target/linux/brcm47xx/patches-3.14/152-Revert-MIPS-Delete-unused-function-add_temporary_ent.patch

   1 From d377732c8c9aac14ccb900b65678558b0fb8f0f3 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <zajec5@gmail.com>
   3 Date: Thu, 17 Jul 2014 23:26:32 +0200
   4 Subject: [PATCH 152/153] Revert "MIPS: Delete unused function
   5  add_temporary_entry."
   6 MIME-Version: 1.0
   7 Content-Type: text/plain; charset=UTF-8
   8 Content-Transfer-Encoding: 8bit
   9
  10 This reverts commit d7a887a73dec6c387b02a966a71aac767bbd9ce6.
  11
  12 Function add_temporary_entry is needed by bcm47xx to support highmem. We
  13 need to add a temporary entry to check for amount of RAM.
  14 The only change made in this revert was replacing (ENTER|EXIT)_CRITICAL.
  15
  16 Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
  17 Cc: linux-mips@linux-mips.org
  18 Cc: Hauke Mehrtens <hauke@hauke-m.de>
  19 Patchwork: https://patchwork.linux-mips.org/patch/7395/
  20 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  21 ---
  22  arch/mips/include/asm/pgtable-32.h | 10 ++++++++
  23  arch/mips/mm/tlb-r4k.c             | 47 ++++++++++++++++++++++++++++++++++++++
  24  2 files changed, 57 insertions(+)
  25
  26 --- a/arch/mips/include/asm/pgtable-32.h
  27 +++ b/arch/mips/include/asm/pgtable-32.h
  28 @@ -19,6 +19,16 @@
  29  #include <asm-generic/pgtable-nopmd.h>
  30
  31  /*
  32 + * - add_temporary_entry() add a temporary TLB entry. We use TLB entries
  33 + *     starting at the top and working down. This is for populating the
  34 + *     TLB before trap_init() puts the TLB miss handler in place. It
  35 + *     should be used only for entries matching the actual page tables,
  36 + *     to prevent inconsistencies.
  37 + */
  38 +extern int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
  39 +                              unsigned long entryhi, unsigned long pagemask);
  40 +
  41 +/*
  42   * Basically we have the same two-level (which is the logical three level
  43   * Linux page table layout folded) page tables as the i386.  Some day
  44   * when we have proper page coloring support we can have a 1% quicker
  45 --- a/arch/mips/mm/tlb-r4k.c
  46 +++ b/arch/mips/mm/tlb-r4k.c
  47 @@ -411,6 +411,51 @@ int __init has_transparent_hugepage(void
  48
  49  #endif /* CONFIG_TRANSPARENT_HUGEPAGE  */
  50
  51 +/*
  52 + * Used for loading TLB entries before trap_init() has started, when we
  53 + * don't actually want to add a wired entry which remains throughout the
  54 + * lifetime of the system
  55 + */
  56 +
  57 +static int temp_tlb_entry __cpuinitdata;
  58 +
  59 +__init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1,
  60 +                              unsigned long entryhi, unsigned long pagemask)
  61 +{
  62 +       int ret = 0;
  63 +       unsigned long flags;
  64 +       unsigned long wired;
  65 +       unsigned long old_pagemask;
  66 +       unsigned long old_ctx;
  67 +
  68 +       local_irq_save(flags);
  69 +       /* Save old context and create impossible VPN2 value */
  70 +       old_ctx = read_c0_entryhi();
  71 +       old_pagemask = read_c0_pagemask();
  72 +       wired = read_c0_wired();
  73 +       if (--temp_tlb_entry < wired) {
  74 +               printk(KERN_WARNING
  75 +                      "No TLB space left for add_temporary_entry\n");
  76 +               ret = -ENOSPC;
  77 +               goto out;
  78 +       }
  79 +
  80 +       write_c0_index(temp_tlb_entry);
  81 +       write_c0_pagemask(pagemask);
  82 +       write_c0_entryhi(entryhi);
  83 +       write_c0_entrylo0(entrylo0);
  84 +       write_c0_entrylo1(entrylo1);
  85 +       mtc0_tlbw_hazard();
  86 +       tlb_write_indexed();
  87 +       tlbw_use_hazard();
  88 +
  89 +       write_c0_entryhi(old_ctx);
  90 +       write_c0_pagemask(old_pagemask);
  91 +out:
  92 +       local_irq_restore(flags);
  93 +       return ret;
  94 +}
  95 +
  96  static int ntlb;
  97  static int __init set_ntlb(char *str)
  98  {
  99 @@ -448,6 +493,8 @@ void tlb_init(void)
 100                 write_c0_pagegrain(pg);
 101         }
 102
 103 +       temp_tlb_entry = current_cpu_data.tlbsize - 1;
 104 +
 105         /* From this point on the ARC firmware is dead.  */
 106         local_flush_tlb_all();
 107