[PATCH v3 0/3] tpm: Preserve TPM measurement log across kexec (ppc64)

[PATCH v3 0/3] tpm: Preserve TPM measurement log across kexec (ppc64)

[Stefan Berger]

The of-tree subsystem does not currently preserve the IBM vTPM 1.2 and
vTPM 2.0 measurement logs across a kexec on ppc64. This series fixes this
for the kexec_file_load() syscall using the flattened device tree (fdt) to
carry the measurement log's buffer across kexec.

   Stefan

Stefan Berger (3):
  tpm: of: Make of-tree specific function commonly available
  of: kexec: Refactor IMA buffer related functions to make them reusable
  tpm/kexec: Duplicate TPM measurement log in of-tree for kexec

 drivers/char/Makefile              |   1 +
 drivers/char/tpm/Makefile          |   1 +
 drivers/char/tpm/eventlog/of.c     |  31 +--
 drivers/char/tpm/eventlog/tpm_of.c |  27 +++
 drivers/of/kexec.c                 | 293 +++++++++++++++++++++++++----
 include/linux/kexec.h              |   6 +
 include/linux/of.h                 |   8 +-
 include/linux/tpm.h                |   5 +
 kernel/kexec_file.c                |   6 +
 9 files changed, 315 insertions(+), 63 deletions(-)
 create mode 100644 drivers/char/tpm/eventlog/tpm_of.c

-- 
2.35.1

[PATCH v3 1/3] tpm: of: Make of-tree specific function commonly available

[Stefan Berger]

Simplify tpm_read_log_of() by moving reusable parts of the code into
its own file to make the code commonly available so it can be used also
for kexec support. Call the new of_tpm_get_sml_parameters() function
from the TPM Open Firmware driver.

Compile the new file when CONFIG_OF is enabled so that
of_tpm_get_sml_parameters() can be called from kexec even if the TPM
subsystem is not enabled.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
---
 drivers/char/Makefile              |  1 +
 drivers/char/tpm/Makefile          |  1 +
 drivers/char/tpm/eventlog/of.c     | 31 +++++-------------------------
 drivers/char/tpm/eventlog/tpm_of.c | 27 ++++++++++++++++++++++++++
 include/linux/tpm.h                |  5 +++++
 5 files changed, 39 insertions(+), 26 deletions(-)
 create mode 100644 drivers/char/tpm/eventlog/tpm_of.c

diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 264eb398fdd4..af9edafb944e 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_PCMCIA)		+= pcmcia/
 
 obj-$(CONFIG_HANGCHECK_TIMER)	+= hangcheck-timer.o
 obj-$(CONFIG_TCG_TPM)		+= tpm/
+obj-$(CONFIG_OF)		+= tpm/
 
 obj-$(CONFIG_PS3_FLASH)		+= ps3flash.o
 
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 66d39ea6bd10..3c0eaac81f5c 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -19,6 +19,7 @@ tpm-y += eventlog/tpm2.o
 tpm-$(CONFIG_ACPI) += tpm_ppi.o eventlog/acpi.o
 tpm-$(CONFIG_EFI) += eventlog/efi.o
 tpm-$(CONFIG_OF) += eventlog/of.o
+obj-$(CONFIG_OF) += eventlog/tpm_of.o
 obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
 obj-$(CONFIG_TCG_TIS) += tpm_tis.o
 obj-$(CONFIG_TCG_TIS_SYNQUACER) += tpm_tis_synquacer.o
diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
index a9ce66d09a75..f9462d19632e 100644
--- a/drivers/char/tpm/eventlog/of.c
+++ b/drivers/char/tpm/eventlog/of.c
@@ -12,6 +12,7 @@
 
 #include <linux/slab.h>
 #include <linux/of.h>
+#include <linux/tpm.h>
 #include <linux/tpm_eventlog.h>
 
 #include "../tpm.h"
@@ -20,11 +21,10 @@
 int tpm_read_log_of(struct tpm_chip *chip)
 {
 	struct device_node *np;
-	const u32 *sizep;
-	const u64 *basep;
 	struct tpm_bios_log *log;
 	u32 size;
 	u64 base;
+	int ret;
 
 	log = &chip->log;
 	if (chip->dev.parent && chip->dev.parent->of_node)
@@ -35,30 +35,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
 	if (of_property_read_bool(np, "powered-while-suspended"))
 		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
 
-	sizep = of_get_property(np, "linux,sml-size", NULL);
-	basep = of_get_property(np, "linux,sml-base", NULL);
-	if (sizep == NULL && basep == NULL)
-		return -ENODEV;
-	if (sizep == NULL || basep == NULL)
-		return -EIO;
-
-	/*
-	 * For both vtpm/tpm, firmware has log addr and log size in big
-	 * endian format. But in case of vtpm, there is a method called
-	 * sml-handover which is run during kernel init even before
-	 * device tree is setup. This sml-handover function takes care
-	 * of endianness and writes to sml-base and sml-size in little
-	 * endian format. For this reason, vtpm doesn't need conversion
-	 * but physical tpm needs the conversion.
-	 */
-	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
-	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
-		size = be32_to_cpup((__force __be32 *)sizep);
-		base = be64_to_cpup((__force __be64 *)basep);
-	} else {
-		size = *sizep;
-		base = *basep;
-	}
+	ret = of_tpm_get_sml_parameters(np, &base, &size);
+	if (ret < 0)
+		return ret;
 
 	if (size == 0) {
 		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
diff --git a/drivers/char/tpm/eventlog/tpm_of.c b/drivers/char/tpm/eventlog/tpm_of.c
new file mode 100644
index 000000000000..2e6cfcc87035
--- /dev/null
+++ b/drivers/char/tpm/eventlog/tpm_of.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/export.h>
+#include <linux/tpm.h>
+
+int of_tpm_get_sml_parameters(struct device_node *np, u64 *base, u32 *size)
+{
+	const u32 *sizep;
+	const u64 *basep;
+
+	sizep = of_get_property(np, "linux,sml-size", NULL);
+	basep = of_get_property(np, "linux,sml-base", NULL);
+	if (sizep == NULL && basep == NULL)
+		return -ENODEV;
+	if (sizep == NULL || basep == NULL)
+		return -EIO;
+
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
+	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
+		*size = be32_to_cpup((__force __be32 *)sizep);
+		*base = be64_to_cpup((__force __be64 *)basep);
+	} else {
+		*size = *sizep;
+		*base = *basep;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_tpm_get_sml_parameters);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index dfeb25a0362d..429bf045db80 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -460,4 +460,9 @@ static inline struct tpm_chip *tpm_default_chip(void)
 	return NULL;
 }
 #endif
+
+#ifdef CONFIG_OF
+int of_tpm_get_sml_parameters(struct device_node *np, u64 *base, u32 *size);
+#endif
+
 #endif
-- 
2.35.1

[PATCH v3 2/3] of: kexec: Refactor IMA buffer related functions to make them reusable

[Stefan Berger]

Refactor IMA buffer related functions to make them reusable for carrying
TPM logs across kexec.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
---
 drivers/of/kexec.c | 99 +++++++++++++++++++++++++++++-----------------
 1 file changed, 62 insertions(+), 37 deletions(-)

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index b9bd1cff1793..601ea9727b0e 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -115,6 +115,18 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
 	return 0;
 }
 
+static int get_kexec_buffer(const char *name, unsigned long *addr, size_t *size)
+{
+	const void *prop;
+	int len;
+
+	prop = of_get_property(of_chosen, name, &len);
+	if (!prop)
+		return -ENOENT;
+
+	return do_get_kexec_buffer(prop, len, addr, size);
+}
+
 /**
  * ima_get_kexec_buffer - get IMA buffer from the previous kernel
  * @addr:	On successful return, set to point to the buffer contents.
@@ -124,19 +136,14 @@ static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
  */
 int ima_get_kexec_buffer(void **addr, size_t *size)
 {
-	int ret, len;
+	int ret;
 	unsigned long tmp_addr;
 	size_t tmp_size;
-	const void *prop;
 
 	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
 		return -ENOTSUPP;
 
-	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
-	if (!prop)
-		return -ENOENT;
-
-	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+	ret = get_kexec_buffer("linux,ima-kexec-buffer", &tmp_addr, &tmp_size);
 	if (ret)
 		return ret;
 
@@ -174,6 +181,28 @@ int ima_free_kexec_buffer(void)
 	return memblock_phys_free(addr, size);
 }
 
+static int remove_buffer(void *fdt, int chosen_node, const char *name)
+{
+	int ret, len;
+	unsigned long addr;
+	size_t size;
+	const void *prop;
+
+	prop = fdt_getprop(fdt, chosen_node, name, &len);
+	if (!prop)
+		return -ENOENT;
+
+	ret = do_get_kexec_buffer(prop, len, &addr, &size);
+	fdt_delprop(fdt, chosen_node, name);
+	if (ret)
+		return ret;
+
+	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
+	if (!ret)
+		pr_debug("Remove old %s buffer reserveration", name);
+	return ret;
+}
+
 /**
  * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
  *
@@ -185,29 +214,34 @@ int ima_free_kexec_buffer(void)
  */
 static void remove_ima_buffer(void *fdt, int chosen_node)
 {
-	int ret, len;
-	unsigned long addr;
-	size_t size;
-	const void *prop;
-
 	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
 		return;
 
-	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
-	if (!prop)
-		return;
+	remove_buffer(fdt, chosen_node, "linux,ima-kexec-buffer");
+}
 
-	ret = do_get_kexec_buffer(prop, len, &addr, &size);
-	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+#ifdef CONFIG_IMA_KEXEC
+static int setup_buffer(void *fdt, int chosen_node, const char *name,
+			uint64_t addr, uint64_t size)
+{
+	int ret;
+
+	if (!size)
+		return 0;
+
+	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
+				       name, addr, size);
+	if (ret < 0)
+		return -EINVAL;
+
+	ret = fdt_add_mem_rsv(fdt, addr, size);
 	if (ret)
-		return;
+		return -EINVAL;
+
+	return 0;
 
-	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
-	if (!ret)
-		pr_debug("Removed old IMA buffer reservation.\n");
 }
 
-#ifdef CONFIG_IMA_KEXEC
 /**
  * setup_ima_buffer - add IMA buffer information to the fdt
  * @image:		kexec image being loaded.
@@ -221,23 +255,14 @@ static int setup_ima_buffer(const struct kimage *image, void *fdt,
 {
 	int ret;
 
-	if (!image->ima_buffer_size)
-		return 0;
-
-	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
-				       "linux,ima-kexec-buffer",
-				       image->ima_buffer_addr,
-				       image->ima_buffer_size);
-	if (ret < 0)
-		return -EINVAL;
-
-	ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
-			      image->ima_buffer_size);
+	ret = setup_buffer(fdt, chosen_node, "linux,ima-kexec-buffer",
+			   image->ima_buffer_addr, image->ima_buffer_size);
 	if (ret)
-		return -EINVAL;
+		return ret;
 
-	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
-		 image->ima_buffer_addr, image->ima_buffer_size);
+	if (image->ima_buffer_addr)
+		pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
+			 image->ima_buffer_addr, image->ima_buffer_size);
 
 	return 0;
 }
-- 
2.35.1

[PATCH v3 3/3] tpm/kexec: Duplicate TPM measurement log in of-tree for kexec

[Stefan Berger]

The memory area of the TPM measurement log is currently not properly
duplicated for carrying it across kexec when an Open Firmware
Devicetree is used. Therefore, the contents of the log get corrupted.
Fix this for the kexec_file_load() syscall by allocating a buffer and
copying the contents of the existing log into it. The new buffer is
preserved across the kexec and a pointer to it is available when the new
kernel is started. To achieve this, store the allocated buffer's address
in the flattened device tree (fdt) under the name linux,tpm-kexec-buffer
and search for this entry early in the kernel startup before the TPM
subsystem starts up. Adjust the pointer in the of-tree stored under
linux,sml-base to point to this buffer holding the preserved log. The TPM
driver can then read the base address from this entry when making the log
available.

Use postcore_initcall() to call the function to restore the buffer even if
the TPM subsystem or driver are not used. This allows the buffer to be
carried across the next kexec without involvement of the TPM subsystem
and ensures a valid buffer pointed to by the of-tree.

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
---
 drivers/of/kexec.c    | 198 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/kexec.h |   6 ++
 include/linux/of.h    |   8 +-
 kernel/kexec_file.c   |   6 ++
 4 files changed, 216 insertions(+), 2 deletions(-)

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 601ea9727b0e..efc428b951db 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -18,6 +18,7 @@
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/types.h>
+#include <linux/tpm.h>
 
 #define RNG_SEED_SIZE		128
 
@@ -220,7 +221,6 @@ static void remove_ima_buffer(void *fdt, int chosen_node)
 	remove_buffer(fdt, chosen_node, "linux,ima-kexec-buffer");
 }
 
-#ifdef CONFIG_IMA_KEXEC
 static int setup_buffer(void *fdt, int chosen_node, const char *name,
 			uint64_t addr, uint64_t size)
 {
@@ -242,6 +242,7 @@ static int setup_buffer(void *fdt, int chosen_node, const char *name,
 
 }
 
+#ifdef CONFIG_IMA_KEXEC
 /**
  * setup_ima_buffer - add IMA buffer information to the fdt
  * @image:		kexec image being loaded.
@@ -274,6 +275,198 @@ static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
 }
 #endif /* CONFIG_IMA_KEXEC */
 
+/**
+ * tpm_get_kexec_buffer - get TPM log buffer from the previous kernel
+ * @phyaddr:	On successful return, set to physical address of buffer
+ * @size:	On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int tpm_get_kexec_buffer(void **phyaddr, size_t *size)
+{
+	int ret;
+	unsigned long tmp_addr;
+	size_t tmp_size;
+
+	ret = get_kexec_buffer("linux,tpm-kexec-buffer", &tmp_addr, &tmp_size);
+	if (ret)
+		return ret;
+
+	*phyaddr = (void *)tmp_addr;
+	*size = tmp_size;
+
+	return 0;
+}
+
+/**
+ * tpm_of_remove_kexec_buffer - remove the linux,tpm-kexec-buffer node
+ */
+static int tpm_of_remove_kexec_buffer(void)
+{
+	struct property *prop;
+
+	prop = of_find_property(of_chosen, "linux,tpm-kexec-buffer", NULL);
+	if (!prop)
+		return -ENOENT;
+
+	return of_remove_property(of_chosen, prop);
+}
+
+/**
+ * remove_tpm_buffer - remove the TPM log buffer property and reservation from @fdt
+ *
+ * @fdt: Flattened Device Tree to update
+ * @chosen_node: Offset to the chosen node in the device tree
+ *
+ * The TPM log measurement buffer is of no use to a subsequent kernel, so we always
+ * remove it from the device tree.
+ */
+static void remove_tpm_buffer(void *fdt, int chosen_node)
+{
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return;
+
+	remove_buffer(fdt, chosen_node, "linux,tpm-kexec-buffer");
+}
+
+/**
+ * setup_tpm_buffer - add TPM measurement log buffer information to the fdt
+ * @image:		kexec image being loaded.
+ * @fdt:		Flattened device tree for the next kernel.
+ * @chosen_node:	Offset to the chosen node.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+static int setup_tpm_buffer(const struct kimage *image, void *fdt,
+			    int chosen_node)
+{
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return 0;
+
+	return setup_buffer(fdt, chosen_node, "linux,tpm-kexec-buffer",
+			    image->tpm_buffer_addr, image->tpm_buffer_size);
+}
+
+void tpm_add_kexec_buffer(struct kimage *image)
+{
+	struct kexec_buf kbuf = { .image = image, .buf_align = 1,
+				  .buf_min = 0, .buf_max = ULONG_MAX,
+				  .top_down = true };
+	struct device_node *np;
+	void *buffer;
+	u32 size;
+	u64 base;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return;
+
+	np = of_find_node_by_name(NULL, "vtpm");
+	if (!np)
+		return;
+
+	if (of_tpm_get_sml_parameters(np, &base, &size) < 0)
+		return;
+
+	buffer = vmalloc(size);
+	if (!buffer)
+		return;
+	memcpy(buffer, __va(base), size);
+
+	kbuf.buffer = buffer;
+	kbuf.bufsz = size;
+	kbuf.memsz = size;
+	ret = kexec_add_buffer(&kbuf);
+	if (ret) {
+		pr_err("Error passing over kexec TPM measurement log buffer: %d\n",
+		       ret);
+		return;
+	}
+
+	image->tpm_buffer = buffer;
+	image->tpm_buffer_addr = kbuf.mem;
+	image->tpm_buffer_size = size;
+}
+
+/**
+ * tpm_post_kexec - Make stored TPM log buffer available in of-tree
+ */
+static int __init tpm_post_kexec(void)
+{
+	struct property *newprop;
+	struct device_node *np;
+	void *phyaddr;
+	size_t size;
+	u32 oflogsize;
+	u64 unused;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_PPC64))
+		return 0;
+
+	ret = tpm_get_kexec_buffer(&phyaddr, &size);
+	if (ret)
+		return 0;
+
+	/*
+	 * If any one of the following steps fails then the next kexec will
+	 * cause issues due to linux,sml-base pointing to a stale buffer.
+	 */
+	np = of_find_node_by_name(NULL, "vtpm");
+	if (!np)
+		goto err_free_memblock;
+
+	/* logsize must not have changed */
+	if (of_tpm_get_sml_parameters(np, &unused, &oflogsize) < 0)
+		goto err_free_memblock;
+	if (oflogsize != size)
+		goto err_free_memblock;
+
+	/* replace linux,sml-base with new physical address of buffer */
+	ret = -ENOMEM;
+	newprop = kzalloc(sizeof(*newprop), GFP_KERNEL);
+	if (!newprop)
+		goto err_free_memblock;
+
+	newprop->name = kstrdup("linux,sml-base", GFP_KERNEL);
+	if (!newprop->name)
+		goto err_free_newprop;
+
+	newprop->length = sizeof(phyaddr);
+
+	newprop->value = kmalloc(sizeof(u64), GFP_KERNEL);
+	if (!newprop->value)
+		goto err_free_newprop_struct;
+
+	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
+	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
+		ret = -ENODEV;
+		goto err_free_newprop_struct;
+	} else {
+		*(u64 *)newprop->value = (u64)phyaddr;
+	}
+
+	ret = of_update_property(np, newprop);
+	if (ret) {
+		pr_err("Could not update linux,sml-base with new address");
+		goto err_free_newprop_struct;
+	}
+
+	goto exit;
+
+err_free_newprop_struct:
+	kfree(newprop->name);
+err_free_newprop:
+	kfree(newprop);
+err_free_memblock:
+	memblock_phys_free((phys_addr_t)phyaddr, size);
+exit:
+	tpm_of_remove_kexec_buffer();
+
+	return ret;
+}
+postcore_initcall(tpm_post_kexec);
+
 /*
  * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
  *
@@ -463,6 +656,9 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 	remove_ima_buffer(fdt, chosen_node);
 	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
 
+	remove_tpm_buffer(fdt, chosen_node);
+	ret = setup_tpm_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
+
 out:
 	if (ret) {
 		kvfree(fdt);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 58d1b58a971e..a0fd7ac0398c 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -319,6 +319,12 @@ struct kimage {
 	void *elf_headers;
 	unsigned long elf_headers_sz;
 	unsigned long elf_load_addr;
+
+	/* Virtual address of TPM log buffer for kexec syscall */
+	void *tpm_buffer;
+
+	phys_addr_t tpm_buffer_addr;
+	size_t tpm_buffer_size;
 };
 
 /* kexec interface functions */
diff --git a/include/linux/of.h b/include/linux/of.h
index 04971e85fbc9..a86e07b58f26 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -100,6 +100,8 @@ struct of_reconfig_data {
 	struct property		*old_prop;
 };
 
+struct kimage;
+
 /* initialize a node */
 extern struct kobj_type of_node_ktype;
 extern const struct fwnode_operations of_fwnode_ops;
@@ -436,13 +438,13 @@ int of_map_id(struct device_node *np, u32 id,
 
 phys_addr_t of_dma_get_max_cpu_address(struct device_node *np);
 
-struct kimage;
 void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 				   unsigned long initrd_load_addr,
 				   unsigned long initrd_len,
 				   const char *cmdline, size_t extra_fdt_size);
 int ima_get_kexec_buffer(void **addr, size_t *size);
 int ima_free_kexec_buffer(void);
+void tpm_add_kexec_buffer(struct kimage *image);
 #else /* CONFIG_OF */
 
 static inline void of_core_init(void)
@@ -844,6 +846,10 @@ static inline phys_addr_t of_dma_get_max_cpu_address(struct device_node *np)
 	return PHYS_ADDR_MAX;
 }
 
+static inline void tpm_add_kexec_buffer(struct kimage *image)
+{
+}
+
 #define of_match_ptr(_ptr)	NULL
 #define of_match_node(_matches, _node)	NULL
 #endif /* CONFIG_OF */
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 8347fc158d2b..3f58d044939b 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -27,6 +27,7 @@
 #include <linux/kernel_read_file.h>
 #include <linux/syscalls.h>
 #include <linux/vmalloc.h>
+#include <linux/of.h>
 #include "kexec_internal.h"
 
 static int kexec_calculate_store_digests(struct kimage *image);
@@ -171,6 +172,9 @@ void kimage_file_post_load_cleanup(struct kimage *image)
 	image->ima_buffer = NULL;
 #endif /* CONFIG_IMA_KEXEC */
 
+	vfree(image->tpm_buffer);
+	image->tpm_buffer = NULL;
+
 	/* See if architecture has anything to cleanup post load */
 	arch_kimage_file_post_load_cleanup(image);
 
@@ -277,6 +281,8 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
 
 	/* IMA needs to pass the measurement list to the next kernel. */
 	ima_add_kexec_buffer(image);
+	/* Pass the TPM measurement log to next kernel */
+	tpm_add_kexec_buffer(image);
 
 	/* Call arch image load handlers */
 	ldata = arch_kexec_kernel_image_load(image);
-- 
2.35.1

Re: [PATCH v3 0/3] tpm: Preserve TPM measurement log across kexec (ppc64)

[Stefan Berger]

On 6/28/22 12:58, Stefan Berger wrote:
> The of-tree subsystem does not currently preserve the IBM vTPM 1.2 and
> vTPM 2.0 measurement logs across a kexec on ppc64. This series fixes this
> for the kexec_file_load() syscall using the flattened device tree (fdt) to
> carry the measurement log's buffer across kexec.
> 
>     Stefan
> 

v3:
  - Moved TPM Open Firmware related function to 
drivers/char/tpm/eventlog/tpm_of.c

v2:
  - rearranged patches
  - fixed compilation issues for x86


> Stefan Berger (3):
>    tpm: of: Make of-tree specific function commonly available
>    of: kexec: Refactor IMA buffer related functions to make them reusable
>    tpm/kexec: Duplicate TPM measurement log in of-tree for kexec
> 
>   drivers/char/Makefile              |   1 +
>   drivers/char/tpm/Makefile          |   1 +
>   drivers/char/tpm/eventlog/of.c     |  31 +--
>   drivers/char/tpm/eventlog/tpm_of.c |  27 +++
>   drivers/of/kexec.c                 | 293 +++++++++++++++++++++++++----
>   include/linux/kexec.h              |   6 +
>   include/linux/of.h                 |   8 +-
>   include/linux/tpm.h                |   5 +
>   kernel/kexec_file.c                |   6 +
>   9 files changed, 315 insertions(+), 63 deletions(-)
>   create mode 100644 drivers/char/tpm/eventlog/tpm_of.c
>