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EFIRT: SetVirtualAddressMap with 1:1 mapping after exiting boot services

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This fixes a problem encountered on the Lenovo Thinkpad X220/Yoga 11e where
runtime services would try to inexplicably jump to other parts of memory
where it shouldn't be when attempting to enumerate EFI vars, causing a
panic.

The virtual mapping is enabled by default and can be disabled by setting
efi_disable_vmap in loader.conf(5).

Reviewed by:	kib (earlier version)
MFC after:	3 weeks
Differential Revision:	https://reviews.freebsd.org/D14677
This commit is contained in:
Kyle Evans 2018-03-13 17:10:52 +00:00
parent a95659f75f
commit 63ee68c220
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=330868
3 changed files with 45 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
stand/efi/loader/bootinfo.c
View File

@ -236,17 +236,48 @@ bi_copymodules(vm_offset_t addr)
return(addr);
}
static EFI_STATUS
efi_do_vmap(EFI_MEMORY_DESCRIPTOR *mm, UINTN sz, UINTN mmsz, UINT32 mmver)
{
EFI_MEMORY_DESCRIPTOR *desc, *viter, *vmap;
EFI_STATUS ret;
int curr, ndesc, nset;
nset = 0;
desc = mm;
ndesc = sz / mmsz;
vmap = malloc(sz);
if (vmap == NULL)
/* This isn't really an EFI error case, but pretend it is */
return (EFI_OUT_OF_RESOURCES);
viter = vmap;
for (curr = 0; curr < ndesc;
curr++, desc = NextMemoryDescriptor(desc, mmsz)) {
if ((desc->Attribute & EFI_MEMORY_RUNTIME) != 0) {
++nset;
desc->VirtualStart = desc->PhysicalStart;
*viter = *desc;
viter = NextMemoryDescriptor(viter, mmsz);
}
}
ret = RS->SetVirtualAddressMap(nset * mmsz, mmsz, mmver, vmap);
free(vmap);
return (ret);
}
static int
bi_load_efi_data(struct preloaded_file *kfp)
{
EFI_MEMORY_DESCRIPTOR *mm;
EFI_PHYSICAL_ADDRESS addr;
EFI_STATUS status;
const char *efi_novmap;
size_t efisz;
UINTN efi_mapkey;
UINTN mmsz, pages, retry, sz;
UINT32 mmver;
struct efi_map_header *efihdr;
bool do_vmap;
#if defined(__amd64__) || defined(__aarch64__)
struct efi_fb efifb;
@ -266,6 +297,11 @@ bi_load_efi_data(struct preloaded_file *kfp)
}
#endif
do_vmap = true;
efi_novmap = getenv("efi_disable_vmap");
if (efi_novmap != NULL)
do_vmap = strcasecmp(efi_novmap, "YES") != 0;
efisz = (sizeof(struct efi_map_header) + 0xf) & ~0xf;
/*
@ -321,6 +357,13 @@ bi_load_efi_data(struct preloaded_file *kfp)
}
status = BS->ExitBootServices(IH, efi_mapkey);
if (EFI_ERROR(status) == 0) {
/*
* This may be disabled by setting efi_disable_vmap in
* loader.conf(5). By default we will setup the virtual
* map entries.
*/
if (do_vmap)
efi_do_vmap(mm, sz, mmsz, mmver);
efihdr->memory_size = sz;
efihdr->descriptor_size = mmsz;
efihdr->descriptor_version = mmver;

2
sys/amd64/amd64/efirt_machdep.c
View File

@ -165,7 +165,7 @@ efi_create_1t1_map(struct efi_md *map, int ndesc, int descsz)
descsz)) {
if ((p->md_attr & EFI_MD_ATTR_RT) == 0)
continue;
if (p->md_virt != NULL) {
if (p->md_virt != NULL && (uint64_t)p->md_virt != p->md_phys) {
if (bootverbose)
printf("EFI Runtime entry %d is mapped\n", i);
goto fail;

2
sys/arm64/arm64/efirt_machdep.c
View File

@ -169,7 +169,7 @@ efi_create_1t1_map(struct efi_md *map, int ndesc, int descsz)
descsz)) {
if ((p->md_attr & EFI_MD_ATTR_RT) == 0)
continue;
if (p->md_virt != NULL) {
if (p->md_virt != NULL && (uint64_t)p->md_virt != p->md_phys) {
if (bootverbose)
printf("EFI Runtime entry %d is mapped\n", i);
goto fail;