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Code Issues Releases Activity

powerpc64: Avoid overwriting initrd area

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Currently kexec loads an initrd file into the main memory but does not
mark that region as reserved, thus the area is not protected.

If any initrd/md file is loaded from kexec/petitboot, the region might become
corarupted/overwritten since FreeBSD does not know the region is 'reserved'.

This patch simply adds the initrd area as a reserved memory region.

Approved by: jhibbits
Differential Revision: https://reviews.freebsd.org/D15610
This commit is contained in:
Breno Leitao 2018-06-01 12:43:13 +00:00
parent 57a865f808
commit 48f64992f2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=334485
1 changed files with 77 additions and 36 deletions
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113
sys/powerpc/ofw/ofw_machdep.c
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@ -225,41 +225,19 @@ parse_ofw_memory(phandle_t node, const char *prop, struct mem_region *output)
#ifdef FDT
static int
excise_fdt_reserved(struct mem_region *avail, int asz)
excise_reserved_regions(struct mem_region *avail, int asz,
struct mem_region *exclude, int esz)
{
struct {
uint64_t address;
uint64_t size;
} fdtmap[32];
ssize_t fdtmapsize;
phandle_t chosen;
int i, j, k;
chosen = OF_finddevice("/chosen");
fdtmapsize = OF_getprop(chosen, "fdtmemreserv", fdtmap, sizeof(fdtmap));
for (j = 0; j < fdtmapsize/sizeof(fdtmap[0]); j++) {
fdtmap[j].address = be64toh(fdtmap[j].address) & ~PAGE_MASK;
fdtmap[j].size = round_page(be64toh(fdtmap[j].size));
}
KASSERT(j*sizeof(fdtmap[0]) < sizeof(fdtmap),
("Exceeded number of FDT reservations"));
/* Add a virtual entry for the FDT itself */
if (fdt != NULL) {
fdtmap[j].address = (vm_offset_t)fdt & ~PAGE_MASK;
fdtmap[j].size = round_page(fdt_totalsize(fdt));
fdtmapsize += sizeof(fdtmap[0]);
}
for (i = 0; i < asz; i++) {
for (j = 0; j < fdtmapsize/sizeof(fdtmap[0]); j++) {
for (j = 0; j < esz; j++) {
/*
* Case 1: Exclusion region encloses complete
* available entry. Drop it and move on.
*/
if (fdtmap[j].address <= avail[i].mr_start &&
fdtmap[j].address + fdtmap[j].size >=
if (exclude[j].mr_start <= avail[i].mr_start &&
exclude[j].mr_start + exclude[j].mr_size >=
avail[i].mr_start + avail[i].mr_size) {
for (k = i+1; k < asz; k++)
avail[k-1] = avail[k];
@ -274,20 +252,20 @@ excise_fdt_reserved(struct mem_region *avail, int asz)
* a new available entry with the region after
* the excluded region, if any.
*/
if (fdtmap[j].address >= avail[i].mr_start &&
fdtmap[j].address < avail[i].mr_start +
if (exclude[j].mr_start >= avail[i].mr_start &&
exclude[j].mr_start < avail[i].mr_start +
avail[i].mr_size) {
if (fdtmap[j].address + fdtmap[j].size <
if (exclude[j].mr_start + exclude[j].mr_size <
avail[i].mr_start + avail[i].mr_size) {
avail[asz].mr_start =
fdtmap[j].address + fdtmap[j].size;
exclude[j].mr_start + exclude[j].mr_size;
avail[asz].mr_size = avail[i].mr_start +
avail[i].mr_size -
avail[asz].mr_start;
asz++;
}
avail[i].mr_size = fdtmap[j].address -
avail[i].mr_size = exclude[j].mr_start -
avail[i].mr_start;
}
@ -297,13 +275,13 @@ excise_fdt_reserved(struct mem_region *avail, int asz)
* The case of a contained exclusion zone has already
* been caught in case 2.
*/
if (fdtmap[j].address + fdtmap[j].size >=
avail[i].mr_start && fdtmap[j].address +
fdtmap[j].size < avail[i].mr_start +
if (exclude[j].mr_start + exclude[j].mr_size >=
avail[i].mr_start && exclude[j].mr_start +
exclude[j].mr_size < avail[i].mr_start +
avail[i].mr_size) {
avail[i].mr_size += avail[i].mr_start;
avail[i].mr_start =
fdtmap[j].address + fdtmap[j].size;
exclude[j].mr_start + exclude[j].mr_size;
avail[i].mr_size -= avail[i].mr_start;
}
}
@ -311,6 +289,62 @@ excise_fdt_reserved(struct mem_region *avail, int asz)
return (asz);
}
static int
excise_initrd_region(struct mem_region *avail, int asz)
{
phandle_t chosen;
uint64_t start, end;
ssize_t size;
struct mem_region initrdmap[1];
chosen = OF_finddevice("/chosen");
size = OF_getprop(chosen, "linux,initrd-start", &start, sizeof(start));
if (size <= 0)
return (asz);
size = OF_getprop(chosen, "linux,initrd-end", &end, sizeof(end));
if (size <= 0)
return (asz);
initrdmap[0].mr_start = start;
initrdmap[0].mr_size = end - start;
asz = excise_reserved_regions(avail, asz, initrdmap, 1);
return (asz);
}
static int
excise_fdt_reserved(struct mem_region *avail, int asz)
{
struct mem_region fdtmap[32];
ssize_t fdtmapsize;
phandle_t chosen;
int j, fdtentries;
chosen = OF_finddevice("/chosen");
fdtmapsize = OF_getprop(chosen, "fdtmemreserv", fdtmap, sizeof(fdtmap));
for (j = 0; j < fdtmapsize/sizeof(fdtmap[0]); j++) {
fdtmap[j].mr_start = be64toh(fdtmap[j].mr_start) & ~PAGE_MASK;
fdtmap[j].mr_size = round_page(be64toh(fdtmap[j].mr_size));
}
KASSERT(j*sizeof(fdtmap[0]) < sizeof(fdtmap),
("Exceeded number of FDT reservations"));
/* Add a virtual entry for the FDT itself */
if (fdt != NULL) {
fdtmap[j].mr_start = (vm_offset_t)fdt & ~PAGE_MASK;
fdtmap[j].mr_size = round_page(fdt_totalsize(fdt));
fdtmapsize += sizeof(fdtmap[0]);
}
fdtentries = fdtmapsize/sizeof(fdtmap[0]);
asz = excise_reserved_regions(avail, asz, fdtmap, fdtentries);
return (asz);
}
#endif
/*
@ -364,6 +398,13 @@ ofw_mem_regions(struct mem_region *memp, int *memsz,
phandle = OF_finddevice("/chosen");
if (OF_hasprop(phandle, "fdtmemreserv"))
asz = excise_fdt_reserved(availp, asz);
/* If the kernel is being loaded through kexec, initrd region is listed
* in /chosen but the region is not marked as reserved, so, we might exclude
* it here.
*/
if (OF_hasprop(phandle, "linux,initrd-start"))
asz = excise_initrd_region(availp, asz);
#endif
*memsz = msz;