Re: MMIO and gcc re-ordering issue
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: 2008-05-27 22:02:44
Also in:
linux-arch, lkml
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: 2008-05-27 22:02:44
Also in:
linux-arch, lkml
On Tue, 27 May 2008, Matthew Wilcox wrote:
On Tue, May 27, 2008 at 10:38:22PM +0100, Alan Cox wrote:quoted
quoted
re-ordering, even though I doubt it will be visible in practice. So if you use the "__" versions, you'd better have barriers even on x86!Are we also going to have __ioread*/__iowrite* ?Didn't we already define ioread*() to have loose semantics?
They are supposed to have the same semantics as readl/writel. And yes, it's "loose", but only when compared to inb/outb (which are really very strict, if you want to emulate x86 - an "outb" basically is not only ordered, it doesn't even post the write, and waits until it has hit the bus!) Linus