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Message-ID: <CAMj1kXG_fy6Bye46_6J-tidY8p5PgLOtUMdvvF24QGqHbAPwdQ@mail.gmail.com>
Date: Wed, 9 Jul 2025 20:24:49 +1000
From: Ard Biesheuvel <ardb@...nel.org>
To: Gerd Hoffmann <kraxel@...hat.com>
Cc: linux-efi@...r.kernel.org, kernel test robot <lkp@...el.com>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] efi: remove modular option for ovmf-debug-log
On Wed, 9 Jul 2025 at 20:11, Gerd Hoffmann <kraxel@...hat.com> wrote:
>
> 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(-)
>
Thanks Gerd. I'll fold this into the existing patch instead, so we
don't break bisect needlessly.
> 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
>
>
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