On Sat, 28 Dec 2019 at 20:01, Heinrich Schuchardt <[email protected]> wrote:
> On 12/27/19 3:26 PM, Sughosh Ganu wrote: > > Add support for the EFI_RNG_PROTOCOL routines for the qemu arm64 > > platform. EFI_RNG_PROTOCOL is an uefi boottime service which is > > invoked by the efi stub in the kernel for getting random seed for > > kaslr. > > > > The routines are platform specific, and use the virtio-rng device on > > the platform to get random data. > > > > The feature can be enabled through the following config > > CONFIG_EFI_RNG_PROTOCOL > > > > Signed-off-by: Sughosh Ganu <[email protected]> > > --- > > Changes since V2: > > * Based on review comments from Heinrich Schuchardt, the rng drivers > > read all the bytes requested in the individual > > drivers. Corresponding changes made in getrng routine to remove the > > loop to read the bytes requested, since that would be handled in the > > drivers. > > > > board/emulation/qemu-arm/qemu-arm.c | 41 +++++++++++++++++++ > > include/efi_rng.h | 32 +++++++++++++++ > > lib/efi_loader/Kconfig | 8 ++++ > > lib/efi_loader/Makefile | 1 + > > lib/efi_loader/efi_rng.c | 80 > +++++++++++++++++++++++++++++++++++++ > > 5 files changed, 162 insertions(+) > > create mode 100644 include/efi_rng.h > > create mode 100644 lib/efi_loader/efi_rng.c > > > <snip> > > diff --git a/lib/efi_loader/efi_rng.c b/lib/efi_loader/efi_rng.c > > new file mode 100644 > > index 0000000..eb91aa7 > > --- /dev/null > > +++ b/lib/efi_loader/efi_rng.c > > @@ -0,0 +1,80 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Copyright (c) 2019, Linaro Limited > > + */ > > + > > +#include <common.h> > > +#include <dm.h> > > +#include <efi_loader.h> > > +#include <efi_rng.h> > > +#include <rng.h> > > + > > +DECLARE_GLOBAL_DATA_PTR; > > + > > +static efi_status_t EFIAPI rng_getinfo(struct efi_rng_protocol *this, > > + efi_uintn_t > *rng_algorithm_list_size, > > + efi_guid_t *rng_algorithm_list) > > +{ > > + efi_guid_t rng_algo_guid = EFI_RNG_ALGORITHM_RAW; > > + > > + EFI_ENTRY("%p, %p, %p", this, rng_algorithm_list_size, > > + rng_algorithm_list); > > + > > + if (!this || !rng_algorithm_list_size) > > + return EFI_INVALID_PARAMETER; > > + > > + if (!rng_algorithm_list || > > + *rng_algorithm_list_size < sizeof(*rng_algorithm_list)) { > > + *rng_algorithm_list_size = sizeof(*rng_algorithm_list); > > + return EFI_BUFFER_TOO_SMALL; > > + } > > + > > + /* > > + * For now, use EFI_RNG_ALGORITHM_RAW as the default > > + * algorithm. If a new algorithm gets added in the > > + * future through a Kconfig, rng_algo_guid will be set > > + * based on that Kconfig option > > + */ > > + *rng_algorithm_list_size = sizeof(*rng_algorithm_list); > > + guidcpy(rng_algorithm_list, &rng_algo_guid); > > + > > + return EFI_EXIT(EFI_SUCCESS); > > +} > > + > > +static efi_status_t EFIAPI getrng(struct efi_rng_protocol *this, > > + efi_guid_t *rng_algorithm, > > + efi_uintn_t rng_value_length, > > + uint8_t *rng_value) > > +{ > > + int ret; > > + struct udevice *dev; > > + const efi_guid_t rng_raw_guid = EFI_RNG_ALGORITHM_RAW; > > + > > + EFI_ENTRY("%p, %p, %zu, %p", this, rng_algorithm, rng_value_length, > > + rng_value); > > + > > + if (!this || !rng_value || !rng_value_length) > > + return EFI_INVALID_PARAMETER; > > + > > + if (rng_algorithm) { > > + if (guidcmp(rng_algorithm, &rng_raw_guid)) > > + return EFI_UNSUPPORTED; > > + } > > + > > + ret = platform_get_rng_device(&dev); > > This does not compile for sandbox_defconfig. > > You could replace this by: > > ret = uclass_get_device(UCLASS_RNG, 0, &dev); > Like I had stated in one of my earlier mail, I would prefer having a platform specific routine for fetching the rng device. For example, on qemu, where the rng device is the child of a virtio-pci device, the above logic would not get the rng device without having previously scanned the virtio devices. Instead, i will add a weak function platform_get_rng_device, which uses uclass_get_device. Any platform which has a different topology, can then define it's own platform_get_rng_device function. -sughosh
