4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Michael Ellerman mpe@ellerman.id.au
commit 1e2a9fc7496955faacbbed49461d611b704a7505 upstream.
rfi_flush_enable() includes a check to see if we're already enabled (or disabled), and in that case does nothing.
But that means calling setup_rfi_flush() a 2nd time doesn't actually work, which is a bit confusing.
Move that check into the debugfs code, where it really belongs.
Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Mauricio Faria de Oliveira mauricfo@linux.vnet.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/kernel/setup_64.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
--- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -717,9 +717,6 @@ static void do_nothing(void *unused)
void rfi_flush_enable(bool enable) { - if (rfi_flush == enable) - return; - if (enable) { do_rfi_flush_fixups(enabled_flush_types); on_each_cpu(do_nothing, NULL, 1); @@ -773,13 +770,19 @@ void __init setup_rfi_flush(enum l1d_flu #ifdef CONFIG_DEBUG_FS static int rfi_flush_set(void *data, u64 val) { + bool enable; + if (val == 1) - rfi_flush_enable(true); + enable = true; else if (val == 0) - rfi_flush_enable(false); + enable = false; else return -EINVAL;
+ /* Only do anything if we're changing state */ + if (enable != rfi_flush) + rfi_flush_enable(enable); + return 0; }