Re: Inclusion of x86_64 memorize ioapic at bootup patch

[ebiederm@xmission.com (Eric W. Biederman)]

yhlu <yhlu.kernel@gmail.com> writes:

> andi,
>
> In LinuxBIOS, we don't set the MPS 0x467 and the AP still can be started by BSP.
>
> are these really needed for x86_64?
>
>         Dprintk("Setting warm reset code and vector.\n");
>
>         CMOS_WRITE(0xa, 0xf);
>         local_flush_tlb();
>         Dprintk("1.\n");
>         *((volatile unsigned short *) phys_to_virt(0x469)) = start_rip >> 4;
>         Dprintk("2.\n");
>         *((volatile unsigned short *) phys_to_virt(0x467)) = start_rip & 0xf;
>         Dprintk("3.\n");
>
> the STARTUP IPI should work well with MPS v1.4

There are very large x86 machines that a reset is sent to the remote
cpu and thus 0x40:0x67 and 0x40:0x67 becomes relevant.

YH you didn't do something foolish and put a linuxbios table below
0x500 did you?

Eric
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