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Teach ufs_module.c about bsd labels and probe 'a' partition.

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If the check for a UFS partition at offset 0 on the disk fails, check
to see if there's a BSD disklabel at block 1 (standard) or at offset
512 (install images assume 512 sector size). If found, probe for UFS
on the 'a' partition.

This fixes UEFI booting images from a BSD labeled MBR slice when the
'a' partiton isn't at offset 0. This is a stop-gap fix since we plan
on removing boot1.efi in FreeBSD 12. We can't easily do that for 11.2,
however, hence the short MFC window.

Tested by: emaste@
MFC After: 3 days
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D15598
This commit is contained in:
Warner Losh 2018-05-29 03:58:29 +00:00
parent 23d2383783
commit 9958932695
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=334310
2 changed files with 46 additions and 1 deletions
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1
stand/efi/boot1/boot_module.h
View File

@ -50,6 +50,7 @@ typedef struct dev_info
EFI_DEVICE_PATH *devpath;
EFI_HANDLE *devhandle;
void *devdata;
uint64_t partoff;
BOOLEAN preferred;
struct dev_info *next;
} dev_info_t;

46
stand/efi/boot1/ufs_module.c
View File

@ -36,10 +36,14 @@
#include <stdbool.h>
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/disk/bsd.h>
#include <efi.h>
#include "boot_module.h"
#define BSD_LABEL_BUFFER 8192
#define BSD_LABEL_OFFSET DEV_BSIZE
static dev_info_t *devinfo;
static dev_info_t *devices;
@ -49,6 +53,7 @@ dskread(void *buf, uint64_t lba, int nblk)
int size;
EFI_STATUS status;
lba += devinfo->partoff;
lba = lba / (devinfo->dev->Media->BlockSize / DEV_BSIZE);
size = nblk * DEV_BSIZE;
@ -73,11 +78,50 @@ static struct dmadat __dmadat;
static int
init_dev(dev_info_t* dev)
{
char buffer[BSD_LABEL_BUFFER];
struct disklabel *dl;
uint64_t bs;
int ok;
devinfo = dev;
dmadat = &__dmadat;
return fsread(0, NULL, 0);
/*
* First try offset 0. This is the typical GPT case where we have no
* further partitioning (as well as the degenerate MBR case where
* the bsdlabel has a 0 offset).
*/
devinfo->partoff = 0;
ok = fsread(0, NULL, 0);
if (ok >= 0)
return (ok);
/*
* Next, we look for a bsdlabel. This is technically located in sector
* 1. For 4k sectors, this offset is 4096, for 512b sectors it's
* 512. However, we have to fall back to 512 here because we create
* images that assume 512 byte blocks, but these can be put on devices
* who have 4k (or other) block sizes. If there's a crazy block size, we
* skip the 'at one sector' and go stright to checking at 512 bytes.
* There are other offsets that are historic, but we don't probe those
* since they were never used for MBR disks on FreeBSD on systems that
* could boot UEFI. UEFI is little endian only, as are BSD labels. We
* will retry fsread(0) only if there's a label found with a non-zero
* offset.
*/
if (dskread(buffer, 0, BSD_LABEL_BUFFER / DEV_BSIZE) != 0)
return (-1);
dl = NULL;
bs = devinfo->dev->Media->BlockSize;
if (bs != 0 && bs <= BSD_LABEL_BUFFER / 2)
dl = (struct disklabel *)&buffer[bs];
if (dl == NULL || dl->d_magic != BSD_MAGIC || dl->d_magic2 != BSD_MAGIC)
dl = (struct disklabel *)&buffer[BSD_LABEL_OFFSET];
if (dl->d_magic != BSD_MAGIC || dl->d_magic2 != BSD_MAGIC ||
dl->d_partitions[0].p_offset == 0)
return (-1);
devinfo->partoff = dl->d_partitions[0].p_offset;
return (fsread(0, NULL, 0));
}
static EFI_STATUS