lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 25 Jan 2007 20:45:30 -0500 From: Jeff Garzik <jgarzik@...ox.com> To: Linus Torvalds <torvalds@...ux-foundation.org> CC: David Woodhouse <dwmw2@...radead.org>, Alan <alan@...rguk.ukuu.org.uk>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] libata-sff: Don't call bmdma_stop on non DMA capable controllers Linus Torvalds wrote: > > On Fri, 26 Jan 2007, David Woodhouse wrote: >> You're thinking of MMIO, while the case we were discussing was PIO. My >> laptop is perfectly happy to assign PIO resources from zero. > > I was indeed thinking MMIO, but I really think it should extend to PIO > also. It certainly is (again) true on PC's, where the low IO space is > special and reserved for motherboard/system devices. Via the even-less-of-an-excuse-than-you-thought department: Many (most?) non-x86 handle PIO via special mappings and additional serialization instructions, but otherwise treat PIO register space in a very similar manner to MMIO. Thus, it's /easier/ on non-x86 to ensure that PIO addresses never land at zero, because you must remap /anyway/. It's only on x86 that PIO register spaces are accessed by vastly different CPU instructions. Most other arches convert PIO accesses into massage+mmio R/W+massage. On sparc64, for example, after I pointed this out to DaveM, he was able to implement the new iomap interface without the 'if (pio-mem-area)' branch present on x86. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists