Re: Regression from efi: call get_event_log before ExitBootServices

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 12-03-18 20:55, Thiebaud Weksteen wrote:
> On Mon, Mar 12, 2018 at 7:33 PM Jeremy Cline <jeremy@jcline.org> wrote:
> 
>> On 03/12/2018 02:29 PM, Thiebaud Weksteen wrote:
>>> On Mon, Mar 12, 2018 at 6:30 PM Ard Biesheuvel <
> ard.biesheuvel@linaro.org>
>>> wrote:
>>>
>>>> On 12 March 2018 at 17:01, Jeremy Cline <jeremy@jcline.org> wrote:
>>>>> On 03/12/2018 10:56 AM, Ard Biesheuvel wrote:
>>>>>> On 12 March 2018 at 14:30, Jeremy Cline <jeremy@jcline.org> wrote:
>>>>>>> On 03/12/2018 07:08 AM, Ard Biesheuvel wrote:
>>>>>>>> On 10 March 2018 at 10:45, Thiebaud Weksteen <tweek@google.com>
>>> wrote:
>>>>>>>>> On Fri, Mar 9, 2018 at 5:54 PM Jeremy Cline <jeremy@jcline.org>
>>> wrote:
>>>>>>>>>
>>>>>>>>>> On Fri, Mar 09, 2018 at 10:43:50AM +0000, Thiebaud Weksteen
> wrote:
>>>>>>>>>>> Thanks a lot for trying out the patch!
>>>>>>>>>>>
>>>>>>>>>>> Please don't modify your install at this stage, I think we are
>>> hitting a
>>>>>>>>>>> firmware bug and that would be awesome if we can fix how we are
>>>>>>>>> handling it.
>>>>>>>>>>> So, if we reach that stage in the function it could either be
>>> that:
>>>>>>>>>>> * The allocation did not succeed, somehow, but the firmware
> still
>>>>>>>>> returned
>>>>>>>>>>> EFI_SUCCEED.
>>>>>>>>>>> * The size requested is incorrect (I'm thinking something like a
>>> 1G of
>>>>>>>>>>> log). This would be due to either a miscalculation of log_size
>>>>>>>>> (possible)
>>>>>>>>>>> or; the returned values of GetEventLog are not correct.
>>>>>>>>>>> I'm sending a patch to add checks for these. Could you please
>>> apply and
>>>>>>>>>>> retest?
>>>>>>>>>>> Again, thanks for helping debugging this.
>>>>>>>>>
>>>>>>>>>> No problem, thanks for the help :)
>>>>>>>>>
>>>>>>>>>> With the new patch:
>>>>>>>>>
>>>>>>>>>> Locating the TCG2Protocol
>>>>>>>>>> Calling GetEventLog on TCG2Protocol
>>>>>>>>>> Log returned
>>>>>>>>>> log_location is not empty
>>>>>>>>>> log_size != 0
>>>>>>>>>> log_size < 1M
>>>>>>>>>> Allocating memory for storing the logs
>>>>>>>>>> Returned from memory allocation
>>>>>>>>>> Copying log to new location
>>>>>>>>>
>>>>>>>>>> And then it hangs. I added a couple more print statements:
>>>>>>>>>
>>>>>>>>>> diff --git a/drivers/firmware/efi/libstub/tpm.c
>>>>>>>>> b/drivers/firmware/efi/libstub/tpm.c
>>>>>>>>>> index ee3fac109078..1ab5638bc50e 100644
>>>>>>>>>> --- a/drivers/firmware/efi/libstub/tpm.c
>>>>>>>>>> +++ b/drivers/firmware/efi/libstub/tpm.c
>>>>>>>>>> @@ -148,8 +148,11 @@ void
>>>>>>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
>>>>>>>>>>           efi_printk(sys_table_arg, "Copying log to new
>>> location\n");
>>>>>>>>>
>>>>>>>>>>           memset(log_tbl, 0, sizeof(*log_tbl) + log_size);
>>>>>>>>>> +       efi_printk(sys_table_arg, "Successfully memset log_tbl to
>>> 0\n");
>>>>>>>>>>           log_tbl->size = log_size;
>>>>>>>>>> +       efi_printk(sys_table_arg, "Set log_tbl->size\n");
>>>>>>>>>>           log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
>>>>>>>>>> +       efi_printk(sys_table_arg, "Set log_tbl-version\n");
>>>>>>>>>>           memcpy(log_tbl->log, (void *) first_entry_addr,
> log_size);
>>>>>>>>>
>>>>>>>>>>           efi_printk(sys_table_arg, "Installing the log into the
>>>>>>>>> configuration table\n");
>>>>>>>>>
>>>>>>>>>> and it's hanging at "memset(log_tbl, 0, sizeof(*log_tbl) +
>>> log_size);"
>>>>>>>>>
>>>>>>>>> Thanks. Well, it looks like the memory that is supposedly
> allocated
>>> is not
>>>>>>>>> usable. I'm thinking this is a firmware bug.
>>>>>>>>> Ard, would you agree on this assumption? Thoughts on how to
> proceed?
>>>>>>>>>
>>>>>>>>
>>>>>>>> I am rather puzzled why the allocate_pool() should succeed and the
>>>>>>>> subsequent memset() should fail. This does not look like an issue
>>> that
>>>>>>>> is intimately related to TPM2 support, rather an issue in the
>>> firmware
>>>>>>>> that happens to get tickled after the change.
>>>>>>>>
>>>>>>>> Would you mind trying replacing EFI_LOADER_DATA with
>>>>>>>> EFI_BOOT_SERVICES_DATA in the allocate_pool() call?
>>>>>>>
>>>>>>> Replacing EFI_LOADER_DATA with EFI_BOOT_SERVICES_DATA still hangs at
>>> the
>>>>>>> memset() call.
>>>>>>>
>>>>>>
>>>>>> Could you try the following please? (attached as well in case gmail
>>> mangles it)
>>>>>>
>>>>>> diff --git a/drivers/firmware/efi/libstub/tpm.c
>>>>>> b/drivers/firmware/efi/libstub/tpm.c
>>>>>> index 2298560cea72..30d960a344b7 100644
>>>>>> --- a/drivers/firmware/efi/libstub/tpm.c
>>>>>> +++ b/drivers/firmware/efi/libstub/tpm.c
>>>>>> @@ -70,6 +70,8 @@ void
>>>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
>>>>>>          size_t log_size, last_entry_size;
>>>>>>          efi_bool_t truncated;
>>>>>>          void *tcg2_protocol;
>>>>>> +       unsigned long num_pages;
>>>>>> +       efi_physical_addr_t log_tbl_alloc;
>>>>>>
>>>>>>          status = efi_call_early(locate_protocol, &tcg2_guid, NULL,
>>>>>>                                  &tcg2_protocol);
>>>>>> @@ -104,9 +106,12 @@ void
>>>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
>>>>>>          }
>>>>>>
>>>>>>          /* Allocate space for the logs and copy them. */
>>>>>> -       status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
>>>>>> -                               sizeof(*log_tbl) + log_size,
>>>>>> -                               (void **) &log_tbl);
>>>>>> +       num_pages = DIV_ROUND_UP(sizeof(*log_tbl) + log_size,
>>> EFI_PAGE_SIZE);
>>>>>> +       status = efi_call_early(allocate_pages,
>>>>>> +                               EFI_ALLOCATE_ANY_PAGES,
>>>>>> +                               EFI_LOADER_DATA,
>>>>>> +                               num_pages,
>>>>>> +                               &log_tbl_alloc);
>>>>>>
>>>>>>          if (status != EFI_SUCCESS) {
>>>>>>                  efi_printk(sys_table_arg,
>>>>>> @@ -114,6 +119,7 @@ void
>>>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
>>>>>>                  return;
>>>>>>          }
>>>>>>
>>>>>> +       log_tbl = (struct linux_efi_tpm_eventlog *)(unsigned
>>> long)log_tbl_alloc;
>>>>>>          memset(log_tbl, 0, sizeof(*log_tbl) + log_size);
>>>>>>          log_tbl->size = log_size;
>>>>>>          log_tbl->version = EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
>>>>>> @@ -126,7 +132,7 @@ void
>>>>>> efi_retrieve_tpm2_eventlog_1_2(efi_system_table_t *sys_table_arg)
>>>>>>          return;
>>>>>>
>>>>>>   err_free:
>>>>>> -       efi_call_early(free_pool, log_tbl);
>>>>>> +       efi_call_early(free_pages, log_tbl_alloc, num_pages);
>>>>>>   }
>>>>>>
>>>>>>   void efi_retrieve_tpm2_eventlog(efi_system_table_t *sys_table_arg)
>>>>>>
>>>>>
>>>>> Hi Ard,
>>>>>
>>>>> When I apply this, it starts hanging at
>>>>>
>>>>> status = efi_call_proto(efi_tcg2_protocol, get_event_log,
> tcg2_protocol,
>>>>>                          EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2,
>>>>>                          &log_location, &log_last_entry, &truncated);
>>>>>
>>>>> rather than at the memset() call.
>>>>>
>>>
>>>> That is *very* surprising, given that the change only affects code
>>>> that executes after that.
>>>
> 
> Hans, you said you configured the tablet to use the 32-bit version of grub
> instead
> of 64. Why's that?

Because this tablet, like (almost?) all Bay Trail hardware has a 32 bit UEFI,
even though the processor is 64 bit capable (AFAIK 64 bit Windows drivers were
not ready in time so all Bay Trail devices shipped with a 32 bit Windows).

So this is running a 32 bit grub which boots a 64 bit kernel.

> Jeremy, could you confirm if you are building the kernel in 64bit mode? Is
> your Android install working? (that is, what happens if you boot Boot0000)?

AFAIK the kernel on Jeremy's tablet (which I initially installed) is 64 bit.

Could the problem perhaps be that the new code for the TPM event-log is
missing some handling to deal with running on a 32 bit firmware? I know the
rest of the kernel has special code to deal with this.

Regards,

Hans