Re: [BUG] Linux 3.14 fails to boot with new EFI changes

[Alex Thorlton <athorlton-sJ/iWh9BUns@public.gmane.org>]

On Fri, Jan 31, 2014 at 03:23:18PM +0100, Borislav Petkov wrote:
> And now my question:
> 
> How can I reliably find out which region contains that
> uv_systab.function call?
> 
> I need it so that I can map it in the EFI page table and you can
> continue to call that function and you can get back to your reliable way
> to boot.

While working on an answer to this question, I ran across another issue
on some newer hardware, that looks like it's definitely related to this
problem, and might be the root cause.

When booting on a UV2 we die in efi_enter_virtual_mode:

BUG: unable to handle kernel paging request at 0000008f7e848020
IP: [<000000007dadb6a9>] 0x7dadb6a8
PGD 0
Oops: 0000 [#1] SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.11.0-medusa-00038-gd2f7cbe #821
Hardware name: SGI UV2000/ROMLEY, BIOS SGI UV 2000/3000 series BIOS 01/15/2013
task: ffffffff817ae400 ti: ffffffff8179e000 task.ti: ffffffff8179e000
RIP: 0010:[<000000007dadb6a9>]  [<000000007dadb6a9>] 0x7dadb6a8
RSP: 0000:ffffffff8179fd90  EFLAGS: 00010202
RAX: 000000007d9b8e01 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000007db074f8 RSI: 000000007d9b8e18 RDI: 0000008f7e848000
RBP: 000000007db074f8 R08: 0000000000000001 R09: 0000008f7e848000
R10: 0000000000000030 R11: ffff880ffffda000 R12: 8000000000000000
R13: 000077ff80000000 R14: ffff888f7e848000 R15: 000000000009b000
FS:  0000000000000000(0000) GS:ffff880fffc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000008f7e848020 CR3: 000000000009b000 CR4: 00000000000406b0
Stack:
 fffffffef6000000 0000000000000000 0000000000000000 80000000000001e3
 0000000000000030 000000007dadd540 0000000000001f20 0000000060000202
 000000007d9b8da0 000000007daf8c6b ffffffff810fd2bc 00000000000000d0
Call Trace:
 [<ffffffff810fd2bc>] ? cache_grow+0x1e5/0x236
 [<ffffffff8103adac>] ? efi_call4+0x6c/0xf0
 [<ffffffff8186452f>] ? efi_enter_virtual_mode+0x1ac/0x328
 [<ffffffff8184de98>] ? start_kernel+0x35b/0x3ed
 [<ffffffff8184d950>] ? repair_env_string+0x60/0x60
 [<ffffffff8184d479>] ? x86_64_start_reservations+0x2e/0x30
 [<ffffffff8184d5a3>] ? x86_64_start_kernel+0x128/0x12f
Code:  Bad RIP value.
RIP  [<000000007dadb6a9>] 0x7dadb6a8
 RSP <ffffffff8179fd90>
CR2: 0000008f7e848020

Let me know what other information you need and I'll get it to you ASAP.

Thanks!

- Alex