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:

    b3b42ac2 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: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NH. 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

The SGI Visual Workstation seems to be dead; remove support so we
don't have to continue maintaining it.

Cc: Andrey Panin <pazke@donpac.ru>
Cc: Michael Reed <mdr@sgi.com>
Link: http://lkml.kernel.org/r/530CFD6C.7040705@zytor.comSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

The ramdisk can possibly get relocated if the whole image is not mapped.
And since we're going over it in the microcode loader and fishing out
the relevant microcode patches, we want access it at its new location.
Thus, export it.
Signed-off-by: NBorislav Petkov <bp@suse.de>
Tested-by: NAravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>

mrst is used as common name to represent all intel_mid type
soc's. But moorsetwon is just one of the intel_mid soc. So
renamed them to use intel_mid.

This patch mainly renames the variables and related
functions that uses *mrst* prefix with *intel_mid*.

To ensure that there are no functional changes, I have compared
the objdump of related files before and after rename and found
the only difference is symbol and name changes.
Signed-off-by: NKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: http://lkml.kernel.org/r/1382049336-21316-6-git-send-email-david.a.cohen@linux.intel.comSigned-off-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Obviously these functions have to be visible, otherwise
the whole kernel could be optimized away.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-5-git-send-email-andi@firstfloor.orgSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NMichael Kerrisk <mtk.manpages@gmail.com>
Acked-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: NDave Jones <davej@redhat.com>

This sets all up the other bits that need to be INTEL_MID
specific rather than Moorestown specific.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Link: http://lkml.kernel.org/r/20111217174318.7207.91543.stgit@bob.linux.org.ukSigned-off-by: NIngo Molnar <mingo@elte.hu>

The section called .discard.text has tracing attached to it and is
currently ignored by ftrace. But it does include a call to the mcount
stub. Adding a notrace to the code keeps gcc from adding the useless
mcount caller to it.

Link: http://lkml.kernel.org/r/20110421023739.243651696@goodmis.orgSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

The section called .discard.text has tracing attached to it and is
currently ignored by ftrace. But it does include a call to the mcount
stub. Adding a notrace to the code keeps gcc from adding the useless
mcount caller to it.

Link: http://lkml.kernel.org/r/20110421023739.243651696@goodmis.orgSigned-off-by: NSteven Rostedt <rostedt@goodmis.org>

The isci driver needs to retrieve its preboot OROM image which contains
necessary runtime parameters like platform specific sas addresses and
phy configuration.  There is no ROM BAR associated with this area,
instead we will need to scan legacy expansion ROM space.

1/ Promote the probe_roms_32 implementation to x86-64
2/ Add a facility to find and map an adapter rom by pci device (according to
   PCI Firmware Specification Revision 3.0)
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
LKML-Reference: <20110308183226.6246.90354.stgit@localhost6.localdomain6>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Add CE4100 platform support. CE4100 needs early setup like
moorestown.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NDirk Brandewie <dirk.brandewie@gmail.com>
LKML-Reference: <94720fd7f5564a12ebf202cf2c4f4c0d619aab35.1289331834.git.dirk.brandewie@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Useful when converting static arrays into boottime brk allocated objects.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

This is useful when converting static arrays into boot-time brk
allocated objects.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
LKML-Reference: <4C805EEA.1080205@goop.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

gcc 4.4.4 will complain if you use a .discard section for both text and
data ("causes a section type conflict").  Add support for ".discard.*"
sections, and use .discard.text for a dummy function in the x86
RESERVE_BRK() macro.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

The PCI initialization in pci_subsys_init() is a mess. pci_numaq_init,
pci_acpi_init, pci_visws_init and pci_legacy_init are called and each
implementation checks and eventually modifies the global variable
pcibios_scanned.

x86_init functions allow us to do this more elegant. The pci.init
function pointer is preset to pci_legacy_init. numaq, acpi and visws
can modify the pointer in their early setup functions. The functions
return 0 when they did the full initialization including bus scan. A
non zero return value indicates that pci_legacy_init needs to be
called either because the selected function failed or wants the
generic bus scan in pci_legacy_init to happen (e.g. visws).
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80CFE@orsmsx508.amr.corp.intel.com>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NJacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Moorestown MID devices need to be detected early in the boot process
to setup and do not call x86_default_early_setup as there is no EBDA
region to reserve.

[ Copied the minimal code from Jacobs latest MRST series ]
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Jacob Pan <jacob.jun.pan@intel.com>

The timer init code is convoluted with several quirks and the paravirt
timer chooser. Figuring out which code path is actually taken is not
for the faint hearted.

Move the numaq TSC quirk to tsc_pre_init x86_init_ops function and
replace the paravirt time chooser and the remaining x86 quirk with a
simple x86_init_ops function.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

We really do not need two paravirt/x86_init_ops functions which are
called in two consecutive source lines. Move the only user of
post_allocator_init into the already existing pagetable_setup_done
function.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Replace the quirks by a simple x86_init_ops function.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

irq_init is overridden by x86_quirks and by paravirts. Unify the whole
mess and make it an unconditional x86_init_ops function which defaults
to the standard function and can be overridden by the early platform
code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Replace the quirk machinery by a x86_init_ops function which
defaults to the standard implementation. This is also a preparatory
patch for Moorestown support which needs to replace the default
init_ISA_irqs as well.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Replace the quirk machinery by a x86_init_ops function which defaults
to the standard implementation.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Move smp_read_mpc_oem from quirks to x86_init.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The mpc_apic_id setup is handled by a x86_quirk. Make it a
x86_init_ops function with a default implementation.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

32bit and also the numaq code have special requirements on the
ioapic_id setup. Convert it to a x86_init_ops function and get rid
of the quirks and #ifdefs
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The x86 quirkification introduced an extra ugly hackery with a
variable pointer in the mpparse code. If the pointer is initialized
then it is dereferenced and the variable set to 0 or incremented.

Create a x86_init_ops function and let the affected numaq code
hold the function. Default init is a setup noop.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

memory_setup is overridden by x86_quirks and by paravirts with weak
functions and quirks. Unify the whole mess and make it an
unconditional x86_init_ops function which defaults to the standard
function and can be overridden by the early platform code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The 32bit and the 64bit code are slighty different in the reservation
of standard resources. Also the upcoming Moorestown support needs its
own version of that.

Add it to x86_init_ops and initialize it with the 64bit default. 32bit
overrides it in early boot. Now moorestown can add it's own override
w/o sprinkling the code with more #ifdefs
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The upcoming Moorestown support brings the embedded world to x86. The
setup code of x86 has already a couple of hooks which are either
x86_quirks or paravirt ops. Some of those setup hooks are pretty
convoluted like the timer setup and the tsc calibration code. But
there are other places which could do with a cleanup.

Instead of having inline functions/macros which are modified at
compile time I decided to introduce x86_init ops which are
unconditional in the code and make it clear that they can be changed
either during compile time or in the early boot process. The function
pointers are initialized by default functions which can be noops so
that the pointer can be called unconditionally in the most cases. This
also allows us to remove 32bit/64bit, paravirt and other #ifdeffery.

paravirt guests are just a hardware platform in the setup code, so we
should treat them as such and not hide all behind multiple layers of
indirection and compile time dependencies.

It's more obvious that x86_init.timers.timer_init() is a function
pointer than the late_time_init = choose_time_init() obscurity. It's
also way simpler to grep for x86_init.timers.timer_init and find all
the places which modify that function pointer instead of analyzing
weak functions, macros and paravirt indirections.

Note. This is not a general paravirt_ops replacement. It just will
move setup related hooks which are potentially useful for other
platform setup purposes as well out of the paravirt domain.

Add the base infrastructure without any functionality.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Impact: cleanup

In preparation for unifying irqinit_{32,64}.c, make
x86_quirk_pre_intr_init() local to irqinit_32.c.

Reviewed-by Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

'make headers_check' warn us about leaking of kernel private
(mostly compile time vars) data to userspace in headers. Fix it.

Guard this one by __KERNEL__.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Partial revert of commit 129d8bc8
titled 'x86: don't compile vsmp_64 for 32bit'

Commit reverted to compile vsmp_64.c if CONFIG_X86_64 is defined,
since is_vsmp_box() needs to indicate that TSCs are not synchronized, and
hence, not a valid time source, even when CONFIG_X86_VSMP is not defined.
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: shai@scalex86.org
LKML-Reference: <20090324061429.GH7278@localdomain>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: bulletproofing, clarification

The brk reservation symbols are just there to document the amount
of space reserved by brk users in the final vmlinux file.  Their
addresses are irrelevent, and using their addresses will cause
certain havok.  Name them ".brk.NAME", which is a valid asm symbol
but C can't reference it; it also highlights their special
role in the symbol table.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Impact: new interface; remove hard-coded limit

Add RESERVE_BRK(name, size) macro to reserve space in the brk
area.  This should be a conservative (ie, larger) estimate of
how much space might possibly be required from the brk area.
Any unused space will be freed, so there's no real downside
on making the reservation too large (within limits).

The name should be unique within a given file, and somewhat
descriptive.

The C definition of RESERVE_BRK() ends up being more complex than
one would expect to work around a cluster of gcc infelicities:

  The first attempt was to simply try putting __section(.brk_reservation)
  on a variable.  This doesn't work because it ends up making it a
  @progbits section, which gets actual space allocated in the vmlinux
  executable.

  The second attempt was to emit the space into a section using asm,
  but gcc doesn't allow arguments to be passed to file-level asm()
  statements, making it hard to pass in the size.

  The final attempt is to wrap the asm() in a function to allow
  it to have arguments, and put the function itself into the
  .discard section, which vmlinux*.lds drops entirely from the
  emitted vmlinux.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: use new interface instead of previous ad hoc implementation

Rather than having special purpose init_pg_table_start/end variables
to delimit the kernel pagetable built by head_32.S, just use the brk
mechanism to extend the bss for the new pagetable.

This patch removes init_pg_table_start/end and pg0, defines __brk_base
(which is page-aligned and immediately follows _end), initializes
the brk region to start there, and uses it for the 32-bit pagetable.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: new interface

Add a brk()-like allocator which effectively extends the bss in order
to allow very early code to do dynamic allocations.  This is better than
using statically allocated arrays for data in subsystems which may never
get used.

The space for brk allocations is in the bss ELF segment, so that the
space is mapped properly by the code which maps the kernel, and so
that bootloaders keep the space free rather than putting a ramdisk or
something into it.

The bss itself, delimited by __bss_stop, ends before the brk area
(__brk_base to __brk_limit).  The kernel text, data and bss is reserved
up to __bss_stop.

Any brk-allocated data is reserved separately just before the kernel
pagetable is built, as that code allocates from unreserved spaces
in the e820 map, potentially allocating from any unused brk memory.
Ultimately any unused memory in the brk area is used in the general
kernel memory pool.

Initially the brk space is set to 1MB, which is probably much larger
than any user needs (the largest current user is i386 head_32.S's code
to build the pagetables to map the kernel, which can get fairly large
with a big kernel image and no PSE support).  So long as the system
has sufficient memory for the bootloader to reserve the kernel+1MB brk,
there are no bad effects resulting from an over-large brk.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: cleanup

that is only needed when CONFIG_X86_VSMP is defined with 64bit
also remove dead code about PCI, because CONFIG_X86_VSMP depends on PCI
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

x86_quirks->update_apic() calling looks crazy. so try to remove it:

 1. every apic take wakeup_cpu member directly
 2. separate es7000_apic to es7000_apic_cluster
 3. use uv_wakeup_cpu directly
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>