[PATCH] firmware_loader: rework crypto dependencies

[Arnd Bergmann]

From: Arnd Bergmann <arnd@xxxxxxxx>

The crypto dependencies for the firmwware loader are incomplete,
in particular a built-in FW_LOADER fails to link against a modular
crypto hash driver:

ld.lld: error: undefined symbol: crypto_alloc_shash
ld.lld: error: undefined symbol: crypto_shash_digest
ld.lld: error: undefined symbol: crypto_destroy_tfm
>>> referenced by main.c
>>>               drivers/base/firmware_loader/main.o:(fw_log_firmware_info) in archive vmlinux.a

Rework this to use the usual 'select' from the driver module,
to respect the built-in vs module dependencies, and add a
more verbose crypto dependency to the debug option to prevent
configurations that lead to a link failure.

Fixes: 02fe26f25325 ("firmware_loader: Add debug message with checksum for FW file")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
Tested on a few hundred randconfig builds
---
 drivers/base/firmware_loader/Kconfig | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 0cabc783d67a..5ca00e02fe82 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -3,6 +3,8 @@ menu "Firmware loader"
 
 config FW_LOADER
 	tristate "Firmware loading facility" if EXPERT
+	select CRYPTO_HASH if FW_LOADER_DEBUG
+	select CRYPTO_SHA256 if FW_LOADER_DEBUG
 	default y
 	help
 	  This enables the firmware loading facility in the kernel. The kernel
@@ -26,10 +28,9 @@ config FW_LOADER
 
 config FW_LOADER_DEBUG
 	bool "Log filenames and checksums for loaded firmware"
+	depends on CRYPTO = FW_LOADER || CRYPTO=y
 	depends on DYNAMIC_DEBUG
 	depends on FW_LOADER
-	depends on CRYPTO
-	depends on CRYPTO_SHA256
 	default FW_LOADER
 	help
 	  Select this option to use dynamic debug to log firmware filenames and
-- 
2.39.2