Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
MIPS: Fix mdelay(1) for 64bit kernel with HZ == 1000 mdelay(1) (i.e. udelay(1000)) does not work correctly due to overflow. 1000 * 0x004189374BC6A7f0 = 0x10000000000000180 (>= 2**64) 0x004189374BC6A7ef (0x004189374BC6A7f0 - 1) is OK and it is exactly same as catchall case (0x8000000000000000UL / (500000 / HZ)). Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
authored by
Atsushi Nemoto
and committed by
f12555d2
6c355852
+2
-4
include/asm-mips/delay.h
+2
-4
include/asm-mips/delay.h
···
52
52
unsigned long lo;
53
53
54
54
/*
55
-
* The common rates of 1000 and 128 are rounded wrongly by the
56
-
* catchall case for 64-bit. Excessive precission? Probably ...
55
+
* The rates of 128 is rounded wrongly by the catchall case
56
+
* for 64-bit. Excessive precission? Probably ...
57
57
*/
58
58
#if defined(CONFIG_64BIT) && (HZ == 128)
59
59
usecs *= 0x0008637bd05af6c7UL; /* 2**64 / (1000000 / HZ) */
60
-
#elif defined(CONFIG_64BIT) && (HZ == 1000)
61
-
usecs *= 0x004189374BC6A7f0UL; /* 2**64 / (1000000 / HZ) */
62
60
#elif defined(CONFIG_64BIT)
63
61
usecs *= (0x8000000000000000UL / (500000 / HZ));
64
62
#else /* 32-bit junk follows here */