The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_devmap.c

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    1 /*-
    2  * Copyright (c) 2013 Ian Lepore <ian@freebsd.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD: releng/11.0/sys/kern/subr_devmap.c 300694 2016-05-25 19:44:26Z ian $");
   29 
   30 /* Routines for mapping device memory. */
   31 
   32 #include "opt_ddb.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/devmap.h>
   37 #include <vm/vm.h>
   38 #include <vm/vm_extern.h>
   39 #include <vm/pmap.h>
   40 #include <machine/vmparam.h>
   41 
   42 static const struct devmap_entry *devmap_table;
   43 static boolean_t devmap_bootstrap_done = false;
   44 
   45 /*
   46  * The allocated-kva (akva) devmap table and metadata.  Platforms can call
   47  * devmap_add_entry() to add static device mappings to this table using
   48  * automatically allocated virtual addresses carved out of the top of kva space.
   49  * Allocation begins immediately below the ARM_VECTORS_HIGH address.
   50  */
   51 #define AKVA_DEVMAP_MAX_ENTRIES 32
   52 static struct devmap_entry      akva_devmap_entries[AKVA_DEVMAP_MAX_ENTRIES];
   53 static u_int                    akva_devmap_idx;
   54 static vm_offset_t              akva_devmap_vaddr = DEVMAP_MAX_VADDR;
   55 
   56 #if defined(__aarch64__) || defined(__riscv__)
   57 extern int early_boot;
   58 #endif
   59 
   60 /*
   61  * Print the contents of the static mapping table using the provided printf-like
   62  * output function (which will be either printf or db_printf).
   63  */
   64 static void
   65 devmap_dump_table(int (*prfunc)(const char *, ...))
   66 {
   67         const struct devmap_entry *pd;
   68 
   69         if (devmap_table == NULL || devmap_table[0].pd_size == 0) {
   70                 prfunc("No static device mappings.\n");
   71                 return;
   72         }
   73 
   74         prfunc("Static device mappings:\n");
   75         for (pd = devmap_table; pd->pd_size != 0; ++pd) {
   76                 prfunc("  0x%08x - 0x%08x mapped at VA 0x%08x\n",
   77                     pd->pd_pa, pd->pd_pa + pd->pd_size - 1, pd->pd_va);
   78         }
   79 }
   80 
   81 /*
   82  * Print the contents of the static mapping table.  Used for bootverbose.
   83  */
   84 void
   85 devmap_print_table()
   86 {
   87         devmap_dump_table(printf);
   88 }
   89 
   90 /*
   91  * Return the "last" kva address used by the registered devmap table.  It's
   92  * actually the lowest address used by the static mappings, i.e., the address of
   93  * the first unusable byte of KVA.
   94  */
   95 vm_offset_t
   96 devmap_lastaddr()
   97 {
   98         const struct devmap_entry *pd;
   99         vm_offset_t lowaddr;
  100 
  101         if (akva_devmap_idx > 0)
  102                 return (akva_devmap_vaddr);
  103 
  104         lowaddr = DEVMAP_MAX_VADDR;
  105         for (pd = devmap_table; pd != NULL && pd->pd_size != 0; ++pd) {
  106                 if (lowaddr > pd->pd_va)
  107                         lowaddr = pd->pd_va;
  108         }
  109 
  110         return (lowaddr);
  111 }
  112 
  113 /*
  114  * Add an entry to the internal "akva" static devmap table using the given
  115  * physical address and size and a virtual address allocated from the top of
  116  * kva.  This automatically registers the akva table on the first call, so all a
  117  * platform has to do is call this routine to install as many mappings as it
  118  * needs and when initarm() calls devmap_bootstrap() it will pick up all the
  119  * entries in the akva table automatically.
  120  */
  121 void
  122 devmap_add_entry(vm_paddr_t pa, vm_size_t sz)
  123 {
  124         struct devmap_entry *m;
  125 
  126         if (devmap_bootstrap_done)
  127                 panic("devmap_add_entry() after devmap_bootstrap()");
  128 
  129         if (akva_devmap_idx == (AKVA_DEVMAP_MAX_ENTRIES - 1))
  130                 panic("AKVA_DEVMAP_MAX_ENTRIES is too small");
  131 
  132         if (akva_devmap_idx == 0)
  133                 devmap_register_table(akva_devmap_entries);
  134 
  135         /*
  136          * Allocate virtual address space from the top of kva downwards.  If the
  137          * range being mapped is aligned and sized to 1MB boundaries then also
  138          * align the virtual address to the next-lower 1MB boundary so that we
  139          * end up with a nice efficient section mapping.
  140          */
  141 #ifdef __arm__
  142         if ((pa & 0x000fffff) == 0 && (sz & 0x000fffff) == 0) {
  143                 akva_devmap_vaddr = trunc_1mpage(akva_devmap_vaddr - sz);
  144         } else
  145 #endif
  146         {
  147                 akva_devmap_vaddr = trunc_page(akva_devmap_vaddr - sz);
  148         }
  149         m = &akva_devmap_entries[akva_devmap_idx++];
  150         m->pd_va    = akva_devmap_vaddr;
  151         m->pd_pa    = pa;
  152         m->pd_size  = sz;
  153 }
  154 
  155 /*
  156  * Register the given table as the one to use in devmap_bootstrap().
  157  */
  158 void
  159 devmap_register_table(const struct devmap_entry *table)
  160 {
  161 
  162         devmap_table = table;
  163 }
  164 
  165 /*
  166  * Map all of the static regions in the devmap table, and remember the devmap
  167  * table so the mapdev, ptov, and vtop functions can do lookups later.
  168  *
  169  * If a non-NULL table pointer is given it is used unconditionally, otherwise
  170  * the previously-registered table is used.  This smooths transition from legacy
  171  * code that fills in a local table then calls this function passing that table,
  172  * and newer code that uses devmap_register_table() in platform-specific
  173  * code, then lets the common initarm() call this function with a NULL pointer.
  174  */
  175 void
  176 devmap_bootstrap(vm_offset_t l1pt, const struct devmap_entry *table)
  177 {
  178         const struct devmap_entry *pd;
  179 
  180         devmap_bootstrap_done = true;
  181 
  182         /*
  183          * If given a table pointer, use it.  Otherwise, if a table was
  184          * previously registered, use it.  Otherwise, no work to do.
  185          */
  186         if (table != NULL)
  187                 devmap_table = table;
  188         else if (devmap_table == NULL)
  189                 return;
  190 
  191         for (pd = devmap_table; pd->pd_size != 0; ++pd) {
  192 #if defined(__arm__)
  193 #if __ARM_ARCH >= 6
  194                 pmap_preboot_map_attr(pd->pd_pa, pd->pd_va, pd->pd_size,
  195                     VM_PROT_READ | VM_PROT_WRITE, VM_MEMATTR_DEVICE);
  196 #else
  197                 pmap_map_chunk(l1pt, pd->pd_va, pd->pd_pa, pd->pd_size,
  198                     VM_PROT_READ | VM_PROT_WRITE, PTE_DEVICE);
  199 #endif
  200 #elif defined(__aarch64__) || defined(__riscv__)
  201                 pmap_kenter_device(pd->pd_va, pd->pd_size, pd->pd_pa);
  202 #endif
  203         }
  204 }
  205 
  206 /*
  207  * Look up the given physical address in the static mapping data and return the
  208  * corresponding virtual address, or NULL if not found.
  209  */
  210 void *
  211 devmap_ptov(vm_paddr_t pa, vm_size_t size)
  212 {
  213         const struct devmap_entry *pd;
  214 
  215         if (devmap_table == NULL)
  216                 return (NULL);
  217 
  218         for (pd = devmap_table; pd->pd_size != 0; ++pd) {
  219                 if (pa >= pd->pd_pa && pa + size <= pd->pd_pa + pd->pd_size)
  220                         return ((void *)(pd->pd_va + (pa - pd->pd_pa)));
  221         }
  222 
  223         return (NULL);
  224 }
  225 
  226 /*
  227  * Look up the given virtual address in the static mapping data and return the
  228  * corresponding physical address, or DEVMAP_PADDR_NOTFOUND if not found.
  229  */
  230 vm_paddr_t
  231 devmap_vtop(void * vpva, vm_size_t size)
  232 {
  233         const struct devmap_entry *pd;
  234         vm_offset_t va;
  235 
  236         if (devmap_table == NULL)
  237                 return (DEVMAP_PADDR_NOTFOUND);
  238 
  239         va = (vm_offset_t)vpva;
  240         for (pd = devmap_table; pd->pd_size != 0; ++pd) {
  241                 if (va >= pd->pd_va && va + size <= pd->pd_va + pd->pd_size)
  242                         return ((vm_paddr_t)(pd->pd_pa + (va - pd->pd_va)));
  243         }
  244 
  245         return (DEVMAP_PADDR_NOTFOUND);
  246 }
  247 
  248 /*
  249  * Map a set of physical memory pages into the kernel virtual address space.
  250  * Return a pointer to where it is mapped.
  251  *
  252  * This uses a pre-established static mapping if one exists for the requested
  253  * range, otherwise it allocates kva space and maps the physical pages into it.
  254  *
  255  * This routine is intended to be used for mapping device memory, NOT real
  256  * memory; the mapping type is inherently VM_MEMATTR_DEVICE in
  257  * pmap_kenter_device().
  258  */
  259 void *
  260 pmap_mapdev(vm_offset_t pa, vm_size_t size)
  261 {
  262         vm_offset_t va, offset;
  263         void * rva;
  264 
  265         /* First look in the static mapping table. */
  266         if ((rva = devmap_ptov(pa, size)) != NULL)
  267                 return (rva);
  268 
  269         offset = pa & PAGE_MASK;
  270         pa = trunc_page(pa);
  271         size = round_page(size + offset);
  272 
  273 #if defined(__aarch64__) || defined(__riscv__)
  274         if (early_boot) {
  275                 akva_devmap_vaddr = trunc_page(akva_devmap_vaddr - size);
  276                 va = akva_devmap_vaddr;
  277                 KASSERT(va >= VM_MAX_KERNEL_ADDRESS - L2_SIZE,
  278                     ("Too many early devmap mappings"));
  279         } else
  280 #endif
  281                 va = kva_alloc(size);
  282         if (!va)
  283                 panic("pmap_mapdev: Couldn't alloc kernel virtual memory");
  284 
  285         pmap_kenter_device(va, size, pa);
  286 
  287         return ((void *)(va + offset));
  288 }
  289 
  290 /*
  291  * Unmap device memory and free the kva space.
  292  */
  293 void
  294 pmap_unmapdev(vm_offset_t va, vm_size_t size)
  295 {
  296         vm_offset_t offset;
  297 
  298         /* Nothing to do if we find the mapping in the static table. */
  299         if (devmap_vtop((void*)va, size) != DEVMAP_PADDR_NOTFOUND)
  300                 return;
  301 
  302         offset = va & PAGE_MASK;
  303         va = trunc_page(va);
  304         size = round_page(size + offset);
  305 
  306         pmap_kremove_device(va, size);
  307         kva_free(va, size);
  308 }
  309 
  310 #ifdef DDB
  311 #include <ddb/ddb.h>
  312 
  313 DB_SHOW_COMMAND(devmap, db_show_devmap)
  314 {
  315         devmap_dump_table(db_printf);
  316 }
  317 
  318 #endif /* DDB */
  319 

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