On Tue, Nov 20, 2018 at 03:33:00PM +0100, Ard Biesheuvel wrote:
> Our poor man's implementation of EnterS3WithImmediateWake () currently
> sets a high TPL level to disable interrupts, and simply calls the
> PEI entrypoint again after disabling the MMU.
>
> Unfortunately, this is not sufficient: DMA capable devices such as
> network controllers or USB controllers may still be enabled and
> writing to memory, e.g., in response to incoming network packets.
>
> So instead, do the full ExitBootServices() dance: allocate space and
> get the memory map, call ExitBootServices(), and in case it fails, get
> the memory map again and call ExitBootServices() again. This ensures
> that all cleanup related to DMA capable devices is performed before
> doing the warm reset.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
> ---
> ArmPkg/Include/Library/ArmLib.h | 1 +
> ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c | 51
> ++++++++++++++++++--
> 2 files changed, 49 insertions(+), 3 deletions(-)
>
> diff --git a/ArmPkg/Include/Library/ArmLib.h b/ArmPkg/Include/Library/ArmLib.h
> index e46df447b33d..ffda50e9d767 100644
> --- a/ArmPkg/Include/Library/ArmLib.h
> +++ b/ArmPkg/Include/Library/ArmLib.h
> @@ -59,6 +59,7 @@ typedef enum {
>
> typedef struct {
> EFI_PHYSICAL_ADDRESS PhysicalBase;
> + EFI_VIRTUAL_ADDRESS VirtualBase;
> UINT64 Length;
> ARM_MEMORY_REGION_ATTRIBUTES Attributes;
> } ARM_MEMORY_REGION_DESCRIPTOR;
Without the above hunk:
Reviewed-by: Leif Lindholm <leif.lindh...@linaro.org>
> diff --git
> a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> index 10ceafd14d5d..c9c42ab3b244 100644
> --- a/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> +++ b/ArmPkg/Library/ArmSmcPsciResetSystemLib/ArmSmcPsciResetSystemLib.c
> @@ -1,7 +1,7 @@
> /** @file
> ResetSystemLib implementation using PSCI calls
>
> - Copyright (c) 2017, Linaro Ltd. All rights reserved.<BR>
> + Copyright (c) 2017 - 2018, Linaro Ltd. All rights reserved.<BR>
>
> This program and the accompanying materials
> are licensed and made available under the terms and conditions of the BSD
> License
> @@ -92,7 +92,13 @@ EnterS3WithImmediateWake (
> VOID
> )
> {
> - VOID (*Reset)(VOID);
> + VOID (*Reset)(VOID);
> + EFI_PHYSICAL_ADDRESS Alloc;
> + EFI_MEMORY_DESCRIPTOR *MemMap;
> + UINTN MemMapSize;
> + UINTN MapKey, DescriptorSize;
> + UINT32 DescriptorVersion;
> + EFI_STATUS Status;
>
> if (FeaturePcdGet (PcdArmReenterPeiForCapsuleWarmReboot) &&
> !EfiAtRuntime ()) {
> @@ -103,7 +109,46 @@ EnterS3WithImmediateWake (
> //
> Reset = (VOID (*)(VOID))(UINTN)FixedPcdGet64 (PcdFvBaseAddress);
>
> - gBS->RaiseTPL (TPL_HIGH_LEVEL);
> + //
> + // Obtain the size of the memory map
> + //
> + MemMapSize = 0;
> + Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey,
> &DescriptorSize,
> + &DescriptorVersion);
> + ASSERT (Status == EFI_BUFFER_TOO_SMALL);
> +
> + //
> + // Add some slack to the allocation to cater for changes in the memory
> + // map if ExitBootServices () fails the first time around.
> + //
> + MemMapSize += SIZE_4KB;
> + Status = gBS->AllocatePages (AllocateAnyPages, EfiBootServicesData,
> + EFI_SIZE_TO_PAGES (MemMapSize), &Alloc);
> + ASSERT_EFI_ERROR (Status);
> +
> + MemMap = (EFI_MEMORY_DESCRIPTOR *)(UINTN)Alloc;
> +
> + Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey,
> &DescriptorSize,
> + &DescriptorVersion);
> + ASSERT_EFI_ERROR (Status);
> +
> + Status = gBS->ExitBootServices (gImageHandle, MapKey);
> + if (EFI_ERROR (Status)) {
> + //
> + // ExitBootServices () may fail the first time around if an event fired
> + // right after the call to GetMemoryMap() which allocated or freed
> memory.
> + // Since that first call to ExitBootServices () will disarm the timer,
> + // this is guaranteed not to happen again, so one additional attempt
> + // should suffice.
> + //
> + Status = gBS->GetMemoryMap (&MemMapSize, MemMap, &MapKey,
> &DescriptorSize,
> + &DescriptorVersion);
> + ASSERT_EFI_ERROR (Status);
> +
> + Status = gBS->ExitBootServices (gImageHandle, MapKey);
> + ASSERT_EFI_ERROR (Status);
> + }
> +
> ArmDisableMmu ();
> Reset ();
> }
> --
> 2.17.1
>
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