[PATCH v5 2/4] efi/cper: Add a new helper function to print bitmasks

Mauro Carvalho Chehab
2024-06-24T09:19:50Z

Sometimes it is desired to produce a single log line for errors.
Add a new helper function for such purpose.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
drivers/firmware/efi/cper.c | 41 +++++++++++++++++++++++++++++++++++++
include/linux/cper.h | 2 ++
2 files changed, 43 insertions(+)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index 7d2cdd9e2227..4cf56657afde 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -106,6 +106,47 @@ 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
+ * @mask: a continuous bitmask used to detect the first valid bit of the
+ * bitmap.
+ *
+ * Add to @buf the bitmask in hexadecimal. Then, for each set bit in @bits
+ * mask, add the corresponding string describing the bit in @strs to @buf.
+ */
+char *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;
+
+ for_each_set_bit(i, &bits, strs_size) {
+ if (!(bits & (1U << (i))))
+ continue;
+
+ if (*buf && len > 0) {
+ *str = '|';
+ len--;
+ str++;
+ }
+
+ size = strscpy(str, strs[i], len);
+ if (size < 0)
+ break;
+
+ len -= size;
+ str += size;
+ }
+ return buf;
+}
+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 265b0f8fc0b3..c2f14b916bfb 100644
--- a/include/linux/cper.h
+++ b/include/linux/cper.h
@@ -584,6 +584,8 @@ 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);
+char *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 *,
--
2.45.2