cross-distro April 2018

cross-distro@lists.linaro.org

3 participants
2 discussions

[PATCH v2] ArmPkg/TimerDxe: remove workaround for KVM timer handling

by Ard Biesheuvel

When we first ported EDK2 to KVM/arm, we implemented a workaround for the quirky timer handling on the KVM side. This has been fixed in Linux commit f120cd6533d2 ("KVM: arm/arm64: timer: Allow the timer to control the active state") dated 23 June 2014, which was incorporated into Linux release 4.3. So almost 4 years later, it should be safe to drop this workaround on the EDK2 side. This reverts commit b1a633434ddc. Cc: cross-distro(a)lists.linaro.org Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Ard Biesheuvel <ard.biesheuvel(a)linaro.org> Acked-by: Marc Zyngier <marc.zyngier(a)arm.com> Reviewed-by: Leif Lindholm <leif.lindholm(a)linaro.org> Acked-by: Laszlo Ersek <lersek(a)redhat.com> --- v2: add acks Note to cross-distro readers: this means guest firmware built with this patch will not work on KVM/ARM hosts using kernel v4.2 or earlier. ArmPkg/Drivers/TimerDxe/TimerDxe.c | 1 - ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c | 10 ---------- 2 files changed, 11 deletions(-) diff --git a/ArmPkg/Drivers/TimerDxe/TimerDxe.c b/ArmPkg/Drivers/TimerDxe/TimerDxe.c index a3202fa056f3..bd616d2efc73 100644 --- a/ArmPkg/Drivers/TimerDxe/TimerDxe.c +++ b/ArmPkg/Drivers/TimerDxe/TimerDxe.c @@ -337,7 +337,6 @@ TimerInterruptHandler ( // Set next compare value ArmGenericTimerSetCompareVal (CompareValue); - ArmGenericTimerEnableTimer (); ArmInstructionSynchronizationBarrier (); } diff --git a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c index 69a4ceb62db6..c941895a3574 100644 --- a/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c +++ b/ArmPkg/Library/ArmGenericTimerVirtCounterLib/ArmGenericTimerVirtCounterLib.c @@ -26,16 +26,6 @@ ArmGenericTimerEnableTimer ( TimerCtrlReg = ArmReadCntvCtl (); TimerCtrlReg |= ARM_ARCH_TIMER_ENABLE; - - // - // When running under KVM, we need to unmask the interrupt on the timer side - // as KVM will mask it when servicing the interrupt at the hypervisor level - // and delivering the virtual timer interrupt to the guest. Otherwise, the - // interrupt will fire again, trapping into the hypervisor again, etc. etc. - // This is scheduled to be fixed on the KVM side, but there is no harm in - // leaving this in once KVM gets fixed. - // - TimerCtrlReg &= ~ARM_ARCH_TIMER_IMASK; ArmWriteCntvCtl (TimerCtrlReg); } -- 2.17.0

6 years, 1 month

ARMv8.1-Atomics awareness in Glibc

by Steve Capper

Hello, For information, a patch has been posted to the glibc development list: https://sourceware.org/ml/libc-alpha/2018-04/msg00393.html which enables searching of "atomics" subdirectories when ld loads libraries, for systems where 8.1 atomics are enabled. This should allow one to employ the 8.1 atomics "baked in" to an optimised self-contained library rather than have to decouple them with alternative code paths, ifuncs, custom loaders etc. As an example, with this patch applied and running in a test model with 8.1 atomics enabled, and a filesystem with an extra libc supplied; I got the following from /proc/self/maps: /lib/aarch64-linux-gnu/atomics/libc.so.6 (re-running the model without atomics enabled gave the libc in /lib/aarch64-linux-gnu/ instead). Cheers, -- Steve

6 years, 1 month

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cross-distro April 2018