[PATCH v2] arch/x86/lib: implement cmdline configuration property

[Guillaume Ranquet <ranquet.guillaume@gmail.com>]

Implement the cmdline configuration property as described in the spec
[1]

[1]: https://fitspec.osfw.foundation/#id10

Signed-off-by: Guillaume Ranquet <granquet@missingno.tech>
---
Changes in v2:
- EDITME: describe what is new in this series revision.
- EDITME: use bulletpoints and terse descriptions.
- Link to v1: https://lore.kernel.org/r/20260401-cmdline-v1-1-c56577f82960@missingno.tech
---
 arch/x86/include/asm/zimage.h |  2 +-
 arch/x86/lib/bootm.c          | 10 +++++++++-
 arch/x86/lib/zimage.c         |  6 +++---
 boot/image-fit.c              | 30 +++++++++++++++++++++++++++++-
 include/image.h               |  3 +++
 5 files changed, 45 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/zimage.h b/arch/x86/include/asm/zimage.h
index 8b5426051701c8266395afd9232eb1ff30d38304..ee0114a227a2b067a3a3126d7d80ab0cc89cea6e 100644
--- a/arch/x86/include/asm/zimage.h
+++ b/arch/x86/include/asm/zimage.h
@@ -132,7 +132,7 @@ struct boot_params *load_zimage(char *image, unsigned long kernel_size,
  * Return: 0 (always)
  */
 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
-		 ulong initrd_addr, ulong initrd_size, ulong cmdline_force);
+		 ulong initrd_addr, ulong initrd_size, const char *cmdline_force);
 
 /**
  * zboot_start() - Prepare to boot a zimage
diff --git a/arch/x86/lib/bootm.c b/arch/x86/lib/bootm.c
index cde4fbf35574a267b856a668659ece7e0a36367f..e029cc1ff18bd53eb873c0e56fd9d3b0a331b4c2 100644
--- a/arch/x86/lib/bootm.c
+++ b/arch/x86/lib/bootm.c
@@ -61,6 +61,7 @@ int arch_fixup_memory_node(void *blob)
 static int boot_prep_linux(struct bootm_headers *images)
 {
 	char *cmd_line_dest = NULL;
+	const char *cmd_line_override = NULL;
 	struct legacy_img_hdr *hdr;
 	int is_zimage = 0;
 	void *data = NULL;
@@ -99,6 +100,13 @@ static int boot_prep_linux(struct bootm_headers *images)
 			puts("Can't get image data/size!\n");
 			goto error;
 		}
+
+		ret = fit_image_get_cmdline(images->fit_hdr_os,
+					    images->fit_noffset_cfg,
+					    &cmd_line_override);
+		if (ret)
+			debug("unable to retrieve cmdline for zimage\n");
+
 		is_zimage = 1;
 #endif
 	}
@@ -125,7 +133,7 @@ static int boot_prep_linux(struct bootm_headers *images)
 	printf("Setup at %#08lx\n", images->ep);
 	ret = setup_zimage((void *)images->ep, cmd_line_dest,
 			0, images->rd_start,
-			images->rd_end - images->rd_start, 0);
+			images->rd_end - images->rd_start, cmd_line_override);
 
 	if (ret) {
 		printf("## Setting up boot parameters failed ...\n");
diff --git a/arch/x86/lib/zimage.c b/arch/x86/lib/zimage.c
index a5f2231aa523356de93368338b5fd249b8abad6e..af7ee8dbcf3e8f402cb0c76767b8a587f205ad5d 100644
--- a/arch/x86/lib/zimage.c
+++ b/arch/x86/lib/zimage.c
@@ -276,7 +276,7 @@ struct boot_params *load_zimage(char *image, unsigned long kernel_size,
 }
 
 int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
-		 ulong initrd_addr, ulong initrd_size, ulong cmdline_force)
+		 ulong initrd_addr, ulong initrd_size, const char *cmdline_force)
 {
 	struct setup_header *hdr = &setup_base->hdr;
 	int bootproto = get_boot_protocol(hdr, false);
@@ -333,7 +333,7 @@ int setup_zimage(struct boot_params *setup_base, char *cmd_line, int auto_boot,
 
 		/* build command line at COMMAND_LINE_OFFSET */
 		if (cmdline_force)
-			strcpy(cmd_line, (char *)cmdline_force);
+			strcpy(cmd_line, cmdline_force);
 		else
 			build_command_line(cmd_line, auto_boot);
 		if (IS_ENABLED(CONFIG_CMD_BOOTM)) {
@@ -404,7 +404,7 @@ int zboot_setup(void)
 
 	ret = setup_zimage(base_ptr, (char *)base_ptr + COMMAND_LINE_OFFSET,
 			   0, state.initrd_addr, state.initrd_size,
-			   (ulong)state.cmdline);
+			   state.cmdline);
 	if (ret)
 		return -EINVAL;
 
diff --git a/boot/image-fit.c b/boot/image-fit.c
index e7c7212195f4a291e26ed6d3440a1b42274dacab..1790af4a8e5a9c7d11f7dee5f67226071f8f057e 100644
--- a/boot/image-fit.c
+++ b/boot/image-fit.c
@@ -1096,6 +1096,32 @@ int fit_image_get_data(const void *fit, int noffset, const void **data,
 	return ret;
 }
 
+/**
+ * fit_image_get_cmdline - get image configuration command line
+ * @fit: pointer to the FIT format image header
+ * @cfg_noffset: configuration node offset
+ * @cmdline: double pointer to char, will hold pointer to the cmdline
+ *
+ * fit_image_get_cmdline() gets the cmdline from the configuration node.
+ * If the property is found its data start address is returned to the caller.
+ *
+ * returns:
+ *     0, on success
+ *     -1, on failure
+ */
+int fit_image_get_cmdline(const void *fit, int noffset, const char **cmdline)
+{
+	int len;
+
+	*cmdline = (const char *)fdt_getprop(fit, noffset, FIT_CMDLINE_PROP, &len);
+	if (!*cmdline) {
+		fit_get_debug(fit, noffset, FIT_CMDLINE_PROP, len);
+		return -1;
+	}
+
+	return 0;
+}
+
 /**
  * fit_image_hash_get_algo - get hash algorithm name
  * @fit: pointer to the FIT format image header
@@ -2136,8 +2162,10 @@ int fit_image_load(struct bootm_headers *images, ulong addr,
 		fit_base_uname_config = fdt_get_name(fit, cfg_noffset, NULL);
 		printf("   Using '%s' configuration\n", fit_base_uname_config);
 		/* Remember this config */
-		if (image_type == IH_TYPE_KERNEL)
+		if (image_type == IH_TYPE_KERNEL) {
 			images->fit_uname_cfg = fit_base_uname_config;
+			images->fit_noffset_cfg = cfg_noffset;
+		}
 
 		if (FIT_IMAGE_ENABLE_VERIFY && images->verify) {
 			puts("   Verifying Hash Integrity ... ");
diff --git a/include/image.h b/include/image.h
index 34efac6056dd29307df359dce21e4f94d5fcbf2d..9916e67168e3a4f5412fc26d318af32047c239e2 100644
--- a/include/image.h
+++ b/include/image.h
@@ -365,6 +365,7 @@ struct bootm_headers {
 	 * format, even for SPL, this extra data size seems worth it.
 	 */
 	const char	*fit_uname_cfg;	/* configuration node unit name */
+	int		fit_noffset_cfg;	/* configuration node offset */
 
 	void		*fit_hdr_os;	/* os FIT image header */
 	const char	*fit_uname_os;	/* os subimage node unit name */
@@ -1108,6 +1109,7 @@ int booti_setup(ulong image, ulong *relocated_addr, ulong *size,
 #define FIT_TFA_BL31_PROP	"tfa-bl31"
 #define FIT_TEE_PROP		"tee"
 #define FIT_COMPAT_PROP		"compatible"
+#define FIT_CMDLINE_PROP	"cmdline"
 
 #define FIT_MAX_HASH_LEN	HASH_MAX_DIGEST_SIZE
 
@@ -1259,6 +1261,7 @@ int fit_get_data_node(const void *fit, const char *image_uname,
 int fit_get_data_conf_prop(const void *fit, const char *prop_name,
 			   const void **data, size_t *size);
 
+int fit_image_get_cmdline(const void *fit, int noffset, const char **cmdline);
 int fit_image_hash_get_algo(const void *fit, int noffset, const char **algo);
 int fit_image_hash_get_value(const void *fit, int noffset, uint8_t **value,
 				int *value_len);

---
base-commit: 98cf83d81617f489d7ff7bf78d33e693e2799254
change-id: 20260401-cmdline-ab954a4e8828

Best regards,
-- 
Guillaume Ranquet <granquet@missingno.tech>