在看MMU一章中的问题----read-lock-write 什么意思

DONG1035

在看MMU一章中的问题----read-lock-write 什么意思 [复制链接]

如题

625wangpeng

有没有更多的上下文？

heda969240

原文贴来看看

csfcsf

EXTERNAL ABORTS
In addition to the MMU-generated aborts the ARM920T can be externally aborted by the AMBA bus, which may be used to flag an error on an external memory access. However, not all accesses can be aborted in this way and the Bus Interface Unit (BIU) ignores external aborts that can not be handled.
The following accesses may be aborted:
non-cached reads；
unbuffered writes；
read-lock-write sequence, to non-cacheable memory.
In the case of a read-lock-write (SWP) sequence in which the read aborts, the write will always be attempted.

csw20066

这属于比较深的主题,如果你设计处理器,并且要支持多处理器(SMP),才要考虑这个问题.

多处理器系统中,共享数据的完整性,由"read-lock-write sequence"来实现.

wtjxnf

这属于比较深的主题,如果你设计处理器,并且要支持多处理器,才要考虑这个问题.

多处理器系统中,共享数据的完整性,由"read-lock-write sequence"来实现.

(去掉上面一行中的括弧中的SMP....我也有点不明白....被它的"SWP"干扰了....不清楚那是啥)

kimheeseon

好像是SWP指令......这段文字的意思好像是说,SWP指令如果在读的时候产生abort异常,处理器仍会尝试进行写. (读异常写正常/读异常写异常....它没有细说)


前面的理解可能有误...