From:   Andrew Donnellan <ajd@linux.ibm.com>
To:     linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org
Cc:     ruscur@russell.cc, bgray@linux.ibm.com, nayna@linux.ibm.com,
        gcwilson@linux.ibm.com, gjoyce@linux.ibm.com, brking@linux.ibm.com,
        stefanb@linux.ibm.com, sudhakar@linux.ibm.com,
        erichte@linux.ibm.com, gregkh@linuxfoundation.org,
        linux-kernel@vger.kernel.org, zohar@linux.ibm.com, joel@jms.id.au,
        npiggin@gmail.com
Subject: [PATCH v5 08/25] powerpc/secvar: Handle max object size in the consumer
Date:   Tue, 31 Jan 2023 17:39:11 +1100
Message-Id: <20230131063928.388035-9-ajd@linux.ibm.com>
In-Reply-To: <20230131063928.388035-1-ajd@linux.ibm.com>
References: <20230131063928.388035-1-ajd@linux.ibm.com>
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From: Russell Currey <ruscur@russell.cc>

Currently the max object size is handled in the core secvar code with an
entirely OPAL-specific implementation, so create a new max_size() op and
move the existing implementation into the powernv platform.  Should be
no functional change.

Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>

---

v3: Change uint64_t type to u64 (mpe)

v4: Return immediately if node is NULL (gjoyce)
---
 arch/powerpc/include/asm/secvar.h            |  1 +
 arch/powerpc/kernel/secvar-sysfs.c           | 17 +++------------
 arch/powerpc/platforms/powernv/opal-secvar.c | 22 ++++++++++++++++++++
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
index 1a2c696a48ad..bf396215903d 100644
--- a/arch/powerpc/include/asm/secvar.h
+++ b/arch/powerpc/include/asm/secvar.h
@@ -18,6 +18,7 @@ struct secvar_operations {
 	int (*get_next)(const char *key, u64 *key_len, u64 keybufsize);
 	int (*set)(const char *key, u64 key_len, u8 *data, u64 data_size);
 	ssize_t (*format)(char *buf, size_t bufsize);
+	int (*max_size)(u64 *max_size);
 };
 
 #ifdef CONFIG_PPC_SECURE_BOOT
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
index e4661559c855..0966806f28c7 100644
--- a/arch/powerpc/kernel/secvar-sysfs.c
+++ b/arch/powerpc/kernel/secvar-sysfs.c
@@ -132,27 +132,16 @@ static struct kobj_type secvar_ktype = {
 static int update_kobj_size(void)
 {
 
-	struct device_node *node;
 	u64 varsize;
-	int rc = 0;
+	int rc = secvar_ops->max_size(&varsize);
 
-	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
-	if (!of_device_is_available(node)) {
-		rc = -ENODEV;
-		goto out;
-	}
-
-	rc = of_property_read_u64(node, "max-var-size", &varsize);
 	if (rc)
-		goto out;
+		return rc;
 
 	data_attr.size = varsize;
 	update_attr.size = varsize;
 
-out:
-	of_node_put(node);
-
-	return rc;
+	return 0;
 }
 
 static int secvar_sysfs_load(void)
diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c
index e33bb703ecbc..a8436bf35e2f 100644
--- a/arch/powerpc/platforms/powernv/opal-secvar.c
+++ b/arch/powerpc/platforms/powernv/opal-secvar.c
@@ -122,11 +122,33 @@ static ssize_t opal_secvar_format(char *buf, size_t bufsize)
 	return rc;
 }
 
+static int opal_secvar_max_size(u64 *max_size)
+{
+	int rc;
+	struct device_node *node;
+
+	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
+	if (!node)
+		return -ENODEV;
+
+	if (!of_device_is_available(node)) {
+		rc = -ENODEV;
+		goto out;
+	}
+
+	rc = of_property_read_u64(node, "max-var-size", max_size);
+
+out:
+	of_node_put(node);
+	return rc;
+}
+
 static const struct secvar_operations opal_secvar_ops = {
 	.get = opal_get_variable,
 	.get_next = opal_get_next_variable,
 	.set = opal_set_variable,
 	.format = opal_secvar_format,
+	.max_size = opal_secvar_max_size,
 };
 
 static int opal_secvar_probe(struct platform_device *pdev)
-- 
2.39.1