linux-stable.git/arch, branch v3.14.16 Linux kernel stable tree x86/espfix/xen: Fix allocation of pages for paravirt page tables 2014-08-07T21:52:39+00:00 Boris Ostrovsky boris.ostrovsky@oracle.com 2014-07-09T17:18:18+00:00 d2d34110bee55c04a7ad74aa99ad2ef15ff5c011 commit 8762e5092828c4dc0f49da5a47a644c670df77f3 upstream. init_espfix_ap() is currently off by one level when informing hypervisor that allocated pages will be used for ministacks' page tables. The most immediate effect of this on a PV guest is that if 'stack_page = __get_free_page()' returns a non-zeroed-out page the hypervisor will refuse to use it for a page table (which it shouldn't be anyway). This will result in warnings by both Xen and Linux. More importantly, a subsequent write to that page (again, by a PV guest) is likely to result in fatal page fault. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: http://lkml.kernel.org/r/1404926298-5565-1-git-send-email-boris.ostrovsky@oracle.com Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8762e5092828c4dc0f49da5a47a644c670df77f3 upstream.

init_espfix_ap() is currently off by one level when informing hypervisor
that allocated pages will be used for ministacks' page tables.

The most immediate effect of this on a PV guest is that if
'stack_page = __get_free_page()' returns a non-zeroed-out page the hypervisor
will refuse to use it for a page table (which it shouldn't be anyway). This will
result in warnings by both Xen and Linux.

More importantly, a subsequent write to that page (again, by a PV guest) is
likely to result in fatal page fault.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: http://lkml.kernel.org/r/1404926298-5565-1-git-send-email-boris.ostrovsky@oracle.com
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xtensa: add fixup for double exception raised in window overflow 2014-08-07T21:52:39+00:00 Max Filippov jcmvbkbc@gmail.com 2014-05-24T17:48:28+00:00 e4cbf9a98c9ed2d1578399928bb101dca7b95c5e commit 17290231df16eeee5dfc198dbf5ee4b419996dcd upstream. There are two FIXMEs in the double exception handler 'for the extremely unlikely case'. This case gets hit by gcc during kernel build once in a few hours, resulting in an unrecoverable exception condition. Provide missing fixup routine to handle this case. Double exception literals now need 8 more bytes, add them to the linker script. Also replace bbsi instructions with bbsi.l as we're branching depending on 8th and 7th LSB-based bits of exception address. This may be tested by adding the explicit DTLB invalidation to window overflow handlers, like the following: # --- a/arch/xtensa/kernel/vectors.S # +++ b/arch/xtensa/kernel/vectors.S # @@ -592,6 +592,14 @@ ENDPROC(_WindowUnderflow4) # ENTRY_ALIGN64(_WindowOverflow8) # # s32e a0, a9, -16 # + bbsi.l a9, 31, 1f # + rsr a0, ccount # + bbsi.l a0, 4, 1f # + pdtlb a0, a9 # + idtlb a0 # + movi a0, 9 # + idtlb a0 # +1: # l32e a0, a1, -12 # s32e a2, a9, -8 # s32e a1, a9, -12 Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 17290231df16eeee5dfc198dbf5ee4b419996dcd upstream.

There are two FIXMEs in the double exception handler 'for the extremely
unlikely case'. This case gets hit by gcc during kernel build once in
a few hours, resulting in an unrecoverable exception condition.

Provide missing fixup routine to handle this case. Double exception
literals now need 8 more bytes, add them to the linker script.

Also replace bbsi instructions with bbsi.l as we're branching depending
on 8th and 7th LSB-based bits of exception address.

This may be tested by adding the explicit DTLB invalidation to window
overflow handlers, like the following:

#    --- a/arch/xtensa/kernel/vectors.S
#    +++ b/arch/xtensa/kernel/vectors.S
#    @@ -592,6 +592,14 @@ ENDPROC(_WindowUnderflow4)
#     ENTRY_ALIGN64(_WindowOverflow8)
#
#    	s32e	a0, a9, -16
#    +	bbsi.l	a9, 31, 1f
#    +	rsr	a0, ccount
#    +	bbsi.l	a0, 4, 1f
#    +	pdtlb	a0, a9
#    +	idtlb	a0
#    +	movi	a0, 9
#    +	idtlb	a0
#    +1:
#    	l32e    a0, a1, -12
#    	s32e    a2, a9,  -8
#    	s32e    a1, a9, -12

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/xen: no need to explicitly register an NMI callback 2014-08-07T21:52:39+00:00 David Vrabel david.vrabel@citrix.com 2014-06-16T11:07:00+00:00 c1bf0e867cb6364eb4e17c757120ae01d4623a0e commit ea9f9274bf4337ba7cbab241c780487651642d63 upstream. Remove xen_enable_nmi() to fix a 64-bit guest crash when registering the NMI callback on Xen 3.1 and earlier. It's not needed since the NMI callback is set by a set_trap_table hypercall (in xen_load_idt() or xen_write_idt_entry()). It's also broken since it only set the current VCPU's callback. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com> Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Steven Noonan <steven@uplinklabs.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ea9f9274bf4337ba7cbab241c780487651642d63 upstream.

Remove xen_enable_nmi() to fix a 64-bit guest crash when registering
the NMI callback on Xen 3.1 and earlier.

It's not needed since the NMI callback is set by a set_trap_table
hypercall (in xen_load_idt() or xen_write_idt_entry()).

It's also broken since it only set the current VCPU's callback.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ARM: dts: dra7-evm: Make VDDA_1V8_PHY supply always on 2014-08-07T21:52:38+00:00 Roger Quadros rogerq@ti.com 2014-07-04T09:55:43+00:00 87f493856c36f6030b74b78f8cb631984964ad67 commit e120fb459693bbc1ac3eabdd65c3659d7cfbfd2a upstream. After clarification from the hardware team it was found that this 1.8V PHY supply can't be switched OFF when SoC is Active. Since the PHY IPs don't contain isolation logic built in the design to allow the power rail to be switched off, there is a very high risk of IP reliability and additional leakage paths which can result in additional power consumption. The only scenario where this rail can be switched off is part of Power on reset sequencing, but it needs to be kept always-on during operation. This patch is required for proper functionality of USB, SATA and PCIe on DRA7-evm. CC: Rajendra Nayak <rnayak@ti.com> CC: Tero Kristo <t-kristo@ti.com> Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e120fb459693bbc1ac3eabdd65c3659d7cfbfd2a upstream.

After clarification from the hardware team it was found that
this 1.8V PHY supply can't be switched OFF when SoC is Active.

Since the PHY IPs don't contain isolation logic built in the design to
allow the power rail to be switched off, there is a very high risk
of IP reliability and additional leakage paths which can result in
additional power consumption.

The only scenario where this rail can be switched off is part of Power on
reset sequencing, but it needs to be kept always-on during operation.

This patch is required for proper functionality of USB, SATA
and PCIe on DRA7-evm.

CC: Rajendra Nayak <rnayak@ti.com>
CC: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86_64/entry/xen: Do not invoke espfix64 on Xen 2014-08-07T21:52:38+00:00 Andy Lutomirski luto@amacapital.net 2014-07-23T15:34:11+00:00 74020e9499a3df5e5f21d9f22c980e510fa8dfe0 commit 7209a75d2009dbf7745e2fd354abf25c3deb3ca3 upstream. This moves the espfix64 logic into native_iret. To make this work, it gets rid of the native patch for INTERRUPT_RETURN: INTERRUPT_RETURN on native kernels is now 'jmp native_iret'. This changes the 16-bit SS behavior on Xen from OOPSing to leaking some bits of the Xen hypervisor's RSP (I think). [ hpa: this is a nonzero cost on native, but probably not enough to measure. Xen needs to fix this in their own code, probably doing something equivalent to espfix64. ] Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1406129132.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7209a75d2009dbf7745e2fd354abf25c3deb3ca3 upstream.

This moves the espfix64 logic into native_iret.  To make this work,
it gets rid of the native patch for INTERRUPT_RETURN:
INTERRUPT_RETURN on native kernels is now 'jmp native_iret'.

This changes the 16-bit SS behavior on Xen from OOPSing to leaking
some bits of the Xen hypervisor's RSP (I think).

[ hpa: this is a nonzero cost on native, but probably not enough to
  measure. Xen needs to fix this in their own code, probably doing
  something equivalent to espfix64. ]

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/7b8f1d8ef6597cb16ae004a43c56980a7de3cf94.1406129132.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86, espfix: Make it possible to disable 16-bit support 2014-08-07T21:52:38+00:00 H. Peter Anvin hpa@zytor.com 2014-05-04T17:36:22+00:00 345e588e67c56983be11816c8af9b1767b6b4907 commit 34273f41d57ee8d854dcd2a1d754cbb546cb548f upstream. Embedded systems, which may be very memory-size-sensitive, are extremely unlikely to ever encounter any 16-bit software, so make it a CONFIG_EXPERT option to turn off support for any 16-bit software whatsoever. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 34273f41d57ee8d854dcd2a1d754cbb546cb548f upstream.

Embedded systems, which may be very memory-size-sensitive, are
extremely unlikely to ever encounter any 16-bit software, so make it
a CONFIG_EXPERT option to turn off support for any 16-bit software
whatsoever.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86, espfix: Make espfix64 a Kconfig option, fix UML 2014-08-07T21:52:38+00:00 H. Peter Anvin hpa@zytor.com 2014-05-04T17:00:49+00:00 09aaa9748aa1aea0b2fa339a823b754285c8ad6c commit 197725de65477bc8509b41388157c1a2283542bb upstream. Make espfix64 a hidden Kconfig option. This fixes the x86-64 UML build which had broken due to the non-existence of init_espfix_bsp() in UML: since UML uses its own Kconfig, this option does not appear in the UML build. This also makes it possible to make support for 16-bit segments a configuration option, for the people who want to minimize the size of the kernel. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Richard Weinberger <richard@nod.at> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 197725de65477bc8509b41388157c1a2283542bb upstream.

Make espfix64 a hidden Kconfig option.  This fixes the x86-64 UML
build which had broken due to the non-existence of init_espfix_bsp()
in UML: since UML uses its own Kconfig, this option does not appear in
the UML build.

This also makes it possible to make support for 16-bit segments a
configuration option, for the people who want to minimize the size of
the kernel.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86, espfix: Fix broken header guard 2014-08-07T21:52:38+00:00 H. Peter Anvin hpa@linux.intel.com 2014-05-02T18:33:51+00:00 1ce1f063cc68d326ed6c303d4c1a8bcca6fce35f commit 20b68535cd27183ebd3651ff313afb2b97dac941 upstream. Header guard is #ifndef, not #ifdef... Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 20b68535cd27183ebd3651ff313afb2b97dac941 upstream.

Header guard is #ifndef, not #ifdef...

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86, espfix: Move espfix definitions into a separate header file 2014-08-07T21:52:38+00:00 H. Peter Anvin hpa@linux.intel.com 2014-05-01T21:12:23+00:00 5e03b3d8ef01cddcbd1a7200406327e27451822e commit e1fe9ed8d2a4937510d0d60e20705035c2609aea upstream. Sparse warns that the percpu variables aren't declared before they are defined. Rather than hacking around it, move espfix definitions into a proper header file. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e1fe9ed8d2a4937510d0d60e20705035c2609aea upstream.

Sparse warns that the percpu variables aren't declared before they are
defined.  Rather than hacking around it, move espfix definitions into
a proper header file.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stack 2014-08-07T21:52:38+00:00 H. Peter Anvin hpa@linux.intel.com 2014-04-29T23:46:09+00:00 7ecbe6e0a0b46ea942117cec3a588edff1fb8057 commit 3891a04aafd668686239349ea58f3314ea2af86b upstream. The IRET instruction, when returning to a 16-bit segment, only restores the bottom 16 bits of the user space stack pointer. This causes some 16-bit software to break, but it also leaks kernel state to user space. We have a software workaround for that ("espfix") for the 32-bit kernel, but it relies on a nonzero stack segment base which is not available in 64-bit mode. In checkin: b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels we "solved" this by forbidding 16-bit segments on 64-bit kernels, with the logic that 16-bit support is crippled on 64-bit kernels anyway (no V86 support), but it turns out that people are doing stuff like running old Win16 binaries under Wine and expect it to work. This works around this by creating percpu "ministacks", each of which is mapped 2^16 times 64K apart. When we detect that the return SS is on the LDT, we copy the IRET frame to the ministack and use the relevant alias to return to userspace. The ministacks are mapped readonly, so if IRET faults we promote #GP to #DF which is an IST vector and thus has its own stack; we then do the fixup in the #DF handler. (Making #GP an IST exception would make the msr_safe functions unsafe in NMI/MC context, and quite possibly have other effects.) Special thanks to: - Andy Lutomirski, for the suggestion of using very small stack slots and copy (as opposed to map) the IRET frame there, and for the suggestion to mark them readonly and let the fault promote to #DF. - Konrad Wilk for paravirt fixup and testing. - Borislav Petkov for testing help and useful comments. Reported-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andrew Lutomriski <amluto@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dirk Hohndel <dirk@hohndel.org> Cc: Arjan van de Ven <arjan.van.de.ven@intel.com> Cc: comex <comexk@gmail.com> Cc: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: <stable@vger.kernel.org> # consider after upstream merge Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3891a04aafd668686239349ea58f3314ea2af86b upstream.

The IRET instruction, when returning to a 16-bit segment, only
restores the bottom 16 bits of the user space stack pointer.  This
causes some 16-bit software to break, but it also leaks kernel state
to user space.  We have a software workaround for that ("espfix") for
the 32-bit kernel, but it relies on a nonzero stack segment base which
is not available in 64-bit mode.

In checkin:

    b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels

we "solved" this by forbidding 16-bit segments on 64-bit kernels, with
the logic that 16-bit support is crippled on 64-bit kernels anyway (no
V86 support), but it turns out that people are doing stuff like
running old Win16 binaries under Wine and expect it to work.

This works around this by creating percpu "ministacks", each of which
is mapped 2^16 times 64K apart.  When we detect that the return SS is
on the LDT, we copy the IRET frame to the ministack and use the
relevant alias to return to userspace.  The ministacks are mapped
readonly, so if IRET faults we promote #GP to #DF which is an IST
vector and thus has its own stack; we then do the fixup in the #DF
handler.

(Making #GP an IST exception would make the msr_safe functions unsafe
in NMI/MC context, and quite possibly have other effects.)

Special thanks to:

- Andy Lutomirski, for the suggestion of using very small stack slots
  and copy (as opposed to map) the IRET frame there, and for the
  suggestion to mark them readonly and let the fault promote to #DF.
- Konrad Wilk for paravirt fixup and testing.
- Borislav Petkov for testing help and useful comments.

Reported-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andrew Lutomriski <amluto@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dirk Hohndel <dirk@hohndel.org>
Cc: Arjan van de Ven <arjan.van.de.ven@intel.com>
Cc: comex <comexk@gmail.com>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: <stable@vger.kernel.org> # consider after upstream merge
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>