using RPL==1 causes generic arch code to take
incorrect code paths because it uses "testl $3, <CS>, je foo"
type tests for a userspace CS and this considers 1==userspace.

This issue was previously masked because get_kernel_rpl() was
omitted when setting CS in kernel_thread(). This was fixed when
kernel_thread() was unified with 32 bit in
f443ff4201dd25cd4dec183f9919ecba90c8edc2.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1263377768-19600-2-git-send-email-ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/xen/enlighten.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 2b26dd5..36daccb 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1151,9 +1151,13 @@ asmlinkage void __init xen_start_kernel(void)
 
 	/* keep using Xen gdt for now; no urgent need to change it */
 
+#ifdef CONFIG_X86_32
 	pv_info.kernel_rpl = 1;
 	if (xen_feature(XENFEAT_supervisor_mode_kernel))
 		pv_info.kernel_rpl = 0;
+#else
+	pv_info.kernel_rpl = 0;
+#endif
 
 	/* set the limit of our address space */
 	xen_reserve_top();