Re: [PATCH 1/2] moduleparams: Add hex type parameter

["Christian König" <christian.koenig@amd.com>]

Am 02.07.20 um 16:01 schrieb Paul Menzel:
> For bitmasks printing values in hex is more convenient.
>
> Prefix with 0x (#) to make it clear, that it’s a hex value.
>
> 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>

Good idea.

I'm just not sure how well this is received upstream because it only 
covers u32

On the other hand that is probably also the most used.

Christian.

> ---
>   include/linux/moduleparam.h | 7 ++++++-
>   kernel/params.c             | 1 +
>   2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
> index 3ef917ff0964..408978fcfe27 100644
> --- a/include/linux/moduleparam.h
> +++ b/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, hex, 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_hex;
> +extern int param_set_hex(const char *val, const struct kernel_param *kp);
> +extern int param_get_hex(char *buffer, const struct kernel_param *kp);
> +#define param_check_hex(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);
> diff --git a/kernel/params.c b/kernel/params.c
> index 8e56f8b12d8f..ceca8394dac5 100644
> --- a/kernel/params.c
> +++ b/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(hex,		unsigned int,		"%#x",  kstrtouint);
>   
>   int param_set_charp(const char *val, const struct kernel_param *kp)
>   {