Re: [platforms: PATCH 1/8] Marvell/Armada: Implement EFI_RNG_PROTOCOL driver for EIP76 TRNG

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 11 October 2017 at 17:47, Leif Lindholm <leif.lindholm@linaro.org> wrote:
> On Wed, Oct 11, 2017 at 05:40:42PM +0200, Marcin Wojtas wrote:
>> From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>
>> Add an implementation of EFI_RNG_PROTOCOL so that the OS loader has
>> access to entropy for KASLR and other purposes (i.e., seeding the OS's
>> entropy pool very early on).
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> Signed-off-by: Marcin Wojtas <mw@semihalf.com>
>> ---
>>  Platform/Marvell/Armada/Armada.dsc.inc                                |   4 +
>>  Platform/Marvell/Armada/Armada70x0.fdf                                |   1 +
>>  Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.c   | 254 ++++++++++++++++++++
>>  Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf |  47 ++++
>>  Platform/Marvell/Marvell.dec                                          |   3 +
>>  5 files changed, 309 insertions(+)
>>
>> diff --git a/Platform/Marvell/Armada/Armada.dsc.inc b/Platform/Marvell/Armada/Armada.dsc.inc
>> index 1aa485c..ec24d76 100644
>> --- a/Platform/Marvell/Armada/Armada.dsc.inc
>> +++ b/Platform/Marvell/Armada/Armada.dsc.inc
>> @@ -364,6 +364,9 @@
>>    gArmTokenSpaceGuid.PcdSystemMemorySize|0x40000000
>>    gArmTokenSpaceGuid.PcdArmScr|0x531
>>
>> +  # TRNG
>> +  gMarvellTokenSpaceGuid.PcdEip76TrngBaseAddress|0xF2760000
>> +
>>  ################################################################################
>>  #
>>  # Components Section - list of all EDK II Modules needed by this Platform
>> @@ -400,6 +403,7 @@
>>    Platform/Marvell/Drivers/I2c/Devices/MvEeprom/MvEeprom.inf
>>    Platform/Marvell/Drivers/Spi/MvSpiDxe.inf
>>    Platform/Marvell/Drivers/Spi/Devices/MvSpiFlash.inf
>> +  Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf
>>
>>    # Network support
>>    MdeModulePkg/Universal/Network/SnpDxe/SnpDxe.inf
>> diff --git a/Platform/Marvell/Armada/Armada70x0.fdf b/Platform/Marvell/Armada/Armada70x0.fdf
>> index 933c3ed..a94a9ff 100644
>> --- a/Platform/Marvell/Armada/Armada70x0.fdf
>> +++ b/Platform/Marvell/Armada/Armada70x0.fdf
>> @@ -113,6 +113,7 @@ FvNameGuid         = 5eda4200-2c5f-43cb-9da3-0baf74b1b30c
>>    INF Platform/Marvell/Drivers/I2c/Devices/MvEeprom/MvEeprom.inf
>>    INF Platform/Marvell/Drivers/Spi/MvSpiDxe.inf
>>    INF Platform/Marvell/Drivers/Spi/Devices/MvSpiFlash.inf
>> +  INF Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf
>>
>>    # Network support
>>    INF MdeModulePkg/Universal/Network/SnpDxe/SnpDxe.inf
>> diff --git a/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.c b/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.c
>> new file mode 100644
>> index 0000000..dca6dcc
>> --- /dev/null
>> +++ b/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.c
>> @@ -0,0 +1,254 @@
>> +/** @file
>> +
>> +  This driver produces an EFI_RNG_PROTOCOL instance for the Armada 70x0 TRNG
>> +
>> +  Copyright (C) 2017, 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 which accompanies this
>> +  distribution. The full text of the license may be found at
>> +  http://opensource.org/licenses/bsd-license.php
>> +
>> +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
>> +  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>> +
>> +**/
>> +
>> +#include <Library/BaseMemoryLib.h>
>> +#include <Library/IoLib.h>
>> +#include <Library/PcdLib.h>
>> +#include <Library/UefiBootServicesTableLib.h>
>> +
>> +#include <Protocol/Rng.h>
>> +
>> +#define TRNG_OUTPUT_REG                         mTrngBaseAddress
>> +#define TRNG_OUTPUT_SIZE                        0x10
>> +
>> +#define TRNG_STATUS_REG                         (mTrngBaseAddress + 0x10)
>> +#define TRNG_STATUS_READY                       BIT0
>> +
>> +#define TRNG_INTACK_REG                         (mTrngBaseAddress + 0x10)
>> +#define TRNG_INTACK_READY                       BIT0
>> +
>> +#define TRNG_CONTROL_REG                        (mTrngBaseAddress + 0x14)
>> +#define TRNG_CONTROL_REG_ENABLE                 BIT10
>> +
>> +#define TRNG_CONFIG_REG                         (mTrngBaseAddress + 0x18)
>> +#define __MIN_REFILL_SHIFT                      0
>> +#define __MAX_REFILL_SHIFT                      16
>> +#define TRNG_CONFIG_MIN_REFILL_CYCLES           (0x05 << __MIN_REFILL_SHIFT)
>> +#define TRNG_CONFIG_MAX_REFILL_CYCLES           (0x22 << __MAX_REFILL_SHIFT)
>> +
>> +#define TRNG_FRODETUNE_REG                      (mTrngBaseAddress + 0x24)
>> +#define TRNG_FRODETUNE_MASK                     0x0
>> +
>> +#define TRNG_FROENABLE_REG                      (mTrngBaseAddress + 0x20)
>> +#define TRNG_FROENABLE_MASK                     0xffffff
>> +
>> +#define TRNG_MAX_RETRIES                        20
>> +
>> +STATIC EFI_PHYSICAL_ADDRESS                     mTrngBaseAddress;
>> +
>> +/**
>> +  Returns information about the random number generation implementation.
>> +
>> +  @param[in]     This                 A pointer to the EFI_RNG_PROTOCOL
>> +                                      instance.
>> +  @param[in,out] RNGAlgorithmListSize On input, the size in bytes of
>> +                                      RNGAlgorithmList.
>> +                                      On output with a return code of
>> +                                      EFI_SUCCESS, the size in bytes of the
>> +                                      data returned in RNGAlgorithmList. On
>> +                                      output with a return code of
>> +                                      EFI_BUFFER_TOO_SMALL, the size of
>> +                                      RNGAlgorithmList required to obtain the
>> +                                      list.
>> +  @param[out] RNGAlgorithmList        A caller-allocated memory buffer filled
>> +                                      by the driver with one EFI_RNG_ALGORITHM
>> +                                      element for each supported RNG algorithm.
>> +                                      The list must not change across multiple
>> +                                      calls to the same driver. The first
>> +                                      algorithm in the list is the default
>> +                                      algorithm for the driver.
>> +
>> +  @retval EFI_SUCCESS                 The RNG algorithm list was returned
>> +                                      successfully.
>> +  @retval EFI_UNSUPPORTED             The services is not supported by this
>> +                                      driver.
>> +  @retval EFI_DEVICE_ERROR            The list of algorithms could not be
>> +                                      retrieved due to a hardware or firmware
>> +                                      error.
>> +  @retval EFI_INVALID_PARAMETER       One or more of the parameters are
>> +                                      incorrect.
>> +  @retval EFI_BUFFER_TOO_SMALL        The buffer RNGAlgorithmList is too small
>> +                                      to hold the result.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +Armada70x0RngGetInfo (
>> +  IN      EFI_RNG_PROTOCOL        *This,
>> +  IN OUT  UINTN                   *RNGAlgorithmListSize,
>> +  OUT     EFI_RNG_ALGORITHM       *RNGAlgorithmList
>> +  )
>> +{
>> +  if (This == NULL || RNGAlgorithmListSize == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  if (*RNGAlgorithmListSize < sizeof (EFI_RNG_ALGORITHM)) {
>> +    *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);
>> +    return EFI_BUFFER_TOO_SMALL;
>> +  }
>> +
>> +  if (RNGAlgorithmList == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  *RNGAlgorithmListSize = sizeof (EFI_RNG_ALGORITHM);
>> +  CopyGuid (RNGAlgorithmList, &gEfiRngAlgorithmRaw);
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +STATIC
>> +EFI_STATUS
>> +GetTrngData (
>> +  IN    UINTN   Length,
>> +  OUT   UINT8   *Bits
>> +  )
>> +{
>> +  UINTN   Tries;
>> +  UINT32  Buf[TRNG_OUTPUT_SIZE / sizeof (UINT32)];
>> +  UINTN   Index;
>> +
>> +  for (Tries = 0; Tries < TRNG_MAX_RETRIES; Tries++) {
>> +    if (MmioRead32 (TRNG_STATUS_REG) & TRNG_STATUS_READY) {
>> +      for (Index = 0; Index < ARRAY_SIZE (Buf); Index++) {
>> +        Buf[Index] = MmioRead32 (TRNG_OUTPUT_REG + Index * sizeof (UINT32));
>> +      }
>> +      CopyMem (Bits, Buf, Length);
>> +      MmioWrite32 (TRNG_INTACK_REG, TRNG_INTACK_READY);
>> +
>> +      return EFI_SUCCESS;
>> +    }
>> +    gBS->Stall (10);
>
> Why? Why 10? Please add a comment.
>
> No other comments on this patch.
>

I don't remember the details, and I think the 1 ms delay was chosen
arbitrarily, but the purpose of the delay is to allow the hardware to
assume the 'ready' state.


>> +  }
>> +  return EFI_DEVICE_ERROR;
>> +}
>> +
>> +/**
>> +  Produces and returns an RNG value using either the default or specified RNG
>> +  algorithm.
>> +
>> +  @param[in]  This                    A pointer to the EFI_RNG_PROTOCOL
>> +                                      instance.
>> +  @param[in]  RNGAlgorithm            A pointer to the EFI_RNG_ALGORITHM that
>> +                                      identifies the RNG algorithm to use. May
>> +                                      be NULL in which case the function will
>> +                                      use its default RNG algorithm.
>> +  @param[in]  RNGValueLength          The length in bytes of the memory buffer
>> +                                      pointed to by RNGValue. The driver shall
>> +                                      return exactly this numbers of bytes.
>> +  @param[out] RNGValue                A caller-allocated memory buffer filled
>> +                                      by the driver with the resulting RNG
>> +                                      value.
>> +
>> +  @retval EFI_SUCCESS                 The RNG value was returned successfully.
>> +  @retval EFI_UNSUPPORTED             The algorithm specified by RNGAlgorithm
>> +                                      is not supported by this driver.
>> +  @retval EFI_DEVICE_ERROR            An RNG value could not be retrieved due
>> +                                      to a hardware or firmware error.
>> +  @retval EFI_NOT_READY               There is not enough random data available
>> +                                      to satisfy the length requested by
>> +                                      RNGValueLength.
>> +  @retval EFI_INVALID_PARAMETER       RNGValue is NULL or RNGValueLength is
>> +                                      zero.
>> +
>> +**/
>> +STATIC
>> +EFI_STATUS
>> +EFIAPI
>> +Armada70x0RngGetRNG (
>> +  IN EFI_RNG_PROTOCOL            *This,
>> +  IN EFI_RNG_ALGORITHM           *RNGAlgorithm, OPTIONAL
>> +  IN UINTN                       RNGValueLength,
>> +  OUT UINT8                      *RNGValue
>> +  )
>> +{
>> +  UINTN         Length;
>> +  EFI_STATUS    Status;
>> +
>> +  if (This == NULL || RNGValueLength == 0 || RNGValue == NULL) {
>> +    return EFI_INVALID_PARAMETER;
>> +  }
>> +
>> +  //
>> +  // We only support the raw algorithm, so reject requests for anything else
>> +  //
>> +  if (RNGAlgorithm != NULL &&
>> +      !CompareGuid (RNGAlgorithm, &gEfiRngAlgorithmRaw)) {
>> +    return EFI_UNSUPPORTED;
>> +  }
>> +
>> +  do {
>> +    Length = MIN (RNGValueLength, TRNG_OUTPUT_SIZE);
>> +    Status = GetTrngData (Length, RNGValue);
>> +    if (EFI_ERROR (Status)) {
>> +      return Status;
>> +    }
>> +
>> +    RNGValue += Length;
>> +    RNGValueLength -= Length;
>> +  } while (RNGValueLength > 0);
>> +
>> +  return EFI_SUCCESS;
>> +}
>> +
>> +STATIC EFI_RNG_PROTOCOL mArmada70x0RngProtocol = {
>> +  Armada70x0RngGetInfo,
>> +  Armada70x0RngGetRNG
>> +};
>> +
>> +//
>> +// Entry point of this driver.
>> +//
>> +EFI_STATUS
>> +EFIAPI
>> +Armada70x0RngDxeEntryPoint (
>> +  IN EFI_HANDLE       ImageHandle,
>> +  IN EFI_SYSTEM_TABLE *SystemTable
>> +  )
>> +{
>> +  mTrngBaseAddress = PcdGet64 (PcdEip76TrngBaseAddress);
>> +
>> +  //
>> +  // Disable the TRNG before updating its configuration
>> +  //
>> +  MmioAnd32 (TRNG_CONTROL_REG, ~TRNG_CONTROL_REG_ENABLE);
>> +
>> +  //
>> +  // Configure the internal conditioning parameters of the TRNG
>> +  //
>> +  MmioWrite32 (TRNG_CONFIG_REG, TRNG_CONFIG_MIN_REFILL_CYCLES |
>> +                                TRNG_CONFIG_MAX_REFILL_CYCLES);
>> +
>> +  //
>> +  // Configure the FROs
>> +  //
>> +  MmioWrite32 (TRNG_FRODETUNE_REG, TRNG_FRODETUNE_MASK);
>> +  MmioWrite32 (TRNG_FROENABLE_REG, TRNG_FROENABLE_MASK);
>> +
>> +  //
>> +  // Enable the TRNG
>> +  //
>> +  MmioOr32 (TRNG_CONTROL_REG, TRNG_CONTROL_REG_ENABLE);
>> +
>> +  return SystemTable->BootServices->InstallMultipleProtocolInterfaces (
>> +                                      &ImageHandle,
>> +                                      &gEfiRngProtocolGuid,
>> +                                      &mArmada70x0RngProtocol,
>> +                                      NULL
>> +                                      );
>> +}
>> diff --git a/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf b/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf
>> new file mode 100644
>> index 0000000..189ffc5
>> --- /dev/null
>> +++ b/Platform/Marvell/Armada/Drivers/Armada70x0RngDxe/Armada70x0RngDxe.inf
>> @@ -0,0 +1,47 @@
>> +## @file
>> +# This driver produces an EFI_RNG_PROTOCOL instance for the Armada 70x0 TRNG
>> +#
>> +# Copyright (C) 2017, 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 which accompanies this
>> +# distribution. The full text of the license may be found at
>> +# http://opensource.org/licenses/bsd-license.php
>> +#
>> +# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
>> +# WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
>> +#
>> +##
>> +
>> +[Defines]
>> +  INF_VERSION                    = 0x00010019
>> +  BASE_NAME                      = Armada70x0RngDxe
>> +  FILE_GUID                      = dd87096a-cae5-4328-bec1-2ddb755f2e08
>> +  MODULE_TYPE                    = DXE_DRIVER
>> +  VERSION_STRING                 = 1.0
>> +  ENTRY_POINT                    = Armada70x0RngDxeEntryPoint
>> +
>> +[Sources]
>> +  Armada70x0RngDxe.c
>> +
>> +[Packages]
>> +  MdePkg/MdePkg.dec
>> +  Platform/Marvell/Marvell.dec
>> +
>> +[LibraryClasses]
>> +  BaseMemoryLib
>> +  IoLib
>> +  PcdLib
>> +  UefiDriverEntryPoint
>> +
>> +[Pcd]
>> +  gMarvellTokenSpaceGuid.PcdEip76TrngBaseAddress
>> +
>> +[Protocols]
>> +  gEfiRngProtocolGuid              ## PRODUCES
>> +
>> +[Guids]
>> +  gEfiRngAlgorithmRaw
>> +
>> +[Depex]
>> +  TRUE
>> diff --git a/Platform/Marvell/Marvell.dec b/Platform/Marvell/Marvell.dec
>> index e7d7c2c..78f5e53 100644
>> --- a/Platform/Marvell/Marvell.dec
>> +++ b/Platform/Marvell/Marvell.dec
>> @@ -195,6 +195,9 @@
>>  #RTC
>>    gMarvellTokenSpaceGuid.PcdRtcEnabled|{ 0x0 }|VOID*|0x40000052
>>
>> +#TRNG
>> +  gMarvellTokenSpaceGuid.PcdEip76TrngBaseAddress|0x0|UINT64|0x50000053
>> +
>>  [Protocols]
>>    gMarvellEepromProtocolGuid               = { 0x71954bda, 0x60d3, 0x4ef8, { 0x8e, 0x3c, 0x0e, 0x33, 0x9f, 0x3b, 0xc2, 0x2b }}
>>    gMarvellMdioProtocolGuid                 = { 0x40010b03, 0x5f08, 0x496a, { 0xa2, 0x64, 0x10, 0x5e, 0x72, 0xd3, 0x71, 0xaa }}
>> --
>> 2.7.4
>>