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>

6 files changed, 586 insertions, 1 deletions

diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
index 1724e8d..6ca2021 100644
--- a/arch/x86/include/asm/bootparam.h
+++ b/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 */
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 7b2d71d..14f9890 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -132,6 +132,9 @@ enum fixed_addresses {
 #ifdef CONFIG_X86_32
 	FIX_WP_TEST,
 #endif
+#ifdef CONFIG_INTEL_TXT
+	FIX_TBOOT_BASE,
+#endif
 	__end_of_fixed_addresses
 };
 
diff --git a/arch/x86/include/asm/tboot.h b/arch/x86/include/asm/tboot.h
new file mode 100644
index 0000000..b13929d
--- /dev/null
+++ b/arch/x86/include/asm/tboot.h
@@ -0,0 +1,197 @@
+/*
+ * 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 */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 430d5b2..832cb83 100644
--- a/arch/x86/kernel/Makefile
+++ b/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/
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index de2cab1..80d6e9e 100644
--- a/arch/x86/kernel/setup.c
+++ b/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
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
new file mode 100644
index 0000000..263591a
--- /dev/null
+++ b/arch/x86/kernel/tboot.c
@@ -0,0 +1,379 @@
+/*
+ * tboot.c: main implementation of helper 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.
+ *
+ */
+
+#include <linux/dma_remapping.h>
+#include <linux/init_task.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/dmar.h>
+#include <linux/pfn.h>
+#include <linux/mm.h>
+
+#include <asm/trampoline.h>
+#include <asm/processor.h>
+#include <asm/bootparam.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.h>
+#include <asm/setup.h>
+#include <asm/tboot.h>
+#include <asm/e820.h>
+#include <asm/io.h>
+
+#include "acpi/realmode/wakeup.h"
+
+/* Global pointer to shared data; NULL means no measured launch. */
+struct tboot *tboot __read_mostly;
+
+/* timeout for APs (in secs) to enter wait-for-SIPI state during shutdown */
+#define AP_WAIT_TIMEOUT		1
+
+#undef pr_fmt
+#define pr_fmt(fmt)	"tboot: " fmt
+
+static u8 tboot_uuid[16] __initdata = TBOOT_UUID;
+
+void __init tboot_probe(void)
+{
+	/* Look for valid page-aligned address for shared page. */
+	if (!boot_params.tboot_addr)
+		return;
+	/*
+	 * also verify that it is mapped as we expect it before calling
+	 * set_fixmap(), to reduce chance of garbage value causing crash
+	 */
+	if (!e820_any_mapped(boot_params.tboot_addr,
+			     boot_params.tboot_addr, E820_RESERVED)) {
+		pr_warning("non-0 tboot_addr but it is not of type E820_RESERVED\n");
+		return;
+	}
+
+	/* only a natively booted kernel should be using TXT */
+	if (paravirt_enabled()) {
+		pr_warning("non-0 tboot_addr but pv_ops is enabled\n");
+		return;
+	}
+
+	/* Map and check for tboot UUID. */
+	set_fixmap(FIX_TBOOT_BASE, boot_params.tboot_addr);
+	tboot = (struct tboot *)fix_to_virt(FIX_TBOOT_BASE);
+	if (memcmp(&tboot_uuid, &tboot->uuid, sizeof(tboot->uuid))) {
+		pr_warning("tboot at 0x%llx is invalid\n",
+			   boot_params.tboot_addr);
+		tboot = NULL;
+		return;
+	}
+	if (tboot->version < 5) {
+		pr_warning("tboot version is invalid: %u\n", tboot->version);
+		tboot = NULL;
+		return;
+	}
+
+	pr_info("found shared page at phys addr 0x%llx:\n",
+		boot_params.tboot_addr);
+	pr_debug("version: %d\n", tboot->version);
+	pr_debug("log_addr: 0x%08x\n", tboot->log_addr);
+	pr_debug("shutdown_entry: 0x%x\n", tboot->shutdown_entry);
+	pr_debug("tboot_base: 0x%08x\n", tboot->tboot_base);
+	pr_debug("tboot_size: 0x%x\n", tboot->tboot_size);
+}
+
+static pgd_t *tboot_pg_dir;
+static struct mm_struct tboot_mm = {
+	.mm_rb          = RB_ROOT,
+	.pgd            = swapper_pg_dir,
+	.mm_users       = ATOMIC_INIT(2),
+	.mm_count       = ATOMIC_INIT(1),
+	.mmap_sem       = __RWSEM_INITIALIZER(init_mm.mmap_sem),
+	.page_table_lock =  __SPIN_LOCK_UNLOCKED(init_mm.page_table_lock),
+	.mmlist         = LIST_HEAD_INIT(init_mm.mmlist),
+	.cpu_vm_mask    = CPU_MASK_ALL,
+};
+
+static inline void switch_to_tboot_pt(void)
+{
+	write_cr3(virt_to_phys(tboot_pg_dir));
+}
+
+static int map_tboot_page(unsigned long vaddr, unsigned long pfn,
+			  pgprot_t prot)
+{
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	pgd = pgd_offset(&tboot_mm, vaddr);
+	pud = pud_alloc(&tboot_mm, pgd, vaddr);
+	if (!pud)
+		return -1;
+	pmd = pmd_alloc(&tboot_mm, pud, vaddr);
+	if (!pmd)
+		return -1;
+	pte = pte_alloc_map(&tboot_mm, pmd, vaddr);
+	if (!pte)
+		return -1;
+	set_pte_at(&tboot_mm, vaddr, pte, pfn_pte(pfn, prot));
+	pte_unmap(pte);
+	return 0;
+}
+
+static int map_tboot_pages(unsigned long vaddr, unsigned long start_pfn,
+			   unsigned long nr)
+{
+	/* Reuse the original kernel mapping */
+	tboot_pg_dir = pgd_alloc(&tboot_mm);
+	if (!tboot_pg_dir)
+		return -1;
+
+	for (; nr > 0; nr--, vaddr += PAGE_SIZE, start_pfn++) {
+		if (map_tboot_page(vaddr, start_pfn, PAGE_KERNEL_EXEC))
+			return -1;
+	}
+
+	return 0;
+}
+
+void tboot_create_trampoline(void)
+{
+	u32 map_base, map_size;
+
+	if (!tboot_enabled())
+		return;
+
+	/* Create identity map for tboot shutdown code. */
+	map_base = PFN_DOWN(tboot->tboot_base);
+	map_size = PFN_UP(tboot->tboot_size);
+	if (map_tboot_pages(map_base << PAGE_SHIFT, map_base, map_size))
+		panic("tboot: Error mapping tboot pages (mfns) @ 0x%x, 0x%x\n", map_base, map_size);
+}
+
+static void set_mac_regions(void)
+{
+	tboot->num_mac_regions = 3;
+	/* S3 resume code */
+	tboot->mac_regions[0].start = PFN_PHYS(PFN_DOWN(acpi_wakeup_address));
+	tboot->mac_regions[0].size = PFN_UP(WAKEUP_SIZE) << PAGE_SHIFT;
+	/* AP trampoline code */
+	tboot->mac_regions[1].start =
+			PFN_PHYS(PFN_DOWN(virt_to_phys(trampoline_base)));
+	tboot->mac_regions[1].size = PFN_UP(TRAMPOLINE_SIZE) << PAGE_SHIFT;
+	/* kernel code + data + bss */
+	tboot->mac_regions[2].start = PFN_PHYS(PFN_DOWN(virt_to_phys(&_text)));
+	tboot->mac_regions[2].size = PFN_PHYS(PFN_UP(virt_to_phys(&_end))) -
+				     PFN_PHYS(PFN_DOWN(virt_to_phys(&_text)));
+}
+
+void tboot_shutdown(u32 shutdown_type)
+{
+	void (*shutdown)(void);
+
+	if (!tboot_enabled())
+		return;
+
+	/*
+	 * if we're being called before the 1:1 mapping is set up then just
+	 * return and let the normal shutdown happen; this should only be
+	 * due to very early panic()
+	 */
+	if (!tboot_pg_dir)
+		return;
+
+	/* if this is S3 then set regions to MAC */
+	if (shutdown_type == TB_SHUTDOWN_S3)
+		set_mac_regions();
+
+	tboot->shutdown_type = shutdown_type;
+
+	switch_to_tboot_pt();
+
+	shutdown = (void(*)(void))(unsigned long)tboot->shutdown_entry;
+	shutdown();
+
+	/* should not reach here */
+	while (1)
+		halt();
+}
+
+static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
+{
+#define TB_COPY_GAS(tbg, g)			\
+	tbg.space_id     = g.space_id;		\
+	tbg.bit_width    = g.bit_width;		\
+	tbg.bit_offset   = g.bit_offset;	\
+	tbg.access_width = g.access_width;	\
+	tbg.address      = g.address;
+
+	TB_COPY_GAS(tboot->acpi_sinfo.pm1a_cnt_blk, fadt->xpm1a_control_block);
+	TB_COPY_GAS(tboot->acpi_sinfo.pm1b_cnt_blk, fadt->xpm1b_control_block);
+	TB_COPY_GAS(tboot->acpi_sinfo.pm1a_evt_blk, fadt->xpm1a_event_block);
+	TB_COPY_GAS(tboot->acpi_sinfo.pm1b_evt_blk, fadt->xpm1b_event_block);
+
+	/*
+	 * We need phys addr of waking vector, but can't use virt_to_phys() on
+	 * &acpi_gbl_FACS because it is ioremap'ed, so calc from FACS phys
+	 * addr.
+	 */
+	tboot->acpi_sinfo.wakeup_vector = fadt->facs +
+		offsetof(struct acpi_table_facs, firmware_waking_vector);
+}
+
+void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
+{
+	static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
+		/* S0,1,2: */ -1, -1, -1,
+		/* S3: */ TB_SHUTDOWN_S3,
+		/* S4: */ TB_SHUTDOWN_S4,
+		/* S5: */ TB_SHUTDOWN_S5 };
+
+	if (!tboot_enabled())
+		return;
+
+	tboot_copy_fadt(&acpi_gbl_FADT);
+	tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
+	tboot->acpi_sinfo.pm1b_cnt_val = pm1b_control;
+	/* we always use the 32b wakeup vector */
+	tboot->acpi_sinfo.vector_width = 32;
+	tboot->acpi_sinfo.kernel_s3_resume_vector = acpi_wakeup_address;
+
+	if (sleep_state >= ACPI_S_STATE_COUNT ||
+	    acpi_shutdown_map[sleep_state] == -1) {
+		pr_warning("unsupported sleep state 0x%x\n", sleep_state);
+		return;
+	}
+
+	tboot_shutdown(acpi_shutdown_map[sleep_state]);
+}
+
+int tboot_wait_for_aps(int num_aps)
+{
+	unsigned long timeout;
+
+	if (!tboot_enabled())
+		return 0;
+
+	timeout = jiffies + AP_WAIT_TIMEOUT*HZ;
+	while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
+	       time_before(jiffies, timeout))
+		cpu_relax();
+
+	return time_before(jiffies, timeout) ? 0 : 1;
+}
+
+/*
+ * TXT configuration registers (offsets from TXT_{PUB, PRIV}_CONFIG_REGS_BASE)
+ */
+
+#define TXT_PUB_CONFIG_REGS_BASE       0xfed30000
+#define TXT_PRIV_CONFIG_REGS_BASE      0xfed20000
+
+/* # pages for each config regs space - used by fixmap */
+#define NR_TXT_CONFIG_PAGES     ((TXT_PUB_CONFIG_REGS_BASE -                \
+				  TXT_PRIV_CONFIG_REGS_BASE) >> PAGE_SHIFT)
+
+/* offsets from pub/priv config space */
+#define TXTCR_HEAP_BASE             0x0300
+#define TXTCR_HEAP_SIZE             0x0308
+
+#define SHA1_SIZE      20
+
+struct sha1_hash {
+	u8 hash[SHA1_SIZE];
+};
+
+struct sinit_mle_data {
+	u32               version;             /* currently 6 */
+	struct sha1_hash  bios_acm_id;
+	u32               edx_senter_flags;
+	u64               mseg_valid;
+	struct sha1_hash  sinit_hash;
+	struct sha1_hash  mle_hash;
+	struct sha1_hash  stm_hash;
+	struct sha1_hash  lcp_policy_hash;
+	u32               lcp_policy_control;
+	u32               rlp_wakeup_addr;
+	u32               reserved;
+	u32               num_mdrs;
+	u32               mdrs_off;
+	u32               num_vtd_dmars;
+	u32               vtd_dmars_off;
+} __packed;
+
+struct acpi_table_header *tboot_get_dmar_table(struct acpi_table_header *dmar_tbl)
+{
+	void *heap_base, *heap_ptr, *config;
+
+	if (!tboot_enabled())
+		return dmar_tbl;
+
+	/*
+	 * ACPI tables may not be DMA protected by tboot, so use DMAR copy
+	 * SINIT saved in SinitMleData in TXT heap (which is DMA protected)
+	 */
+
+	/* map config space in order to get heap addr */
+	config = ioremap(TXT_PUB_CONFIG_REGS_BASE, NR_TXT_CONFIG_PAGES *
+			 PAGE_SIZE);
+	if (!config)
+		return NULL;
+
+	/* now map TXT heap */
+	heap_base = ioremap(*(u64 *)(config + TXTCR_HEAP_BASE),
+			    *(u64 *)(config + TXTCR_HEAP_SIZE));
+	iounmap(config);
+	if (!heap_base)
+		return NULL;
+
+	/* walk heap to SinitMleData */
+	/* skip BiosData */
+	heap_ptr = heap_base + *(u64 *)heap_base;
+	/* skip OsMleData */
+	heap_ptr += *(u64 *)heap_ptr;
+	/* skip OsSinitData */
+	heap_ptr += *(u64 *)heap_ptr;
+	/* now points to SinitMleDataSize; set to SinitMleData */
+	heap_ptr += sizeof(u64);
+	/* get addr of DMAR table */
+	dmar_tbl = (struct acpi_table_header *)(heap_ptr +
+		   ((struct sinit_mle_data *)heap_ptr)->vtd_dmars_off -
+		   sizeof(u64));
+
+	/* don't unmap heap because dmar.c needs access to this */
+
+	return dmar_tbl;
+}
+
+int tboot_force_iommu(void)
+{
+	if (!tboot_enabled())
+		return 0;
+
+	if (no_iommu || swiotlb || dmar_disabled)
+		pr_warning("Forcing Intel-IOMMU to enabled\n");
+
+	dmar_disabled = 0;
+#ifdef CONFIG_SWIOTLB
+	swiotlb = 0;
+#endif
+	no_iommu = 0;
+
+	return 1;
+}