[alsa-devel] [PATCH 35/38] Annotate hardware config module parameters in sound/drivers/

[David Howells]

When the kernel is running in secure boot mode, we lock down the kernel to
prevent userspace from modifying the running kernel image.  Whilst this
includes prohibiting access to things like /dev/mem, it must also prevent
access by means of configuring driver modules in such a way as to cause a
device to access or modify the kernel image.

To this end, annotate module_param* statements that refer to hardware
configuration and indicate for future reference what type of parameter they
specify.  The parameter parser in the core sees this information and can
skip such parameters with an error message if the kernel is locked down.
The module initialisation then runs as normal, but just sees whatever the
default values for those parameters is.

Note that we do still need to do the module initialisation because some
drivers have viable defaults set in case parameters aren't specified and
some drivers support automatic configuration (e.g. PNP or PCI) in addition
to manually coded parameters.

This patch annotates drivers in sound/drivers/.

Suggested-by: Alan Cox <gnomes at lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells at redhat.com>
cc: Jaroslav Kysela <perex at perex.cz>
cc: Takashi Iwai <tiwai at suse.com>
cc: alsa-devel at alsa-project.org
---

 sound/drivers/mpu401/mpu401.c |    4 ++--
 sound/drivers/mtpav.c         |    4 ++--
 sound/drivers/serial-u16550.c |    4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/sound/drivers/mpu401/mpu401.c b/sound/drivers/mpu401/mpu401.c
index fed7e7e2177b..9b86e00d7d95 100644
--- a/sound/drivers/mpu401/mpu401.c
+++ b/sound/drivers/mpu401/mpu401.c
@@ -53,9 +53,9 @@ MODULE_PARM_DESC(enable, "Enable MPU-401 device.");
 module_param_array(pnp, bool, NULL, 0444);
 MODULE_PARM_DESC(pnp, "PnP detection for MPU-401 device.");
 #endif
-module_param_array(port, long, NULL, 0444);
+module_param_hw_array(port, long, ioport, NULL, 0444);
 MODULE_PARM_DESC(port, "Port # for MPU-401 device.");
-module_param_array(irq, int, NULL, 0444);
+module_param_hw_array(irq, int, irq, NULL, 0444);
 MODULE_PARM_DESC(irq, "IRQ # for MPU-401 device.");
 module_param_array(uart_enter, bool, NULL, 0444);
 MODULE_PARM_DESC(uart_enter, "Issue UART_ENTER command at open.");
diff --git a/sound/drivers/mtpav.c b/sound/drivers/mtpav.c
index 00b31f92c504..0f6392001e30 100644
--- a/sound/drivers/mtpav.c
+++ b/sound/drivers/mtpav.c
@@ -86,9 +86,9 @@ module_param(index, int, 0444);
 MODULE_PARM_DESC(index, "Index value for MotuMTPAV MIDI.");
 module_param(id, charp, 0444);
 MODULE_PARM_DESC(id, "ID string for MotuMTPAV MIDI.");
-module_param(port, long, 0444);
+module_param_hw(port, long, ioport, 0444);
 MODULE_PARM_DESC(port, "Parallel port # for MotuMTPAV MIDI.");
-module_param(irq, int, 0444);
+module_param_hw(irq, int, irq, 0444);
 MODULE_PARM_DESC(irq, "Parallel IRQ # for MotuMTPAV MIDI.");
 module_param(hwports, int, 0444);
 MODULE_PARM_DESC(hwports, "Hardware ports # for MotuMTPAV MIDI.");
diff --git a/sound/drivers/serial-u16550.c b/sound/drivers/serial-u16550.c
index 60d51ac4ccfe..88e66ea0306d 100644
--- a/sound/drivers/serial-u16550.c
+++ b/sound/drivers/serial-u16550.c
@@ -84,9 +84,9 @@ module_param_array(id, charp, NULL, 0444);
 MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
 module_param_array(enable, bool, NULL, 0444);
 MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
-module_param_array(port, long, NULL, 0444);
+module_param_hw_array(port, long, ioport, NULL, 0444);
 MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
-module_param_array(irq, int, NULL, 0444);
+module_param_hw_array(irq, int, irq, NULL, 0444);
 MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
 module_param_array(speed, int, NULL, 0444);
 MODULE_PARM_DESC(speed, "Speed in bauds.");