linux-kernel - [PATCH 33/38] Annotate hardware config module parameters in drivers/watchdog/

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Message-ID: <149141170399.29162.13331435039842686737.stgit@warthog.procyon.org.uk>
Date:   Wed, 05 Apr 2017 18:01:44 +0100
From:   David Howells <dhowells@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     gnomes@...rguk.ukuu.org.uk, linux-watchdog@...r.kernel.org,
        Zwane Mwaikambo <zwanem@...il.com>,
        linux-security-module@...r.kernel.org, dhowells@...hat.com,
        Wim Van Sebroeck <wim@...ana.be>, keyrings@...r.kernel.org,
        gregkh@...uxfoundation.org, Guenter Roeck <linux@...ck-us.net>
Subject: [PATCH 33/38] Annotate hardware config module parameters in
 drivers/watchdog/

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 drivers/watchdog/.

Suggested-by: Alan Cox <gnomes@...rguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@...hat.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
cc: Wim Van Sebroeck <wim@...ana.be>
cc: Zwane Mwaikambo <zwanem@...il.com>
cc: linux-watchdog@...r.kernel.org
---

 drivers/watchdog/cpu5wdt.c     |    2 +-
 drivers/watchdog/eurotechwdt.c |    4 ++--
 drivers/watchdog/pc87413_wdt.c |    2 +-
 drivers/watchdog/sc1200wdt.c   |    2 +-
 drivers/watchdog/wdt.c         |    4 ++--
 5 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/watchdog/cpu5wdt.c b/drivers/watchdog/cpu5wdt.c
index 6d03e8e30f8b..6c3f78e45c26 100644
--- a/drivers/watchdog/cpu5wdt.c
+++ b/drivers/watchdog/cpu5wdt.c
@@ -289,7 +289,7 @@ MODULE_DESCRIPTION("sma cpu5 watchdog driver");
 MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
 MODULE_LICENSE("GPL");
 
-module_param(port, int, 0);
+module_param_hw(port, int, ioport, 0);
 MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");
 
 module_param(verbose, int, 0);
diff --git a/drivers/watchdog/eurotechwdt.c b/drivers/watchdog/eurotechwdt.c
index 23ee53240c4c..38e96712264f 100644
--- a/drivers/watchdog/eurotechwdt.c
+++ b/drivers/watchdog/eurotechwdt.c
@@ -97,9 +97,9 @@ MODULE_PARM_DESC(nowayout,
 #define WDT_TIMER_CFG		0xf3
 
 
-module_param(io, int, 0);
+module_param_hw(io, int, ioport, 0);
 MODULE_PARM_DESC(io, "Eurotech WDT io port (default=0x3f0)");
-module_param(irq, int, 0);
+module_param_hw(irq, int, irq, 0);
 MODULE_PARM_DESC(irq, "Eurotech WDT irq (default=10)");
 module_param(ev, charp, 0);
 MODULE_PARM_DESC(ev, "Eurotech WDT event type (default is `int')");
diff --git a/drivers/watchdog/pc87413_wdt.c b/drivers/watchdog/pc87413_wdt.c
index 9f15dd9435d1..06a892e36a8d 100644
--- a/drivers/watchdog/pc87413_wdt.c
+++ b/drivers/watchdog/pc87413_wdt.c
@@ -579,7 +579,7 @@ MODULE_AUTHOR("Marcus Junker <junker@...uras.de>");
 MODULE_DESCRIPTION("PC87413 WDT driver");
 MODULE_LICENSE("GPL");
 
-module_param(io, int, 0);
+module_param_hw(io, int, ioport, 0);
 MODULE_PARM_DESC(io, MODNAME " I/O port (default: "
 					__MODULE_STRING(IO_DEFAULT) ").");
 
diff --git a/drivers/watchdog/sc1200wdt.c b/drivers/watchdog/sc1200wdt.c
index 131193a7acdf..b34d3d5ba632 100644
--- a/drivers/watchdog/sc1200wdt.c
+++ b/drivers/watchdog/sc1200wdt.c
@@ -88,7 +88,7 @@ MODULE_PARM_DESC(isapnp,
 	"When set to 0 driver ISA PnP support will be disabled");
 #endif
 
-module_param(io, int, 0);
+module_param_hw(io, int, ioport, 0);
 MODULE_PARM_DESC(io, "io port");
 module_param(timeout, int, 0);
 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
diff --git a/drivers/watchdog/wdt.c b/drivers/watchdog/wdt.c
index e0206b5b7d89..e481fbbc4ae7 100644
--- a/drivers/watchdog/wdt.c
+++ b/drivers/watchdog/wdt.c
@@ -78,9 +78,9 @@ static int irq = 11;
 
 static DEFINE_SPINLOCK(wdt_lock);
 
-module_param(io, int, 0);
+module_param_hw(io, int, ioport, 0);
 MODULE_PARM_DESC(io, "WDT io port (default=0x240)");
-module_param(irq, int, 0);
+module_param_hw(irq, int, irq, 0);
 MODULE_PARM_DESC(irq, "WDT irq (default=11)");
 
 /* Support for the Fan Tachometer on the WDT501-P */