um: Fix hostaudio build errors

Use "select" to ensure that the required kconfig symbols are set
as expected.
Drop HOSTAUDIO since it is now equivalent to UML_SOUND.

Set CONFIG_SOUND=m in ARCH=um defconfig files to maintain the
status quo of the default configs.

Allow SOUND with UML regardless of HAS_IOMEM. Otherwise there is a
kconfig warning for unmet dependencies. (This was not an issue when
SOUND was defined in arch/um/drivers/Kconfig. I have done 50 randconfig
builds and didn't find any issues.)

This fixes build errors when CONFIG_SOUND is not set:

ld: arch/um/drivers/hostaudio_kern.o: in function `hostaudio_cleanup_module':
hostaudio_kern.c:(.exit.text+0xa): undefined reference to `unregister_sound_mixer'
ld: hostaudio_kern.c:(.exit.text+0x15): undefined reference to `unregister_sound_dsp'
ld: arch/um/drivers/hostaudio_kern.o: in function `hostaudio_init_module':
hostaudio_kern.c:(.init.text+0x19): undefined reference to `register_sound_dsp'
ld: hostaudio_kern.c:(.init.text+0x31): undefined reference to `register_sound_mixer'
ld: hostaudio_kern.c:(.init.text+0x49): undefined reference to `unregister_sound_dsp'

and this kconfig warning:
WARNING: unmet direct dependencies detected for SOUND

Fixes: 1da177e ("Linux-2.6.12-rc2")
Fixes: d886e87 ("sound: make OSS sound core optional")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: lore.kernel.org/r/202307141416.vxuRVpFv-lkp@intel.com
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: linux-um@lists.infradead.org
Cc: Tejun Heo <tj@kernel.org>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: linux-kbuild@vger.kernel.org
Cc: alsa-devel@alsa-project.org
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

arch/um/configs/i386_defconfig

@@ -34,6 +34,7 @@ CONFIG_TTY_CHAN=y
 CONFIG_XTERM_CHAN=y
 CONFIG_CON_CHAN="pts"
 CONFIG_SSL_CHAN="pts"
+CONFIG_SOUND=m
 CONFIG_UML_SOUND=m
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y

arch/um/configs/x86_64_defconfig

@@ -32,6 +32,7 @@ CONFIG_TTY_CHAN=y
 CONFIG_XTERM_CHAN=y
 CONFIG_CON_CHAN="pts"
 CONFIG_SSL_CHAN="pts"
+CONFIG_SOUND=m
 CONFIG_UML_SOUND=m
 CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y

arch/um/drivers/Kconfig

@@ -111,24 +111,14 @@ config SSL_CHAN
 
 config UML_SOUND
 	tristate "Sound support"
+	depends on SOUND
+	select SOUND_OSS_CORE
 	help
 	  This option enables UML sound support.  If enabled, it will pull in
-	  soundcore and the UML hostaudio relay, which acts as a intermediary
+	  the UML hostaudio relay, which acts as a intermediary
 	  between the host's dsp and mixer devices and the UML sound system.
 	  It is safe to say 'Y' here.
 
-config SOUND
-	tristate
-	default UML_SOUND
-
-config SOUND_OSS_CORE
-	bool
-	default UML_SOUND
-
-config HOSTAUDIO
-	tristate
-	default UML_SOUND
-
 endmenu
 
 menu "UML Network Devices"

arch/um/drivers/Makefile

@@ -54,7 +54,7 @@ obj-$(CONFIG_UML_NET) += net.o
 obj-$(CONFIG_MCONSOLE) += mconsole.o
 obj-$(CONFIG_MMAPPER) += mmapper_kern.o 
 obj-$(CONFIG_BLK_DEV_UBD) += ubd.o 
-obj-$(CONFIG_HOSTAUDIO) += hostaudio.o
+obj-$(CONFIG_UML_SOUND) += hostaudio.o
 obj-$(CONFIG_NULL_CHAN) += null.o 
 obj-$(CONFIG_PORT_CHAN) += port.o
 obj-$(CONFIG_PTY_CHAN) += pty.o

sound/Kconfig

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 menuconfig SOUND
 	tristate "Sound card support"
-	depends on HAS_IOMEM
+	depends on HAS_IOMEM || UML
 	help
 	  If you have a sound card in your computer, i.e. if it can say more
 	  than an occasional beep, say Y.