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

From: Christian KÃnig
Date: Thu Jul 02 2020 - 10:42:51 EST


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 itâs 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@xxxxxxxxxxxxxxx
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>

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)
{