Re: [PATCH 1/2] moduleparams: Add hex type parameter
Dear Linus, dear Christian, Am 02.07.20 um 21:42 schrieb Linus Torvalds: On Thu, Jul 2, 2020 at 7:42 AM Christian König wrote: 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. Not necessarily true. I'd argue that "unsigned long" is equally possible for some bit mask (or other hex-likely) type. So don't call it just "hex". Call it "hexint" (the hex does imply "unsigned", I feel - showing hex numbers with a sign sounds insane). That way, if somebody ends up wanting it for unsigned long values, we're not stuck. Good idea. Don.e Another option is to just say that hex values always have bit _sizes_. So "hex32" and "hex64" would also make sense as names to me. I went for int to be consistent in the naming, and kstrtouint is used in the macro. While at it, should the hex numbers always be padded out to the size? The example Paul used doesn't have that issue (high bit being set). Bbut often it may make sense to show a 32-bit hex number as "%#08x" because it really makes things clearer when you're looking at high bits, say. It's really hard to tell the difference between "just bit 27 set" and "just bit 31" set otherwise, and that's not all that uncommon when the bitmasks are sparse. Also good idea. Done. I just sent out the v2. Kind regards, Paul
Re: [PATCH 1/2] moduleparams: Add hex type parameter
On Thu, Jul 2, 2020 at 7:42 AM Christian König wrote: > > 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. Not necessarily true. I'd argue that "unsigned long" is equally possible for some bit mask (or other hex-likely) type. So don't call it just "hex". Call it "hexint" (the hex does imply "unsigned", I feel - showing hex numbers with a sign sounds insane). That way, if somebody ends up wanting it for unsigned long values, we're not stuck. Another option is to just say that hex values always have bit _sizes_. So "hex32" and "hex64" would also make sense as names to me. While at it, should the hex numbers always be padded out to the size? The example Paul used doesn't have that issue (high bit being set). Bbut often it may make sense to show a 32-bit hex number as "%#08x" because it really makes things clearer when you're looking at high bits, say. It's really hard to tell the difference between "just bit 27 set" and "just bit 31" set otherwise, and that's not all that uncommon when the bitmasks are sparse. Linus
Re: [PATCH 1/2] moduleparams: Add hex type parameter
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
0xbfff
Cc: linux-kernel@vger.kernel.org
Cc: amd-...@lists.freedesktop.org
Signed-off-by: Paul Menzel
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)
{
