Hi,

My current finding suggests that the problem exists in the e820 stuff.
Maybe some changes to the handling of realModeData.

Any help is appreciated.

Best regards
Anders

2011/12/16 Anders Handler <[email protected]>

> Hi again,
>
> I enabled memory debugging and got the following output.
>
> [    0.000000]     memblock_x86_reserve_range: [0x000f0050-0x000f005f]   *
> MP-table mpf
> [    0.000000]     memblock_x86_reserve_range: [0x000f0060-0x000f019f]   *
> MP-table mpc
> [    0.000000]     memblock_x86_reserve_range: [0x01de3000-0x01de3012]
>          BRK
> [    0.000000] MEMBLOCK configuration:
> [    0.000000]  memory size = 0x7f00000
> [    0.000000]  memory.cnt  = 0x1
> [    0.000000]  memory[0x0] [0x00000000100000-0x00000007ffffff],
> 0x7f00000 bytes
> [    0.000000]  reserved.cnt  = 0x2
> [    0.000000]  reserved[0x0] [0x0000000009f000-0x000000000fffff],
> 0x61000 bytes
> [    0.000000]  reserved[0x1] [0x00000001000000-0x00000001de3012],
> 0xde3013 bytes
>
> This looks rather normal to me. So still no idea about why it does not
> work.
>
> / Anders
>
> 2011/12/16 Anders Handler <[email protected]>
>
>> Hi,
>>
>> I did indeed create a trace file, and it's huge. The check is correct,
>> but the values are false. The memblockbase is fetched from
>> memblock.memory.regions[i].base, which has been initialized with a wrong
>> value (0x10000), which is the same as top.
>>
>> I have not yet tracked down where memblock.memory.regions[i].base is
>> initialized.
>>
>> Best regards
>> Anders
>>
>>
>> 2011/12/15 Gabe Black <[email protected]>
>>
>>> **
>>> Also, if you haven't seen it, this page documents some of the methods
>>> you can use to debug what's going on.
>>>
>>> http://www.gem5.org/Debugging
>>>
>>> The section called "Trace-based debugging" will probably be the most
>>> useful. Be sure to only trace a portion of execution at a time. Tracing too
>>> much creates some enormous files that are hard to work with.
>>>
>>> Gabe
>>>
>>>
>>> On 12/15/11 15:25, Gabe Black wrote:
>>>
>>> Where bottom >= top, is bottom really greater than or equal to top? Or
>>> in other words, is the comparison returning the wrong result, or are the
>>> values wrong in the first place? If it's the comparison that's wrong, that
>>> would be a bit surprising but easier to debug because it's pretty
>>> contained. If it's the values you'll need to figure out where those get
>>> corrupted, or if they were passed to Linux incorrectly from the start.
>>> Thank you for digging into the problem on your own.
>>>
>>> Gabe
>>>
>>> On 12/15/11 06:21, Anders Handler wrote:
>>>
>>> Hi,
>>>
>>>  X86 kernels version >2.6.32 (here 3.1.0) still gets the error "Cannot
>>> allocate trampoline". Seems like the memory regions does not get
>>> initialized correctly.
>>>
>>>  The stack trace is:
>>>  [    0.000000] Kernel panic - not syncing: Cannot allocate trampoline
>>> [    0.000000]
>>> [    0.000000] Pid: 0, comm: swapper Not tainted 3.1.0-gentoo #13
>>> [    0.000000] Call Trace:
>>> [    0.000000]  [<ffffffff816772ab>] panic+0x8c/0x192
>>> [    0.000000]  [<ffffffff81c9f733>] setup_trampolines+0x52/0xb1
>>> [    0.000000]  [<ffffffff81c9ce1b>] setup_arch+0x5ca/0xabb
>>> [    0.000000]  [<ffffffff816773ed>] ? printk+0x3c/0x3e
>>> [    0.000000]  [<ffffffff81cad37e>] ? cgroup_init_early+0x25b/0x276
>>> [    0.000000]  [<ffffffff81c998a1>] start_kernel+0x82/0x312
>>> [    0.000000]  [<ffffffff81c99322>]
>>> x86_64_start_reservations+0x132/0x136
>>> [    0.000000]  [<ffffffff81c99417>] x86_64_start_kernel+0xf1/0xf8
>>> [    0.000000]  [<ffffffff81c99326>]
>>> x86_64_start_reservations+0x136/0x136
>>>
>>>  A further investigation shows that in /arch/x86/kernel/trampoline.c
>>> function setup_trampolines we call /mm/memblock.c, memblock_find_in_range
>>> which again calls memblock_find_base.
>>> Here we loop through the memory regions, where there is only 1, but that
>>> is expected. Unfortunatly the line:
>>> if (bottom >= top)
>>> Evaluates to true, thus we never have a chance to call
>>> memblock_find_region.
>>> http://lxr.linux.no/linux+v3.1/mm/memblock.c#L111
>>>
>>>  Gem5 does not cast any faults.
>>>
>>>  Any help/suggestions is really appreciated.
>>>
>>>
>>>  Best regards
>>> Anders
>>>
>>>
>>>  On Tue, Nov 29, 2011 at 10:15 AM, huangyongbing <
>>> [email protected]> wrote:
>>>
>>>>  Hi,
>>>>
>>>> The Linue kernel 3.1 can pass gem5's checkes using the patch. However,
>>>> there exists a kernel panic "Kernel panic - not syncing: Cannot allocate 
>>>> trampoline".  Additional
>>>> work are needed.
>>>>
>>>>
>>>> Yongbing Huang
>>>>
>>>>
>>>>    ------------------------------
>>>>  *发件人:* Gabe Black
>>>> *发送时间:* 2011-11-29  16:05:31
>>>> *收件人:* gem5-users
>>>>  *抄送:*
>>>> *主题:* Re: [gem5-users] Problem with Linux kernel 3.1
>>>>   I haven't tested this at all (even to make sure it compiles) but
>>>> give this a shot. This is a quick attempt to actually fix the check.
>>>>
>>>> Gabe
>>>>
>>>> On 11/28/11 20:35, huangyongbing wrote:
>>>>
>>>> Hi,
>>>>
>>>> I just tested your patch on my PC (Intel Nehalem), but unfortunately it
>>>> didn't work.
>>>>
>>>>
>>>> Yongbing Huang
>>>>
>>>> **
>>>> ------------------------------
>>>> *发件人:* Anders Handler
>>>> *发送时间:* 2011-11-29  06:47:33
>>>> *收件人:* gem5 users mailing list
>>>> *抄送:*
>>>> *主题:* Re: [gem5-users] Problem with Linux kernel 3.1
>>>> Hi,
>>>>
>>>>  The attached patch will make it work (just disables some checks). I
>>>> will make the right checks and send it here on Wednesday.
>>>>
>>>>  The problem was some faulty checks in
>>>> src/arch/x86/isa/microops/regop.isa, where the descriptor-table register
>>>> might fail. I'll find the appropriate checks in the AMD manual.
>>>>
>>>>  Anders
>>>>
>>>>
>>>> On Mon, Nov 28, 2011 at 10:38 PM, Gabe Black <[email protected]>wrote:
>>>>
>>>>> What CPU are you using? How did you determine this is where it gets
>>>>> stuck? Have you traced execution near there? Does it get stuck in the
>>>>> microcode looping forever, executing the same instruction over and over,
>>>>> etc., or does it stop executing instructions all together, perpetually
>>>>> trying to vector to an exception handler for instance?
>>>>>
>>>>> My off hand guess to what's going on is that the check that makes sure
>>>>> the selector is ok isn't handling a NULL selector properly. The AMD
>>>>> architecture manal says this:
>>>>>
>>>>> "Null selectors can only be loaded into the DS, ES, FS and GS
>>>>> data-segment registers, and into the LDTR descriptor-table register. A #GP
>>>>> occurs if software attempts to load the CS register with a null selector 
>>>>> or
>>>>> if software attempts to load the SS register with a null selector in non
>>>>> 64-bit mode or at CPL 3."
>>>>>
>>>>> It sounds like you've determined that %eax should really be 0 when
>>>>> that instruction executes.
>>>>>
>>>>> With some more information I'll try to look at this sometime in the
>>>>> next week or two.
>>>>>
>>>>> Gabe
>>>>>
>>>>>
>>>>> On 11/28/11 05:16, Anders Handler wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>>  I have the same problem. The last instruction decoded in a kernel
>>>>> >2.6.32 is
>>>>>
>>>>> 8e d0                   mov    %eax,%ss
>>>>> where %eax contains 0 (xor    %eax,%eax).
>>>>>
>>>>>  In 2.6.32 and earlier the segment registers was set to "movl
>>>>> $__KERNEL_DS,%eax", which in my 2.6.32 kernel was 0x18.
>>>>>
>>>>>  The code is found in head_64.S in entry point "secondary_startup_64".
>>>>>
>>>>>  Any clue why the simulator gets stuck here?
>>>>>
>>>>>
>>>>>  Best regards
>>>>> Anders
>>>>>
>>>>> 2011/11/28 huangyongbing <[email protected]>
>>>>>
>>>>>>  Hi all,
>>>>>>
>>>>>> I try to run Gem5 using X86_FS and Linux kernel 3.1. The
>>>>>> configuration file I use is downloaded from Gem5 website which contained 
>>>>>> in
>>>>>> file 'config-x86.tar.gz'. No errors are printed out by gem5. However,
>>>>>> there is also nothing printed out in m5term console. Using the same
>>>>>> configuration file, Linux kernel 2.6.32 is runnable on Gem5. Thus, what's
>>>>>> the problem?
>>>>>>
>>>>>>
>>>>>> 2011-11-28
>>>>>>  ------------------------------
>>>>>>  -- Yongbing Huang
>>>>>>
>>>>>> _______________________________________________
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>>>>>>
>>>>>
>>>>>
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