This is a note to let you know that I've just added the patch titled

powerpc/64s: Allow control of RFI flush via debugfs

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: powerpc-64s-allow-control-of-rfi-flush-via-debugfs.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 236003e6b5443c45c18e613d2b0d776a9f87540e Mon Sep 17 00:00:00 2001

From: Michael Ellerman mpe@ellerman.id.au Date: Tue, 16 Jan 2018 22:17:18 +1100 Subject: powerpc/64s: Allow control of RFI flush via debugfs

From: Michael Ellerman mpe@ellerman.id.au

commit 236003e6b5443c45c18e613d2b0d776a9f87540e upstream.

Expose the state of the RFI flush (enabled/disabled) via debugfs, and allow it to be enabled/disabled at runtime.

eg: $ cat /sys/kernel/debug/powerpc/rfi_flush 1 $ echo 0 > /sys/kernel/debug/powerpc/rfi_flush $ cat /sys/kernel/debug/powerpc/rfi_flush 0

Signed-off-by: Michael Ellerman mpe@ellerman.id.au Reviewed-by: Nicholas Piggin npiggin@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/kernel/setup_64.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)

--- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -38,6 +38,7 @@ #include <linux/memory.h> #include <linux/nmi.h>

+#include <asm/debugfs.h> #include <asm/io.h> #include <asm/kdump.h> #include <asm/prom.h> @@ -885,6 +886,35 @@ void __init setup_rfi_flush(enum l1d_flu rfi_flush_enable(enable); }

+#ifdef CONFIG_DEBUG_FS +static int rfi_flush_set(void *data, u64 val) +{ + if (val == 1) + rfi_flush_enable(true); + else if (val == 0) + rfi_flush_enable(false); + else + return -EINVAL; + + return 0; +} + +static int rfi_flush_get(void *data, u64 *val) +{ + *val = rfi_flush ? 1 : 0; + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n"); + +static __init int rfi_flush_debugfs_init(void) +{ + debugfs_create_file("rfi_flush", 0600, powerpc_debugfs_root, NULL, &fops_rfi_flush); + return 0; +} +device_initcall(rfi_flush_debugfs_init); +#endif + ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { if (rfi_flush)

Patches currently in stable-queue which might be from mpe@ellerman.id.au are

queue-4.14/powerpc-64s-allow-control-of-rfi-flush-via-debugfs.patch queue-4.14/powerpc-64s-wire-up-cpu_show_meltdown.patch