moduleparams: Add hexint type parameter

For bitmasks printing values in hex is more convenient.

Prefix with `0x` to make it clear, that it’s a hex value, and pad it
out.

Using the helper for `amdgpu.ppfeaturemask`, it will look like below.

Before:

    $ more /sys/module/amdgpu/parameters/ppfeaturemask
    4294950911

After:

    $ more /sys/module/amdgpu/parameters/ppfeaturemask
    0xffffbfff

Cc: linux-kernel@vger.kernel.org
Cc: amd-gfx@lists.freedesktop.org
Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/374726/

include/linux/moduleparam.h

@@ -118,7 +118,7 @@ struct kparam_array
  * you can create your own by defining those variables.
  *
  * Standard types are:
- *	byte, short, ushort, int, uint, long, ulong
+ *	byte, hexint, short, ushort, int, uint, long, ulong
  *	charp: a character pointer
  *	bool: a bool, values 0/1, y/n, Y/N.
  *	invbool: the above, only sense-reversed (N = true).
@@ -448,6 +448,11 @@ extern int param_set_ullong(const char *val, const struct kernel_param *kp);
 extern int param_get_ullong(char *buffer, const struct kernel_param *kp);
 #define param_check_ullong(name, p) __param_check(name, p, unsigned long long)
 
+extern const struct kernel_param_ops param_ops_hexint;
+extern int param_set_hexint(const char *val, const struct kernel_param *kp);
+extern int param_get_hexint(char *buffer, const struct kernel_param *kp);
+#define param_check_hexint(name, p) param_check_uint(name, p)
+
 extern const struct kernel_param_ops param_ops_charp;
 extern int param_set_charp(const char *val, const struct kernel_param *kp);
 extern int param_get_charp(char *buffer, const struct kernel_param *kp);

kernel/params.c

@@ -241,6 +241,7 @@ STANDARD_PARAM_DEF(uint,	unsigned int,		"%u",	kstrtouint);
 STANDARD_PARAM_DEF(long,	long,			"%li",		kstrtol);
 STANDARD_PARAM_DEF(ulong,	unsigned long,		"%lu",		kstrtoul);
 STANDARD_PARAM_DEF(ullong,	unsigned long long,	"%llu",		kstrtoull);
+STANDARD_PARAM_DEF(hexint,	unsigned int,		"%#08x", 	kstrtouint);
 
 int param_set_charp(const char *val, const struct kernel_param *kp)
 {