Question/bug in ArmPkg (ArmArchTimerLib)

Question/bug in ArmPkg (ArmArchTimerLib)

[Gierszynski, Przemyslaw]

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Hi All,

My name is Przemysław Gierszyński and I work as a Firmware Engineer in Intel Technology Poland.
I was doing some work that required review of some parts of EDK2 and I think I have found a small bug in ArmPkg module.
Here below are some details concerning the issue:
File: edk2/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c
Function: TimerContructor ( VOID ) - line 56
Description:
The comment above says: "If the security extension is not implemented, set Timer Frequency here.".
In releases from the past in the if condition there was direct accessing to ID_PFR1, and it was changed in the commit shown below.
[cid:image001.png@01D93185.A4DC9070]
But if we go into the body of the ArmHasSecurityExtensions () function, we can see that the result of the function is a negation of the condition from the past:
[cid:image002.png@01D93186.59443040]

Proposal of solution:
Change the if condition in TimerContructor () function from: if (ArmHasSecurityExtensions ()) to if (!ArmHasSecurityExtensions ())

Thank you for your help!

Best regards
Przemek

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Re: Question/bug in ArmPkg (ArmArchTimerLib)

[Ard Biesheuvel]

On Thu, 26 Jan 2023 at 13:06, Gierszynski, Przemyslaw
<przemyslaw.gierszynski@intel.com> wrote:
>
> Hi All,
>
> My name is Przemysław Gierszyński and I work as a Firmware Engineer in Intel Technology Poland.
> I was doing some work that required review of some parts of EDK2 and I think I have found a small bug in ArmPkg module.
> Here below are some details concerning the issue:
> File: edk2/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c
> Function: TimerContructor ( VOID ) – line 56
> Description:
> The comment above says: “If the security extension is not implemented, set Timer Frequency here.”.
> In releases from the past in the if condition there was direct accessing to ID_PFR1, and it was changed in the commit shown below.
>
> But if we go into the body of the ArmHasSecurityExtensions () function, we can see that the result of the function is a negation of the condition from the past:
>
>
> Proposal of solution:
> Change the if condition in TimerContructor () function from: if (ArmHasSecurityExtensions ()) to if (!ArmHasSecurityExtensions ())
>

Good catch!

Please submit a patch to the mailing list.

Thanks,
Ard.