summaryrefslogtreecommitdiffstats
path: root/arch/arm/include/asm/div64.h
AgeCommit message (Collapse)Author
2014-04-22ARM: 8027/1: fix do_div() bug in big-endian systemsXiangyu Lu
In big-endian systems, "%1" get the most significant part of the value, cause the instruction to get the wrong result. When viewing ftrace record in big-endian ARM systems, we found that the timestamp errors: swapper-0 [001] 1325.970000: 0:120:R ==> [001] 16:120:R events/1 events/1-16 [001] 1325.970000: 16:120:S ==> [001] 0:120:R swapper swapper-0 [000] 1325.1000000: 0:120:R + [000] 15:120:R events/0 swapper-0 [000] 1325.1000000: 0:120:R ==> [000] 15:120:R events/0 swapper-0 [000] 1326.030000: 0:120:R + [000] 1150:120:R sshd swapper-0 [000] 1326.030000: 0:120:R ==> [000] 1150:120:R sshd When viewed ftrace records, it will call the do_div(n, base) function, which achieved arch/arm/include/asm/div64.h in. When n = 10000000, base = 1000000, in do_div(n, base) will execute "umull %Q0, %R0, %1, %Q2". Reviewed-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Cc: <stable@vger.kernel.org> # 2.6.20+ Signed-off-by: Alex Wu <wuquanming@huawei.com> Signed-off-by: Xiangyu Lu <luxiangyu@huawei.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2013-05-15ARM: 7705/1: use optimized do_div only for EABIArnd Bergmann
In OABI configurations, some uses of the do_div function cause gcc to run out of registers. To work around that, we can force the use of the out-of-line version for configurations that build a OABI kernel. Without this patch, building netx_defconfig results in: net/core/pktgen.c: In function 'pktgen_if_show': net/core/pktgen.c:682:2775: error: can't find a register in class 'GENERAL_REGS' while reloading 'asm' net/core/pktgen.c:682:3153: error: can't find a register in class 'GENERAL_REGS' while reloading 'asm' net/core/pktgen.c:682:2775: error: 'asm' operand has impossible constraints net/core/pktgen.c:682:3153: error: 'asm' operand has impossible constraints Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-03-28Disintegrate asm/system.h for ARMDavid Howells
Disintegrate asm/system.h for ARM. Signed-off-by: David Howells <dhowells@redhat.com> cc: Russell King <linux@arm.linux.org.uk> cc: linux-arm-kernel@lists.infradead.org
2008-10-23[ARM] 5320/1: fix assembly constraints in implementation of do_div()Nicolas Pitre
Those inline assembly segments using the umlal instruction must have the & modifier so to be sure that a purely input register won't alias one of the registers used as input+output. In most cases, the inputs are still used after the outputs are touched, and most binutil versions insist on "rdhi, rdlo and rm must all be different" even for ARMv6+. Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2008-08-02[ARM] move include/asm-arm to arch/arm/include/asmRussell King
Move platform independent header files to arch/arm/include/asm, leaving those in asm/arch* and asm/plat* alone. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>