[PATCH v4 3/3] tpm: get tpm event log from bloblist

[Heinrich Schuchardt]

Am 10. Januar 2025 22:56:35 MEZ schrieb Raymond Mao <raymond.mao at linaro.org>:
>Get tpm event log from bloblist instead of FDT when bloblist is
>enabled and valid from previous boot stage.
>
>As a fallback, when no event log from previous stage is observed
>and no user buffer is passed, malloc a default buffer to initialize
>the event log.
>
>Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
>---
>Changes in v2
>- Remove patch dependency.
>- Remove the fallback to FDT when BLOBLIST is selected.
>Changes in v3
>- Malloc an 8KB buffer when user eventlog buffer does not exist.
>Changes in v4
>- Replace the default eventlog size with TPM2_EVENT_LOG_SIZE.
>
> lib/tpm_tcg2.c | 55 +++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 36 insertions(+), 19 deletions(-)
>
>diff --git a/lib/tpm_tcg2.c b/lib/tpm_tcg2.c
>index 7f868cc883..685699688b 100644
>--- a/lib/tpm_tcg2.c
>+++ b/lib/tpm_tcg2.c
>@@ -5,6 +5,7 @@
> 
> #include <dm.h>
> #include <dm/of_access.h>
>+#include <malloc.h>
> #include <tpm_api.h>
> #include <tpm-common.h>
> #include <tpm-v2.h>
>@@ -19,6 +20,7 @@
> #include <linux/unaligned/generic.h>
> #include <linux/unaligned/le_byteshift.h>
> #include "tpm-utils.h"
>+#include <bloblist.h>
> 
> int tcg2_get_pcr_info(struct udevice *dev, u32 *supported_pcr, u32 *active_pcr,
> 		      u32 *pcr_banks)
>@@ -607,15 +609,24 @@ int tcg2_log_prepare_buffer(struct udevice *dev, struct tcg2_event_log *elog,
> 		elog->found = log.found;
> 	}
> 
>+	if (elog->found)
>+		return 0;
>+
> 	/*
>-	 * Initialize the log buffer if no log was discovered and the buffer is
>-	 * valid. User's can pass in their own buffer as a fallback if no
>-	 * memory region is found.
>+	 * Initialize the log buffer if no log was discovered.
>+	 * User can pass in their own buffer as a fallback if no memory region
>+	 * is found, else malloc a buffer if it does not exist.
> 	 */
>-	if (!elog->found && elog->log_size)
>-		rc = tcg2_log_init(dev, elog);
>+	if (!elog->log_size) {
>+		elog->log = malloc(TPM2_EVENT_LOG_SIZE);
>+		if (!elog->log)
>+			return -ENOMEM;
>+
>+		memset(elog->log, 0, TPM2_EVENT_LOG_SIZE);
>+		elog->log_size = TPM2_EVENT_LOG_SIZE;
>+	}
> 
>-	return rc;
>+	return tcg2_log_init(dev, elog);
> }
> 
> int tcg2_measurement_init(struct udevice **dev, struct tcg2_event_log *elog,
>@@ -668,10 +679,19 @@ __weak int tcg2_platform_get_log(struct udevice *dev, void **addr, u32 *size)
> 	const __be32 *size_prop;
> 	int asize;
> 	int ssize;
>+	struct ofnode_phandle_args args;
>+	phys_addr_t a;
>+	fdt_size_t s;
> 
> 	*addr = NULL;
> 	*size = 0;
> 
>+	*addr = bloblist_get_blob(BLOBLISTT_TPM_EVLOG, size);
>+	if (*addr && *size)
>+		return 0;
>+	else if (CONFIG_IS_ENABLED(BLOBLIST))
>+		return -ENODEV;
>+

You are querying the CONFIG value. Why call function bloblist_get_blob if blobs are not supported? Please, simply skip in this case.

Best regards

Heinrich

> 	addr_prop = dev_read_prop(dev, "tpm_event_log_addr", &asize);
> 	if (!addr_prop)
> 		addr_prop = dev_read_prop(dev, "linux,sml-base", &asize);
>@@ -686,22 +706,19 @@ __weak int tcg2_platform_get_log(struct udevice *dev, void **addr, u32 *size)
> 
> 		*addr = map_physmem(a, s, MAP_NOCACHE);
> 		*size = (u32)s;
>-	} else {
>-		struct ofnode_phandle_args args;
>-		phys_addr_t a;
>-		fdt_size_t s;
> 
>-		if (dev_read_phandle_with_args(dev, "memory-region", NULL, 0,
>-					       0, &args))
>-			return -ENODEV;
>+		return 0;
>+	}
> 
>-		a = ofnode_get_addr_size(args.node, "reg", &s);
>-		if (a == FDT_ADDR_T_NONE)
>-			return -ENOMEM;
>+	if (dev_read_phandle_with_args(dev, "memory-region", NULL, 0, 0, &args))
>+		return -ENODEV;
> 
>-		*addr = map_physmem(a, s, MAP_NOCACHE);
>-		*size = (u32)s;
>-	}
>+	a = ofnode_get_addr_size(args.node, "reg", &s);
>+	if (a == FDT_ADDR_T_NONE)
>+		return -ENOMEM;
>+
>+	*addr = map_physmem(a, s, MAP_NOCACHE);
>+	*size = (u32)s;
> 
> 	return 0;
> }