Messages in this thread |  | | Date | Mon, 23 Oct 2000 15:01:41 -0700 | From | Jeremy Fitzhardinge <> | Subject | Re: The zen of kernel virtual addresses |
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On Sat, Oct 21, 2000 at 01:37:26PM -0600, Jonathan Corbet wrote: > physical address > An address as known by the low-level hardware. In the modern > world, these can be 64-bit quantities, even on 32-bit systems. > These are the addresses used by /dev/mem - which appears to work > only for low memory.
A phyical address is the address the CPU uses to talk to memory. It is not necessarily the same kind of address a device uses to see memory: they use bus addresses. The simple case is bus address == physical address, but there are many variations. Systems with an IOMMU (or equiv) present devices with a completely different view of system memory.
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