On Fri, 26 Aug 2005, Martin Wilck wrote:
> Unless I am mistaken, the MP spec does not say that _CPUs_ must start from 0.
> We had an IO-APIC at 0. The MP spec says that the IDs must be unique (I am
> told this isn't true any more because an IO APIC and a CPU may have the same
> ID) and _need not_ be consecutive.
You are unfortunately mistaken -- the spec is explicit about *local* APIC
IDs having to start at 0. There are at least two places in the spec that
refer to that.
> We tried different setups; one had IO APICs at 0,1,2 and CPUs starting at 16.
> I can't see that this is forbidden (the reason is that the IO-APICs have only
> 4-bit APIC ID registers). Anyway we changed it now to have both IO-APICs and
> CPUs start at 0.
You can always assign 0, 16, 17, etc. to local APICs and then 1, 2, 3,
etc. for I/O APICs. Frankly I don't know what the actual justification
behind the requirement is. Note that the ID of 0 need not necessarily
belong to the BSP.
Maciej
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |