[PATCH v7 4/4] fw_load: add fw_load02 for custom firmware path

From: Andrea Cervesato <andrea.cervesato-IBi9RG/[email protected]>

Add fw_load02 which points the kernel firmware loader at the writable
LTP temporary directory via /sys/module/firmware_class/parameters/path.
Unlike fw_load01, it does not rely on a writable /lib/firmware and so
works on read-only and immutable root filesystems while still exercising
request_firmware() for both successful loads and the not-found case.

Move test inside the header so both fw_load01 and fw_load02 will share
the same test function.

Signed-off-by: Andrea Cervesato <andrea.cervesato-IBi9RG/[email protected]>
---
 runtest/kernel_misc                           |  1 +
 testcases/kernel/firmware/fw_load/.gitignore  |  1 +
 testcases/kernel/firmware/fw_load/Makefile    |  2 +-
 testcases/kernel/firmware/fw_load/fw_load.h   | 69 ++++++++++++++++++++
 testcases/kernel/firmware/fw_load/fw_load01.c | 72 +++------------------
 testcases/kernel/firmware/fw_load/fw_load02.c | 93 +++++++++++++++++++++++++++
 6 files changed, 174 insertions(+), 64 deletions(-)

diff --git a/runtest/kernel_misc b/runtest/kernel_misc
index 19caee1d81da9cf0503088138ecfda13436b96cf..cc3562cb78cfa9b657692fcbd8fb732f2879092e 100644
--- a/runtest/kernel_misc
+++ b/runtest/kernel_misc
@@ -1,6 +1,7 @@
 cn_pec_sh cn_pec.sh
 kmsg01 kmsg01
 fw_load01 fw_load01
+fw_load02 fw_load02
 rtc01 rtc01
 rtc02 rtc02
 block_dev block_dev
diff --git a/testcases/kernel/firmware/fw_load/.gitignore b/testcases/kernel/firmware/fw_load/.gitignore
index 57eca444c161e6ba642561664cc7de3a8f134841..0bacefd371fc3ac6cf043102398b5a0c74b0b66d 100644
--- a/testcases/kernel/firmware/fw_load/.gitignore
+++ b/testcases/kernel/firmware/fw_load/.gitignore
@@ -6,3 +6,4 @@
 /.tmp_versions/
 modules.livepatch
 fw_load01
+fw_load02
diff --git a/testcases/kernel/firmware/fw_load/Makefile b/testcases/kernel/firmware/fw_load/Makefile
index 91e8d8d153b43c459a899aff2124db612ec9e960..bf6f9abd7517654066a5a92ac481e8eb1f959a41 100644
--- a/testcases/kernel/firmware/fw_load/Makefile
+++ b/testcases/kernel/firmware/fw_load/Makefile
@@ -17,7 +17,7 @@ include $(top_srcdir)/include/mk/testcases.mk
 REQ_VERSION_MAJOR   := 3
 REQ_VERSION_PATCH   := 7
 
-MAKE_TARGETS	:= fw_load01 ltp_fw_load.ko
+MAKE_TARGETS	:= fw_load01 fw_load02 ltp_fw_load.ko
 
 include $(top_srcdir)/include/mk/module.mk
 include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/firmware/fw_load/fw_load.h b/testcases/kernel/firmware/fw_load/fw_load.h
index 39f207cc30810e2ed9ea76176cedd98aa902d887..9692c0c90e046d1c13d3082d187076b2b43f84f5 100644
--- a/testcases/kernel/firmware/fw_load/fw_load.h
+++ b/testcases/kernel/firmware/fw_load/fw_load.h
@@ -6,6 +6,8 @@
 #ifndef FW_LOAD_H
 #define FW_LOAD_H
 
+#include "tst_test.h"
+
 #define MNAME_KO "ltp_fw_load.ko"
 #define FW_NAME	"load_tst.fw"
 #define FW_SIZE	0x1000
@@ -15,4 +17,71 @@
 #define DEV_RESULT "/sys/devices/ltp_fw_load/result"
 #define LIB_PATH "/lib/firmware"
 
+struct fw_data {
+	char dir[PATH_MAX];
+	char file[PATH_MAX];
+	int fake;
+	int created_dir;
+};
+
+static inline void create_firmware(struct fw_data *firmware,
+				   int *fw_count, const char *dir)
+{
+	struct fw_data *fw = &firmware[*fw_count];
+	char buf[FW_SIZE];
+	int fd;
+
+	snprintf(fw->dir, sizeof(fw->dir), "%s", dir);
+
+	if (access(dir, X_OK) == -1) {
+		SAFE_MKDIR(dir, 0755);
+		fw->created_dir = 1;
+	}
+
+	snprintf(fw->file, sizeof(fw->file), "%s/n%d_%s", dir, *fw_count, FW_NAME);
+	memset(buf, *fw_count, FW_SIZE);
+
+	fd = SAFE_OPEN(fw->file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	SAFE_WRITE(SAFE_WRITE_ALL, fd, buf, FW_SIZE);
+	SAFE_CLOSE(fd);
+
+	(*fw_count)++;
+}
+
+static inline void create_fake_firmware(struct fw_data *firmware, int *fw_count)
+{
+	snprintf(firmware[*fw_count].file, sizeof(firmware[*fw_count].file),
+		 "/n%d_%s", *fw_count, FW_NAME);
+
+	firmware[*fw_count].fake = 1;
+	(*fw_count)++;
+}
+
+static inline void do_test(struct fw_data *firmware, int fw_count)
+{
+	struct fw_data *fw;
+	int result = 0;
+	int pass, offset;
+
+	SAFE_FILE_PRINTF(DEV_FWNUM, "%d", fw_count);
+	SAFE_FILE_SCANF(DEV_RESULT, "%d", &result);
+
+	for (int i = 0; i < fw_count; i++) {
+		fw = &firmware[i];
+
+		pass = result & (1 << i);
+		offset = fw->dir[0] ? strlen(fw->dir) : 0;
+
+		if (fw->fake) {
+			tst_res(pass ? TFAIL : TPASS,
+				"Firmware '%s' correctly not loaded",
+				fw->file + offset);
+		} else {
+			tst_res(pass ? TPASS : TFAIL,
+				"Firmware '%s' loaded",
+				fw->file + offset);
+		}
+	}
+}
+
 #endif
diff --git a/testcases/kernel/firmware/fw_load/fw_load01.c b/testcases/kernel/firmware/fw_load/fw_load01.c
index 402e2c71f508fdbb9c3f73fcd42bf87da280137b..4b30a3b40fb1e3db8f300b2c56d5f29e8e37a7ff 100644
--- a/testcases/kernel/firmware/fw_load/fw_load01.c
+++ b/testcases/kernel/firmware/fw_load/fw_load01.c
@@ -40,61 +40,11 @@
 
 static int module_loaded;
 static int fw_count;
-
-static struct fw_data {
-	char dir[PATH_MAX];
-	char file[PATH_MAX];
-	int fake;
-	int created_dir;
-} firmware[FW_NUM];
-
-static void create_firmware(const char *dir)
-{
-	struct fw_data *fw = &firmware[fw_count];
-	char buf[FW_SIZE];
-	int fd = -1;
-
-	snprintf(fw->dir, sizeof(fw->dir), "%s", dir);
-	if (access(dir, X_OK) == -1) {
-		SAFE_MKDIR(dir, 0755);
-		fw->created_dir = 1;
-	}
-
-	snprintf(fw->file, sizeof(fw->file), "%s/n%d_%s", dir, fw_count, FW_NAME);
-	memset(buf, fw_count, FW_SIZE);
-
-	fd = SAFE_OPEN(fw->file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
-	SAFE_WRITE(SAFE_WRITE_ALL, fd, buf, FW_SIZE);
-	SAFE_CLOSE(fd);
-
-	fw_count++;
-}
+static struct fw_data firmware[FW_NUM];
 
 static void run(void)
 {
-	struct fw_data *fw;
-	int result = 0;
-	int pass, offset;
-
-	SAFE_FILE_PRINTF(DEV_FWNUM, "%d", fw_count);
-	SAFE_FILE_SCANF(DEV_RESULT, "%d", &result);
-
-	for (int i = 0; i < fw_count; i++) {
-		fw = &firmware[i];
-
-		pass = result & (1 << i);
-		offset = fw->dir[0] ? strlen(fw->dir) : 0;
-
-		if (fw->fake) {
-			tst_res(pass ? TFAIL : TPASS,
-				"Firmware '%s' correctly not loaded",
-				fw->file + offset);
-		} else {
-			tst_res(pass ? TPASS : TFAIL,
-				"Firmware '%s' loaded",
-				fw->file + offset);
-		}
-	}
+	do_test(firmware, fw_count);
 }
 
 static void setup(void)
@@ -104,7 +54,8 @@ static void setup(void)
 	struct utsname name;
 
 	if (access(LIB_PATH, W_OK) == -1)
-		tst_brk(TCONF, "Skipping test due to read-only %s", LIB_PATH);
+		tst_brk(TCONF, "Skipping test due to read-only %s",
+			LIB_PATH);
 
 	tst_requires_module_signature_disabled();
 
@@ -114,25 +65,20 @@ static void setup(void)
 	tst_module_load(MNAME_KO, mod_params);
 	module_loaded = 1;
 
-	create_firmware(LIB_PATH);
+	create_firmware(firmware, &fw_count, LIB_PATH);
 
 	uname(&name);
 
 	snprintf(fw_dir, sizeof(fw_dir), "%s/%s", LIB_PATH, name.release);
-	create_firmware(fw_dir);
+	create_firmware(firmware, &fw_count, fw_dir);
 
 	snprintf(fw_dir, sizeof(fw_dir), "%s/updates", LIB_PATH);
-	create_firmware(fw_dir);
+	create_firmware(firmware, &fw_count, fw_dir);
 
 	snprintf(fw_dir, sizeof(fw_dir), "%s/updates/%s", LIB_PATH, name.release);
-	create_firmware(fw_dir);
-
-	/* add a fake file */
-	snprintf(firmware[fw_count].file, sizeof(firmware[fw_count].file),
-		 "/n%d_%s", fw_count, FW_NAME);
+	create_firmware(firmware, &fw_count, fw_dir);
 
-	firmware[fw_count].fake = 1;
-	fw_count++;
+	create_fake_firmware(firmware, &fw_count);
 }
 
 static void cleanup(void)
diff --git a/testcases/kernel/firmware/fw_load/fw_load02.c b/testcases/kernel/firmware/fw_load/fw_load02.c
new file mode 100644
index 0000000000000000000000000000000000000000..8d2063772c0f0aadeb5e46fcba6bf2a6bba4d327
--- /dev/null
+++ b/testcases/kernel/firmware/fw_load/fw_load02.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All Rights Reserved.
+ *	Alexey Kodanev <[email protected]>
+ * Copyright (c) 2026 SUSE LLC Andrea Cervesato <andrea.cervesato-IBi9RG/[email protected]>
+ */
+
+/*\
+ * Verifies that the kernel firmware loader (``CONFIG_FW_LOADER``)
+ * can find and load firmware files from a custom firmware search
+ * path.
+ *
+ * A helper kernel module (``ltp_fw_load.ko``) registers a virtual
+ * device that calls :kernel_doc:`request_firmware` for a set of
+ * numbered firmware blobs. Each blob is verified in-kernel against
+ * its expected size and byte pattern.
+ *
+ * The kernel firmware loader is pointed at the writable LTP
+ * temporary directory through
+ * ``/sys/module/firmware_class/parameters/path``.
+ * This avoids writing into ``/lib/firmware`` and therefore works
+ * on read-only or immutable root filesystems. The original value
+ * is saved and restored automatically.
+ *
+ * [Algorithm]
+ *
+ * - Set the firmware search path to the LTP temporary directory
+ * - Load the helper module with ``fw_size`` matching the blob size
+ * - Create ``FW_NUM - 1`` firmware files there, each named
+ *   ``n<i>_load_tst.fw`` and filled with a known byte pattern
+ * - Add one fake firmware entry that has no file on disk
+ * - Write the firmware count to ``/sys/devices/ltp_fw_load/fwnum``
+ *   to trigger :kernel_doc:`request_firmware` calls in-kernel
+ * - Read the result bitmask from ``/sys/devices/ltp_fw_load/result``
+ * - Verify that every real firmware file was loaded successfully
+ *   and that the fake entry was correctly rejected
+ */
+
+#include "tst_test.h"
+#include "tst_module.h"
+#include "fw_load.h"
+
+static int module_loaded;
+static int fw_count;
+static struct fw_data firmware[FW_NUM];
+
+static void run(void)
+{
+	do_test(firmware, fw_count);
+}
+
+static void setup(void)
+{
+	char fw_size_param[32];
+	char *tmpdir = tst_tmpdir_path();
+
+	tst_requires_module_signature_disabled();
+
+	SAFE_FILE_PRINTF(FW_PATH, "%s", tmpdir);
+
+	snprintf(fw_size_param, sizeof(fw_size_param), "fw_size=%d", FW_SIZE);
+	char *const mod_params[] = {fw_size_param, NULL};
+
+	tst_module_load(MNAME_KO, mod_params);
+	module_loaded = 1;
+
+	for (int i = 0; i < FW_NUM - 1; i++)
+		create_firmware(firmware, &fw_count, tmpdir);
+
+	create_fake_firmware(firmware, &fw_count);
+}
+
+static void cleanup(void)
+{
+	if (module_loaded)
+		tst_module_unload(MNAME_KO);
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.needs_kconfigs = (const char *[]) {
+		"CONFIG_FW_LOADER=y|CONFIG_FW_LOADER=m",
+		NULL,
+	},
+	.save_restore = (const struct tst_path_val[]) {
+		{FW_PATH, NULL, TST_SR_TCONF},
+		{},
+	},
+};

-- 
2.51.0


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