Re: [PATCH v2 05/16] x86/efi: Get entropy through EFI random number generator protocol

joeyli
2015-08-27T04:51:32Z

On Thu, Aug 20, 2015 at 03:47:06PM +0100, Matt Fleming wrote:
> On Tue, 11 Aug, at 02:16:25PM, Lee, Chun-Yi wrote:
> > To grab random numbers through EFI protocol as one of the entropies
> > source of swsusp key, this patch adds the logic for accessing EFI RNG
> > (random number generator) protocol that's introduced since UEFI 2.4.
> >
> > Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
> > ---
> > arch/x86/boot/compressed/efi_random.c | 209 ++++++++++++++++++++++++++++++++++
> > include/linux/efi.h | 13 +++
> > 2 files changed, 222 insertions(+)
>
> [...]
>
> Most of this looks good.
>
> > +static unsigned long efi_get_rng(efi_system_table_t *sys_table)
> > +{
> > + const struct efi_config *efi_early = __efi_early();
> > + unsigned long random = 0;
> > + efi_status_t status;
> > + void **rng_handle = NULL;
> > +
> > + status = efi_locate_rng(sys_table, &rng_handle);
> > + if (status != EFI_SUCCESS)
> > + return 0;
> > +
> > + if (efi_early->is64)
> > + random = efi_get_rng64(sys_table, rng_handle);
> > + else
> > + random = efi_get_rng32(sys_table, rng_handle);
> > +
> > + efi_call_early(free_pool, rng_handle);
> > +
> > + return random;
> > +}
>
> I think this function is named particularly poorly in the UEFI spec
> (GetRNG), can we maybe make this efi_get_rng_number(),
> efi_get_rng_value() or efi_get_rng_long() to match the existing
> naming?
>

Thanks for your suggestion, I will change the naming of functions.

> > diff --git a/include/linux/efi.h b/include/linux/efi.h
> > index 85ef051..8914d60 100644
> > --- a/include/linux/efi.h
> > +++ b/include/linux/efi.h
> > @@ -427,6 +427,16 @@ typedef struct {
> > #define EFI_PCI_IO_ATTRIBUTE_VGA_PALETTE_IO_16 0x20000
> > #define EFI_PCI_IO_ATTRIBUTE_VGA_IO_16 0x40000
> >
> > +typedef struct {
> > + u32 get_info;
> > + u32 get_rng;
> > +} efi_rng_protocol_32;
> > +
> > +typedef struct {
> > + u64 get_info;
> > + u64 get_rng;
> > +} efi_rng_protocol_64;
> > +
>
> We've been kinda slack with the naming conventions in efi.h but these
> should really both be 'efi_rng_protocol_*_t'.
>

I will also change the name of struct here.

> --
> Matt Fleming, Intel Open Source Technology Center

Thanks a lot!
Joey Lee