q3k/linux
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity
linux/arch/powerpc/mm/lmb.c
David Gibson eb6de28637 [POWERPC] Allow duplicate lmb_reserve() calls 
At present calling lmb_reserve() (and hence lmb_add_region()) twice
for exactly the same memory region will cause strange behaviour.

This makes life difficult when booting from a flat device tree with
memory reserve map.  Which regions are automatically reserved by the
kernel has changed over time, so it's quite possible a newer kernel
could attempt to auto-reserve a region which is also explicitly listed
in the device tree's reserve map, leading to trouble.

This patch avoids the problem by making lmb_reserve() ignore a call to
reserve a previously reserved region.  It also removes a now redundant
test designed to avoid one specific case of the problem noted above.

At present, this patch deals only with duplicate reservations of an
identical region.  Attempting to reserve two different, but
overlapping regions will still cause problems.  I might post another
patch later dealing with this case, but I'm avoiding it now since it
is substantially more complicated to deal with, less likely to occur
and more likely to indicate a genuine bug elsewhere if it does occur.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-08 15:43:28 +11:00

344 lines
8.1 KiB
C
Raw Blame History

/*
* Procedures for maintaining information about logical memory blocks.
*
* Peter Bergner, IBM Corp. June 2001.
* Copyright (C) 2001 Peter Bergner.
*
* This program 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
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <asm/types.h>
#include <asm/page.h>
#include <asm/prom.h>
#include <asm/lmb.h>
#ifdef CONFIG_PPC32
#include "mmu_decl.h" /* for __max_low_memory */
#endif
#undef DEBUG
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
#define LMB_ALLOC_ANYWHERE 0
struct lmb lmb;
void lmb_dump_all(void)
{
#ifdef DEBUG
unsigned long i;
DBG("lmb_dump_all:\n");
DBG(" memory.cnt = 0x%lx\n", lmb.memory.cnt);
DBG(" memory.size = 0x%lx\n", lmb.memory.size);
for (i=0; i < lmb.memory.cnt ;i++) {
DBG(" memory.region[0x%x].base = 0x%lx\n",
i, lmb.memory.region[i].base);
DBG(" .size = 0x%lx\n",
lmb.memory.region[i].size);
}
DBG("\n reserved.cnt = 0x%lx\n", lmb.reserved.cnt);
DBG(" reserved.size = 0x%lx\n", lmb.reserved.size);
for (i=0; i < lmb.reserved.cnt ;i++) {
DBG(" reserved.region[0x%x].base = 0x%lx\n",
i, lmb.reserved.region[i].base);
DBG(" .size = 0x%lx\n",
lmb.reserved.region[i].size);
}
#endif /* DEBUG */
}
static unsigned long __init lmb_addrs_overlap(unsigned long base1,
unsigned long size1, unsigned long base2, unsigned long size2)
{
return ((base1 < (base2+size2)) && (base2 < (base1+size1)));
}
static long __init lmb_addrs_adjacent(unsigned long base1, unsigned long size1,
unsigned long base2, unsigned long size2)
{
if (base2 == base1 + size1)
return 1;
else if (base1 == base2 + size2)
return -1;
return 0;
}
static long __init lmb_regions_adjacent(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
unsigned long base1 = rgn->region[r1].base;
unsigned long size1 = rgn->region[r1].size;
unsigned long base2 = rgn->region[r2].base;
unsigned long size2 = rgn->region[r2].size;
return lmb_addrs_adjacent(base1, size1, base2, size2);
}
static void __init lmb_remove_region(struct lmb_region *rgn, unsigned long r)
{
unsigned long i;
for (i = r; i < rgn->cnt - 1; i++) {
rgn->region[i].base = rgn->region[i + 1].base;
rgn->region[i].size = rgn->region[i + 1].size;
}
rgn->cnt--;
}
/* Assumption: base addr of region 1 < base addr of region 2 */
static void __init lmb_coalesce_regions(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
rgn->region[r1].size += rgn->region[r2].size;
lmb_remove_region(rgn, r2);
}
/* This routine called with relocation disabled. */
void __init lmb_init(void)
{
/* Create a dummy zero size LMB which will get coalesced away later.
* This simplifies the lmb_add() code below...
*/
lmb.memory.region[0].base = 0;
lmb.memory.region[0].size = 0;
lmb.memory.cnt = 1;
/* Ditto. */
lmb.reserved.region[0].base = 0;
lmb.reserved.region[0].size = 0;
lmb.reserved.cnt = 1;
}
/* This routine may be called with relocation disabled. */
void __init lmb_analyze(void)
{
int i;
lmb.memory.size = 0;
for (i = 0; i < lmb.memory.cnt; i++)
lmb.memory.size += lmb.memory.region[i].size;
}
/* This routine called with relocation disabled. */
static long __init lmb_add_region(struct lmb_region *rgn, unsigned long base,
unsigned long size)
{
unsigned long i, coalesced = 0;
long adjacent;
/* First try and coalesce this LMB with another. */
for (i=0; i < rgn->cnt; i++) {
unsigned long rgnbase = rgn->region[i].base;
unsigned long rgnsize = rgn->region[i].size;
if ((rgnbase == base) && (rgnsize == size))
/* Already have this region, so we're done */
return 0;
adjacent = lmb_addrs_adjacent(base,size,rgnbase,rgnsize);
if ( adjacent > 0 ) {
rgn->region[i].base -= size;
rgn->region[i].size += size;
coalesced++;
break;
}
else if ( adjacent < 0 ) {
rgn->region[i].size += size;
coalesced++;
break;
}
}
if ((i < rgn->cnt-1) && lmb_regions_adjacent(rgn, i, i+1) ) {
lmb_coalesce_regions(rgn, i, i+1);
coalesced++;
}
if (coalesced)
return coalesced;
if (rgn->cnt >= MAX_LMB_REGIONS)
return -1;
/* Couldn't coalesce the LMB, so add it to the sorted table. */
for (i = rgn->cnt-1; i >= 0; i--) {
if (base < rgn->region[i].base) {
rgn->region[i+1].base = rgn->region[i].base;
rgn->region[i+1].size = rgn->region[i].size;
} else {
rgn->region[i+1].base = base;
rgn->region[i+1].size = size;
break;
}
}
rgn->cnt++;
return 0;
}
/* This routine may be called with relocation disabled. */
long __init lmb_add(unsigned long base, unsigned long size)
{
struct lmb_region *_rgn = &(lmb.memory);
/* On pSeries LPAR systems, the first LMB is our RMO region. */
if (base == 0)
lmb.rmo_size = size;
return lmb_add_region(_rgn, base, size);
}
long __init lmb_reserve(unsigned long base, unsigned long size)
{
struct lmb_region *_rgn = &(lmb.reserved);
BUG_ON(0 == size);
return lmb_add_region(_rgn, base, size);
}
long __init lmb_overlaps_region(struct lmb_region *rgn, unsigned long base,
unsigned long size)
{
unsigned long i;
for (i=0; i < rgn->cnt; i++) {
unsigned long rgnbase = rgn->region[i].base;
unsigned long rgnsize = rgn->region[i].size;
if ( lmb_addrs_overlap(base,size,rgnbase,rgnsize) ) {
break;
}
}
return (i < rgn->cnt) ? i : -1;
}
unsigned long __init lmb_alloc(unsigned long size, unsigned long align)
{
return lmb_alloc_base(size, align, LMB_ALLOC_ANYWHERE);
}
unsigned long __init lmb_alloc_base(unsigned long size, unsigned long align,
unsigned long max_addr)
{
unsigned long alloc;
alloc = __lmb_alloc_base(size, align, max_addr);
if (alloc == 0)
panic("ERROR: Failed to allocate 0x%lx bytes below 0x%lx.\n",
size, max_addr);
return alloc;
}
unsigned long __init __lmb_alloc_base(unsigned long size, unsigned long align,
unsigned long max_addr)
{
long i, j;
unsigned long base = 0;
BUG_ON(0 == size);
#ifdef CONFIG_PPC32
/* On 32-bit, make sure we allocate lowmem */
if (max_addr == LMB_ALLOC_ANYWHERE)
max_addr = __max_low_memory;
#endif
for (i = lmb.memory.cnt-1; i >= 0; i--) {
unsigned long lmbbase = lmb.memory.region[i].base;
unsigned long lmbsize = lmb.memory.region[i].size;
if (max_addr == LMB_ALLOC_ANYWHERE)
base = _ALIGN_DOWN(lmbbase + lmbsize - size, align);
else if (lmbbase < max_addr) {
base = min(lmbbase + lmbsize, max_addr);
base = _ALIGN_DOWN(base - size, align);
} else
continue;
while ((lmbbase <= base) &&
((j = lmb_overlaps_region(&lmb.reserved, base, size)) >= 0) )
base = _ALIGN_DOWN(lmb.reserved.region[j].base - size,
align);
if ((base != 0) && (lmbbase <= base))
break;
}
if (i < 0)
return 0;
lmb_add_region(&lmb.reserved, base, size);
return base;
}
/* You must call lmb_analyze() before this. */
unsigned long __init lmb_phys_mem_size(void)
{
return lmb.memory.size;
}
unsigned long __init lmb_end_of_DRAM(void)
{
int idx = lmb.memory.cnt - 1;
return (lmb.memory.region[idx].base + lmb.memory.region[idx].size);
}
/* You must call lmb_analyze() after this. */
void __init lmb_enforce_memory_limit(unsigned long memory_limit)
{
unsigned long i, limit;
struct lmb_property *p;
if (! memory_limit)
return;
/* Truncate the lmb regions to satisfy the memory limit. */
limit = memory_limit;
for (i = 0; i < lmb.memory.cnt; i++) {
if (limit > lmb.memory.region[i].size) {
limit -= lmb.memory.region[i].size;
continue;
}
lmb.memory.region[i].size = limit;
lmb.memory.cnt = i + 1;
break;
}
if (lmb.memory.region[0].size < lmb.rmo_size)
lmb.rmo_size = lmb.memory.region[0].size;
/* And truncate any reserves above the limit also. */
for (i = 0; i < lmb.reserved.cnt; i++) {
p = &lmb.reserved.region[i];
if (p->base > memory_limit)
p->size = 0;
else if ((p->base + p->size) > memory_limit)
p->size = memory_limit - p->base;
if (p->size == 0) {
lmb_remove_region(&lmb.reserved, i);
i--;
}
}
}
Reference in a new issue View git blame Copy permalink