Commit 2bf95a9b authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Greg Kroah-Hartman
Browse files

serial: 8250: Fix 8250_rsa symbol loop 



Depmod fails for a kernel made with:
  make allnoconfig
  echo -e "CONFIG_MODULES=y\nCONFIG_SERIAL_8250=m\nCONFIG_SERIAL_8250_EXTENDED=y\nCONFIG_SERIAL_8250_RSA=y" >> .config
  make olddefconfig

...due to a dependency loop:

  depmod: ERROR: Cycle detected: 8250 -> 8250_base -> 8250
  depmod: ERROR: Found 2 modules in dependency cycles!

This is caused by the move of 8250 RSA code from 8250_port.c (in
8250_base.ko) into 8250_rsa.c (in 8250.ko) by the commit 5a128fb4
("serial: 8250: move RSA functions to 8250_rsa.c"). The commit
b20d6576 ("serial: 8250: export RSA functions") tried to fix a
missing symbol issue with EXPORTs but those then cause this dependency
cycle.

Break dependency loop by moving 8250_rsa.o from 8250.ko to 8250_base.ko
and by passing univ8250_port_base_ops to univ8250_rsa_support() that
can make a local copy of it.

Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Reported-by: default avatarAlex Davis <alex47794@gmail.com>
Fixes: 5a128fb4 ("serial: 8250: move RSA functions to 8250_rsa.c")
Fixes: b20d6576 ("serial: 8250: export RSA functions")
Cc: stable <stable@kernel.org>
Link: https://lore.kernel.org/all/87frc3sd8d.fsf@posteo.net/
Link: https://lore.kernel.org/all/CADiockCvM6v+d+UoFZpJSMoLAdpy99_h-hJdzUsdfaWGn3W7-g@mail.gmail.com/


Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: default avatarJiri Slaby <jirislaby@kernel.org>
Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20251110105043.4062-1-ilpo.jarvinen@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent eb4917f5

drivers/tty/serial/8250/8250.h

+2 −2
Original line number Diff line number Diff line
@@ -322,13 +322,13 @@ static inline void serial8250_pnp_exit(void) { } 
#endif



#ifdef CONFIG_SERIAL_8250_RSA

void univ8250_rsa_support(struct uart_ops *ops);

void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops);

void rsa_enable(struct uart_8250_port *up);

void rsa_disable(struct uart_8250_port *up);

void rsa_autoconfig(struct uart_8250_port *up);

void rsa_reset(struct uart_8250_port *up);

#else

static inline void univ8250_rsa_support(struct uart_ops *ops) { }

static inline void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops) { }

static inline void rsa_enable(struct uart_8250_port *up) {}

static inline void rsa_disable(struct uart_8250_port *up) {}

static inline void rsa_autoconfig(struct uart_8250_port *up) {}

drivers/tty/serial/8250/8250_platform.c

+1 −1
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ static void __init __serial8250_isa_init_ports(void) 


	/* chain base port ops to support Remote Supervisor Adapter */

	univ8250_port_ops = *univ8250_port_base_ops;

	univ8250_rsa_support(&univ8250_port_ops);

	univ8250_rsa_support(&univ8250_port_ops, univ8250_port_base_ops);



	if (share_irqs)

		irqflag = IRQF_SHARED;

drivers/tty/serial/8250/8250_rsa.c

+17 −9
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
static unsigned long probe_rsa[PORT_RSA_MAX];

static unsigned int probe_rsa_count;



static const struct uart_ops *core_port_base_ops;



static int rsa8250_request_resource(struct uart_8250_port *up)

{

	struct uart_port *port = &up->port;
@@ -67,7 +69,7 @@ static void univ8250_config_port(struct uart_port *port, int flags) 
		}

	}



	univ8250_port_base_ops->config_port(port, flags);

	core_port_base_ops->config_port(port, flags);



	if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)

		rsa8250_release_resource(up);
@@ -78,11 +80,11 @@ static int univ8250_request_port(struct uart_port *port) 
	struct uart_8250_port *up = up_to_u8250p(port);

	int ret;



	ret = univ8250_port_base_ops->request_port(port);

	ret = core_port_base_ops->request_port(port);

	if (ret == 0 && port->type == PORT_RSA) {

		ret = rsa8250_request_resource(up);

		if (ret < 0)

			univ8250_port_base_ops->release_port(port);

			core_port_base_ops->release_port(port);

	}



	return ret;
@@ -94,15 +96,25 @@ static void univ8250_release_port(struct uart_port *port) 


	if (port->type == PORT_RSA)

		rsa8250_release_resource(up);

	univ8250_port_base_ops->release_port(port);

	core_port_base_ops->release_port(port);

}



void univ8250_rsa_support(struct uart_ops *ops)

/*

 * It is not allowed to directly reference any symbols from 8250.ko here as

 * that would result in a dependency loop between the 8250.ko and

 * 8250_base.ko modules. This function is called from 8250.ko and is used to

 * break the symbolic dependency cycle. Anything that is needed from 8250.ko

 * has to be passed as pointers to this function which then can adjust those

 * variables on 8250.ko side or store them locally as needed.

 */

void univ8250_rsa_support(struct uart_ops *ops, const struct uart_ops *core_ops)

{

	core_port_base_ops = core_ops;

	ops->config_port  = univ8250_config_port;

	ops->request_port = univ8250_request_port;

	ops->release_port = univ8250_release_port;

}

EXPORT_SYMBOL_FOR_MODULES(univ8250_rsa_support, "8250");



module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);

MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
@@ -146,7 +158,6 @@ void rsa_enable(struct uart_8250_port *up) 
	if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)

		serial_out(up, UART_RSA_FRR, 0);

}

EXPORT_SYMBOL_FOR_MODULES(rsa_enable, "8250_base");



/*

 * Attempts to turn off the RSA FIFO and resets the RSA board back to 115kbps compat mode. It is
@@ -178,7 +189,6 @@ void rsa_disable(struct uart_8250_port *up) 
	if (result)

		up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;

}

EXPORT_SYMBOL_FOR_MODULES(rsa_disable, "8250_base");



void rsa_autoconfig(struct uart_8250_port *up)

{
@@ -191,7 +201,6 @@ void rsa_autoconfig(struct uart_8250_port *up) 
	if (__rsa_enable(up))

		up->port.type = PORT_RSA;

}

EXPORT_SYMBOL_FOR_MODULES(rsa_autoconfig, "8250_base");



void rsa_reset(struct uart_8250_port *up)

{
@@ -200,7 +209,6 @@ void rsa_reset(struct uart_8250_port *up) 


	serial_out(up, UART_RSA_FRR, 0);

}

EXPORT_SYMBOL_FOR_MODULES(rsa_reset, "8250_base");



#ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS

#ifndef MODULE

drivers/tty/serial/8250/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ obj-$(CONFIG_SERIAL_8250) += 8250.o 
8250-y					:= 8250_core.o

8250-y					+= 8250_platform.o

8250-$(CONFIG_SERIAL_8250_PNP)		+= 8250_pnp.o

8250-$(CONFIG_SERIAL_8250_RSA)		+= 8250_rsa.o



obj-$(CONFIG_SERIAL_8250)		+= 8250_base.o

8250_base-y				:= 8250_port.o
@@ -15,6 +14,7 @@ obj-$(CONFIG_SERIAL_8250) += 8250_base.o 
8250_base-$(CONFIG_SERIAL_8250_DWLIB)	+= 8250_dwlib.o

8250_base-$(CONFIG_SERIAL_8250_FINTEK)	+= 8250_fintek.o

8250_base-$(CONFIG_SERIAL_8250_PCILIB)	+= 8250_pcilib.o

8250_base-$(CONFIG_SERIAL_8250_RSA)	+= 8250_rsa.o



obj-$(CONFIG_SERIAL_8250_CONSOLE)	+= 8250_early.o