linux-kernel - [PATCH v3] mlxbf-bootctl: correctly identify secure boot with development keys

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Date:   Thu, 30 Nov 2023 13:35:15 -0500
From:   David Thompson <davthompson@...dia.com>
To:     <hdegoede@...hat.com>, <ilpo.jarvinen@...ux.intel.com>,
        <markgross@...nel.org>, <vadimp@...dia.com>,
        <platform-driver-x86@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <kblaiech@...dia.com>,
        David Thompson <davthompson@...dia.com>
Subject: [PATCH v3] mlxbf-bootctl: correctly identify secure boot with development keys

The secure boot state of the BlueField SoC is represented by two bits:
                0 = production state
                1 = secure boot enabled
                2 = non-secure (secure boot disabled)
                3 = RMA state
There is also a single bit to indicate whether production keys or
development keys are being used when secure boot is enabled.
This single bit (specified by MLXBF_BOOTCTL_SB_DEV_MASK) only has
meaning if secure boot state equals 1 (secure boot enabled).

The secure boot states are as follows:
- “GA secured” is when secure boot is enabled with official production keys.
- “Secured (development)” is when secure boot is enabled with development keys.

Without this fix “GA Secured” is displayed on development cards which is
misleading. This patch updates the logic in "lifecycle_state_show()" to
handle the case where the SoC is configured for secure boot and is using
development keys.

Fixes: 79e29cb8fbc5c ("platform/mellanox: Add bootctl driver for Mellanox BlueField Soc")
Reviewed-by: Khalil Blaiech <kblaiech@...dia.com>
Signed-off-by: David Thompson <davthompson@...dia.com>
---
v3
a) added more description of SB_DEV_MASK and its usage
b) added status_bits, use_dev_key, and test_state variables to clarify logic
v2
a) commit message was expanded and re-worded for clarity
b) replaced use of hardcoded 0x10 with BIT(4) for MLXBF_BOOTCTL_SB_DEV_MASK
---
 drivers/platform/mellanox/mlxbf-bootctl.c | 39 +++++++++++++++--------
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/mellanox/mlxbf-bootctl.c b/drivers/platform/mellanox/mlxbf-bootctl.c
index 1ac7dab22c63..1a687600b8b6 100644
--- a/drivers/platform/mellanox/mlxbf-bootctl.c
+++ b/drivers/platform/mellanox/mlxbf-bootctl.c
@@ -20,6 +20,7 @@
 
 #define MLXBF_BOOTCTL_SB_SECURE_MASK		0x03
 #define MLXBF_BOOTCTL_SB_TEST_MASK		0x0c
+#define MLXBF_BOOTCTL_SB_DEV_MASK		BIT(4)
 
 #define MLXBF_SB_KEY_NUM			4
 
@@ -40,11 +41,18 @@ static struct mlxbf_bootctl_name boot_names[] = {
 	{ MLXBF_BOOTCTL_NONE, "none" },
 };
 
+enum {
+	MLXBF_BOOTCTL_SB_LIFECYCLE_PRODUCTION = 0,
+	MLXBF_BOOTCTL_SB_LIFECYCLE_GA_SECURE = 1,
+	MLXBF_BOOTCTL_SB_LIFECYCLE_GA_NON_SECURE = 2,
+	MLXBF_BOOTCTL_SB_LIFECYCLE_RMA = 3
+};
+
 static const char * const mlxbf_bootctl_lifecycle_states[] = {
-	[0] = "Production",
-	[1] = "GA Secured",
-	[2] = "GA Non-Secured",
-	[3] = "RMA",
+	[MLXBF_BOOTCTL_SB_LIFECYCLE_PRODUCTION] = "Production",
+	[MLXBF_BOOTCTL_SB_LIFECYCLE_GA_SECURE] = "GA Secured",
+	[MLXBF_BOOTCTL_SB_LIFECYCLE_GA_NON_SECURE] = "GA Non-Secured",
+	[MLXBF_BOOTCTL_SB_LIFECYCLE_RMA] = "RMA",
 };
 
 /* Log header format. */
@@ -247,25 +255,30 @@ static ssize_t second_reset_action_store(struct device *dev,
 static ssize_t lifecycle_state_show(struct device *dev,
 				    struct device_attribute *attr, char *buf)
 {
+	int status_bits;
+	int use_dev_key;
+	int test_state;
 	int lc_state;
 
-	lc_state = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS,
-				     MLXBF_BOOTCTL_FUSE_STATUS_LIFECYCLE);
-	if (lc_state < 0)
-		return lc_state;
+	status_bits = mlxbf_bootctl_smc(MLXBF_BOOTCTL_GET_TBB_FUSE_STATUS,
+					MLXBF_BOOTCTL_FUSE_STATUS_LIFECYCLE);
+	if (status_bits < 0)
+		return status_bits;
 
-	lc_state &=
-		MLXBF_BOOTCTL_SB_TEST_MASK | MLXBF_BOOTCTL_SB_SECURE_MASK;
+	use_dev_key = status_bits & MLXBF_BOOTCTL_SB_DEV_MASK;
+	test_state = status_bits & MLXBF_BOOTCTL_SB_TEST_MASK;
+	lc_state = status_bits & MLXBF_BOOTCTL_SB_SECURE_MASK;
 
 	/*
 	 * If the test bits are set, we specify that the current state may be
 	 * due to using the test bits.
 	 */
-	if (lc_state & MLXBF_BOOTCTL_SB_TEST_MASK) {
-		lc_state &= MLXBF_BOOTCTL_SB_SECURE_MASK;
-
+	if (test_state) {
 		return sprintf(buf, "%s(test)\n",
 			       mlxbf_bootctl_lifecycle_states[lc_state]);
+	} else if ((use_dev_key) &&
+		   (lc_state == MLXBF_BOOTCTL_SB_LIFECYCLE_GA_SECURE)) {
+		return sprintf(buf, "Secured (development)\n");
 	}
 
 	return sprintf(buf, "%s\n", mlxbf_bootctl_lifecycle_states[lc_state]);
-- 
2.30.1