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txt_info: add as a patch config fragment
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Hosting txt_info.c as an out-of-tree module with its sources in the
layer is not very elegant. The changes are small and configurable, and
useful only to dom0.

Make the out-of-tree module a patch against the kernel and create the
associated configuration fragment so dom0's kernel can select it.

Signed-off-by: Eric Chanudet <[email protected]>
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Eric Chanudet committed Jun 29, 2021
1 parent 99e75f8 commit e2e8a63
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Showing 10 changed files with 232 additions and 213 deletions.
1 change: 0 additions & 1 deletion recipes-core/images/openxt-dom0-image.bb
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Expand Up @@ -42,7 +42,6 @@ IMAGE_INSTALL += "\
packagegroup-xenclient-dom0 \
packagegroup-openxt-test \
argo-module \
txt-info-module \
xenclient-preload-hs-libs \
linux-firmware-i915 \
devicemodel-stubdom \
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1 change: 0 additions & 1 deletion recipes-kernel/linux/files/openxt-kmeta/patches/xen-txt-evtlog/xen-txt-evtlog.cfg
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227 changes: 227 additions & 0 deletions ...es/openxt-kmeta/patches/xen-txt/0001-txt_info-expose-TXT-conf-registers-to-userland.patch
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@@ -0,0 +1,227 @@
From acff0fec046e730871aa7342fe8118479eb092d2 Mon Sep 17 00:00:00 2001
From: Eric Chanudet <[email protected]>
Date: Wed, 23 Jun 2021 10:12:42 -0400
Subject: [PATCH] txt_info: expose TXT conf registers to userland

TXT exposes configuration registers documented in its Software
Development Guide. Accessing these registers in sometimes necessary for
userland software to perform checks and validate compatibility with
software resources.

Expose the previously mentioned resources through a platform device
driver in the sysfs.

Signed-off-by: Eric Chanudet <[email protected]>
---
drivers/misc/Kconfig | 10 +++
drivers/misc/Makefile | 1 +
drivers/misc/txt_info.c | 167 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 178 insertions(+)
create mode 100644 drivers/misc/txt_info.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index c55b63750757..2d3479593610 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -466,6 +466,16 @@ config PVPANIC
a paravirtualized device provided by QEMU; it lets a virtual machine
(guest) communicate panic events to the host.

+config TXT_INFO
+ tristate "Add TXT configuration registers in securityfs"
+ depends on X86 && TCG_TPM
+ default n
+ help
+ Expose the values of TXT configuration registers via the sysfs for
+ use in userland. To compile this as a module choose M.
+
+ If unsure, say N.
+
source "drivers/misc/c2port/Kconfig"
source "drivers/misc/eeprom/Kconfig"
source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c1860d35dc7e..4ebacab15df2 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -57,3 +57,4 @@ obj-y += cardreader/
obj-$(CONFIG_PVPANIC) += pvpanic.o
obj-$(CONFIG_HABANA_AI) += habanalabs/
obj-$(CONFIG_XILINX_SDFEC) += xilinx_sdfec.o
+obj-$(CONFIG_TXT_INFO) += txt_info.o
diff --git a/drivers/misc/txt_info.c b/drivers/misc/txt_info.c
new file mode 100644
index 000000000000..ebece6a50612
--- /dev/null
+++ b/drivers/misc/txt_info.c
@@ -0,0 +1,167 @@
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#define TXT_PUB_CR_BASE 0xfed30000
+#define TXT_PUB_CR_SIZE 0x10000
+static const struct resource txt_resources[] = {
+ {
+ .start = TXT_PUB_CR_BASE,
+ .end = TXT_PUB_CR_BASE + TXT_PUB_CR_SIZE - 1,
+ .flags = IORESOURCE_MEM,
+ },
+};
+#define TXT_PUB_CR_INDEX 0
+
+struct platform_device *pdev;
+struct txt_info {
+ void __iomem *cr_pub;
+ void __iomem *cr_priv;
+};
+static struct txt_info txt_info;
+
+static void __iomem *txt_info_map_regs(struct platform_device *pdev,
+ size_t index)
+{
+ struct resource *res;
+ void __iomem *base;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, index);
+ if (IS_ERR(res)) {
+ dev_dbg(&pdev->dev,
+ "Failed to access IOMEM resource %zu.\n", index);
+ return res;
+ }
+
+ base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+ if (IS_ERR(base))
+ dev_dbg(&pdev->dev,
+ "Failed to ioremap configuration registers.\n");
+
+ return base;
+}
+
+/* Registers offset from TXT_PUB_CR_BASE */
+#define TXT_STS_OFFSET 0x000
+#define TXT_ESTS_OFFSET 0x008
+#define TXT_ERRORCODE_OFFSET 0x030
+#define TXT_VER_FSBIF_OFFSET 0x100
+#define TXT_DIDVID_OFFSET 0x110
+#define TXT_VER_QPIIF_OFFSET 0x200
+
+#define DECLARE_PUB_SHOW_U8(name, offset) \
+static ssize_t name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+{ \
+ uint8_t v = ioread8(txt_info.cr_pub + (offset)); \
+ return sprintf(buf, "%#04x\n", v); \
+} \
+static struct kobj_attribute txt_attr_##name = __ATTR_RO(name);
+
+#define DECLARE_PUB_SHOW_U32(name, offset) \
+static ssize_t name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+{ \
+ uint32_t v = ioread32(txt_info.cr_pub + (offset)); \
+ return sprintf(buf, "%#010x\n", v); \
+} \
+static struct kobj_attribute txt_attr_##name = __ATTR_RO(name);
+
+#define DECLARE_PUB_SHOW_U64(name, offset) \
+static ssize_t name##_show(struct kobject *kobj, \
+ struct kobj_attribute *attr, char *buf) \
+{ \
+ uint64_t v = ioread32(txt_info.cr_pub + (offset) + 0x4); \
+ v <<= 32; \
+ v |= ioread32(txt_info.cr_pub + (offset)); \
+ return sprintf(buf, "%#018llx\n", v); \
+} \
+static struct kobj_attribute txt_attr_##name = __ATTR_RO(name);
+
+DECLARE_PUB_SHOW_U64(sts, TXT_STS_OFFSET);
+DECLARE_PUB_SHOW_U8(ests, TXT_ESTS_OFFSET);
+DECLARE_PUB_SHOW_U32(errorcode, TXT_ERRORCODE_OFFSET);
+DECLARE_PUB_SHOW_U32(ver_fsbif, TXT_VER_FSBIF_OFFSET);
+DECLARE_PUB_SHOW_U64(didvid, TXT_DIDVID_OFFSET);
+DECLARE_PUB_SHOW_U32(ver_qpiif, TXT_VER_QPIIF_OFFSET);
+
+static struct attribute *txt_subsys_attrs[] = {
+ &txt_attr_sts.attr,
+ &txt_attr_ests.attr,
+ &txt_attr_errorcode.attr,
+ &txt_attr_ver_fsbif.attr,
+ &txt_attr_didvid.attr,
+ &txt_attr_ver_qpiif.attr,
+ NULL,
+};
+
+static umode_t txt_attr_is_visible(struct kobject *kobj,
+ struct attribute *attr, int n)
+{
+ return attr->mode;
+}
+
+static const struct attribute_group txt_subsys_attr_group = {
+ .attrs = txt_subsys_attrs,
+ .is_visible = txt_attr_is_visible,
+};
+
+struct kobject *txt_kobj;
+
+static int __init init_txt_info(void)
+{
+ int rc;
+ void __iomem *base;
+
+ pr_info("%s\n", __func__);
+
+ pdev = platform_device_register_simple(
+ "txt", -1, txt_resources, ARRAY_SIZE(txt_resources));
+ if (IS_ERR(pdev)) {
+ rc = PTR_ERR(pdev);
+ pr_err("Failed to register txt platform device driver (%d).\n", rc);
+ goto fail_register;
+ }
+
+ base = txt_info_map_regs(pdev, TXT_PUB_CR_INDEX);
+ if (IS_ERR(base)) {
+ rc = PTR_ERR(base);
+ dev_err(&pdev->dev,
+ "Failed to map TXT public resources (%d).\n", rc);
+ goto fail_map_pub;
+ }
+ txt_info.cr_pub = base;
+
+ rc = sysfs_create_group(&pdev->dev.kobj, &txt_subsys_attr_group);
+ if (rc) {
+ dev_err(&pdev->dev, "Failed to create sysfs group (%d).\n", rc);
+ goto fail_sysfs;
+ }
+
+ return 0;
+
+fail_sysfs:
+ devm_iounmap(&pdev->dev, txt_info.cr_pub);
+fail_map_pub:
+ platform_device_unregister(pdev);
+fail_register:
+ return rc;
+}
+
+static void __exit cleanup_txt_info(void)
+{
+ pr_info("%s\n", __func__);
+
+ if (pdev)
+ platform_device_unregister(pdev);
+}
+
+module_init(init_txt_info);
+module_exit(cleanup_txt_info);
+
+MODULE_AUTHOR("Assured Information Security, Inc");
+MODULE_DESCRIPTION("TXT driver.");
+MODULE_VERSION("1.0");
+MODULE_LICENSE("GPL");
--
2.17.1

0 ...xen-txt-add-xen-txt-eventlog-module.patch → ...xen-txt-add-xen-txt-eventlog-module.patch
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2 changes: 2 additions & 0 deletions recipes-kernel/linux/files/openxt-kmeta/patches/xen-txt/xen-txt.cfg
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@@ -0,0 +1,2 @@
CONFIG_XEN_TXT=y
CONTIG_TXT_INFO=y
4 changes: 3 additions & 1 deletion ...patches/xen-txt-evtlog/xen-txt-evtlog.scc → .../openxt-kmeta/patches/xen-txt/xen-txt.scc
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Expand Up @@ -4,5 +4,7 @@ define KFEATURE_COMPATIBILITY all

# Use Xen custom hypercall to retrieve and expose the eventlog in the securityfs.
patch xen-txt-add-xen-txt-eventlog-module.patch
# Add a small platform device to expose TXT configuration registers in the securityfs.
patch 0001-txt_info-expose-TXT-conf-registers-to-userland.patch

kconf hardware xen-txt-evtlog.cfg
kconf hardware xen-txt.cfg
3 changes: 0 additions & 3 deletions recipes-openxt/txt-info-module/files/sources/Kbuild
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20 changes: 0 additions & 20 deletions recipes-openxt/txt-info-module/files/sources/Makefile
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