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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-15 12:19:20 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-15 12:19:20 -0400
commit1aaf2e59135fd67321f47c11c64a54aac27014e9 (patch)
tree633ffa4db3ac6e8d566cba549510561ffd61d8f4
parent66a4fe0cb80a9fde8cb173289afb863fd279466a (diff)
parent936e894a976dd3b0f07f1f6f43c17b77b7e6146d (diff)
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
-rw-r--r--Documentation/intel_txt.txt210
-rw-r--r--Documentation/x86/zero-page.txt1
-rw-r--r--arch/x86/Kconfig4
-rw-r--r--arch/x86/include/asm/bootparam.h3
-rw-r--r--arch/x86/include/asm/fixmap.h3
-rw-r--r--arch/x86/kernel/Makefile1
-rw-r--r--arch/x86/kernel/reboot.c7
-rw-r--r--arch/x86/kernel/setup.c3
-rw-r--r--arch/x86/kernel/smpboot.c2
-rw-r--r--arch/x86/kernel/tboot.c447
-rw-r--r--drivers/acpi/acpica/hwsleep.c3
-rw-r--r--drivers/pci/dmar.c7
-rw-r--r--drivers/pci/intel-iommu.c17
-rw-r--r--include/linux/tboot.h162
-rw-r--r--kernel/cpu.c1
-rw-r--r--security/Kconfig30
16 files changed, 898 insertions, 3 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 @@
1Intel(R) TXT Overview:
2=====================
3
4Intel's technology for safer computing, Intel(R) Trusted Execution
5Technology (Intel(R) TXT), defines platform-level enhancements that
6provide the building blocks for creating trusted platforms.
7
8Intel TXT was formerly known by the code name LaGrande Technology (LT).
9
10Intel TXT in Brief:
11o Provides dynamic root of trust for measurement (DRTM)
12o Data protection in case of improper shutdown
13o Measurement and verification of launched environment
14
15Intel TXT is part of the vPro(TM) brand and is also available some
16non-vPro systems. It is currently available on desktop systems
17based on the Q35, X38, Q45, and Q43 Express chipsets (e.g. Dell
18Optiplex 755, HP dc7800, etc.) and mobile systems based on the GM45,
19PM45, and GS45 Express chipsets.
20
21For more information, see http://www.intel.com/technology/security/.
22This site also has a link to the Intel TXT MLE Developers Manual,
23which has been updated for the new released platforms.
24
25Intel TXT has been presented at various events over the past few
26years, some of which are:
27 LinuxTAG 2008:
28 http://www.linuxtag.org/2008/en/conf/events/vp-donnerstag/
29 details.html?talkid=110
30 TRUST2008:
31 http://www.trust2008.eu/downloads/Keynote-Speakers/
32 3_David-Grawrock_The-Front-Door-of-Trusted-Computing.pdf
33 IDF 2008, Shanghai:
34 http://inteldeveloperforum.com.edgesuite.net/shanghai_2008/
35 aep/PROS003/index.html
36 IDFs 2006, 2007 (I'm not sure if/where they are online)
37
38Trusted Boot Project Overview:
39=============================
40
41Trusted Boot (tboot) is an open source, pre- kernel/VMM module that
42uses Intel TXT to perform a measured and verified launch of an OS
43kernel/VMM.
44
45It is hosted on SourceForge at http://sourceforge.net/projects/tboot.
46The mercurial source repo is available at http://www.bughost.org/
47repos.hg/tboot.hg.
48
49Tboot currently supports launching Xen (open source VMM/hypervisor
50w/ TXT support since v3.2), and now Linux kernels.
51
52
53Value Proposition for Linux or "Why should you care?"
54=====================================================
55
56While there are many products and technologies that attempt to
57measure or protect the integrity of a running kernel, they all
58assume the kernel is "good" to begin with. The Integrity
59Measurement Architecture (IMA) and Linux Integrity Module interface
60are examples of such solutions.
61
62To get trust in the initial kernel without using Intel TXT, a
63static root of trust must be used. This bases trust in BIOS
64starting at system reset and requires measurement of all code
65executed between system reset through the completion of the kernel
66boot as well as data objects used by that code. In the case of a
67Linux kernel, this means all of BIOS, any option ROMs, the
68bootloader and the boot config. In practice, this is a lot of
69code/data, much of which is subject to change from boot to boot
70(e.g. changing NICs may change option ROMs). Without reference
71hashes, these measurement changes are difficult to assess or
72confirm as benign. This process also does not provide DMA
73protection, memory configuration/alias checks and locks, crash
74protection, or policy support.
75
76By using the hardware-based root of trust that Intel TXT provides,
77many of these issues can be mitigated. Specifically: many
78pre-launch components can be removed from the trust chain, DMA
79protection is provided to all launched components, a large number
80of platform configuration checks are performed and values locked,
81protection is provided for any data in the event of an improper
82shutdown, and there is support for policy-based execution/verification.
83This provides a more stable measurement and a higher assurance of
84system configuration and initial state than would be otherwise
85possible. Since the tboot project is open source, source code for
86almost all parts of the trust chain is available (excepting SMM and
87Intel-provided firmware).
88
89How Does it Work?
90=================
91
92o Tboot is an executable that is launched by the bootloader as
93 the "kernel" (the binary the bootloader executes).
94o It performs all of the work necessary to determine if the
95 platform supports Intel TXT and, if so, executes the GETSEC[SENTER]
96 processor instruction that initiates the dynamic root of trust.
97 - If tboot determines that the system does not support Intel TXT
98 or is not configured correctly (e.g. the SINIT AC Module was
99 incorrect), it will directly launch the kernel with no changes
100 to any state.
101 - Tboot will output various information about its progress to the
102 terminal, serial port, and/or an in-memory log; the output
103 locations can be configured with a command line switch.
104o The GETSEC[SENTER] instruction will return control to tboot and
105 tboot then verifies certain aspects of the environment (e.g. TPM NV
106 lock, e820 table does not have invalid entries, etc.).
107o It will wake the APs from the special sleep state the GETSEC[SENTER]
108 instruction had put them in and place them into a wait-for-SIPI
109 state.
110 - Because the processors will not respond to an INIT or SIPI when
111 in the TXT environment, it is necessary to create a small VT-x
112 guest for the APs. When they run in this guest, they will
113 simply wait for the INIT-SIPI-SIPI sequence, which will cause
114 VMEXITs, and then disable VT and jump to the SIPI vector. This
115 approach seemed like a better choice than having to insert
116 special code into the kernel's MP wakeup sequence.
117o Tboot then applies an (optional) user-defined launch policy to
118 verify the kernel and initrd.
119 - This policy is rooted in TPM NV and is described in the tboot
120 project. The tboot project also contains code for tools to
121 create and provision the policy.
122 - Policies are completely under user control and if not present
123 then any kernel will be launched.
124 - Policy action is flexible and can include halting on failures
125 or simply logging them and continuing.
126o Tboot adjusts the e820 table provided by the bootloader to reserve
127 its own location in memory as well as to reserve certain other
128 TXT-related regions.
129o As part of it's launch, tboot DMA protects all of RAM (using the
130 VT-d PMRs). Thus, the kernel must be booted with 'intel_iommu=on'
131 in order to remove this blanket protection and use VT-d's
132 page-level protection.
133o Tboot will populate a shared page with some data about itself and
134 pass this to the Linux kernel as it transfers control.
135 - The location of the shared page is passed via the boot_params
136 struct as a physical address.
137o The kernel will look for the tboot shared page address and, if it
138 exists, map it.
139o As one of the checks/protections provided by TXT, it makes a copy
140 of the VT-d DMARs in a DMA-protected region of memory and verifies
141 them for correctness. The VT-d code will detect if the kernel was
142 launched with tboot and use this copy instead of the one in the
143 ACPI table.
144o At this point, tboot and TXT are out of the picture until a
145 shutdown (S<n>)
146o In order to put a system into any of the sleep states after a TXT
147 launch, TXT must first be exited. This is to prevent attacks that
148 attempt to crash the system to gain control on reboot and steal
149 data left in memory.
150 - The kernel will perform all of its sleep preparation and
151 populate the shared page with the ACPI data needed to put the
152 platform in the desired sleep state.
153 - Then the kernel jumps into tboot via the vector specified in the
154 shared page.
155 - Tboot will clean up the environment and disable TXT, then use the
156 kernel-provided ACPI information to actually place the platform
157 into the desired sleep state.
158 - In the case of S3, tboot will also register itself as the resume
159 vector. This is necessary because it must re-establish the
160 measured environment upon resume. Once the TXT environment
161 has been restored, it will restore the TPM PCRs and then
162 transfer control back to the kernel's S3 resume vector.
163 In order to preserve system integrity across S3, the kernel
164 provides tboot with a set of memory ranges (kernel
165 code/data/bss, S3 resume code, and AP trampoline) that tboot
166 will calculate a MAC (message authentication code) over and then
167 seal with the TPM. On resume and once the measured environment
168 has been re-established, tboot will re-calculate the MAC and
169 verify it against the sealed value. Tboot's policy determines
170 what happens if the verification fails.
171
172That's pretty much it for TXT support.
173
174
175Configuring the System:
176======================
177
178This code works with 32bit, 32bit PAE, and 64bit (x86_64) kernels.
179
180In BIOS, the user must enable: TPM, TXT, VT-x, VT-d. Not all BIOSes
181allow these to be individually enabled/disabled and the screens in
182which to find them are BIOS-specific.
183
184grub.conf needs to be modified as follows:
185 title Linux 2.6.29-tip w/ tboot
186 root (hd0,0)
187 kernel /tboot.gz logging=serial,vga,memory
188 module /vmlinuz-2.6.29-tip intel_iommu=on ro
189 root=LABEL=/ rhgb console=ttyS0,115200 3
190 module /initrd-2.6.29-tip.img
191 module /Q35_SINIT_17.BIN
192
193The kernel option for enabling Intel TXT support is found under the
194Security top-level menu and is called "Enable Intel(R) Trusted
195Execution Technology (TXT)". It is marked as EXPERIMENTAL and
196depends on the generic x86 support (to allow maximum flexibility in
197kernel build options), since the tboot code will detect whether the
198platform actually supports Intel TXT and thus whether any of the
199kernel code is executed.
200
201The Q35_SINIT_17.BIN file is what Intel TXT refers to as an
202Authenticated Code Module. It is specific to the chipset in the
203system and can also be found on the Trusted Boot site. It is an
204(unencrypted) module signed by Intel that is used as part of the
205DRTM process to verify and configure the system. It is signed
206because it operates at a higher privilege level in the system than
207any other macrocode and its correct operation is critical to the
208establishment of the DRTM. The process for determining the correct
209SINIT ACM for a system is documented in the SINIT-guide.txt file
210that 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
12000/040 ALL screen_info Text mode or frame buffer information 12000/040 ALL screen_info Text mode or frame buffer information
13 (struct screen_info) 13 (struct screen_info)
14040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) 14040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info)
15058/008 ALL tboot_addr Physical address of tboot shared page
15060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information 16060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information
16 (struct ist_info) 17 (struct ist_info)
17080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! 18080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!!
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fc20fdc0f7f2..74bf3e30ce75 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -179,6 +179,10 @@ config ARCH_SUPPORTS_OPTIMIZED_INLINING
179config ARCH_SUPPORTS_DEBUG_PAGEALLOC 179config ARCH_SUPPORTS_DEBUG_PAGEALLOC
180 def_bool y 180 def_bool y
181 181
182config HAVE_INTEL_TXT
183 def_bool y
184 depends on EXPERIMENTAL && DMAR && ACPI
185
182# Use the generic interrupt handling code in kernel/irq/: 186# Use the generic interrupt handling code in kernel/irq/:
183config GENERIC_HARDIRQS 187config GENERIC_HARDIRQS
184 bool 188 bool
diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
index 1724e8de317c..6ca20218dd72 100644
--- a/arch/x86/include/asm/bootparam.h
+++ b/arch/x86/include/asm/bootparam.h
@@ -85,7 +85,8 @@ struct efi_info {
85struct boot_params { 85struct boot_params {
86 struct screen_info screen_info; /* 0x000 */ 86 struct screen_info screen_info; /* 0x000 */
87 struct apm_bios_info apm_bios_info; /* 0x040 */ 87 struct apm_bios_info apm_bios_info; /* 0x040 */
88 __u8 _pad2[12]; /* 0x054 */ 88 __u8 _pad2[4]; /* 0x054 */
89 __u64 tboot_addr; /* 0x058 */
89 struct ist_info ist_info; /* 0x060 */ 90 struct ist_info ist_info; /* 0x060 */
90 __u8 _pad3[16]; /* 0x070 */ 91 __u8 _pad3[16]; /* 0x070 */
91 __u8 hd0_info[16]; /* obsolete! */ /* 0x080 */ 92 __u8 hd0_info[16]; /* obsolete! */ /* 0x080 */
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 7b2d71df39a6..14f9890eb495 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -132,6 +132,9 @@ enum fixed_addresses {
132#ifdef CONFIG_X86_32 132#ifdef CONFIG_X86_32
133 FIX_WP_TEST, 133 FIX_WP_TEST,
134#endif 134#endif
135#ifdef CONFIG_INTEL_TXT
136 FIX_TBOOT_BASE,
137#endif
135 __end_of_fixed_addresses 138 __end_of_fixed_addresses
136}; 139};
137 140
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 430d5b24af7b..832cb838cb48 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_X86_DS_SELFTEST) += ds_selftest.o
52obj-$(CONFIG_X86_32) += tls.o 52obj-$(CONFIG_X86_32) += tls.o
53obj-$(CONFIG_IA32_EMULATION) += tls.o 53obj-$(CONFIG_IA32_EMULATION) += tls.o
54obj-y += step.o 54obj-y += step.o
55obj-$(CONFIG_INTEL_TXT) += tboot.o
55obj-$(CONFIG_STACKTRACE) += stacktrace.o 56obj-$(CONFIG_STACKTRACE) += stacktrace.o
56obj-y += cpu/ 57obj-y += cpu/
57obj-y += acpi/ 58obj-y += acpi/
diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index a06e8d101844..27349f92a6d7 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -4,6 +4,7 @@
4#include <linux/pm.h> 4#include <linux/pm.h>
5#include <linux/efi.h> 5#include <linux/efi.h>
6#include <linux/dmi.h> 6#include <linux/dmi.h>
7#include <linux/tboot.h>
7#include <acpi/reboot.h> 8#include <acpi/reboot.h>
8#include <asm/io.h> 9#include <asm/io.h>
9#include <asm/apic.h> 10#include <asm/apic.h>
@@ -508,6 +509,8 @@ static void native_machine_emergency_restart(void)
508 if (reboot_emergency) 509 if (reboot_emergency)
509 emergency_vmx_disable_all(); 510 emergency_vmx_disable_all();
510 511
512 tboot_shutdown(TB_SHUTDOWN_REBOOT);
513
511 /* Tell the BIOS if we want cold or warm reboot */ 514 /* Tell the BIOS if we want cold or warm reboot */
512 *((unsigned short *)__va(0x472)) = reboot_mode; 515 *((unsigned short *)__va(0x472)) = reboot_mode;
513 516
@@ -634,6 +637,8 @@ static void native_machine_halt(void)
634 /* stop other cpus and apics */ 637 /* stop other cpus and apics */
635 machine_shutdown(); 638 machine_shutdown();
636 639
640 tboot_shutdown(TB_SHUTDOWN_HALT);
641
637 /* stop this cpu */ 642 /* stop this cpu */
638 stop_this_cpu(NULL); 643 stop_this_cpu(NULL);
639} 644}
@@ -645,6 +650,8 @@ static void native_machine_power_off(void)
645 machine_shutdown(); 650 machine_shutdown();
646 pm_power_off(); 651 pm_power_off();
647 } 652 }
653 /* a fallback in case there is no PM info available */
654 tboot_shutdown(TB_SHUTDOWN_HALT);
648} 655}
649 656
650struct machine_ops machine_ops = { 657struct machine_ops machine_ops = {
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 63f32d220ef2..61f86f241420 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -66,6 +66,7 @@
66 66
67#include <linux/percpu.h> 67#include <linux/percpu.h>
68#include <linux/crash_dump.h> 68#include <linux/crash_dump.h>
69#include <linux/tboot.h>
69 70
70#include <video/edid.h> 71#include <video/edid.h>
71 72
@@ -977,6 +978,8 @@ void __init setup_arch(char **cmdline_p)
977 paravirt_pagetable_setup_done(swapper_pg_dir); 978 paravirt_pagetable_setup_done(swapper_pg_dir);
978 paravirt_post_allocator_init(); 979 paravirt_post_allocator_init();
979 980
981 tboot_probe();
982
980#ifdef CONFIG_X86_64 983#ifdef CONFIG_X86_64
981 map_vsyscall(); 984 map_vsyscall();
982#endif 985#endif
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index c36cc1452cdc..9d8319183aae 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -47,6 +47,7 @@
47#include <linux/bootmem.h> 47#include <linux/bootmem.h>
48#include <linux/err.h> 48#include <linux/err.h>
49#include <linux/nmi.h> 49#include <linux/nmi.h>
50#include <linux/tboot.h>
50 51
51#include <asm/acpi.h> 52#include <asm/acpi.h>
52#include <asm/desc.h> 53#include <asm/desc.h>
@@ -1318,6 +1319,7 @@ void play_dead_common(void)
1318void native_play_dead(void) 1319void native_play_dead(void)
1319{ 1320{
1320 play_dead_common(); 1321 play_dead_common();
1322 tboot_shutdown(TB_SHUTDOWN_WFS);
1321 wbinvd_halt(); 1323 wbinvd_halt();
1322} 1324}
1323 1325
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
new file mode 100644
index 000000000000..86c9f91b48ae
--- /dev/null
+++ b/arch/x86/kernel/tboot.c
@@ -0,0 +1,447 @@
1/*
2 * tboot.c: main implementation of helper functions used by kernel for
3 * runtime support of Intel(R) Trusted Execution Technology
4 *
5 * Copyright (c) 2006-2009, Intel Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 */
21
22#include <linux/dma_remapping.h>
23#include <linux/init_task.h>
24#include <linux/spinlock.h>
25#include <linux/delay.h>
26#include <linux/sched.h>
27#include <linux/init.h>
28#include <linux/dmar.h>
29#include <linux/cpu.h>
30#include <linux/pfn.h>
31#include <linux/mm.h>
32#include <linux/tboot.h>
33
34#include <asm/trampoline.h>
35#include <asm/processor.h>
36#include <asm/bootparam.h>
37#include <asm/pgtable.h>
38#include <asm/pgalloc.h>
39#include <asm/fixmap.h>
40#include <asm/proto.h>
41#include <asm/setup.h>
42#include <asm/e820.h>
43#include <asm/io.h>
44
45#include "acpi/realmode/wakeup.h"
46
47/* Global pointer to shared data; NULL means no measured launch. */
48struct tboot *tboot __read_mostly;
49
50/* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
51#define AP_WAIT_TIMEOUT 1
52
53#undef pr_fmt
54#define pr_fmt(fmt) "tboot: " fmt
55
56static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
57
58void __init tboot_probe(void)
59{
60 /* Look for valid page-aligned address for shared page. */
61 if (!boot_params.tboot_addr)
62 return;
63 /*
64 * also verify that it is mapped as we expect it before calling
65 * set_fixmap(), to reduce chance of garbage value causing crash
66 */
67 if (!e820_any_mapped(boot_params.tboot_addr,
68 boot_params.tboot_addr, E820_RESERVED)) {
69 pr_warning("non-0 tboot_addr but it is not of type E820_RESERVED\n");
70 return;
71 }
72
73 /* only a natively booted kernel should be using TXT */
74 if (paravirt_enabled()) {
75 pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
76 return;
77 }
78
79 /* Map and check for tboot UUID. */
80 set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
81 tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
82 if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
83 pr_warning("tboot at 0x%llx is invalid\n",
84 boot_params.tboot_addr);
85 tboot = NULL;
86 return;
87 }
88 if (tboot->version < 5) {
89 pr_warning("tboot version is invalid: %u\n", tboot->version);
90 tboot = NULL;
91 return;
92 }
93
94 pr_info("found shared page at phys addr 0x%llx:\n",
95 boot_params.tboot_addr);
96 pr_debug("version: %d\n", tboot->version);
97 pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
98 pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
99 pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
100 pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
101}
102
103static pgd_t *tboot_pg_dir;
104static struct mm_struct tboot_mm = {
105 .mm_rb = RB_ROOT,
106 .pgd = swapper_pg_dir,
107 .mm_users = ATOMIC_INIT(2),
108 .mm_count = ATOMIC_INIT(1),
109 .mmap_sem = __RWSEM_INITIALIZER(init_mm.mmap_sem),
110 .page_table_lock = __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
111 .mmlist = LIST_HEAD_INIT(init_mm.mmlist),
112 .cpu_vm_mask = CPU_MASK_ALL,
113};
114
115static inline void switch_to_tboot_pt(void)
116{
117 write_cr3(virt_to_phys(tboot_pg_dir));
118}
119
120static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
121 pgprot_t prot)
122{
123 pgd_t *pgd;
124 pud_t *pud;
125 pmd_t *pmd;
126 pte_t *pte;
127
128 pgd = pgd_offset(&tboot_mm, vaddr);
129 pud = pud_alloc(&tboot_mm, pgd, vaddr);
130 if (!pud)
131 return -1;
132 pmd = pmd_alloc(&tboot_mm, pud, vaddr);
133 if (!pmd)
134 return -1;
135 pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
136 if (!pte)
137 return -1;
138 set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
139 pte_unmap(pte);
140 return 0;
141}
142
143static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
144 unsigned long nr)
145{
146 /* Reuse the original kernel mapping */
147 tboot_pg_dir = pgd_alloc(&tboot_mm);
148 if (!tboot_pg_dir)
149 return -1;
150
151 for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
152 if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
153 return -1;
154 }
155
156 return 0;
157}
158
159static void tboot_create_trampoline(void)
160{
161 u32 map_base, map_size;
162
163 /* Create identity map for tboot shutdown code. */
164 map_base = PFN_DOWN(tboot->tboot_base);
165 map_size = PFN_UP(tboot->tboot_size);
166 if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
167 panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n",
168 map_base, map_size);
169}
170
171#ifdef CONFIG_ACPI_SLEEP
172
173static void add_mac_region(phys_addr_t start, unsigned long size)
174{
175 struct tboot_mac_region *mr;
176 phys_addr_t end = start + size;
177
178 if (start && size) {
179 mr = &tboot->mac_regions[tboot->num_mac_regions++];
180 mr->start = round_down(start, PAGE_SIZE);
181 mr->size = round_up(end, PAGE_SIZE) - mr->start;
182 }
183}
184
185static int tboot_setup_sleep(void)
186{
187 tboot->num_mac_regions = 0;
188
189 /* S3 resume code */
190 add_mac_region(acpi_wakeup_address, WAKEUP_SIZE);
191
192#ifdef CONFIG_X86_TRAMPOLINE
193 /* AP trampoline code */
194 add_mac_region(virt_to_phys(trampoline_base), TRAMPOLINE_SIZE);
195#endif
196
197 /* kernel code + data + bss */
198 add_mac_region(virt_to_phys(_text), _end - _text);
199
200 tboot->acpi_sinfo.kernel_s3_resume_vector = acpi_wakeup_address;
201
202 return 0;
203}
204
205#else /* no CONFIG_ACPI_SLEEP */
206
207static int tboot_setup_sleep(void)
208{
209 /* S3 shutdown requested, but S3 not supported by the kernel... */
210 BUG();
211 return -1;
212}
213
214#endif
215
216void tboot_shutdown(u32 shutdown_type)
217{
218 void (*shutdown)(void);
219
220 if (!tboot_enabled())
221 return;
222
223 /*
224 * if we're being called before the 1:1 mapping is set up then just
225 * return and let the normal shutdown happen; this should only be
226 * due to very early panic()
227 */
228 if (!tboot_pg_dir)
229 return;
230
231 /* if this is S3 then set regions to MAC */
232 if (shutdown_type == TB_SHUTDOWN_S3)
233 if (tboot_setup_sleep())
234 return;
235
236 tboot->shutdown_type = shutdown_type;
237
238 switch_to_tboot_pt();
239
240 shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
241 shutdown();
242
243 /* should not reach here */
244 while (1)
245 halt();
246}
247
248static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
249{
250#define TB_COPY_GAS(tbg, g) \
251 tbg.space_id = g.space_id; \
252 tbg.bit_width = g.bit_width; \
253 tbg.bit_offset = g.bit_offset; \
254 tbg.access_width = g.access_width; \
255 tbg.address = g.address;
256
257 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
258 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
259 TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
260 TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
261
262 /*
263 * We need phys addr of waking vector, but can't use virt_to_phys() on
264 * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
265 * addr.
266 */
267 tboot->acpi_sinfo.wakeup_vector = fadt->facs +
268 offsetof(struct acpi_table_facs, firmware_waking_vector);
269}
270
271void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
272{
273 static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
274 /* S0,1,2: */ -1, -1, -1,
275 /* S3: */ TB_SHUTDOWN_S3,
276 /* S4: */ TB_SHUTDOWN_S4,
277 /* S5: */ TB_SHUTDOWN_S5 };
278
279 if (!tboot_enabled())
280 return;
281
282 tboot_copy_fadt(&acpi_gbl_FADT);
283 tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
284 tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
285 /* we always use the 32b wakeup vector */
286 tboot->acpi_sinfo.vector_width = 32;
287
288 if (sleep_state >= ACPI_S_STATE_COUNT ||
289 acpi_shutdown_map[sleep_state] == -1) {
290 pr_warning("unsupported sleep state 0x%x\n", sleep_state);
291 return;
292 }
293
294 tboot_shutdown(acpi_shutdown_map[sleep_state]);
295}
296
297static atomic_t ap_wfs_count;
298
299static int tboot_wait_for_aps(int num_aps)
300{
301 unsigned long timeout;
302
303 timeout = AP_WAIT_TIMEOUT*HZ;
304 while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
305 timeout) {
306 mdelay(1);
307 timeout--;
308 }
309
310 if (timeout)
311 pr_warning("tboot wait for APs timeout\n");
312
313 return !(atomic_read((atomic_t *)&tboot->num_in_wfs) == num_aps);
314}
315
316static int __cpuinit tboot_cpu_callback(struct notifier_block *nfb,
317 unsigned long action, void *hcpu)
318{
319 switch (action) {
320 case CPU_DYING:
321 atomic_inc(&ap_wfs_count);
322 if (num_online_cpus() == 1)
323 if (tboot_wait_for_aps(atomic_read(&ap_wfs_count)))
324 return NOTIFY_BAD;
325 break;
326 }
327 return NOTIFY_OK;
328}
329
330static struct notifier_block tboot_cpu_notifier __cpuinitdata =
331{
332 .notifier_call = tboot_cpu_callback,
333};
334
335static __init int tboot_late_init(void)
336{
337 if (!tboot_enabled())
338 return 0;
339
340 tboot_create_trampoline();
341
342 atomic_set(&ap_wfs_count, 0);
343 register_hotcpu_notifier(&tboot_cpu_notifier);
344 return 0;
345}
346
347late_initcall(tboot_late_init);
348
349/*
350 * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
351 */
352
353#define TXT_PUB_CONFIG_REGS_BASE 0xfed30000
354#define TXT_PRIV_CONFIG_REGS_BASE 0xfed20000
355
356/* # pages for each config regs space - used by fixmap */
357#define NR_TXT_CONFIG_PAGES ((TXT_PUB_CONFIG_REGS_BASE - \
358 TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
359
360/* offsets from pub/priv config space */
361#define TXTCR_HEAP_BASE 0x0300
362#define TXTCR_HEAP_SIZE 0x0308
363
364#define SHA1_SIZE 20
365
366struct sha1_hash {
367 u8 hash[SHA1_SIZE];
368};
369
370struct sinit_mle_data {
371 u32 version; /* currently 6 */
372 struct sha1_hash bios_acm_id;
373 u32 edx_senter_flags;
374 u64 mseg_valid;
375 struct sha1_hash sinit_hash;
376 struct sha1_hash mle_hash;
377 struct sha1_hash stm_hash;
378 struct sha1_hash lcp_policy_hash;
379 u32 lcp_policy_control;
380 u32 rlp_wakeup_addr;
381 u32 reserved;
382 u32 num_mdrs;
383 u32 mdrs_off;
384 u32 num_vtd_dmars;
385 u32 vtd_dmars_off;
386} __packed;
387
388struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
389{
390 void *heap_base, *heap_ptr, *config;
391
392 if (!tboot_enabled())
393 return dmar_tbl;
394
395 /*
396 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
397 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
398 */
399
400 /* map config space in order to get heap addr */
401 config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
402 PAGE_SIZE);
403 if (!config)
404 return NULL;
405
406 /* now map TXT heap */
407 heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
408 *(u64 *)(config + TXTCR_HEAP_SIZE));
409 iounmap(config);
410 if (!heap_base)
411 return NULL;
412
413 /* walk heap to SinitMleData */
414 /* skip BiosData */
415 heap_ptr = heap_base + *(u64 *)heap_base;
416 /* skip OsMleData */
417 heap_ptr += *(u64 *)heap_ptr;
418 /* skip OsSinitData */
419 heap_ptr += *(u64 *)heap_ptr;
420 /* now points to SinitMleDataSize; set to SinitMleData */
421 heap_ptr += sizeof(u64);
422 /* get addr of DMAR table */
423 dmar_tbl = (struct acpi_table_header *)(heap_ptr +
424 ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
425 sizeof(u64));
426
427 /* don't unmap heap because dmar.c needs access to this */
428
429 return dmar_tbl;
430}
431
432int tboot_force_iommu(void)
433{
434 if (!tboot_enabled())
435 return 0;
436
437 if (no_iommu || swiotlb || dmar_disabled)
438 pr_warning("Forcing Intel-IOMMU to enabled\n");
439
440 dmar_disabled = 0;
441#ifdef CONFIG_SWIOTLB
442 swiotlb = 0;
443#endif
444 no_iommu = 0;
445
446 return 1;
447}
diff --git a/drivers/acpi/acpica/hwsleep.c b/drivers/acpi/acpica/hwsleep.c
index db307a356f08..cc22f9a585b0 100644
--- a/drivers/acpi/acpica/hwsleep.c
+++ b/drivers/acpi/acpica/hwsleep.c
@@ -45,6 +45,7 @@
45#include <acpi/acpi.h> 45#include <acpi/acpi.h>
46#include "accommon.h" 46#include "accommon.h"
47#include "actables.h" 47#include "actables.h"
48#include <linux/tboot.h>
48 49
49#define _COMPONENT ACPI_HARDWARE 50#define _COMPONENT ACPI_HARDWARE
50ACPI_MODULE_NAME("hwsleep") 51ACPI_MODULE_NAME("hwsleep")
@@ -342,6 +343,8 @@ acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state)
342 343
343 ACPI_FLUSH_CPU_CACHE(); 344 ACPI_FLUSH_CPU_CACHE();
344 345
346 tboot_sleep(sleep_state, pm1a_control, pm1b_control);
347
345 /* Write #2: Write both SLP_TYP + SLP_EN */ 348 /* Write #2: Write both SLP_TYP + SLP_EN */
346 349
347 status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control); 350 status = acpi_hw_write_pm1_control(pm1a_control, pm1b_control);
diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index 7b287cb38b7a..ab99783dccec 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -33,6 +33,7 @@
33#include <linux/timer.h> 33#include <linux/timer.h>
34#include <linux/irq.h> 34#include <linux/irq.h>
35#include <linux/interrupt.h> 35#include <linux/interrupt.h>
36#include <linux/tboot.h>
36 37
37#undef PREFIX 38#undef PREFIX
38#define PREFIX "DMAR:" 39#define PREFIX "DMAR:"
@@ -413,6 +414,12 @@ parse_dmar_table(void)
413 */ 414 */
414 dmar_table_detect(); 415 dmar_table_detect();
415 416
417 /*
418 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
419 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
420 */
421 dmar_tbl = tboot_get_dmar_table(dmar_tbl);
422
416 dmar = (struct acpi_table_dmar *)dmar_tbl; 423 dmar = (struct acpi_table_dmar *)dmar_tbl;
417 if (!dmar) 424 if (!dmar)
418 return -ENODEV; 425 return -ENODEV;
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 2314ad7ee5fe..562221e11917 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -37,6 +37,7 @@
37#include <linux/iommu.h> 37#include <linux/iommu.h>
38#include <linux/intel-iommu.h> 38#include <linux/intel-iommu.h>
39#include <linux/sysdev.h> 39#include <linux/sysdev.h>
40#include <linux/tboot.h>
40#include <asm/cacheflush.h> 41#include <asm/cacheflush.h>
41#include <asm/iommu.h> 42#include <asm/iommu.h>
42#include "pci.h" 43#include "pci.h"
@@ -3183,12 +3184,22 @@ static int __init init_iommu_sysfs(void)
3183int __init intel_iommu_init(void) 3184int __init intel_iommu_init(void)
3184{ 3185{
3185 int ret = 0; 3186 int ret = 0;
3187 int force_on = 0;
3186 3188
3187 if (dmar_table_init()) 3189 /* VT-d is required for a TXT/tboot launch, so enforce that */
3190 force_on = tboot_force_iommu();
3191
3192 if (dmar_table_init()) {
3193 if (force_on)
3194 panic("tboot: Failed to initialize DMAR table\n");
3188 return -ENODEV; 3195 return -ENODEV;
3196 }
3189 3197
3190 if (dmar_dev_scope_init()) 3198 if (dmar_dev_scope_init()) {
3199 if (force_on)
3200 panic("tboot: Failed to initialize DMAR device scope\n");
3191 return -ENODEV; 3201 return -ENODEV;
3202 }
3192 3203
3193 /* 3204 /*
3194 * Check the need for DMA-remapping initialization now. 3205 * Check the need for DMA-remapping initialization now.
@@ -3204,6 +3215,8 @@ int __init intel_iommu_init(void)
3204 3215
3205 ret = init_dmars(); 3216 ret = init_dmars();
3206 if (ret) { 3217 if (ret) {
3218 if (force_on)
3219 panic("tboot: Failed to initialize DMARs\n");
3207 printk(KERN_ERR "IOMMU: dmar init failed\n"); 3220 printk(KERN_ERR "IOMMU: dmar init failed\n");
3208 put_iova_domain(&reserved_iova_list); 3221 put_iova_domain(&reserved_iova_list);
3209 iommu_exit_mempool(); 3222 iommu_exit_mempool();
diff --git a/include/linux/tboot.h b/include/linux/tboot.h
new file mode 100644
index 000000000000..bf2a0c748878
--- /dev/null
+++ b/include/linux/tboot.h
@@ -0,0 +1,162 @@
1/*
2 * tboot.h: shared data structure with tboot and kernel and functions
3 * used by kernel for runtime support of Intel(R) Trusted
4 * Execution Technology
5 *
6 * Copyright (c) 2006-2009, Intel Corporation
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program; if not, write to the Free Software Foundation, Inc.,
19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 */
22
23#ifndef _LINUX_TBOOT_H
24#define _LINUX_TBOOT_H
25
26/* these must have the values from 0-5 in this order */
27enum {
28 TB_SHUTDOWN_REBOOT = 0,
29 TB_SHUTDOWN_S5,
30 TB_SHUTDOWN_S4,
31 TB_SHUTDOWN_S3,
32 TB_SHUTDOWN_HALT,
33 TB_SHUTDOWN_WFS
34};
35
36#ifdef CONFIG_INTEL_TXT
37#include <acpi/acpi.h>
38/* used to communicate between tboot and the launched kernel */
39
40#define TB_KEY_SIZE 64 /* 512 bits */
41
42#define MAX_TB_MAC_REGIONS 32
43
44struct tboot_mac_region {
45 u64 start; /* must be 64 byte -aligned */
46 u32 size; /* must be 64 byte -granular */
47} __packed;
48
49/* GAS - Generic Address Structure (ACPI 2.0+) */
50struct tboot_acpi_generic_address {
51 u8 space_id;
52 u8 bit_width;
53 u8 bit_offset;
54 u8 access_width;
55 u64 address;
56} __packed;
57
58/*
59 * combines Sx info from FADT and FACS tables per ACPI 2.0+ spec
60 * (http://www.acpi.info/)
61 */
62struct tboot_acpi_sleep_info {
63 struct tboot_acpi_generic_address pm1a_cnt_blk;
64 struct tboot_acpi_generic_address pm1b_cnt_blk;
65 struct tboot_acpi_generic_address pm1a_evt_blk;
66 struct tboot_acpi_generic_address pm1b_evt_blk;
67 u16 pm1a_cnt_val;
68 u16 pm1b_cnt_val;
69 u64 wakeup_vector;
70 u32 vector_width;
71 u64 kernel_s3_resume_vector;
72} __packed;
73
74/*
75 * shared memory page used for communication between tboot and kernel
76 */
77struct tboot {
78 /*
79 * version 3+ fields:
80 */
81
82 /* TBOOT_UUID */
83 u8 uuid[16];
84
85 /* version number: 5 is current */
86 u32 version;
87
88 /* physical addr of tb_log_t log */
89 u32 log_addr;
90
91 /*
92 * physical addr of entry point for tboot shutdown and
93 * type of shutdown (TB_SHUTDOWN_*) being requested
94 */
95 u32 shutdown_entry;
96 u32 shutdown_type;
97
98 /* kernel-specified ACPI info for Sx shutdown */
99 struct tboot_acpi_sleep_info acpi_sinfo;
100
101 /* tboot location in memory (physical) */
102 u32 tboot_base;
103 u32 tboot_size;
104
105 /* memory regions (phys addrs) for tboot to MAC on S3 */
106 u8 num_mac_regions;
107 struct tboot_mac_region mac_regions[MAX_TB_MAC_REGIONS];
108
109
110 /*
111 * version 4+ fields:
112 */
113
114 /* symmetric key for use by kernel; will be encrypted on S3 */
115 u8 s3_key[TB_KEY_SIZE];
116
117
118 /*
119 * version 5+ fields:
120 */
121
122 /* used to 4byte-align num_in_wfs */
123 u8 reserved_align[3];
124
125 /* number of processors in wait-for-SIPI */
126 u32 num_in_wfs;
127} __packed;
128
129/*
130 * UUID for tboot data struct to facilitate matching
131 * defined as {663C8DFF-E8B3-4b82-AABF-19EA4D057A08} by tboot, which is
132 * represented as {} in the char array used here
133 */
134#define TBOOT_UUID {0xff, 0x8d, 0x3c, 0x66, 0xb3, 0xe8, 0x82, 0x4b, 0xbf,\
135 0xaa, 0x19, 0xea, 0x4d, 0x5, 0x7a, 0x8}
136
137extern struct tboot *tboot;
138
139static inline int tboot_enabled(void)
140{
141 return tboot != NULL;
142}
143
144extern void tboot_probe(void);
145extern void tboot_shutdown(u32 shutdown_type);
146extern void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control);
147extern struct acpi_table_header *tboot_get_dmar_table(
148 struct acpi_table_header *dmar_tbl);
149extern int tboot_force_iommu(void);
150
151#else
152
153#define tboot_probe() do { } while (0)
154#define tboot_shutdown(shutdown_type) do { } while (0)
155#define tboot_sleep(sleep_state, pm1a_control, pm1b_control) \
156 do { } while (0)
157#define tboot_get_dmar_table(dmar_tbl) (dmar_tbl)
158#define tboot_force_iommu() 0
159
160#endif /* !CONFIG_INTEL_TXT */
161
162#endif /* _LINUX_TBOOT_H */
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 8ce10043e4ac..67a60076dd7e 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -401,6 +401,7 @@ int disable_nonboot_cpus(void)
401 break; 401 break;
402 } 402 }
403 } 403 }
404
404 if (!error) { 405 if (!error) {
405 BUG_ON(num_online_cpus() > 1); 406 BUG_ON(num_online_cpus() > 1);
406 /* Make sure the CPUs won't be enabled by someone else */ 407 /* Make sure the CPUs won't be enabled by someone else */
diff --git a/security/Kconfig b/security/Kconfig
index 4c865345caa0..fb363cd81cf6 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -113,6 +113,36 @@ config SECURITY_ROOTPLUG
113 113
114 If you are unsure how to answer this question, answer N. 114 If you are unsure how to answer this question, answer N.
115 115
116config INTEL_TXT
117 bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
118 depends on HAVE_INTEL_TXT
119 help
120 This option enables support for booting the kernel with the
121 Trusted Boot (tboot) module. This will utilize
122 Intel(R) Trusted Execution Technology to perform a measured launch
123 of the kernel. If the system does not support Intel(R) TXT, this
124 will have no effect.
125
126 Intel TXT will provide higher assurance of system configuration and
127 initial state as well as data reset protection. This is used to
128 create a robust initial kernel measurement and verification, which
129 helps to ensure that kernel security mechanisms are functioning
130 correctly. This level of protection requires a root of trust outside
131 of the kernel itself.
132
133 Intel TXT also helps solve real end user concerns about having
134 confidence that their hardware is running the VMM or kernel that
135 it was configured with, especially since they may be responsible for
136 providing such assurances to VMs and services running on it.
137
138 See <http://www.intel.com/technology/security/> for more information
139 about Intel(R) TXT.
140 See <http://tboot.sourceforge.net> for more information about tboot.
141 See Documentation/intel_txt.txt for a description of how to enable
142 Intel TXT support in a kernel boot.
143
144 If you are unsure as to whether this is required, answer N.
145
116config LSM_MMAP_MIN_ADDR 146config LSM_MMAP_MIN_ADDR
117 int "Low address space for LSM to protect from user allocation" 147 int "Low address space for LSM to protect from user allocation"
118 depends on SECURITY && SECURITY_SELINUX 148 depends on SECURITY && SECURITY_SELINUX