lkml.org 
[lkml]   [2017]   [Dec]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 2/3] x86/smpboot: Remove stale tlb flush invocations

* Thomas Gleixner <tglx@linutronix.de> wrote:

> 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 aera 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.

s/tlb/TLB

>
> Remove them along with the pointless pr_debugs which come from the same 2.1
> change.
>
> Reported-by: Dominik Brodowski <linux@dominikbrodowski.net>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> arch/x86/kernel/smpboot.c | 9 ---------
> 1 file changed, 9 deletions(-)
>
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -128,14 +128,10 @@ 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)
> @@ -143,11 +139,6 @@ 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.
> */

Really nice archeology! :-)

Reviewed-by: Ingo Molnar <mingo@kernel.org>

Thanks,

Ingo

\
 
 \ /
  Last update: 2017-12-30 22:33    [W:0.067 / U:4.580 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site