diff mbox series

[v6,4/6] tpm: of: Make of-tree specific function commonly available

Message ID 20220707172026.831614-5-stefanb@linux.ibm.com (mailing list archive)
State New, archived
Headers show
Series tpm: Preserve TPM measurement log across kexec (ppc64) | expand

Commit Message

Stefan Berger July 7, 2022, 5:20 p.m. UTC 
Simplify tpm_read_log_of() by moving reusable parts of the code into
an inline function that makes it 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.

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>

---
v4:
 - converted to inline function
---
 drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
 include/linux/tpm.h            | 27 +++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 26 deletions(-)

Comments

Mimi Zohar July 11, 2022, 10:04 p.m. UTC | #1 
Hi Stefan,

On Thu, 2022-07-07 at 13:20 -0400, Stefan Berger wrote:
> -       /*
> -        * 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.
> -        */

This comment is dropped.  Perhaps not in such detail, but shouldn't a
comment or function description exist in the new function.

Otherwise,
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

thanks,

Mimi
Stefan Berger July 12, 2022, 1:25 p.m. UTC | #2 
On 7/11/22 18:04, Mimi Zohar wrote:
> Hi Stefan,
> 
> On Thu, 2022-07-07 at 13:20 -0400, Stefan Berger wrote:
>> -       /*
>> -        * 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.
>> -        */
> 
> This comment is dropped.  Perhaps not in such detail, but shouldn't a
> comment or function description exist in the new function.

I am adding back the comment in v7.

> 
> Otherwise,
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> 
> thanks,
> 
> Mimi
> 
> 
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
diff mbox series

Patch

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/include/linux/tpm.h b/include/linux/tpm.h
index dfeb25a0362d..b3dff255bc58 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -460,4 +460,31 @@  static inline struct tpm_chip *tpm_default_chip(void)
 	return NULL;
 }
 #endif
+
+#ifdef CONFIG_OF
+static inline 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;
+}
+#endif
+
 #endif