linux-kernel - [PATCH] efi: remove modular option for ovmf-debug-log

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Message-ID: <20250709101119.927808-1-kraxel@redhat.com>
Date: Wed,  9 Jul 2025 12:11:18 +0200
From: Gerd Hoffmann <kraxel@...hat.com>
To: linux-efi@...r.kernel.org
Cc: Gerd Hoffmann <kraxel@...hat.com>,
	kernel test robot <lkp@...el.com>,
	Ard Biesheuvel <ardb@...nel.org>,
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] efi: remove modular option for ovmf-debug-log

Flip the driver from tristate to bool, so it can not be built modular
any more.  Also drop the platform device boilerplate, simply call the
probe function directly instead.

Reported-by: kernel test robot <lkp@...el.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202507091432.rbbrjGoU-lkp@intel.com/
Suggested-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
---
 include/linux/efi.h                   |  2 ++
 drivers/firmware/efi/efi.c            |  2 +-
 drivers/firmware/efi/ovmf-debug-log.c | 43 ++++++---------------------
 drivers/firmware/efi/Kconfig          |  2 +-
 4 files changed, 13 insertions(+), 36 deletions(-)

diff --git a/include/linux/efi.h b/include/linux/efi.h
index a71830608422..f6da5c226fda 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1346,6 +1346,8 @@ bool efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table)
 
 umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n);
 
+int ovmf_log_probe(unsigned long ovmf_debug_log_table);
+
 /*
  * efivar ops event type
  */
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 3161f918ce53..1ce428e2ac8a 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -476,7 +476,7 @@ static int __init efisubsys_init(void)
 
 	if (IS_ENABLED(CONFIG_OVMF_DEBUG_LOG) &&
 	    efi.ovmf_debug_log != EFI_INVALID_TABLE_ADDR)
-		platform_device_register_simple("ovmf_debug_log", 0, NULL, 0);
+		ovmf_log_probe(efi.ovmf_debug_log);
 
 	return 0;
 
diff --git a/drivers/firmware/efi/ovmf-debug-log.c b/drivers/firmware/efi/ovmf-debug-log.c
index d4fec178fa9f..b292f35109b6 100644
--- a/drivers/firmware/efi/ovmf-debug-log.c
+++ b/drivers/firmware/efi/ovmf-debug-log.c
@@ -64,38 +64,33 @@ static struct bin_attribute ovmf_log_bin_attr = {
 	.read = ovmf_log_read,
 };
 
-static int ovmf_log_probe(struct platform_device *dev)
+__init int ovmf_log_probe(unsigned long ovmf_debug_log_table)
 {
 	u64 size;
 	int ret = -EINVAL;
 
-	if (efi.ovmf_debug_log == EFI_INVALID_TABLE_ADDR) {
-		dev_err(&dev->dev, "OVMF debug log: not available\n");
-		return -EINVAL;
-	}
-
 	/* map + verify header */
-	hdr = memremap(efi.ovmf_debug_log, sizeof(*hdr), MEMREMAP_WB);
+	hdr = memremap(ovmf_debug_log_table, sizeof(*hdr), MEMREMAP_WB);
 	if (!hdr) {
-		dev_err(&dev->dev, "OVMF debug log: header map failed\n");
+		printk(KERN_ERR "OVMF debug log: header map failed\n");
 		return -EINVAL;
 	}
 
 	if (hdr->magic1 != OVMF_DEBUG_LOG_MAGIC1 ||
 	    hdr->magic2 != OVMF_DEBUG_LOG_MAGIC2) {
-		dev_err(&dev->dev, "OVMF debug log: magic mismatch\n");
+		printk(KERN_ERR "OVMF debug log: magic mismatch\n");
 		goto err_unmap;
 	}
 
 	size = hdr->hdr_size + hdr->log_size;
-	dev_info(&dev->dev, "firmware version: \"%s\"\n", hdr->fw_version);
-	dev_info(&dev->dev, "log buffer size: %lluk\n", size / 1024);
+	printk(KERN_INFO "OVMF debug log: firmware version: \"%s\"\n", hdr->fw_version);
+	printk(KERN_INFO "OVMF debug log: buffer size: %lluk\n", size / 1024);
 
 	/* map complete log buffer */
 	memunmap(hdr);
-	hdr = memremap(efi.ovmf_debug_log, size, MEMREMAP_WB);
+	hdr = memremap(ovmf_debug_log_table, size, MEMREMAP_WB);
 	if (!hdr) {
-		dev_err(&dev->dev, "OVMF debug log: buffer map failed\n");
+		printk(KERN_ERR "OVMF debug log: buffer map failed\n");
 		return -EINVAL;
 	}
 	logbuf = (void *)hdr + hdr->hdr_size;
@@ -104,7 +99,7 @@ static int ovmf_log_probe(struct platform_device *dev)
 	ovmf_log_bin_attr.size = size;
 	ret = sysfs_create_bin_file(efi_kobj, &ovmf_log_bin_attr);
 	if (ret != 0) {
-		dev_err(&dev->dev, "OVMF debug log: sysfs register failed\n");
+		printk(KERN_ERR "OVMF debug log: sysfs register failed\n");
 		goto err_unmap;
 	}
 
@@ -114,23 +109,3 @@ static int ovmf_log_probe(struct platform_device *dev)
 	memunmap(hdr);
 	return ret;
 }
-
-static void ovmf_log_remove(struct platform_device *dev)
-{
-	memunmap(hdr);
-}
-
-static struct platform_driver ovmf_log_driver = {
-	.probe = ovmf_log_probe,
-	.remove = ovmf_log_remove,
-	.driver = {
-		.name = "ovmf_debug_log",
-	},
-};
-
-module_platform_driver(ovmf_log_driver);
-
-MODULE_DESCRIPTION("OVMF debug log");
-MODULE_AUTHOR("Gerd Hoffmann <kraxel@...hat.com>");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:ovmf_debug_log");
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index ac0a03ec3452..eb1bff6968a5 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -264,7 +264,7 @@ config EFI_COCO_SECRET
 	  allows userspace programs to access the injected secrets.
 
 config OVMF_DEBUG_LOG
-	tristate "Expose OVMF firmware debug log via sysfs"
+	bool "Expose OVMF firmware debug log via sysfs"
 	depends on EFI
 	help
 	  Recent OVMF versions (edk2-stable202508 + newer) can write
-- 
2.50.0