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

powerpc/64s: Wire up cpu_show_meltdown()

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-wire-up-cpu_show_meltdown.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 fd6e440f20b1a4304553775fc55938848ff617c9 Mon Sep 17 00:00:00 2001

From: Michael Ellerman mpe@ellerman.id.au Date: Tue, 16 Jan 2018 21:20:05 +1100 Subject: powerpc/64s: Wire up cpu_show_meltdown()

From: Michael Ellerman mpe@ellerman.id.au

commit fd6e440f20b1a4304553775fc55938848ff617c9 upstream.

The recent commit 87590ce6e373 ("sysfs/cpu: Add vulnerability folder") added a generic folder and set of files for reporting information on CPU vulnerabilities. One of those was for meltdown:

/sys/devices/system/cpu/vulnerabilities/meltdown

This commit wires up that file for 64-bit Book3S powerpc.

For now we default to "Vulnerable" unless the RFI flush is enabled. That may not actually be true on all hardware, further patches will refine the reporting based on the CPU/platform etc. But for now we default to being pessimists.

Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- arch/powerpc/Kconfig | 1 + arch/powerpc/kernel/setup_64.c | 8 ++++++++ 2 files changed, 9 insertions(+)

--- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -164,6 +164,7 @@ config PPC select GENERIC_CLOCKEVENTS_BROADCAST if SMP select GENERIC_CMOS_UPDATE select GENERIC_CPU_AUTOPROBE + select GENERIC_CPU_VULNERABILITIES if PPC_BOOK3S_64 select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL select GENERIC_SMP_IDLE_THREAD --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -884,4 +884,12 @@ void __init setup_rfi_flush(enum l1d_flu if (!no_rfi_flush) rfi_flush_enable(enable); } + +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) +{ + if (rfi_flush) + return sprintf(buf, "Mitigation: RFI Flush\n"); + + return sprintf(buf, "Vulnerable\n"); +} #endif /* CONFIG_PPC_BOOK3S_64 */

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