[lkml]   [2022]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v2] random: handle archrandom in plural words
"Jason A. Donenfeld" <> writes:
> The archrandom interface was originally designed for x86, which supplies
> RDRAND/RDSEED for receiving random words into registers, resulting in
> one function to generate an int and another to generate a long. However,
> other architectures don't follow this.
> On arm64, the SMCCC TRNG interface can return between 1 and 3 words. On
> s390, the CPACF TRNG interface can return between 1 and 32 words for the
> same cost as for one word. On UML, the os_getrandom() interface can return
> arbitrary amounts.
> So change the api signature to take a "words" parameter designating the
> maximum number of words requested, and then return the number of words
> generated.

On powerpc a word is 32-bits and a doubleword is 64-bits (at least
according to the ISA). I think that's also true on other 64-bit

You could avoid any confusion by defining the API in terms of "longs"
rather than "words".

But that's just a comment, see what others think.

> arch/powerpc/include/asm/archrandom.h | 30 ++------
> arch/powerpc/kvm/book3s_hv.c | 2 +-

Acked-by: Michael Ellerman <> (powerpc)


 \ /
  Last update: 2022-07-18 08:31    [W:0.082 / U:0.428 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site