From: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> bcd2bin(0x0A) happily returns 10, despite this being an invalid BCD value. RTC drivers converting possibly corrupted BCD timestamps might want to validate their input before calling bcd2bin(). Provide a macro to do so. Unlike bcd2bin and bin2bcd, out-of-line versions are not implemented. Should the macro experience enough use, this can be retrofitted. Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> --- include/linux/bcd.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/include/linux/bcd.h b/include/linux/bcd.h index 118bea36d7d49..abbc8149178e6 100644 --- a/include/linux/bcd.h +++ b/include/linux/bcd.h @@ -14,8 +14,12 @@ const_bin2bcd(x) : \ _bin2bcd(x)) +#define bcd_is_valid(x) \ + const_bcd_is_valid(x) + #define const_bcd2bin(x) (((x) & 0x0f) + ((x) >> 4) * 10) #define const_bin2bcd(x) ((((x) / 10) << 4) + (x) % 10) +#define const_bcd_is_valid(x) (((x) & 0x0f) < 10 && ((x) >> 4) < 10) unsigned _bcd2bin(unsigned char val) __attribute_const__; unsigned char _bin2bcd(unsigned val) __attribute_const__; -- 2.30.2
