Patch "x86/smpboot: Remove stale TLB flush invocations" has been added to the 4.9-stable tree

Patch "x86/smpboot: Remove stale TLB flush invocations" has been added to the 4.9-stable tree

[gregkh]

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

    x86/smpboot: Remove stale TLB flush invocations

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:
     x86-smpboot-remove-stale-tlb-flush-invocations.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@vger.kernel.org> know about it.


>From 322f8b8b340c824aef891342b0f5795d15e11562 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sat, 30 Dec 2017 22:13:53 +0100
Subject: x86/smpboot: Remove stale TLB flush invocations

From: Thomas Gleixner <tglx@linutronix.de>

commit 322f8b8b340c824aef891342b0f5795d15e11562 upstream.

smpboot_setup_warm_reset_vector() and smpboot_restore_warm_reset_vector()
invoke local_flush_tlb() for no obvious reason.

Digging in history revealed that the original code in the 2.1 era added
those because the code manipulated a swapper_pg_dir pagetable entry. The
pagetable manipulation was removed long ago in the 2.3 timeframe, but the
TLB flush invocations stayed around forever.

Remove them along with the pointless pr_debug()s which come from the same 2.1
change.

Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171230211829.586548655@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/smpboot.c |    9 ---------
 1 file changed, 9 deletions(-)

--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -115,14 +115,10 @@ static inline void smpboot_setup_warm_re
 	spin_lock_irqsave(&rtc_lock, flags);
 	CMOS_WRITE(0xa, 0xf);
 	spin_unlock_irqrestore(&rtc_lock, flags);
-	local_flush_tlb();
-	pr_debug("1.\n");
 	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
 							start_eip >> 4;
-	pr_debug("2.\n");
 	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
 							start_eip & 0xf;
-	pr_debug("3.\n");
 }
 
 static inline void smpboot_restore_warm_reset_vector(void)
@@ -130,11 +126,6 @@ static inline void smpboot_restore_warm_
 	unsigned long flags;
 
 	/*
-	 * Install writable page 0 entry to set BIOS data area.
-	 */
-	local_flush_tlb();
-
-	/*
 	 * Paranoid:  Set warm reset code and vector here back
 	 * to default values.
 	 */


Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.9/nohz-prevent-a-timer-interrupt-storm-in-tick_nohz_stop_sched_tick.patch
queue-4.9/timers-invoke-timer_start_debug-where-it-makes-sense.patch
queue-4.9/x86-vm86-32-switch-to-flush_tlb_mm_range-in-mark_screen_rdonly.patch
queue-4.9/x86-mm-add-the-nopcid-boot-option-to-turn-off-pcid.patch
queue-4.9/x86-mm-enable-cr4.pcide-on-supported-systems.patch
queue-4.9/sync-objtool-s-copy-of-x86-opcode-map.txt.patch
queue-4.9/x86-smpboot-remove-stale-tlb-flush-invocations.patch
queue-4.9/timers-use-deferrable-base-independent-of-base-nohz_active.patch
queue-4.9/x86-mm-remove-the-up-asm-tlbflush.h-code-always-use-the-formerly-smp-code.patch
queue-4.9/x86-mm-reimplement-flush_tlb_page-using-flush_tlb_mm_range.patch
queue-4.9/x86-mm-make-flush_tlb_mm_range-more-predictable.patch
queue-4.9/x86-mm-remove-flush_tlb-and-flush_tlb_current_task.patch
queue-4.9/x86-mm-disable-pcid-on-32-bit-kernels.patch
queue-4.9/timers-reinitialize-per-cpu-bases-on-hotplug.patch
queue-4.9/x86-mm-64-fix-reboot-interaction-with-cr4.pcide.patch