On Friday 12 May 2023 22:58:04 Randy Dunlap wrote: > In a randconfig with CONFIG_SERIAL_CPM=m and > CONFIG_PPC_EARLY_DEBUG_CPM=y, there is a build error: > ERROR: modpost: "udbg_putc" [drivers/tty/serial/cpm_uart/cpm_uart.ko] > undefined! > > The build can be fixed by exporting "udbg_putc" in udbg.c. > > OTOH, maybe something like this is more appropriate in > arch/powerpc/Kconfig.debug? > > config PPC_EARLY_DEBUG_CPM > bool "Early serial debugging for Freescale CPM-based serial ports" > - depends on SERIAL_CPM > + depends on SERIAL_CPM=y > > Signed-off-by: Randy Dunlap <rdun...@infradead.org> > Cc: Michael Ellerman <m...@ellerman.id.au> > Cc: Nicholas Piggin <npig...@gmail.com> > Cc: Christophe Leroy <christophe.le...@csgroup.eu> > Cc: linuxppc-dev@lists.ozlabs.org > Cc: Arnd Bergmann <a...@arndb.de> > Cc: "Pali Rohár" <p...@kernel.org> > --- > arch/powerpc/kernel/udbg.c | 1 + > 1 file changed, 1 insertion(+) > > diff -- a/arch/powerpc/kernel/udbg.c b/arch/powerpc/kernel/udbg.c > --- a/arch/powerpc/kernel/udbg.c > +++ b/arch/powerpc/kernel/udbg.c > @@ -14,6 +14,7 @@ > #include <asm/udbg.h> > > void (*udbg_putc)(char c); > +EXPORT_SYMBOL(udbg_putc); > void (*udbg_flush)(void); > int (*udbg_getc)(void); > int (*udbg_getc_poll)(void);
Hello! I do not think that it is a good idea to export udbg functions for kernel modules. I have quickly looked at the cpm_uart driver file drivers/tty/serial/cpm_uart/cpm_uart_core.c and it looks like that once udbg from it is registered then there is no code for unregistering it. So I have feeling that compiling cpm_uart driver as module should not be allowed when CONFIG_SERIAL_CPM_CONSOLE is enabled, and early debug should depend on CONFIG_CONSOLE_POLL || CONFIG_SERIAL_CPM_CONSOLE. Any other opinion?
