git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From febe42964fe182281859b3d43d844bb25ca49367 Mon Sep 17 00:00:00 2001
   2 From: John David Anglin <dave.anglin@bell.net>
   3 Date: Tue, 6 Dec 2016 22:02:01 -0500
   4 Subject: parisc: Remove unnecessary TLB purges from flush_dcache_page_asm and flush_icache_page_asm
   5
   6 From: John David Anglin <dave.anglin@bell.net>
   7
   8 commit febe42964fe182281859b3d43d844bb25ca49367 upstream.
   9
  10 We have four routines in pacache.S that use temporary alias pages:
  11 copy_user_page_asm(), clear_user_page_asm(), flush_dcache_page_asm() and
  12 flush_icache_page_asm().  copy_user_page_asm() and clear_user_page_asm()
  13 don't purge the TLB entry used for the operation.
  14 flush_dcache_page_asm() and flush_icache_page_asm do purge the entry.
  15
  16 Presumably, this was thought to optimize TLB use.  However, the
  17 operation is quite heavy weight on PA 1.X processors as we need to take
  18 the TLB lock and a TLB broadcast is sent to all processors.
  19
  20 This patch removes the purges from flush_dcache_page_asm() and
  21 flush_icache_page_asm.
  22
  23 Signed-off-by: John David Anglin  <dave.anglin@bell.net>
  24 Signed-off-by: Helge Deller <deller@gmx.de>
  25 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  26
  27 ---
  28  arch/parisc/kernel/pacache.S |   22 +---------------------
  29  1 file changed, 1 insertion(+), 21 deletions(-)
  30
  31 --- a/arch/parisc/kernel/pacache.S
  32 +++ b/arch/parisc/kernel/pacache.S
  33 @@ -886,19 +886,10 @@ ENTRY(flush_dcache_page_asm)
  34         fdc,m           r31(%r28)
  35         fdc,m           r31(%r28)
  36         fdc,m           r31(%r28)
  37 -       cmpb,COND(<<)           %r28, %r25,1b
  38 +       cmpb,COND(<<)   %r28, %r25,1b
  39         fdc,m           r31(%r28)
  40
  41         sync
  42 -
  43 -#ifdef CONFIG_PA20
  44 -       pdtlb,l         %r0(%r25)
  45 -#else
  46 -       tlb_lock        %r20,%r21,%r22
  47 -       pdtlb           %r0(%r25)
  48 -       tlb_unlock      %r20,%r21,%r22
  49 -#endif
  50 -
  51         bv              %r0(%r2)
  52         nop
  53         .exit
  54 @@ -973,17 +964,6 @@ ENTRY(flush_icache_page_asm)
  55         fic,m           %r31(%sr4,%r28)
  56
  57         sync
  58 -
  59 -#ifdef CONFIG_PA20
  60 -       pdtlb,l         %r0(%r28)
  61 -       pitlb,l         %r0(%sr4,%r25)
  62 -#else
  63 -       tlb_lock        %r20,%r21,%r22
  64 -       pdtlb           %r0(%r28)
  65 -       pitlb           %r0(%sr4,%r25)
  66 -       tlb_unlock      %r20,%r21,%r22
  67 -#endif
  68 -
  69         bv              %r0(%r2)
  70         nop
  71         .exit