* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > Here's a UNTESTED patch for x86 that may or may not compile and > > work, and which serializes (on a compiler level) the IO accesses > > against regular memory accesses. > > Ok, so it at least boots on x86-32. Thus probably on x86-64 too (since > the code is now shared). I didn't look at whether it generates much > bigger code due to the potential extra serialization, but some of the > code generation I looked at looked fine. > > IOW, it doesn't at least create any _obviously_ worse code, and it > should be arguably safer than assuming the compiler does volatile > accesses the way we want it to. ok, to pursue this topic of making readl*/writel*() more robust i picked up your patch into -tip and created a new topic branch for it: tip/x86/mmio. The patch passed initial light testing in -tip (~30 successful random self-builds and bootups on various mixed 32-bit/64-bit boxes) but it's still v2.6.27 material IMO. Failures in this area are subtle so there's no good way to tell whether it works as intended - we need wider testing. I've also added the tip/x86/mmio topic to tip/auto-x86-next rules as well so these changes will be picked up by tomorrow's linux-next tree as well, and by the next -mm iteration. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
