On 10/20/20 9:22 AM, ivanhu wrote:
On 10/20/20 2:46 PM, Ard Biesheuvel wrote:
On Tue, 20 Oct 2020 at 08:20, ivanhu <ivan.hu@xxxxxxxxxxxxx> wrote:
On 10/19/20 7:25 PM, Heinrich Schuchardt wrote:
On 19.10.20 13:01, Ard Biesheuvel wrote:
On Mon, 19 Oct 2020 at 13:00, Heinrich Schuchardt <xypron.glpk@xxxxxx> wrote:
On 19.10.20 12:03, Ard Biesheuvel wrote:
On Mon, 19 Oct 2020 at 12:00, Heinrich Schuchardt <xypron.glpk@xxxxxx> wrote:
On 19.10.20 11:31, Ard Biesheuvel wrote:
On Wed, 14 Oct 2020 at 20:41, Heinrich Schuchardt <xypron.glpk@xxxxxx> wrote:
On 14.10.20 19:58, Ard Biesheuvel wrote:
On Wed, 14 Oct 2020 at 19:45, Heinrich Schuchardt <xypron.glpk@xxxxxx> wrote:
On 14.10.20 19:31, Heinrich Schuchardt wrote:
Dear all,
the fwts fails on U-Boot due to testing for a non-existent
RuntimeServicesSupported variable.
If you look at the UEFI specification 2.8 (Errata B) [1] you will
discover in the change log:
2.8 A2049
RuntimeServicesSupported EFI variable should be a config table
February 2020
Please, read the configuration table to determine if a runtime service
is available on UEFI 2.8 systems.
On lower UEFI firmware version neither the variable nor the table exists.
Best regards
Heinrich
[1] UEFI Specification Version 2.8 (Errata B) (released June 2020),
https://uefi.org/sites/default/files/resources/UEFI%20Spec%202.8B%20May%202020.pdf
Hello Ard,
what is your idea how the EFI_RT_PROPERTIES_TABLE shall be exposed to
the efi_test driver?
Will the EFI runtime wrapper simply return EFI_UNSUPPORTED if the
function is not marked as supported in the table? Or will the
configuration table itself be make available?
The UEFI spec permits that runtime services return EFI_UNSUPPORTED at
runtime, but requires that they are marked as such in the
EFI_RT_PROPERTIES_TABLE.
So assuming that the purpose of efi_test is compliance with the spec,
it should only allow EFI_UNSUPPORTED as a return value for each of the
tested runtime services if it is omitted from
efi.runtime_supported_mask.
Since the efi_test ioctl returns both an error code and the actual EFI
status code, we should only fail the call on a EFI_UNSUPPORTED status
code if the RTPROP mask does not allow that.
E.g.,
--- a/drivers/firmware/efi/test/efi_test.c
+++ b/drivers/firmware/efi/test/efi_test.c
@@ -265,7 +265,12 @@ static long efi_runtime_set_variable(unsigned long arg)
goto out;
}
- rv = status == EFI_SUCCESS ? 0 : -EINVAL;
+ if (status == EFI_SUCCESS ||
+ (status == EFI_UNSUPPORTED &&
+ !efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)))
+ rv = 0;
+ else
+ rv = -EINVAL;
out:
kfree(data);
Do you think that could work?
The current fwts implementation assumes that EFI_UNSUPPORTED leads to
ioctl() returning -1. This value should not be changed. It would be
preferable to use another error code than -EINVAL, e.g. -EDOM if there
is a mismatch with the EFI_RT_PROPERTIES_TABLE configuration table. Then
a future verision of fwts can evaluate errno to discover the problem.
Do I read you correctly: the EFI runtime wrapper does not fend of calls
to runtime services marked as disallowed in EFI_RT_PROPERTIES_TABLE?
Directly returning an error code might help to avoid crashes on
non-compliant firmware.
It is not the kernel's job to work around non-compliant firmware. The
EFI spec is crystal clear that every runtime service needs to be
implemented, but is permitted to return EFI_UNSUPPORTED after
ExitBootServices(). This means EFI_RT_PROPERTIES_TABLE does not tell
you calling certain runtime services is disallowed, it tells you that
there is no point in even trying. That is why users such as efi-pstore
now take this information into account in their probe path (and
efivarfs will only mount read/write if SetVariable() is not marked as
unsupported).
How about the return code?
As I attempted to explain, I think EFI_UNSUPPORTED should not be
reported as an error if RT_PROP_TABLE permits it. The caller has
access to the raw efi_status_t that was returned, so it can
distinguish between the two cases.
The fwts tires to figure out if a firmware implementation is compliant.
The return value according to you suggestion would be as follows
depending on the UEFI status and the entry in EFI_RT_PROPERTIES_TABLE.
| EFI_SUCCESS | EFI_UNSUPPORTED | EFI_INVALID_PARAMETER
----------|--------------|-----------------|----------------------
Available | | |
according | 0 | -EINVAL | -EINVAL
EFT_RT_PRO| | |
-------------------------------------------------------------------
Not | | |
available | | |
according | 0 | 0 | -EINVAL
EFT_RT_PRO| | |
-------------------------------------------------------------------
fwts would not be able to detect that according to the
EFI_RT_PROPERTIES_TABLE the service is marked as not available
but returns a value other than EFI_UNSUPPORTED.
But that would be permitted by the spec anyway. A runtime service is
not required to always return EFI_UNSUPPORTED if it is marked as
unavaialble in EFI_RT_PROP.
In the chapter "EFI_RT _PROPERTIES_TABLE" you can find this description:
"*RuntimeServicesSupported* mask of which calls are or are not
supported, where a bit set to 1 indicates that the call is supported,
and 0 indicates that it is not."
This leaves no room for implementing a service that is marked as not
supported.
In the descriptions of the return codes of the individual runtime services:
"*EFI_UNSUPPORTED* This call is not supported by this platform at the
time the call is made. The platform should describe this runtime service
as unsupported at runtime via an EFI_RT_PROPERTIES_TABLE configuration
table."
From the spec, it clearly describes
If a platform cannot support calls defined in EFI_RUNTIME_SERVICES after
ExitBootServices() is called, that platform is permitted to provide
implementations of those runtime services that return EFI_UNSUPPORTED
when invoked at runtime. On such systems, an EFI_RT_PROPERTIES_TABLE
configuration table should be published describing which runtime
services are supported at runtime.
I think it's better not to modify efi_test base on the
EFI_RT_PROPERTIES_TABLE or RuntimeServicesSupported, let efi_test be
simply ioctl and FWTS tests can do the modifications.
Doesn't that mean FTWS would need to be able to access the
EFI_RT_PROPERTIES_TABLE?
Right, FWTS need to be able to get the RuntimeServicesSupported value.
I'm not sure if kernel will implement it or not, if not, maybe efi_test
can help to get and export the RuntimeServicesSupported from configure
table to FWTS.
Hello Ard,
what are you plans to get the issue solved?
Best regards
Heinrich
