Patch "powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code" has been added to the 4.9-stable tree

[gregkh at linuxfoundation.org]

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

    powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code

to the 4.9-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-rfi-flush-move-the-logic-to-avoid-a-redo-into-the-debugfs-code.patch
and it can be found in the queue-4.9 subdirectory.

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


>From foo at baz Sat Jun  2 15:29:05 CEST 2018
From: Michael Ellerman <mpe at ellerman.id.au>
Date: Sat,  2 Jun 2018 21:08:49 +1000
Subject: powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code
To: gregkh at linuxfoundation.org
Cc: stable at vger.kernel.org, linuxppc-dev at ozlabs.org
Message-ID: <20180602110908.29773-5-mpe at ellerman.id.au>

From: Michael Ellerman <mpe at 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 at ellerman.id.au>
Signed-off-by: Mauricio Faria de Oliveira <mauricfo at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh at 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;
 }
 


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

queue-4.9/powerpc-64s-clear-pcr-on-boot.patch
queue-4.9/powerpc-rfi-flush-differentiate-enabled-and-patched-flush-types.patch
queue-4.9/powerpc-64s-fix-section-mismatch-warnings-from-setup_rfi_flush.patch
queue-4.9/powerpc-pseries-fix-clearing-of-security-feature-flags.patch
queue-4.9/powerpc-powernv-set-or-clear-security-feature-flags.patch
queue-4.9/powerpc-64s-move-cpu_show_meltdown.patch
queue-4.9/powerpc-rfi-flush-call-setup_rfi_flush-after-lpm-migration.patch
queue-4.9/powerpc-pseries-set-or-clear-security-feature-flags.patch
queue-4.9/powerpc-rfi-flush-make-it-possible-to-call-setup_rfi_flush-again.patch
queue-4.9/powerpc-move-default-security-feature-flags.patch
queue-4.9/powerpc-powernv-use-the-security-flags-in-pnv_setup_rfi_flush.patch
queue-4.9/powerpc-add-security-feature-flags-for-spectre-meltdown.patch
queue-4.9/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch
queue-4.9/powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch
queue-4.9/powerpc-rfi-flush-move-out-of-hardlockup_detector-ifdef.patch
queue-4.9/powerpc-rfi-flush-always-enable-fallback-flush-on-pseries.patch
queue-4.9/powerpc-rfi-flush-move-the-logic-to-avoid-a-redo-into-the-debugfs-code.patch
queue-4.9/powerpc-pseries-restore-default-security-feature-flags-on-setup.patch
queue-4.9/powerpc-pseries-add-new-h_get_cpu_characteristics-flags.patch
queue-4.9/powerpc-64s-add-support-for-a-store-forwarding-barrier-at-kernel-entry-exit.patch
queue-4.9/powerpc-64s-wire-up-cpu_show_spectre_v1.patch
queue-4.9/powerpc-powernv-support-firmware-disable-of-rfi-flush.patch
queue-4.9/powerpc-pseries-support-firmware-disable-of-rfi-flush.patch
queue-4.9/powerpc-64s-wire-up-cpu_show_spectre_v2.patch