Without a prototype, we'll have to add a prototype for each architecture
implementing vDSO getrandom. As most architectures will likely have the
vDSO getrandom implemented in a near future, and we'd like to keep the
declarations compatible everywhere (to ease the libc implementor work),
we should really just have one copy of the prototype.
This also is what's already done inside of include/vdso/gettime.h for
those vDSO functions, so this continues that convention.
Suggested-by: Huacai Chen <chenhuacai@kernel.org>
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Acked-by: Huacai Chen <chenhuacai@kernel.org>
[Jason: rewrite docbook comment for prototype.]
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Hook up the generic vDSO implementation to the x86 vDSO data page. Since
the existing vDSO infrastructure is heavily based on the timekeeping
functionality, which works over arrays of bases, a new macro is
introduced for vvars that are not arrays.
The vDSO function requires a ChaCha20 implementation that does not write
to the stack, yet can still do an entire ChaCha20 permutation, so
provide this using SSE2, since this is userland code that must work on
all x86-64 processors.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Samuel Neves <sneves@dei.uc.pt> # for vgetrandom-chacha.S
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
