Why are these patches being backported?

On Mon, 15 Dec 2025 at 12:08, Sasha Levin sashal@kernel.org wrote:

This is a note to let you know that I've just added the patch titled

efi/cper: Add a new helper function to print bitmasks

to the 6.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: efi-cper-add-a-new-helper-function-to-print-bitmasks.patch and it can be found in the queue-6.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

commit 06d39b93424e64e47244b0ccb97a3c6b2c033cfe Author: Mauro Carvalho Chehab mchehab+huawei@kernel.org Date: Thu Aug 14 09:52:54 2025 -0700

efi/cper: Add a new helper function to print bitmasks

[ Upstream commit a976d790f49499ccaa0f991788ad8ebf92e7fd5c ]

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@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c index 928409199a1a4..79ba688a64f8d 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 0ed60a91eca9d..58f40477c824e 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 *,