[v4,1/2] powerpc32: memcpy: only use dcbz once cache is enabled

Michael Ellerman mpe at ellerman.id.au
Thu Sep 17 15:13:27 AEST 2015

On Wed, 2015-16-09 at 10:04:51 UTC, LEROY Christophe wrote:
> memcpy() uses instruction dcbz to speed up copy by not wasting time
> loading cache line with data that will be overwritten.
> Some platform like mpc52xx do no have cache active at startup and
> can therefore not use memcpy(). Allthough no part of the code
> explicitly uses memcpy(), GCC makes calls to it.
> This patch modifies memcpy() such that at startup, memcpy()
> unconditionally jumps to generic_memcpy() which doesn't use
> the dcbz instruction.
> Once the initial MMU is set up, in machine_init() we patch memcpy()
> by replacing this inconditional jump by a NOP
> Reported-by: Michal Sojka <sojkam1 at fel.cvut.cz>
> Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>

Applied to powerpc fixes, thanks.



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