mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-26 00:41:17 +00:00
49 lines
1.7 KiB
Diff
49 lines
1.7 KiB
Diff
From f5b973489beb1a1239dfad53e3ad6e36ff7ee958 Mon Sep 17 00:00:00 2001
|
|
From: Segher Boessenkool <segher@kernel.crashing.org>
|
|
Date: Thu, 9 Oct 2008 21:18:27 +0100
|
|
Subject: [PATCH] fix-gcc-4.3-false-modulo-optimization.patch
|
|
|
|
I tried to compile the current stable kernel
|
|
(a2ef813d2f439a3e9f377d33a2e5baad098afb7e)
|
|
and get the following errors:
|
|
|
|
kernel/built-in.o: In function `timespec_add_ns':
|
|
/mnt/data/Freerunner/Gentoo/rootinstall/usr/src/linux/include/linux/time.h:174:
|
|
undefined reference to `__aeabi_uldivmod'
|
|
/mnt/data/Freerunner/Gentoo/rootinstall/usr/src/linux/include/linux/time.h:179:
|
|
undefined reference to `__aeabi_uldivmod'
|
|
/mnt/data/Freerunner/Gentoo/rootinstall/usr/src/linux/include/linux/time.h:174:
|
|
undefined reference to `__aeabi_uldivmod'
|
|
/mnt/data/Freerunner/Gentoo/rootinstall/usr/src/linux/include/linux/time.h:179:
|
|
undefined reference to `__aeabi_uldivmod'
|
|
|
|
applying the following patch solved the problem:
|
|
--------
|
|
Prevent gcc-4.3 form "optimizing" the while loop into a costly modulo operation.
|
|
Patch found at http://lkml.org/lkml/2008/2/22/464.
|
|
|
|
Reported-by: Sven Rebhan <odinshorse@googlemail.com>
|
|
Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
|
|
---
|
|
include/linux/time.h | 4 ++++
|
|
1 files changed, 4 insertions(+), 0 deletions(-)
|
|
|
|
diff --git a/include/linux/time.h b/include/linux/time.h
|
|
index b04136d..3e8fd9e 100644
|
|
--- a/include/linux/time.h
|
|
+++ b/include/linux/time.h
|
|
@@ -173,6 +173,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns)
|
|
{
|
|
ns += a->tv_nsec;
|
|
while(unlikely(ns >= NSEC_PER_SEC)) {
|
|
+ /* The following asm() prevents the compiler from
|
|
+ * optimising this loop into a modulo operation. */
|
|
+ asm("" : "+r"(ns));
|
|
+
|
|
ns -= NSEC_PER_SEC;
|
|
a->tv_sec++;
|
|
}
|
|
--
|
|
1.5.6.5
|
|
|