linux/kernel/range.c
Yinghai Lu fbe06b7bae x86, range: fix missing merge during add range
Christian found v3.9 does not work with E350 with EFI is enabled.

[    1.658832] Trying to unpack rootfs image as initramfs...
[    1.679935] BUG: unable to handle kernel paging request at ffff88006e3fd000
[    1.686940] IP: [<ffffffff813661df>] memset+0x1f/0xb0
[    1.692010] PGD 1f77067 PUD 1f7a067 PMD 61420067 PTE 0

but early memtest report all memory could be accessed without problem.

early page table is set in following sequence:
[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
[    0.000000] init_memory_mapping: [mem 0x6e600000-0x6e7fffff]
[    0.000000] init_memory_mapping: [mem 0x6c000000-0x6e5fffff]
[    0.000000] init_memory_mapping: [mem 0x00100000-0x6bffffff]
[    0.000000] init_memory_mapping: [mem 0x6e800000-0x6ea07fff]
but later efi_enter_virtual_mode try set mapping again wrongly.
[    0.010644] pid_max: default: 32768 minimum: 301
[    0.015302] init_memory_mapping: [mem 0x640c5000-0x6e3fcfff]
that means it fails with pfn_range_is_mapped.

It turns out that we have a bug in add_range_with_merge and it does not
merge range properly when new add one fill the hole between two exsiting
ranges. In the case when [mem 0x00100000-0x6bffffff] is the hole between
[mem 0x00000000-0x000fffff] and [mem 0x6c000000-0x6e7fffff].

Fix the add_range_with_merge by calling itself recursively.

Reported-by: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/CAE9FiQVofGoSk7q5-0irjkBxemqK729cND4hov-1QCBJDhxpgQ@mail.gmail.com
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-05-17 11:49:10 -07:00

163 lines
3.0 KiB
C

/*
* Range add and subtract
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sort.h>
#include <linux/range.h>
int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
{
if (start >= end)
return nr_range;
/* Out of slots: */
if (nr_range >= az)
return nr_range;
range[nr_range].start = start;
range[nr_range].end = end;
nr_range++;
return nr_range;
}
int add_range_with_merge(struct range *range, int az, int nr_range,
u64 start, u64 end)
{
int i;
if (start >= end)
return nr_range;
/* Try to merge it with old one: */
for (i = 0; i < nr_range; i++) {
u64 final_start, final_end;
u64 common_start, common_end;
if (!range[i].end)
continue;
common_start = max(range[i].start, start);
common_end = min(range[i].end, end);
if (common_start > common_end)
continue;
final_start = min(range[i].start, start);
final_end = max(range[i].end, end);
/* clear it and add it back for further merge */
range[i].start = 0;
range[i].end = 0;
return add_range_with_merge(range, az, nr_range,
final_start, final_end);
}
/* Need to add it: */
return add_range(range, az, nr_range, start, end);
}
void subtract_range(struct range *range, int az, u64 start, u64 end)
{
int i, j;
if (start >= end)
return;
for (j = 0; j < az; j++) {
if (!range[j].end)
continue;
if (start <= range[j].start && end >= range[j].end) {
range[j].start = 0;
range[j].end = 0;
continue;
}
if (start <= range[j].start && end < range[j].end &&
range[j].start < end) {
range[j].start = end;
continue;
}
if (start > range[j].start && end >= range[j].end &&
range[j].end > start) {
range[j].end = start;
continue;
}
if (start > range[j].start && end < range[j].end) {
/* Find the new spare: */
for (i = 0; i < az; i++) {
if (range[i].end == 0)
break;
}
if (i < az) {
range[i].end = range[j].end;
range[i].start = end;
} else {
pr_err("%s: run out of slot in ranges\n",
__func__);
}
range[j].end = start;
continue;
}
}
}
static int cmp_range(const void *x1, const void *x2)
{
const struct range *r1 = x1;
const struct range *r2 = x2;
s64 start1, start2;
start1 = r1->start;
start2 = r2->start;
return start1 - start2;
}
int clean_sort_range(struct range *range, int az)
{
int i, j, k = az - 1, nr_range = az;
for (i = 0; i < k; i++) {
if (range[i].end)
continue;
for (j = k; j > i; j--) {
if (range[j].end) {
k = j;
break;
}
}
if (j == i)
break;
range[i].start = range[k].start;
range[i].end = range[k].end;
range[k].start = 0;
range[k].end = 0;
k--;
}
/* count it */
for (i = 0; i < az; i++) {
if (!range[i].end) {
nr_range = i;
break;
}
}
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
return nr_range;
}
void sort_range(struct range *range, int nr_range)
{
/* sort them */
sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
}