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 PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 02 May 2007 14:24:53 -0400 From: Jeff Garzik <jeff@...zik.org> To: Michael Chan <mchan@...adcom.com> CC: David Miller <davem@...emloft.net>, netdev <netdev@...r.kernel.org> Subject: Re: [PATCH 3/20][BNX2]: Add 40-bit DMA workaround for 5708. Michael Chan wrote: > On Wed, 2007-05-02 at 11:29 -0400, Jeff Garzik wrote: >> Michael Chan wrote: >>> A non-IOMMU system using 64-bit dma_addr_t will always set >>> CONFIG_HIGHMEM, right? >> No. >> > May be I misunderstood the code in illegal_highdma() in net/core/dev.c > where it is checking to see if it needs to linearize the SKB when the > device does not support 64-bit DMA. I'm using similar assumptions for > the 40-bit address check in the patch. That function is just checking for highmem pages, no more, no less. Your question quoted far above presumes that no 64-bit systems exist lacking IOMMUs, which is not the case. 64-bit platforms with a 64-bit dma_addr_t will /not/ set CONFIG_HIGHMEM, regardless of IOMMU presence. Probably you want to base your actions on some combination of * CONFIG_64BIT * sizeof(dma_addr_t) * pci_set_dma_mask() for >32 bit platforms Regards, Jeff - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists