When barebox is about to boot a kernel image, it calls shutdown_barebox and then starts the image. When the kernel image is wrapped in a UKI, barebox will not detect it as a kernel image and will thus not call shutdown_barebox beforehand, which can mean that e.g. state is not flushed.
We do not want to treat UKIs completely like kernels (e.g. we do not want to override their built-in bootargs), but we still want to properly shutdown barebox. Resolve this by shutting down barebox whenever we are in a bootm handler, no matter which kind of image is about to be started: bootm is the point of no return. Images run from the shell via binfmt keep returning to barebox afterwards, with the exception of EFI-stubbed kernels, which take over the machine and thus continue to shut barebox down as before. Assisted-by: Claude:opus-5 Signed-off-by: Ahmad Fatoum <[email protected]> --- .../efi-payload-bootm-shutdown.rst | 10 +++++++++ efi/payload/bootm.c | 4 ++-- efi/payload/image.c | 21 +++++++++++++------ efi/payload/image.h | 1 + 4 files changed, 28 insertions(+), 8 deletions(-) create mode 100644 Documentation/migration-guides/migration-master/efi-payload-bootm-shutdown.rst diff --git a/Documentation/migration-guides/migration-master/efi-payload-bootm-shutdown.rst b/Documentation/migration-guides/migration-master/efi-payload-bootm-shutdown.rst new file mode 100644 index 000000000000..2e0a84b536e6 --- /dev/null +++ b/Documentation/migration-guides/migration-master/efi-payload-bootm-shutdown.rst @@ -0,0 +1,10 @@ +EFI applications booted via bootm no longer return to barebox +------------------------------------------------------------- + +When barebox runs as EFI payload, :ref:`command_bootm` now shuts down +barebox before starting any EFI application, not only EFI-stubbed Linux +kernels. If the application returns, barebox exits to the firmware instead +of returning to the shell or trying the next boot entry. + +EFI applications that are expected to return, like an EFI shell, should be +executed directly from the shell instead. diff --git a/efi/payload/bootm.c b/efi/payload/bootm.c index d6a79f0c7795..58b7dd5ea779 100644 --- a/efi/payload/bootm.c +++ b/efi/payload/bootm.c @@ -185,7 +185,7 @@ static int do_bootm_efi_stub(struct image_data *data) if (data->dryrun) goto unload_ramdisk; - ret = efi_execute_image(handle, loaded_image, type); + ret = efi_execute_image(handle, loaded_image, true, type); /* efi_execute_image takes care to unload the image on error, * so we set image_freed and fall through to freeing ramdisk @@ -225,7 +225,7 @@ static int efi_app_execute(struct image_data *data) return 0; } - return efi_execute_image(handle, loaded_image, type); + return efi_execute_image(handle, loaded_image, true, type); } static int linux_efi_handover = true; diff --git a/efi/payload/image.c b/efi/payload/image.c index 76aca1c43cec..4e59c7b4ea10 100644 --- a/efi/payload/image.c +++ b/efi/payload/image.c @@ -100,17 +100,26 @@ int efi_load_image(const char *file, struct efi_loaded_image **loaded_image, int efi_execute_image(efi_handle_t handle, struct efi_loaded_image *loaded_image, + bool is_bootm, enum filetype filetype) { efi_status_t efiret; const char *options; - bool is_driver, is_kernel = false; + bool is_driver; + bool no_return; is_driver = (loaded_image->image_code_type == EFI_BOOT_SERVICES_CODE) || (loaded_image->image_code_type == EFI_RUNTIME_SERVICES_CODE); efi_export_dtb(); + /* + * A bootm handler is the point of no return, but an EFI-stubbed kernel + * started from the shell takes over the machine just the same, so + * barebox needs to be shut down in both cases. + */ + no_return = is_bootm || filetype_is_linux_efi_image(filetype); + if (filetype_is_linux_efi_image(filetype)) { options = linux_bootargs_get(); printf("Booting kernel via StartImage"); @@ -121,11 +130,11 @@ int efi_execute_image(efi_handle_t handle, (strlen(options) + 1) * sizeof(wchar_t); } printf("...\n"); + } + if (no_return) { efi_set_variable_usec("LoaderTimeExecUSec", &efi_systemd_vendor_guid, ktime_to_us(ktime_get())); - - is_kernel = true; shutdown_barebox(); } @@ -135,8 +144,8 @@ int efi_execute_image(efi_handle_t handle, efi_continue_devices(); - if (is_kernel) { - pr_emerg("Kernel image has unexpectedly returned\n"); + if (no_return) { + pr_emerg("Boot image has unexpectedly returned\n"); BS->exit(efi_parent_image, efiret, 0, NULL); } @@ -162,7 +171,7 @@ static int efi_execute(struct binfmt_hook *b, char *file, int argc, char **argv) if (ret) return ret; - return efi_execute_image(handle, loaded_image, b->type); + return efi_execute_image(handle, loaded_image, false, b->type); } static struct binfmt_hook binfmt_efi_hook = { diff --git a/efi/payload/image.h b/efi/payload/image.h index bab1be368c21..33f7e1a21b30 100644 --- a/efi/payload/image.h +++ b/efi/payload/image.h @@ -13,6 +13,7 @@ int efi_load_image(const char *file, struct efi_loaded_image **loaded_image, int efi_execute_image(efi_handle_t handle, struct efi_loaded_image *loaded_image, + bool is_bootm, enum filetype filetype); extern struct image_handler efi_x86_linux_handle_tr; -- 2.47.3
