Re: r336921 broke booting on MBP 2017, EFIRT related

From: Konstantin Belousov <kostikbel_at_gmail.com>
Date: Wed, 29 Aug 2018 13:27:27 +0300
On Wed, Aug 29, 2018 at 12:37:52PM +0300, Yuri Pankov wrote:
> Hi,
> 
> I've noticed that all recent snapshots (ALPHA3, ALPHA2, ALPHA1, 
> 20180802) fail to boot on MBP 2017:
> 
> kbd0 at kbdmux0
> netmap: loaded module
> nexus0
> 
> Fatal trap 12: page fault while in kernel mode
> cpuid = 2: apic id = 02
> fault virtual address  = 0x74c64a50
> fault code             = supervisor read data, page not present
> instruction pointer    = 0x20: 0x7abece31
> stack pointer          = 0x28: 0xffffffff82b2f7c0
> frame pointer          = 0x28: 0xffffffff82b2f810
> code segment           = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, long 1, def32 0, gran 1
> processor eflags       = interrupt enabled, resume, IOPL = 0
> current process        = 0 (swapper)
> [ thread pid 0 tid 100000 ]
> Stopped at      0x7abece31:    calll   *0x18(%rax)
> db>
> 
> Sadly, there's no support for internal keyboard yet (it's connected via 
> SPI), and external USB one stops working.
> 
> A (not so quick) bisect is pointing at r336921, which enabled EFIRT.
> 
> Some questions here:
> - is this something that can/should be fixed?
> - can we print some "enabling EFIRT" message to the console to make
>    guesses about the problem source a bit easier?

It is not in 'enabling'.  Looking at the faulting VA, I believe that
it occurs inside the BIOS code.

Disable efirt by removing the kernel option, then try to load the module
at runtime.  Does it still fault ?  Also, get the efi mem map for the
machine and look at which region the faulting address and the faulting
instruction belong.
Received on Wed Aug 29 2018 - 08:27:40 UTC

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