Patch "powerpc/64s: Wire up cpu_show_meltdown()" has been added to the 4.14-stable tree

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;a=summary

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 <[email protected]> know about it.

From: Michael Ellerman <[email protected]>
Date: Tue, 16 Jan 2018 21:20:05 +1100
Subject: powerpc/64s: Wire up cpu_show_meltdown()

From: Michael Ellerman <[email protected]>

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.

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

@@ -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

@@ -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 [email protected] 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