grub/lib/relocator.c

/*
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2009  Free Software Foundation, Inc.
 *
 *  GRUB is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  GRUB is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <grub/relocator.h>
#include <grub/relocator_private.h>
#include <grub/mm_private.h>
#include <grub/misc.h>

/* TODO: use more efficient data structures if necessary.  */

struct grub_relocator *
grub_relocator_new (void)
{
  struct grub_relocator *ret;

  grub_cpu_relocator_init ();

  ret = grub_zalloc (sizeof (struct grub_relocator));
  if (!ret)
    return NULL;
    
  ret->postchunks = ~(grub_addr_t) 0;
  ret->relocators_size = grub_relocator_jumper_size;  
  return ret;
}

static grub_mm_header_t
get_best_header (struct grub_relocator *rel,
		 grub_addr_t start, grub_addr_t end, grub_addr_t align,
		 grub_size_t size,
		 grub_mm_region_t rb, grub_mm_header_t *prev,
		 grub_addr_t *best_addr, int from_low_priv, int collisioncheck)
{
  grub_mm_header_t h, hp;
  grub_mm_header_t hb = NULL, hbp = NULL;

  auto void try_addr (grub_addr_t allowable_start, grub_addr_t allowable_end);
  void try_addr (grub_addr_t allowable_start, grub_addr_t allowable_end)
  {
    if (from_low_priv)
      {
	grub_addr_t addr;

	addr = ALIGN_UP (allowable_start, align);

	if (addr < start)
	  addr = ALIGN_UP (start, align);

	if (collisioncheck)
	  while (1)
	    {
	      struct grub_relocator_chunk *chunk;
	      for (chunk = rel->chunks; chunk; chunk = chunk->next)
		if ((chunk->target <= addr
		     && addr < chunk->target + chunk->size)
		    || (chunk->target <= addr + size
			&& addr + size < chunk->target + chunk->size)
		    || (addr <= chunk->target && chunk->target < addr + size)
		    || (addr <= chunk->target + chunk->size
			&& chunk->target + chunk->size < addr + size))
		  {
		    addr = ALIGN_UP (chunk->target + chunk->size, align);
		    break;
		  }
	      if (!chunk)
		break;
	    }

	if (allowable_end <= addr + size)
	  return;

	if (addr > end)
	  return;

	if (hb == NULL || *best_addr > addr)
	  {
	    hb = h;
	    hbp = hp;
	    *best_addr = addr;
	  }
      }
    else
      {
	grub_addr_t addr;

	addr = ALIGN_DOWN (allowable_end - size, align);

	if (addr > end)
	  addr = ALIGN_DOWN (end, align);

	if (collisioncheck)
	  while (1)
	    {
	      struct grub_relocator_chunk *chunk;
	      for (chunk = rel->chunks; chunk; chunk = chunk->next)
		if ((chunk->target <= addr
		     && addr < chunk->target + chunk->size)
		    || (chunk->target <= addr + size
			&& addr + size < chunk->target + chunk->size)
		    || (addr <= chunk->target && chunk->target < addr + size)
		    || (addr <= chunk->target + chunk->size
			&& chunk->target + chunk->size < addr + size))
		  {
		    addr = ALIGN_DOWN (chunk->target - size, align);
		    break;
		  }
	      if (!chunk)
		break;
	    }

	if (allowable_start > addr)
	  return;

	if (addr < start)
	  return;

	if (hb == NULL || *best_addr < addr)
	  {
	    hb = h;
	    hbp = hp;
	    *best_addr = addr;
	  }
      }
  }
  
  for (hp = NULL, h = rb->first; h; hp = h, h = h->next)
    {
      grub_addr_t allowable_start, allowable_end;
      allowable_start = (grub_addr_t) h;
      allowable_end = (grub_addr_t) (h + 1 + h->size);
      
      try_addr (allowable_start, allowable_end);
      
      if ((grub_addr_t) h == (grub_addr_t) (rb + 1))
	try_addr (allowable_start - sizeof (*rb) - rb->pre_size,
		  allowable_end - sizeof (*rb));
    }
  *prev = hbp;
  return hb;
}

static int
malloc_in_range (struct grub_relocator *rel,
		 grub_addr_t start, grub_addr_t end, grub_addr_t align,
		 grub_size_t size, grub_addr_t *res, int from_low_priv,
		 int collisioncheck)
{
  grub_mm_region_t rb = NULL, rbp = NULL;
  grub_mm_header_t hb = NULL, hbp = NULL;
  grub_addr_t best_addr;

 again:
  
  {
    grub_mm_region_t r, rp;
    for (rp = NULL, r = grub_mm_base; r; rp = r, r = r->next)
      {
	if ((grub_addr_t) r + r->size + sizeof (*r) > start
	    && (grub_addr_t) r <= end && r->size + sizeof (*r) >= size
	    && (rb == NULL || from_low_priv ? rb > r : rb < r))
	  {
	    rb = r;
	    rbp = rp;
	  }
      }
  }

  if (!rb)
    return 0;

  hb = get_best_header (rel, start, end, align, size, rb, &hbp, &best_addr,
			from_low_priv, collisioncheck);
  if (!hb)
    {
      if (from_low_priv)
	start = (grub_addr_t) (rb + rb->size + sizeof (*rb));
      else
	end = (grub_addr_t) rb - 1;
      goto again;
    }

  /* Special case: relocating region start.  */
  if (best_addr < (grub_addr_t) hbp)
    {
      grub_addr_t newreg_start, newreg_raw_start = best_addr + size;
      grub_addr_t newreg_size, newreg_presize;
      grub_mm_header_t new_header;
      newreg_start = ALIGN_UP (newreg_raw_start, GRUB_MM_ALIGN);
      newreg_presize = newreg_start - newreg_raw_start;
      newreg_size = rb->size - (newreg_start - (grub_addr_t) rb);
      if ((hb->size << GRUB_MM_ALIGN_LOG2) >= newreg_start
	  + (grub_addr_t) rb)
	{
	  grub_mm_header_t newhnext = hb->next;
	  grub_size_t newhsize = ((hb->size << GRUB_MM_ALIGN_LOG2)
				  - newreg_start
				  - (grub_addr_t) rb) >> GRUB_MM_ALIGN_LOG2;
	  new_header = (void *) (newreg_start + sizeof (*rb));
	  new_header->next = newhnext;
	  new_header->size = newhsize;
	  new_header->magic = GRUB_MM_FREE_MAGIC;
	}
      else
	{
	  new_header = hb->next;
	}
      if (hbp || new_header)
	{
	  struct grub_mm_header *newregfirst = rb->first;
	  struct grub_mm_region *newregnext = rb->next;
	  struct grub_mm_region *newreg = (void *) newreg_start;
	  if (hbp)
	    hbp->next = new_header;
	  else
	    newregfirst = new_header;
	  newreg->first = newregfirst;
	  newreg->next = newregnext;
	  newreg->pre_size = newreg_presize;
	  newreg->size = newreg_size;
	  if (rbp)
	    rbp->next = newreg;
	  else
	    grub_mm_base = newreg;
	}
      else
	{
	  if (rbp)
	    rbp->next = rb->next;
	  else
	    grub_mm_base = rb->next;
	}
      *res = best_addr;
      return 1;
    }
  {
    struct grub_mm_header *foll = NULL;
    
    if (best_addr + size <= (grub_addr_t) (hb + hb->size))
      {
	foll = (void *) ALIGN_UP (best_addr + size, GRUB_MM_ALIGN);
	foll->magic = GRUB_MM_FREE_MAGIC;
	foll->size = hb->size - (foll - hb);
      }

    if (best_addr - (grub_addr_t) hb >= sizeof (*hb))
      {
	hb->size = (best_addr - (grub_addr_t) hb) >> GRUB_MM_ALIGN_LOG2;
	if (foll)
	  {
	    foll->next = hb;
	    if (hbp)
	      hbp->next = foll;
	    else
	      rb->first = foll;
	  }
      }
    else
      {
	if (foll)
	  foll->next = hb->next;
	else
	  foll = hb->next;
	if (hbp)
	  hbp->next = foll;
	else
	  rb->first = foll;
      }
    *res = best_addr;
    return 1;
  }
}

grub_err_t
grub_relocator_alloc_chunk_addr (struct grub_relocator *rel, void **src,
				 grub_addr_t target, grub_size_t size)
{
  struct grub_relocator_chunk *chunk;
  grub_addr_t start;
  grub_addr_t min_addr = 0, max_addr;

  max_addr = rel->postchunks;

  /* Keep chunks in memory in the same order as they'll be after relocation.  */
  for (chunk = rel->chunks; chunk; chunk = chunk->next)
    {
      if (chunk->target > target && chunk->src > max_addr)
	max_addr = chunk->src;
      if (chunk->target + chunk->size <= target
	  && chunk->src + chunk->size < min_addr
	  && chunk->src < rel->postchunks)
	min_addr = chunk->src + chunk->size;
      if ((chunk->target <= target && target < chunk->target + chunk->size)
	  || (target <= chunk->target && chunk->target < target + size))
	{
	  return grub_error (GRUB_ERR_BAD_ARGUMENT, "overlap detected");
	}
    }

  chunk = grub_malloc (sizeof (struct grub_relocator_chunk));
  if (!chunk)
    return grub_errno;

  do
    {
      /* A trick to improve Linux allocation.  */
#if defined (__i386__) || defined (__x86_64__)
      if (target < 0x100000)
	if (malloc_in_range (rel, rel->highestnonpostaddr, ~(grub_addr_t)0, 0,
			     size, &start, 1, 0))
	  {
	    if (rel->postchunks < start)
	      rel->postchunks = start;
	    break;
	  }
#endif
      if (malloc_in_range (rel, target, max_addr, 1, size, &start, 1, 0))
	break;

      if (malloc_in_range (rel, min_addr, target, 0, size, &start, 1, 0))
	break;

      grub_free (chunk);
      return grub_error (GRUB_ERR_OUT_OF_MEMORY, "out of memory");
    }
  while (0);

  if (rel->highestaddr < target + size)
    rel->highestaddr = target + size;

  if (rel->highestaddr < start + size)
    rel->highestaddr = start + size;

  if (start < rel->postchunks)
    {
      if (rel->highestnonpostaddr < target + size)
	rel->highestnonpostaddr = target + size;
      
      if (rel->highestnonpostaddr < start + size)
	rel->highestnonpostaddr = start + size;  
    }

  if (start < target)
    rel->relocators_size += grub_relocator_backward_size;
  if (start > target)
    rel->relocators_size += grub_relocator_forward_size;

  chunk->src = start;
  chunk->target = target;
  chunk->size = size;
  chunk->next = rel->chunks;
  rel->chunks = chunk;
  *src = (void *) start;
  return GRUB_ERR_NONE;
}

grub_err_t
grub_relocator_alloc_chunk_align (struct grub_relocator *rel, void **src,
				  grub_addr_t *target,
				  grub_addr_t min_addr, grub_addr_t max_addr,
				  grub_size_t size, grub_size_t align)
{
  grub_addr_t min_addr2 = 0, max_addr2;
  struct grub_relocator_chunk *chunk;
  grub_addr_t start;

  chunk = grub_malloc (sizeof (struct grub_relocator_chunk));
  if (!chunk)
    return grub_errno;

  if (malloc_in_range (rel, min_addr, max_addr, align,
		       size, &start, 1, 1))
    {
      chunk->src = start;
      chunk->target = start;
      chunk->size = size;
      chunk->next = rel->chunks;
      rel->chunks = chunk;
      *src = (void *) start;
      *target = start;
      return GRUB_ERR_NONE;
    }

  max_addr2 = rel->postchunks;
  
  /* Keep chunks in memory in the same order as they'll be after
     relocation.  */
  for (chunk = rel->chunks; chunk; chunk = chunk->next)
    {
      if (chunk->target > max_addr && chunk->src > max_addr2)
	max_addr2 = chunk->src;
      if (chunk->target + chunk->size <= min_addr
	  && chunk->src + chunk->size < min_addr2
	  && chunk->src < rel->postchunks)
	min_addr2 = chunk->src + chunk->size;
    }

  if (!malloc_in_range (rel, min_addr2, max_addr2, align,
			size, &start, 1, 1))
    {
      grub_free (chunk);
      return grub_error (GRUB_ERR_OUT_OF_MEMORY, "out of memory");
    }
  
  chunk->target = ALIGN_UP (min_addr, align);
  while (1)
    {
      struct grub_relocator_chunk *chunk2;
      for (chunk2 = rel->chunks; chunk2; chunk2 = chunk2->next)
	if ((chunk2->target <= chunk->target
	     && chunk->target < chunk2->target + chunk2->size)
	    || (chunk2->target <= chunk->target + size
		&& chunk->target + size < chunk2->target + chunk2->size)
	    || (chunk->target <= chunk2->target && chunk2->target
		< chunk->target + size)
	    || (chunk->target <= chunk2->target + chunk2->size
		&& chunk2->target + chunk2->size < chunk->target + size))
	  {
	    chunk->target = ALIGN_UP (chunk2->target + chunk2->size, align);
	    break;
	  }
      if (!chunk2)
	break;
    }

  if (start < chunk->target)
    rel->relocators_size += grub_relocator_backward_size;
  if (start > chunk->target)
    rel->relocators_size += grub_relocator_forward_size;

  chunk->src = start;
  chunk->size = size;
  chunk->next = rel->chunks;
  rel->chunks = chunk;
  *src = (void *) start;
  *target = chunk->target;
  return GRUB_ERR_NONE;
}

void
grub_relocator_unload (struct grub_relocator *rel)
{
  struct grub_relocator_chunk *chunk, *next;
  for (chunk = rel->chunks; chunk; chunk = next)
    {
      grub_fatal ("Relocator unloading isn't implemented yet");
      next = chunk->next;
      grub_free (chunk);
    }
}

grub_err_t
grub_relocator_prepare_relocs (struct grub_relocator *rel, grub_addr_t addr,
			       grub_addr_t *relstart)
{
  struct grub_relocator_chunk *chunk;
  grub_addr_t rels;
  grub_addr_t rels0;

  if (!malloc_in_range (rel, 0, ~(grub_addr_t)0, grub_relocator_align,
			rel->relocators_size, &rels0, 1, 1))
    return grub_error (GRUB_ERR_OUT_OF_MEMORY, "out of memory");
  rels = rels0;

  for (chunk = rel->chunks; chunk; chunk = chunk->next)
    {
      if (chunk->src < chunk->target)
	{
	  grub_cpu_relocator_backward ((void *) rels,
				       (void *) chunk->src,
				       (void *) chunk->target,
				       chunk->size);
	  rels += grub_relocator_backward_size;
	}
      if (chunk->src > chunk->target)
	{
	  grub_cpu_relocator_forward ((void *) rels,
				      (void *) chunk->src,
				      (void *) chunk->target,
				      chunk->size);
	  rels += grub_relocator_forward_size;
	}
    }
  grub_cpu_relocator_jumper ((void *) rels, addr);
  *relstart = rels0;
  return GRUB_ERR_NONE;
}