Merge branch 'x86-txt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-txt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, intel_txt: clean up the impact on generic code, unbreak non-x86
  x86, intel_txt: Handle ACPI_SLEEP without X86_TRAMPOLINE
  x86, intel_txt: Fix typos in Kconfig help
  x86, intel_txt: Factor out the code for S3 setup
  x86, intel_txt: tboot.c needs <asm/fixmap.h>
  intel_txt: Force IOMMU on for Intel TXT launch
  x86, intel_txt: Intel TXT Sx shutdown support
  x86, intel_txt: Intel TXT reboot/halt shutdown support
  x86, intel_txt: Intel TXT boot support

2 files changed, 211 insertions, 0 deletions

diff --git a/Documentation/intel_txt.txt b/Documentation/intel_txt.txt
new file mode 100644
index 000000000000..f40a1f030019
--- /dev/null
+++ b/Documentation/intel_txt.txt
@@ -0,0 +1,210 @@
+Intel(R) TXT Overview:
+=====================
+
+Intel's technology for safer computing, Intel(R) Trusted Execution
+Technology (Intel(R) TXT), defines platform-level enhancements that
+provide the building blocks for creating trusted platforms.
+
+Intel TXT was formerly known by the code name LaGrande Technology (LT).
+
+Intel TXT in Brief:
+o  Provides dynamic root of trust for measurement (DRTM)
+o  Data protection in case of improper shutdown
+o  Measurement and verification of launched environment
+
+Intel TXT is part of the vPro(TM) brand and is also available some
+non-vPro systems.  It is currently available on desktop systems
+based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell
+Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45,
+PM45, and GS45 Express chipsets.
+
+For more information, see http://www.intel.com/technology/security/.
+This site also has a link to the Intel TXT MLE Developers Manual,
+which has been updated for the new released platforms.
+
+Intel TXT has been presented at various events over the past few
+years, some of which are:
+      LinuxTAG 2008:
+          http://www.linuxtag.org/2008/en/conf/events/vp-donnerstag/
+          details.html?talkid=110
+      TRUST2008:
+          http://www.trust2008.eu/downloads/Keynote-Speakers/
+          3_David-Grawrock_The-Front-Door-of-Trusted-Computing.pdf
+      IDF 2008, Shanghai:
+          http://inteldeveloperforum.com.edgesuite.net/shanghai_2008/
+          aep/PROS003/index.html
+      IDFs 2006, 2007 (I'm not sure if/where they are online)
+
+Trusted Boot Project Overview:
+=============================
+
+Trusted Boot (tboot) is an open source, pre- kernel/VMM module that
+uses Intel TXT to perform a measured and verified launch of an OS
+kernel/VMM.
+
+It is hosted on SourceForge at http://sourceforge.net/projects/tboot.
+The mercurial source repo is available at http://www.bughost.org/
+repos.hg/tboot.hg.
+
+Tboot currently supports launching Xen (open source VMM/hypervisor
+w/ TXT support since v3.2), and now Linux kernels.
+
+
+Value Proposition for Linux or "Why should you care?"
+=====================================================
+
+While there are many products and technologies that attempt to
+measure or protect the integrity of a running kernel, they all
+assume the kernel is "good" to begin with.  The Integrity
+Measurement Architecture (IMA) and Linux Integrity Module interface
+are examples of such solutions.
+
+To get trust in the initial kernel without using Intel TXT, a
+static root of trust must be used.  This bases trust in BIOS
+starting at system reset and requires measurement of all code
+executed between system reset through the completion of the kernel
+boot as well as data objects used by that code.  In the case of a
+Linux kernel, this means all of BIOS, any option ROMs, the
+bootloader and the boot config.  In practice, this is a lot of
+code/data, much of which is subject to change from boot to boot
+(e.g. changing NICs may change option ROMs).  Without reference
+hashes, these measurement changes are difficult to assess or
+confirm as benign.  This process also does not provide DMA
+protection, memory configuration/alias checks and locks, crash
+protection, or policy support.
+
+By using the hardware-based root of trust that Intel TXT provides,
+many of these issues can be mitigated.  Specifically: many
+pre-launch components can be removed from the trust chain, DMA
+protection is provided to all launched components, a large number
+of platform configuration checks are performed and values locked,
+protection is provided for any data in the event of an improper
+shutdown, and there is support for policy-based execution/verification.
+This provides a more stable measurement and a higher assurance of
+system configuration and initial state than would be otherwise
+possible.  Since the tboot project is open source, source code for
+almost all parts of the trust chain is available (excepting SMM and
+Intel-provided firmware).
+
+How Does it Work?
+=================
+
+o  Tboot is an executable that is launched by the bootloader as
+   the "kernel" (the binary the bootloader executes).
+o  It performs all of the work necessary to determine if the
+   platform supports Intel TXT and, if so, executes the GETSEC[SENTER]
+   processor instruction that initiates the dynamic root of trust.
+   -  If tboot determines that the system does not support Intel TXT
+      or is not configured correctly (e.g. the SINIT AC Module was
+      incorrect), it will directly launch the kernel with no changes
+      to any state.
+   -  Tboot will output various information about its progress to the
+      terminal, serial port, and/or an in-memory log; the output
+      locations can be configured with a command line switch.
+o  The GETSEC[SENTER] instruction will return control to tboot and
+   tboot then verifies certain aspects of the environment (e.g. TPM NV
+   lock, e820 table does not have invalid entries, etc.).
+o  It will wake the APs from the special sleep state the GETSEC[SENTER]
+   instruction had put them in and place them into a wait-for-SIPI
+   state.
+   -  Because the processors will not respond to an INIT or SIPI when
+      in the TXT environment, it is necessary to create a small VT-x
+      guest for the APs.  When they run in this guest, they will
+      simply wait for the INIT-SIPI-SIPI sequence, which will cause
+      VMEXITs, and then disable VT and jump to the SIPI vector.  This
+      approach seemed like a better choice than having to insert
+      special code into the kernel's MP wakeup sequence.
+o  Tboot then applies an (optional) user-defined launch policy to
+   verify the kernel and initrd.
+   -  This policy is rooted in TPM NV and is described in the tboot
+      project.  The tboot project also contains code for tools to
+      create and provision the policy.
+   -  Policies are completely under user control and if not present
+      then any kernel will be launched.
+   -  Policy action is flexible and can include halting on failures
+      or simply logging them and continuing.
+o  Tboot adjusts the e820 table provided by the bootloader to reserve
+   its own location in memory as well as to reserve certain other
+   TXT-related regions.
+o  As part of it's launch, tboot DMA protects all of RAM (using the
+   VT-d PMRs).  Thus, the kernel must be booted with 'intel_iommu=on'
+   in order to remove this blanket protection and use VT-d's
+   page-level protection.
+o  Tboot will populate a shared page with some data about itself and
+   pass this to the Linux kernel as it transfers control.
+   -  The location of the shared page is passed via the boot_params
+      struct as a physical address.
+o  The kernel will look for the tboot shared page address and, if it
+   exists, map it.
+o  As one of the checks/protections provided by TXT, it makes a copy
+   of the VT-d DMARs in a DMA-protected region of memory and verifies
+   them for correctness.  The VT-d code will detect if the kernel was
+   launched with tboot and use this copy instead of the one in the
+   ACPI table.
+o  At this point, tboot and TXT are out of the picture until a
+   shutdown (S<n>)
+o  In order to put a system into any of the sleep states after a TXT
+   launch, TXT must first be exited.  This is to prevent attacks that
+   attempt to crash the system to gain control on reboot and steal
+   data left in memory.
+   -  The kernel will perform all of its sleep preparation and
+      populate the shared page with the ACPI data needed to put the
+      platform in the desired sleep state.
+   -  Then the kernel jumps into tboot via the vector specified in the
+      shared page.
+   -  Tboot will clean up the environment and disable TXT, then use the
+      kernel-provided ACPI information to actually place the platform
+      into the desired sleep state.
+   -  In the case of S3, tboot will also register itself as the resume
+      vector.  This is necessary because it must re-establish the
+      measured environment upon resume.  Once the TXT environment
+      has been restored, it will restore the TPM PCRs and then
+      transfer control back to the kernel's S3 resume vector.
+      In order to preserve system integrity across S3, the kernel
+      provides tboot with a set of memory ranges (kernel
+      code/data/bss, S3 resume code, and AP trampoline) that tboot
+      will calculate a MAC (message authentication code) over and then
+      seal with the TPM.  On resume and once the measured environment
+      has been re-established, tboot will re-calculate the MAC and
+      verify it against the sealed value.  Tboot's policy determines
+      what happens if the verification fails.
+
+That's pretty much it for TXT support.
+
+
+Configuring the System:
+======================
+
+This code works with 32bit, 32bit PAE, and 64bit (x86_64) kernels.
+
+In BIOS, the user must enable:  TPM, TXT, VT-x, VT-d.  Not all BIOSes
+allow these to be individually enabled/disabled and the screens in
+which to find them are BIOS-specific.
+
+grub.conf needs to be modified as follows:
+        title Linux 2.6.29-tip w/ tboot
+          root (hd0,0)
+                kernel /tboot.gz logging=serial,vga,memory
+                module /vmlinuz-2.6.29-tip intel_iommu=on ro
+                       root=LABEL=/ rhgb console=ttyS0,115200 3
+                module /initrd-2.6.29-tip.img
+                module /Q35_SINIT_17.BIN
+
+The kernel option for enabling Intel TXT support is found under the
+Security top-level menu and is called "Enable Intel(R) Trusted
+Execution Technology (TXT)".  It is marked as EXPERIMENTAL and
+depends on the generic x86 support (to allow maximum flexibility in
+kernel build options), since the tboot code will detect whether the
+platform actually supports Intel TXT and thus whether any of the
+kernel code is executed.
+
+The Q35_SINIT_17.BIN file is what Intel TXT refers to as an
+Authenticated Code Module.  It is specific to the chipset in the
+system and can also be found on the Trusted Boot site.  It is an
+(unencrypted) module signed by Intel that is used as part of the
+DRTM process to verify and configure the system.  It is signed
+because it operates at a higher privilege level in the system than
+any other macrocode and its correct operation is critical to the
+establishment of the DRTM.  The process for determining the correct
+SINIT ACM for a system is documented in the SINIT-guide.txt file
+that is on the tboot SourceForge site under the SINIT ACM downloads.
diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index 4f913857b8a2..feb37e177010 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -12,6 +12,7 @@ Offset	Proto	Name		Meaning
 000/040 ALL     screen_info     Text mode or frame buffer information
                                 (struct screen_info)
 040/014 ALL     apm_bios_info   APM BIOS information (struct apm_bios_info)
+058/008 ALL     tboot_addr      Physical address of tboot shared page
 060/010 ALL     ist_info        Intel SpeedStep (IST) BIOS support information
                                 (struct ist_info)
 080/010 ALL     hd0_info        hd0 disk parameter, OBSOLETE!!