Re: r336921 broke booting on MBP 2017, EFIRT related

> On 29 Aug 2018, at 14:53, Yuri Pankov <yuripv_at_yuripv.net> wrote:
> 
> Yuri Pankov wrote:
>> Konstantin Belousov wrote:
>>> 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.
>> kldload'ing the efirt module gets the same fault.  Several top lines of backtrace:
>> kernphys() at 0x7abece31
>> efi_get_time() at efi_get_time+0xd9
>> efirtc_probe() at efirtc_probe+0x17
> 
> For the efi mem map, if I'm understanding it correctly, there's the following:
> 
> ...
>   BootServicesData 00007421d000 000000000000 00000a8b UC WC WT WB
> ...
> RuntimeServicesCode 00007ab9f000 000000000000 00000070 UC WC WT WB
> …

if my math is correct, this RTS code area will end at 0x000000007abe5000 and if 0x000000007abece31 is fault location, its just after that RTS code area, that is, 7 pages after… meaning you would need to get the next entry:)

rgds,
toomas