arch/um/kernel/tt/tlb.c

   1 /*
   2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/stddef.h"
   7 #include "linux/kernel.h"
   8 #include "linux/sched.h"
   9 #include "linux/mm.h"
  10 #include "asm/page.h"
  11 #include "asm/pgtable.h"
  12 #include "asm/uaccess.h"
  13 #include "user_util.h"
  14 #include "mem_user.h"
  15 #include "os.h"
  16
  17 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
  18                       unsigned long end_addr, int force)
  19 {
  20         pgd_t *npgd;
  21         pmd_t *npmd;
  22         pte_t *npte;
  23         unsigned long addr;
  24         int r, w, x, err;
  25
  26         if((current->thread.mode.tt.extern_pid != -1) &&
  27            (current->thread.mode.tt.extern_pid != os_getpid()))
  28                 panic("fix_range fixing wrong address space, current = 0x%p",
  29                       current);
  30         if(mm == NULL) return;
  31         for(addr=start_addr;addr<end_addr;){
  32                 if(addr == TASK_SIZE){
  33                         /* Skip over kernel text, kernel data, and physical
  34                          * memory, which don't have ptes, plus kernel virtual
  35                          * memory, which is flushed separately, and remap
  36                          * the process stack.  The only way to get here is
  37                          * if (end_addr == STACK_TOP) > TASK_SIZE, which is
  38                          * only true in the honeypot case.
  39                          */
  40                         addr = STACK_TOP - ABOVE_KMEM;
  41                         continue;
  42                 }
  43                 npgd = pgd_offset(mm, addr);
  44                 npmd = pmd_offset(npgd, addr);
  45                 if(pmd_present(*npmd)){
  46                         npte = pte_offset_kernel(npmd, addr);
  47                         r = pte_read(*npte);
  48                         w = pte_write(*npte);
  49                         x = pte_exec(*npte);
  50                         if(!pte_dirty(*npte)) w = 0;
  51                         if(!pte_young(*npte)){
  52                                 r = 0;
  53                                 w = 0;
  54                         }
  55                         if(force || pte_newpage(*npte)){
  56                                 err = os_unmap_memory((void *) addr,
  57                                                       PAGE_SIZE);
  58                                 if(err < 0)
  59                                         panic("munmap failed, errno = %d\n",
  60                                               -err);
  61                                 if(pte_present(*npte))
  62                                         map_memory(addr,
  63                                                    pte_val(*npte) & PAGE_MASK,
  64                                                    PAGE_SIZE, r, w, x);
  65                         }
  66                         else if(pte_newprot(*npte)){
  67                                 protect_memory(addr, PAGE_SIZE, r, w, x, 1);
  68                         }
  69                         *npte = pte_mkuptodate(*npte);
  70                         addr += PAGE_SIZE;
  71                 }
  72                 else {
  73                         if(force || pmd_newpage(*npmd)){
  74                                 err = os_unmap_memory((void *) addr, PMD_SIZE);
  75                                 if(err < 0)
  76                                         panic("munmap failed, errno = %d\n",
  77                                               -err);
  78                                 pmd_mkuptodate(*npmd);
  79                         }
  80                         addr += PMD_SIZE;
  81                 }
  82         }
  83 }
  84
  85 atomic_t vmchange_seq = ATOMIC_INIT(1);
  86
  87 static void flush_kernel_vm_range(unsigned long start, unsigned long end,
  88                                   int update_seq)
  89 {
  90         struct mm_struct *mm;
  91         pgd_t *pgd;
  92         pmd_t *pmd;
  93         pte_t *pte;
  94         unsigned long addr;
  95         int updated = 0, err;
  96
  97         mm = &init_mm;
  98         for(addr = start; addr < end;){
  99                 pgd = pgd_offset(mm, addr);
 100                 pmd = pmd_offset(pgd, addr);
 101                 if(pmd_present(*pmd)){
 102                         pte = pte_offset_kernel(pmd, addr);
 103                         if(!pte_present(*pte) || pte_newpage(*pte)){
 104                                 updated = 1;
 105                                 err = os_unmap_memory((void *) addr,
 106                                                       PAGE_SIZE);
 107                                 if(err < 0)
 108                                         panic("munmap failed, errno = %d\n",
 109                                               -err);
 110                                 if(pte_present(*pte))
 111                                         map_memory(addr,
 112                                                    pte_val(*pte) & PAGE_MASK,
 113                                                    PAGE_SIZE, 1, 1, 1);
 114                         }
 115                         else if(pte_newprot(*pte)){
 116                                 updated = 1;
 117                                 protect_memory(addr, PAGE_SIZE, 1, 1, 1, 1);
 118                         }
 119                         addr += PAGE_SIZE;
 120                 }
 121                 else {
 122                         if(pmd_newpage(*pmd)){
 123                                 updated = 1;
 124                                 err = os_unmap_memory((void *) addr, PMD_SIZE);
 125                                 if(err < 0)
 126                                         panic("munmap failed, errno = %d\n",
 127                                               -err);
 128                         }
 129                         addr += PMD_SIZE;
 130                 }
 131         }
 132         if(updated && update_seq) atomic_inc(&vmchange_seq);
 133 }
 134
 135 void flush_tlb_kernel_range_tt(unsigned long start, unsigned long end)
 136 {
 137         flush_kernel_vm_range(start, end, 1);
 138 }
 139
 140 static void protect_vm_page(unsigned long addr, int w, int must_succeed)
 141 {
 142         int err;
 143
 144         err = protect_memory(addr, PAGE_SIZE, 1, w, 1, must_succeed);
 145         if(err == 0) return;
 146         else if((err == -EFAULT) || (err == -ENOMEM)){
 147                 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 148                 protect_vm_page(addr, w, 1);
 149         }
 150         else panic("protect_vm_page : protect failed, errno = %d\n", err);
 151 }
 152
 153 void mprotect_kernel_vm(int w)
 154 {
 155         struct mm_struct *mm;
 156         pgd_t *pgd;
 157         pmd_t *pmd;
 158         pte_t *pte;
 159         unsigned long addr;
 160
 161         mm = &init_mm;
 162         for(addr = start_vm; addr < end_vm;){
 163                 pgd = pgd_offset(mm, addr);
 164                 pmd = pmd_offset(pgd, addr);
 165                 if(pmd_present(*pmd)){
 166                         pte = pte_offset_kernel(pmd, addr);
 167                         if(pte_present(*pte)) protect_vm_page(addr, w, 0);
 168                         addr += PAGE_SIZE;
 169                 }
 170                 else addr += PMD_SIZE;
 171         }
 172 }
 173
 174 void flush_tlb_kernel_vm_tt(void)
 175 {
 176         flush_tlb_kernel_range(start_vm, end_vm);
 177 }
 178
 179 void __flush_tlb_one_tt(unsigned long addr)
 180 {
 181         flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 182 }
 183
 184 void flush_tlb_range_tt(struct vm_area_struct *vma, unsigned long start,
 185                      unsigned long end)
 186 {
 187         if(vma->vm_mm != current->mm) return;
 188
 189         /* Assumes that the range start ... end is entirely within
 190          * either process memory or kernel vm
 191          */
 192         if((start >= start_vm) && (start < end_vm))
 193                 flush_kernel_vm_range(start, end, 1);
 194         else fix_range(vma->vm_mm, start, end, 0);
 195 }
 196
 197 void flush_tlb_mm_tt(struct mm_struct *mm)
 198 {
 199         unsigned long seq;
 200
 201         if(mm != current->mm) return;
 202
 203         fix_range(mm, 0, STACK_TOP, 0);
 204
 205         seq = atomic_read(&vmchange_seq);
 206         if(current->thread.mode.tt.vm_seq == seq) return;
 207         current->thread.mode.tt.vm_seq = seq;
 208         flush_kernel_vm_range(start_vm, end_vm, 0);
 209 }
 210
 211 void force_flush_all_tt(void)
 212 {
 213         fix_range(current->mm, 0, STACK_TOP, 1);
 214         flush_kernel_vm_range(start_vm, end_vm, 0);
 215 }
 216
 217 /*
 218  * Overrides for Emacs so that we follow Linus's tabbing style.
 219  * Emacs will notice this stuff at the end of the file and automatically
 220  * adjust the settings for this buffer only.  This must remain at the end
 221  * of the file.
 222  * ---------------------------------------------------------------------------
 223  * Local variables:
 224  * c-file-style: "linux"
 225  * End:
 226  */