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efi: prefer plan9.ini from ESP we loaded from

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currently the EFI loader's behavior is to search all disks in a
firmware-defined order.  we search the list returned by the firmware
in reverse order in the hopes of searching the first 9FAT instead of
the ESP, but this results in unintuitive behavior when there are
multiple FAT partitions (possibly in multiple disks), such as loading
a plan9.ini and kernel from a different disk than the one you executed
the EFI loader from.

to resolve this, we change the EFI loader to instead prefer read
plan9.ini and the kernel from the same disk as the EFI loader was read
from, and then fall back to the old behavior, since the old behavior
is relied on by current installations.
This commit is contained in:
mischief 2020-11-21 14:18:52 -08:00
parent ad9b1234c3
commit 486ce60546
3 changed files with 51 additions and 3 deletions
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16
sys/src/boot/efi/efi.h
View file

@ -48,6 +48,22 @@ typedef struct {
void *Mode;
} EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL;
typedef struct {
UINT32 Revision;
EFI_HANDLE ParentHandle;
void *SystemTable;
EFI_HANDLE DeviceHandle;
void *FilePath;
void *Reserved;
UINT32 LoadOptionsSize;
void *LoadOptions;
void *ImageBase;
UINT64 ImageSize;
UINT32 ImageCodeType;
UINT32 ImageDataType;
void *Unload;
} EFI_LOADED_IMAGE_PROTOCOL;
typedef struct {
UINT32 RedMask;
UINT32 GreenMask;

32
sys/src/boot/efi/fs.c
View file

@ -32,6 +32,12 @@ EFI_GUID EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID = {
0xc9, 0x69, 0x72, 0x3b,
};
static EFI_GUID EFI_LOADED_IMAGE_PROTOCOL_GUID = {
0x5b1b31a1, 0x9562, 0x11d2,
0x8e, 0x3f, 0x00, 0xa0,
0xc9, 0x69, 0x72, 0x3b,
};
static
EFI_FILE_PROTOCOL *fsroot;
@ -87,12 +93,37 @@ int
fsinit(void **pf)
{
EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *fs;
EFI_LOADED_IMAGE_PROTOCOL *image;
EFI_FILE_PROTOCOL *root;
EFI_HANDLE *Handles;
void *f;
UINTN Count;
int i;
image = nil;
/* locate kernel and plan9.ini by deriving a fs protocol
* from the device the loader was read from.
* if that fails, fall back to old method.
*/
if(eficall(ST->BootServices->HandleProtocol, IH,
&EFI_LOADED_IMAGE_PROTOCOL_GUID, &image) == 0 &&
eficall(ST->BootServices->HandleProtocol, image->DeviceHandle,
&EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID, &fs) == 0 &&
eficall(fs->OpenVolume, fs, &root) == 0){
fsroot = root;
f = fsopen("/plan9.ini");
if(f != nil){
if(pf != nil)
*pf = f;
else
fsclose(f);
goto gotit;
}
}
Count = 0;
Handles = nil;
if(eficall(ST->BootServices->LocateHandleBuffer,
@ -126,6 +157,7 @@ fsinit(void **pf)
if(fsroot == nil)
return -1;
gotit:
read = fsread;
close = fsclose;
open = fsopen;

6
sys/src/boot/efi/iso.c
View file

@ -62,7 +62,7 @@ typedef struct {
} EFI_BLOCK_IO_PROTOCOL;
static EFI_GUID
EFI_BLOCK_IO_PROTOCO_GUID = {
EFI_BLOCK_IO_PROTOCOL_GUID = {
0x964e5b21, 0x6459, 0x11d2,
0x8e, 0x39, 0x00, 0xa0,
0xc9, 0x69, 0x72, 0x3b,
@ -191,13 +191,13 @@ isoinit(void **fp)
Count = 0;
Handles = nil;
if(eficall(ST->BootServices->LocateHandleBuffer,
ByProtocol, &EFI_BLOCK_IO_PROTOCO_GUID, nil, &Count, &Handles))
ByProtocol, &EFI_BLOCK_IO_PROTOCOL_GUID, nil, &Count, &Handles))
return -1;
for(i=0; i<Count; i++){
bio = nil;
if(eficall(ST->BootServices->HandleProtocol,
Handles[i], &EFI_BLOCK_IO_PROTOCO_GUID, &bio))
Handles[i], &EFI_BLOCK_IO_PROTOCOL_GUID, &bio))
continue;
media = bio->Media;