[PATCH] tpm: Add reserved memory event log

Eddie James
2023-01-03T16:21:19Z

Some platforms may desire to pass the event log up to linux in the
form of a reserved memory region. Add support for this in the TPM
core to find the reserved memory region and map it.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
drivers/char/tpm/eventlog/of.c | 38 +++++++++++++++++++++++++++++++++-
drivers/char/tpm/tpm-chip.c | 3 ++-
include/linux/tpm.h | 1 +
3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
index a9ce66d09a75..0455d7f61c10 100644
--- a/drivers/char/tpm/eventlog/of.c
+++ b/drivers/char/tpm/eventlog/of.c
@@ -11,12 +11,48 @@
*/

#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
#include <linux/tpm_eventlog.h>

#include "../tpm.h"
#include "common.h"

+static int tpm_read_log_memory_region(struct tpm_chip *chip)
+{
+ struct device_node *node;
+ struct resource res;
+ int rc;
+
+ node = of_parse_phandle(chip->dev.parent->of_node, "memory-region", 0);
+ if (!node) {
+ dev_info(&chip->dev, "no phandle\n");
+ return -ENODEV;
+ }
+
+ rc = of_address_to_resource(node, 0, &res);
+ of_node_put(node);
+ if (rc) {
+ dev_info(&chip->dev, "no mem\n");
+ return rc;
+ }
+
+ chip->log.bios_event_log = memremap(res.start, resource_size(&res), MEMREMAP_WB);
+ if (!chip->log.bios_event_log) {
+ dev_info(&chip->dev, "err memremap\n");
+ return -ENOMEM;
+ }
+
+ chip->log.release = memunmap;
+ chip->log.bios_event_log_end = chip->log.bios_event_log + resource_size(&res);
+
+ return chip->flags & TPM_CHIP_FLAG_TPM2 ? EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 :
+ EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
+}
+
int tpm_read_log_of(struct tpm_chip *chip)
{
struct device_node *np;
@@ -38,7 +74,7 @@ int tpm_read_log_of(struct tpm_chip *chip)
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;
+ return tpm_read_log_memory_region(chip);
if (sizep == NULL || basep == NULL)
return -EIO;

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 741d8f3e8fb3..09ea8145d7c6 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -267,7 +267,7 @@ static void tpm_dev_release(struct device *dev)
idr_remove(&dev_nums_idr, chip->dev_num);
mutex_unlock(&idr_lock);

- kfree(chip->log.bios_event_log);
+ chip->log.release(chip->log.bios_event_log);
kfree(chip->work_space.context_buf);
kfree(chip->work_space.session_buf);
kfree(chip->allocated_banks);
@@ -324,6 +324,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
init_rwsem(&chip->ops_sem);

chip->ops = ops;
+ chip->log.release = (void(*)(void *))kfree;

mutex_lock(&idr_lock);
rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index dfeb25a0362d..f1c0b0eb20a5 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -109,6 +109,7 @@ struct tpm_space {
struct tpm_bios_log {
void *bios_event_log;
void *bios_event_log_end;
+ void (*release)(void *ptr);
};

struct tpm_chip_seqops {
--
2.31.1