powerpc/32: implement fast entry for syscalls on BOOKE
authorChristophe Leroy <christophe.leroy@c-s.fr>
Tue, 30 Apr 2019 12:39:03 +0000 (12:39 +0000)
committerMichael Ellerman <mpe@ellerman.id.au>
Thu, 2 May 2019 15:20:27 +0000 (01:20 +1000)
commit1a4b739bbb4f8857d1b4feb46d6b3ec72269c111
tree1e2212d55c675e3fefcfd9e5049695a5bcbdfd2e
parentb86fb88855ea7881314b935df1df6b1ef1bd0c32
powerpc/32: implement fast entry for syscalls on BOOKE

This patch implements a fast entry for syscalls.

Syscalls don't have to preserve non volatile registers except LR.

This patch then implement a fast entry for syscalls, where
volatile registers get clobbered.

As this entry is dedicated to syscall it always sets MSR_EE
and warns in case MSR_EE was previously off

It also assumes that the call is always from user, system calls are
unexpected from kernel.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/kernel/entry_32.S
arch/powerpc/kernel/head_44x.S
arch/powerpc/kernel/head_booke.h
arch/powerpc/kernel/head_fsl_booke.S