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serial: 8250: Fix 8250_rsa symbol loop

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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 5a128fb475
("serial: 8250: move RSA functions to 8250_rsa.c"). The commit
b20d6576cd ("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: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Alex Davis <alex47794@gmail.com>
Fixes: 5a128fb475 ("serial: 8250: move RSA functions to 8250_rsa.c")
Fixes: b20d6576cd ("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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20251110105043.4062-1-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ilpo Järvinen
2025-11-10 12:50:43 +02:00
committed by Greg Kroah-Hartman
parent eb4917f557
commit 2bf95a9bcb
4 changed files with 21 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/tty/serial/8250/8250.h
View File

@@ -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) {}

2
drivers/tty/serial/8250/8250_platform.c
View File

@@ -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;

26
drivers/tty/serial/8250/8250_rsa.c
View File

@@ -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

2
drivers/tty/serial/8250/Makefile
View File

@@ -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