x86, intel_txt: Intel TXT boot support

This patch adds kernel configuration and boot support for Intel Trusted
Execution Technology (Intel TXT).

Intel's technology for safer computing, Intel Trusted Execution
Technology (Intel 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.

A much more complete description of how these patches support TXT, how to
configure a system for it, etc. is in the Documentation/intel_txt.txt file
in this patch.

This patch provides the TXT support routines for complete functionality,
documentation for TXT support and for the changes to the boot_params structure,
and boot detection of a TXT launch.  Attempts to shutdown (reboot, Sx) the system
will result in platform resets; subsequent patches will support these shutdown modes
properly.

 Documentation/intel_txt.txt      |  210 +++++++++++++++++++++
 Documentation/x86/zero-page.txt  |    1
 arch/x86/include/asm/bootparam.h |    3
 arch/x86/include/asm/fixmap.h    |    3
 arch/x86/include/asm/tboot.h     |  197 ++++++++++++++++++++
 arch/x86/kernel/Makefile         |    1
 arch/x86/kernel/setup.c          |    4
 arch/x86/kernel/tboot.c          |  379 +++++++++++++++++++++++++++++++++++++++
 security/Kconfig                 |   30 +++
 9 files changed, 827 insertions(+), 1 deletion(-)
Signed-off-by: Joseph Cihula <joseph.cihula@intel.com>
Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Gang Wei <gang.wei@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

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!!

arch/x86/include/asm/bootparam.h

@@ -85,7 +85,8 @@ struct efi_info {
 struct boot_params {
 	struct screen_info screen_info;			/* 0x000 */
 	struct apm_bios_info apm_bios_info;		/* 0x040 */
-	__u8  _pad2[12];				/* 0x054 */
+	__u8  _pad2[4];					/* 0x054 */
+	__u64  tboot_addr;				/* 0x058 */
 	struct ist_info ist_info;			/* 0x060 */
 	__u8  _pad3[16];				/* 0x070 */
 	__u8  hd0_info[16];	/* obsolete! */		/* 0x080 */

arch/x86/include/asm/fixmap.h

@@ -131,6 +131,9 @@ enum fixed_addresses {
 #endif
 #ifdef CONFIG_X86_32
 	FIX_WP_TEST,
+#endif
+#ifdef CONFIG_INTEL_TXT
+	FIX_TBOOT_BASE,
 #endif
 	__end_of_fixed_addresses
 };

arch/x86/include/asm/tboot.h

+/*
+ * tboot.h: shared data structure with tboot and kernel and functions
+ *          used by kernel for runtime support of Intel(R) Trusted
+ *          Execution Technology
+ *
+ * Copyright (c) 2006-2009, Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef _ASM_TBOOT_H
+#define _ASM_TBOOT_H
+
+#include <acpi/acpi.h>
+
+/* these must have the values from 0-5 in this order */
+enum {
+	TB_SHUTDOWN_REBOOT = 0,
+	TB_SHUTDOWN_S5,
+	TB_SHUTDOWN_S4,
+	TB_SHUTDOWN_S3,
+	TB_SHUTDOWN_HALT,
+	TB_SHUTDOWN_WFS
+};
+
+#ifdef CONFIG_INTEL_TXT
+
+/* used to communicate between tboot and the launched kernel */
+
+#define TB_KEY_SIZE             64   /* 512 bits */
+
+#define MAX_TB_MAC_REGIONS      32
+
+struct tboot_mac_region {
+	u64  start;         /* must be 64 byte -aligned */
+	u32  size;          /* must be 64 byte -granular */
+} __packed;
+
+/* GAS - Generic Address Structure (ACPI 2.0+) */
+struct tboot_acpi_generic_address {
+	u8  space_id;
+	u8  bit_width;
+	u8  bit_offset;
+	u8  access_width;
+	u64 address;
+} __packed;
+
+/*
+ * combines Sx info from FADT and FACS tables per ACPI 2.0+ spec
+ * (http://www.acpi.info/)
+ */
+struct tboot_acpi_sleep_info {
+	struct tboot_acpi_generic_address pm1a_cnt_blk;
+	struct tboot_acpi_generic_address pm1b_cnt_blk;
+	struct tboot_acpi_generic_address pm1a_evt_blk;
+	struct tboot_acpi_generic_address pm1b_evt_blk;
+	u16 pm1a_cnt_val;
+	u16 pm1b_cnt_val;
+	u64 wakeup_vector;
+	u32 vector_width;
+	u64 kernel_s3_resume_vector;
+} __packed;
+
+/*
+ * shared memory page used for communication between tboot and kernel
+ */
+struct tboot {
+	/*
+	 * version 3+ fields:
+	 */
+
+	/* TBOOT_UUID */
+	u8 uuid[16];
+
+	/* version number: 5 is current */
+	u32 version;
+
+	/* physical addr of tb_log_t log */
+	u32 log_addr;
+
+	/*
+	 * physical addr of entry point for tboot shutdown and
+	 * type of shutdown (TB_SHUTDOWN_*) being requested
+	 */
+	u32 shutdown_entry;
+	u32 shutdown_type;
+
+	/* kernel-specified ACPI info for Sx shutdown */
+	struct tboot_acpi_sleep_info acpi_sinfo;
+
+	/* tboot location in memory (physical) */
+	u32 tboot_base;
+	u32 tboot_size;
+
+	/* memory regions (phys addrs) for tboot to MAC on S3 */
+	u8 num_mac_regions;
+	struct tboot_mac_region mac_regions[MAX_TB_MAC_REGIONS];
+
+
+	/*
+	 * version 4+ fields:
+	 */
+
+	/* symmetric key for use by kernel; will be encrypted on S3 */
+	u8 s3_key[TB_KEY_SIZE];
+
+
+	/*
+	 * version 5+ fields:
+	 */
+
+	/* used to 4byte-align num_in_wfs */
+	u8 reserved_align[3];
+
+	/* number of processors in wait-for-SIPI */
+	u32 num_in_wfs;
+} __packed;
+
+/*
+ * UUID for tboot data struct to facilitate matching
+ * defined as {663C8DFF-E8B3-4b82-AABF-19EA4D057A08} by tboot, which is
+ * represented as {} in the char array used here
+ */
+#define TBOOT_UUID	{0xff, 0x8d, 0x3c, 0x66, 0xb3, 0xe8, 0x82, 0x4b, 0xbf,\
+			 0xaa, 0x19, 0xea, 0x4d, 0x5, 0x7a, 0x8}
+
+extern struct tboot *tboot;
+
+static inline int tboot_enabled(void)
+{
+	return tboot != NULL;
+}
+
+extern void tboot_probe(void);
+extern void tboot_create_trampoline(void);
+extern void tboot_shutdown(u32 shutdown_type);
+extern void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control);
+extern int tboot_wait_for_aps(int num_aps);
+extern struct acpi_table_header *tboot_get_dmar_table(
+				      struct acpi_table_header *dmar_tbl);
+extern int tboot_force_iommu(void);
+
+#else     /* CONFIG_INTEL_TXT */
+
+static inline int tboot_enabled(void)
+{
+	return 0;
+}
+
+static inline void tboot_probe(void)
+{
+}
+
+static inline void tboot_create_trampoline(void)
+{
+}
+
+static inline void tboot_shutdown(u32 shutdown_type)
+{
+}
+
+static inline void tboot_sleep(u8 sleep_state, u32 pm1a_control,
+			       u32 pm1b_control)
+{
+}
+
+static inline int tboot_wait_for_aps(int num_aps)
+{
+	return 0;
+}
+
+static inline struct acpi_table_header *tboot_get_dmar_table(
+					struct acpi_table_header *dmar_tbl)
+{
+	return dmar_tbl;
+}
+
+static inline int tboot_force_iommu(void)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_INTEL_TXT */
+
+#endif /* _ASM_TBOOT_H */

arch/x86/kernel/Makefile

@@ -52,6 +52,7 @@ obj-$(CONFIG_X86_DS_SELFTEST)		+= ds_selftest.o
 obj-$(CONFIG_X86_32)		+= tls.o
 obj-$(CONFIG_IA32_EMULATION)	+= tls.o
 obj-y				+= step.o
+obj-$(CONFIG_INTEL_TXT)		+= tboot.o
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-y				+= cpu/
 obj-y				+= acpi/

arch/x86/kernel/setup.c

@@ -145,6 +145,8 @@ struct boot_params __initdata boot_params;
 struct boot_params boot_params;
 #endif
 
+#include <asm/tboot.h>
+
 /*
  * Machine setup..
  */
@@ -964,6 +966,8 @@ void __init setup_arch(char **cmdline_p)
 	paravirt_pagetable_setup_done(swapper_pg_dir);
 	paravirt_post_allocator_init();
 
+	tboot_probe();
+
 #ifdef CONFIG_X86_64
 	map_vsyscall();
 #endif

security/Kconfig

@@ -113,6 +113,36 @@ config SECURITY_ROOTPLUG
 
 	  If you are unsure how to answer this question, answer N.
 
+config INTEL_TXT
+	bool "Enable Intel(R) Trusted Execution Technology (Intel(R) TXT)"
+	depends on EXPERIMENTAL && X86 && DMAR && ACPI
+	help
+	  This option enables support for booting the kernel with the
+	  Trusted Boot (tboot) module. This will utilize
+	  Intel(R) Trusted Execution Technology to perform a measured launch
+	  of the kernel. If the system does not support Intel(R) TXT, this
+	  will have no effect.
+
+	  Intel TXT will provide higher assurance of sysem configuration and
+	  initial state as well as data reset protection.  This is used to
+	  create a robust initial kernel measurement and verification, which
+	  helps to ensure that kernel security mechanisms are functioning
+	  correctly. This level of protection requires a root of trust outside
+	  of the kernel itself.
+
+	  Intel TXT also helps solve real end user concerns about having
+	  confidence that their hardware is running the VMM or kernel that
+	  it was conigured with, especially since they may be responsible for
+	  providing such assurances to VMs and services running on it.
+
+	  See <http://www.intel.com/technology/security/> for more information
+	  about Intel(R) TXT.
+	  See <http://tboot.sourceforge.net> for more information about tboot.
+	  See Documentation/intel_txt.txt for a description of how to enable
+	  Intel TXT support in a kernel boot.
+
+	  If you are unsure as to whether this is required, answer N.
+
 source security/selinux/Kconfig
 source security/smack/Kconfig
 source security/tomoyo/Kconfig