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/*
* 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;
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