linux/kernel/early_res.c
Ian Campbell eed63519e3 x86: Do not free zero sized per cpu areas
This avoids an infinite loop in free_early_partial().

Add a warning to free_early_partial() to catch future problems.

-v5: put back start > end back into WARN_ONCE()
-v6: use one line for warning, suggested by Linus
-v7: more tests
-v8: remove the function name as suggested by Johannes
     WARN_ONCE() will print out that function name.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Tested-by: Joel Becker <joel.becker@oracle.com>
Tested-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1269830604-26214-4-git-send-email-yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-29 18:55:40 +02:00

584 lines
14 KiB
C

/*
* early_res, could be used to replace bootmem
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mm.h>
#include <linux/early_res.h>
/*
* Early reserved memory areas.
*/
/*
* need to make sure this one is bigger enough before
* find_fw_memmap_area could be used
*/
#define MAX_EARLY_RES_X 32
struct early_res {
u64 start, end;
char name[15];
char overlap_ok;
};
static struct early_res early_res_x[MAX_EARLY_RES_X] __initdata;
static int max_early_res __initdata = MAX_EARLY_RES_X;
static struct early_res *early_res __initdata = &early_res_x[0];
static int early_res_count __initdata;
static int __init find_overlapped_early(u64 start, u64 end)
{
int i;
struct early_res *r;
for (i = 0; i < max_early_res && early_res[i].end; i++) {
r = &early_res[i];
if (end > r->start && start < r->end)
break;
}
return i;
}
/*
* Drop the i-th range from the early reservation map,
* by copying any higher ranges down one over it, and
* clearing what had been the last slot.
*/
static void __init drop_range(int i)
{
int j;
for (j = i + 1; j < max_early_res && early_res[j].end; j++)
;
memmove(&early_res[i], &early_res[i + 1],
(j - 1 - i) * sizeof(struct early_res));
early_res[j - 1].end = 0;
early_res_count--;
}
static void __init drop_range_partial(int i, u64 start, u64 end)
{
u64 common_start, common_end;
u64 old_start, old_end;
old_start = early_res[i].start;
old_end = early_res[i].end;
common_start = max(old_start, start);
common_end = min(old_end, end);
/* no overlap ? */
if (common_start >= common_end)
return;
if (old_start < common_start) {
/* make head segment */
early_res[i].end = common_start;
if (old_end > common_end) {
char name[15];
/*
* Save a local copy of the name, since the
* early_res array could get resized inside
* reserve_early_without_check() ->
* __check_and_double_early_res(), which would
* make the current name pointer invalid.
*/
strncpy(name, early_res[i].name,
sizeof(early_res[i].name) - 1);
/* add another for left over on tail */
reserve_early_without_check(common_end, old_end, name);
}
return;
} else {
if (old_end > common_end) {
/* reuse the entry for tail left */
early_res[i].start = common_end;
return;
}
/* all covered */
drop_range(i);
}
}
/*
* Split any existing ranges that:
* 1) are marked 'overlap_ok', and
* 2) overlap with the stated range [start, end)
* into whatever portion (if any) of the existing range is entirely
* below or entirely above the stated range. Drop the portion
* of the existing range that overlaps with the stated range,
* which will allow the caller of this routine to then add that
* stated range without conflicting with any existing range.
*/
static void __init drop_overlaps_that_are_ok(u64 start, u64 end)
{
int i;
struct early_res *r;
u64 lower_start, lower_end;
u64 upper_start, upper_end;
char name[15];
for (i = 0; i < max_early_res && early_res[i].end; i++) {
r = &early_res[i];
/* Continue past non-overlapping ranges */
if (end <= r->start || start >= r->end)
continue;
/*
* Leave non-ok overlaps as is; let caller
* panic "Overlapping early reservations"
* when it hits this overlap.
*/
if (!r->overlap_ok)
return;
/*
* We have an ok overlap. We will drop it from the early
* reservation map, and add back in any non-overlapping
* portions (lower or upper) as separate, overlap_ok,
* non-overlapping ranges.
*/
/* 1. Note any non-overlapping (lower or upper) ranges. */
strncpy(name, r->name, sizeof(name) - 1);
lower_start = lower_end = 0;
upper_start = upper_end = 0;
if (r->start < start) {
lower_start = r->start;
lower_end = start;
}
if (r->end > end) {
upper_start = end;
upper_end = r->end;
}
/* 2. Drop the original ok overlapping range */
drop_range(i);
i--; /* resume for-loop on copied down entry */
/* 3. Add back in any non-overlapping ranges. */
if (lower_end)
reserve_early_overlap_ok(lower_start, lower_end, name);
if (upper_end)
reserve_early_overlap_ok(upper_start, upper_end, name);
}
}
static void __init __reserve_early(u64 start, u64 end, char *name,
int overlap_ok)
{
int i;
struct early_res *r;
i = find_overlapped_early(start, end);
if (i >= max_early_res)
panic("Too many early reservations");
r = &early_res[i];
if (r->end)
panic("Overlapping early reservations "
"%llx-%llx %s to %llx-%llx %s\n",
start, end - 1, name ? name : "", r->start,
r->end - 1, r->name);
r->start = start;
r->end = end;
r->overlap_ok = overlap_ok;
if (name)
strncpy(r->name, name, sizeof(r->name) - 1);
early_res_count++;
}
/*
* A few early reservtations come here.
*
* The 'overlap_ok' in the name of this routine does -not- mean it
* is ok for these reservations to overlap an earlier reservation.
* Rather it means that it is ok for subsequent reservations to
* overlap this one.
*
* Use this entry point to reserve early ranges when you are doing
* so out of "Paranoia", reserving perhaps more memory than you need,
* just in case, and don't mind a subsequent overlapping reservation
* that is known to be needed.
*
* The drop_overlaps_that_are_ok() call here isn't really needed.
* It would be needed if we had two colliding 'overlap_ok'
* reservations, so that the second such would not panic on the
* overlap with the first. We don't have any such as of this
* writing, but might as well tolerate such if it happens in
* the future.
*/
void __init reserve_early_overlap_ok(u64 start, u64 end, char *name)
{
drop_overlaps_that_are_ok(start, end);
__reserve_early(start, end, name, 1);
}
static void __init __check_and_double_early_res(u64 ex_start, u64 ex_end)
{
u64 start, end, size, mem;
struct early_res *new;
/* do we have enough slots left ? */
if ((max_early_res - early_res_count) > max(max_early_res/8, 2))
return;
/* double it */
mem = -1ULL;
size = sizeof(struct early_res) * max_early_res * 2;
if (early_res == early_res_x)
start = 0;
else
start = early_res[0].end;
end = ex_start;
if (start + size < end)
mem = find_fw_memmap_area(start, end, size,
sizeof(struct early_res));
if (mem == -1ULL) {
start = ex_end;
end = get_max_mapped();
if (start + size < end)
mem = find_fw_memmap_area(start, end, size,
sizeof(struct early_res));
}
if (mem == -1ULL)
panic("can not find more space for early_res array");
new = __va(mem);
/* save the first one for own */
new[0].start = mem;
new[0].end = mem + size;
new[0].overlap_ok = 0;
/* copy old to new */
if (early_res == early_res_x) {
memcpy(&new[1], &early_res[0],
sizeof(struct early_res) * max_early_res);
memset(&new[max_early_res+1], 0,
sizeof(struct early_res) * (max_early_res - 1));
early_res_count++;
} else {
memcpy(&new[1], &early_res[1],
sizeof(struct early_res) * (max_early_res - 1));
memset(&new[max_early_res], 0,
sizeof(struct early_res) * max_early_res);
}
memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
early_res = new;
max_early_res *= 2;
printk(KERN_DEBUG "early_res array is doubled to %d at [%llx - %llx]\n",
max_early_res, mem, mem + size - 1);
}
/*
* Most early reservations come here.
*
* We first have drop_overlaps_that_are_ok() drop any pre-existing
* 'overlap_ok' ranges, so that we can then reserve this memory
* range without risk of panic'ing on an overlapping overlap_ok
* early reservation.
*/
void __init reserve_early(u64 start, u64 end, char *name)
{
if (start >= end)
return;
__check_and_double_early_res(start, end);
drop_overlaps_that_are_ok(start, end);
__reserve_early(start, end, name, 0);
}
void __init reserve_early_without_check(u64 start, u64 end, char *name)
{
struct early_res *r;
if (start >= end)
return;
__check_and_double_early_res(start, end);
r = &early_res[early_res_count];
r->start = start;
r->end = end;
r->overlap_ok = 0;
if (name)
strncpy(r->name, name, sizeof(r->name) - 1);
early_res_count++;
}
void __init free_early(u64 start, u64 end)
{
struct early_res *r;
int i;
i = find_overlapped_early(start, end);
r = &early_res[i];
if (i >= max_early_res || r->end != end || r->start != start)
panic("free_early on not reserved area: %llx-%llx!",
start, end - 1);
drop_range(i);
}
void __init free_early_partial(u64 start, u64 end)
{
struct early_res *r;
int i;
if (start == end)
return;
if (WARN_ONCE(start > end, " wrong range [%#llx, %#llx]\n", start, end))
return;
try_next:
i = find_overlapped_early(start, end);
if (i >= max_early_res)
return;
r = &early_res[i];
/* hole ? */
if (r->end >= end && r->start <= start) {
drop_range_partial(i, start, end);
return;
}
drop_range_partial(i, start, end);
goto try_next;
}
#ifdef CONFIG_NO_BOOTMEM
static void __init subtract_early_res(struct range *range, int az)
{
int i, count;
u64 final_start, final_end;
int idx = 0;
count = 0;
for (i = 0; i < max_early_res && early_res[i].end; i++)
count++;
/* need to skip first one ?*/
if (early_res != early_res_x)
idx = 1;
#define DEBUG_PRINT_EARLY_RES 1
#if DEBUG_PRINT_EARLY_RES
printk(KERN_INFO "Subtract (%d early reservations)\n", count);
#endif
for (i = idx; i < count; i++) {
struct early_res *r = &early_res[i];
#if DEBUG_PRINT_EARLY_RES
printk(KERN_INFO " #%d [%010llx - %010llx] %15s\n", i,
r->start, r->end, r->name);
#endif
final_start = PFN_DOWN(r->start);
final_end = PFN_UP(r->end);
if (final_start >= final_end)
continue;
subtract_range(range, az, final_start, final_end);
}
}
int __init get_free_all_memory_range(struct range **rangep, int nodeid)
{
int i, count;
u64 start = 0, end;
u64 size;
u64 mem;
struct range *range;
int nr_range;
count = 0;
for (i = 0; i < max_early_res && early_res[i].end; i++)
count++;
count *= 2;
size = sizeof(struct range) * count;
end = get_max_mapped();
#ifdef MAX_DMA32_PFN
if (end > (MAX_DMA32_PFN << PAGE_SHIFT))
start = MAX_DMA32_PFN << PAGE_SHIFT;
#endif
mem = find_fw_memmap_area(start, end, size, sizeof(struct range));
if (mem == -1ULL)
panic("can not find more space for range free");
range = __va(mem);
/* use early_node_map[] and early_res to get range array at first */
memset(range, 0, size);
nr_range = 0;
/* need to go over early_node_map to find out good range for node */
nr_range = add_from_early_node_map(range, count, nr_range, nodeid);
#ifdef CONFIG_X86_32
subtract_range(range, count, max_low_pfn, -1ULL);
#endif
subtract_early_res(range, count);
nr_range = clean_sort_range(range, count);
/* need to clear it ? */
if (nodeid == MAX_NUMNODES) {
memset(&early_res[0], 0,
sizeof(struct early_res) * max_early_res);
early_res = NULL;
max_early_res = 0;
}
*rangep = range;
return nr_range;
}
#else
void __init early_res_to_bootmem(u64 start, u64 end)
{
int i, count;
u64 final_start, final_end;
int idx = 0;
count = 0;
for (i = 0; i < max_early_res && early_res[i].end; i++)
count++;
/* need to skip first one ?*/
if (early_res != early_res_x)
idx = 1;
printk(KERN_INFO "(%d/%d early reservations) ==> bootmem [%010llx - %010llx]\n",
count - idx, max_early_res, start, end);
for (i = idx; i < count; i++) {
struct early_res *r = &early_res[i];
printk(KERN_INFO " #%d [%010llx - %010llx] %16s", i,
r->start, r->end, r->name);
final_start = max(start, r->start);
final_end = min(end, r->end);
if (final_start >= final_end) {
printk(KERN_CONT "\n");
continue;
}
printk(KERN_CONT " ==> [%010llx - %010llx]\n",
final_start, final_end);
reserve_bootmem_generic(final_start, final_end - final_start,
BOOTMEM_DEFAULT);
}
/* clear them */
memset(&early_res[0], 0, sizeof(struct early_res) * max_early_res);
early_res = NULL;
max_early_res = 0;
early_res_count = 0;
}
#endif
/* Check for already reserved areas */
static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
{
int i;
u64 addr = *addrp;
int changed = 0;
struct early_res *r;
again:
i = find_overlapped_early(addr, addr + size);
r = &early_res[i];
if (i < max_early_res && r->end) {
*addrp = addr = round_up(r->end, align);
changed = 1;
goto again;
}
return changed;
}
/* Check for already reserved areas */
static inline int __init bad_addr_size(u64 *addrp, u64 *sizep, u64 align)
{
int i;
u64 addr = *addrp, last;
u64 size = *sizep;
int changed = 0;
again:
last = addr + size;
for (i = 0; i < max_early_res && early_res[i].end; i++) {
struct early_res *r = &early_res[i];
if (last > r->start && addr < r->start) {
size = r->start - addr;
changed = 1;
goto again;
}
if (last > r->end && addr < r->end) {
addr = round_up(r->end, align);
size = last - addr;
changed = 1;
goto again;
}
if (last <= r->end && addr >= r->start) {
(*sizep)++;
return 0;
}
}
if (changed) {
*addrp = addr;
*sizep = size;
}
return changed;
}
/*
* Find a free area with specified alignment in a specific range.
* only with the area.between start to end is active range from early_node_map
* so they are good as RAM
*/
u64 __init find_early_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
u64 size, u64 align)
{
u64 addr, last;
addr = round_up(ei_start, align);
if (addr < start)
addr = round_up(start, align);
if (addr >= ei_last)
goto out;
while (bad_addr(&addr, size, align) && addr+size <= ei_last)
;
last = addr + size;
if (last > ei_last)
goto out;
if (last > end)
goto out;
return addr;
out:
return -1ULL;
}
u64 __init find_early_area_size(u64 ei_start, u64 ei_last, u64 start,
u64 *sizep, u64 align)
{
u64 addr, last;
addr = round_up(ei_start, align);
if (addr < start)
addr = round_up(start, align);
if (addr >= ei_last)
goto out;
*sizep = ei_last - addr;
while (bad_addr_size(&addr, sizep, align) && addr + *sizep <= ei_last)
;
last = addr + *sizep;
if (last > ei_last)
goto out;
return addr;
out:
return -1ULL;
}