On Wed, 13 Aug 2025 14:19:16 -0700
Daniel Ferguson <danielf@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> From: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
>
> Add a helper function to print a string with names associated
> to each bit field.
>
> A typical example is:
>
> const char * const bits[] = {
> "bit 3 name",
> "bit 4 name",
> "bit 5 name",
> };
> char str[120];
> unsigned int bitmask = BIT(3) | BIT(5);
>
> #define MASK GENMASK(5,3)
>
> cper_bits_to_str(str, sizeof(str), FIELD_GET(MASK, bitmask),
> bits, ARRAY_SIZE(bits));
>
> The above code fills string "str" with "bit 3 name|bit 5 name".
>
> Reviewed-by; Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
My typo still here :(
So drop that garbage and
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
> Acked-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
> ---
> drivers/firmware/efi/cper.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/cper.h | 2 ++
> 2 files changed, 62 insertions(+)
>
> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index 928409199a1a4009b11cf3189fe036ad8861169c..79ba688a64f8da7af2dad097b9331c72afc73864 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -12,6 +12,7 @@
> * Specification version 2.4.
> */
>
> +#include <linux/bitmap.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> #include <linux/time.h>
> @@ -106,6 +107,65 @@ void cper_print_bits(const char *pfx, unsigned int bits,
> printk("%s\n", buf);
> }
>
> +/**
> + * cper_bits_to_str - return a string for set bits
> + * @buf: buffer to store the output string
> + * @buf_size: size of the output string buffer
> + * @bits: bit mask
> + * @strs: string array, indexed by bit position
> + * @strs_size: size of the string array: @strs
> + *
> + * Add to @buf the bitmask in hexadecimal. Then, for each set bit in @bits,
> + * add the corresponding string describing the bit in @strs to @buf.
> + *
> + * A typical example is::
> + *
> + * const char * const bits[] = {
> + * "bit 3 name",
> + * "bit 4 name",
> + * "bit 5 name",
> + * };
> + * char str[120];
> + * unsigned int bitmask = BIT(3) | BIT(5);
> + * #define MASK GENMASK(5,3)
> + *
> + * cper_bits_to_str(str, sizeof(str), FIELD_GET(MASK, bitmask),
> + * bits, ARRAY_SIZE(bits));
> + *
> + * The above code fills the string ``str`` with ``bit 3 name|bit 5 name``.
> + *
> + * Return: number of bytes stored or an error code if lower than zero.
> + */
> +int cper_bits_to_str(char *buf, int buf_size, unsigned long bits,
> + const char * const strs[], unsigned int strs_size)
> +{
> + int len = buf_size;
> + char *str = buf;
> + int i, size;
> +
> + *buf = '\0';
> +
> + for_each_set_bit(i, &bits, strs_size) {
> + if (!(bits & BIT_ULL(i)))
> + continue;
> +
> + if (*buf && len > 0) {
> + *str = '|';
> + len--;
> + str++;
> + }
> +
> + size = strscpy(str, strs[i], len);
> + if (size < 0)
> + return size;
> +
> + len -= size;
> + str += size;
> + }
> + return len - buf_size;
> +}
> +EXPORT_SYMBOL_GPL(cper_bits_to_str);
> +
> static const char * const proc_type_strs[] = {
> "IA32/X64",
> "IA64",
> diff --git a/include/linux/cper.h b/include/linux/cper.h
> index 0ed60a91eca9d6425c9a41947a927b59f7aa2c71..58f40477c824e61c7f798978947bf1f441ce45ad 100644
> --- a/include/linux/cper.h
> +++ b/include/linux/cper.h
> @@ -588,6 +588,8 @@ const char *cper_mem_err_type_str(unsigned int);
> const char *cper_mem_err_status_str(u64 status);
> void cper_print_bits(const char *prefix, unsigned int bits,
> const char * const strs[], unsigned int strs_size);
> +int cper_bits_to_str(char *buf, int buf_size, unsigned long bits,
> + const char * const strs[], unsigned int strs_size);
> void cper_mem_err_pack(const struct cper_sec_mem_err *,
> struct cper_mem_err_compact *);
> const char *cper_mem_err_unpack(struct trace_seq *,
>
