The linker script uses alphabetic sorting to group the different linker
lists together. Each group has its own struct and potentially its own
alignment. But when the linker packs the structs together it cannot ensure
that a linker list starts on the expected alignment boundary.
For example, if the first list has a struct size of 8 and we place 3 of
them in the image, that means that the next struct will start at offset
0x18 from the start of the linker_list section. If the next struct has
a size of 16 then it will start at an 8-byte aligned offset, but not a
16-byte aligned offset.
With sandbox on x86_64, a reference to a linker list item using
ll_entry_get() can force alignment of that particular linker_list item,
if it is in the same file as the linker_list item is declared.
Consider this example, where struct driver is 0x80 bytes:
ll_entry_declare(struct driver, fred, driver)
...
void *p = ll_entry_get(struct driver, fred, driver)
If these two lines of code are in the same file, then the entry is forced
to be aligned at the 'struct driver' alignment, which is 16 bytes. If the
second line of code is in a different file, then no action is taken, since
the compiler cannot update the alignment of the linker_list item.
In the first case, an 8-byte 'fill' region is added:
.u_boot_list_2_driver_2_testbus_drv
0x0000000000270018 0x80 test/built-in.o
0x0000000000270018 _u_boot_list_2_driver_2_testbus_drv
.u_boot_list_2_driver_2_testfdt1_drv
0x0000000000270098 0x80 test/built-in.o
0x0000000000270098 _u_boot_list_2_driver_2_testfdt1_drv
*fill* 0x0000000000270118 0x8
.u_boot_list_2_driver_2_testfdt_drv
0x0000000000270120 0x80 test/built-in.o
0x0000000000270120 _u_boot_list_2_driver_2_testfdt_drv
.u_boot_list_2_driver_2_testprobe_drv
0x00000000002701a0 0x80 test/built-in.o
0x00000000002701a0 _u_boot_list_2_driver_2_testprobe_drv
With this, the linker_list no-longer works since items after testfdt1_drv
are not at the expected address.
Ideally we would have a way to tell gcc not to align structs in this way.
It is not clear how we could do this, and in any case it would require us
to adjust every struct used by the linker_list feature.
One possible fix is to force each separate linker_list to start on the
largest possible boundary that can be required by the compiler. However
that does not seem to work on x86_64, which uses 16-byte alignment in this
case but needs 32-byte alignment.
So add a Kconfig option to handle this. Set the default value to 4 so
as to avoid changing platforms that don't need it.
Update the ll_entry_start() accordingly.
Signed-off-by: Simon Glass <sjg@chromium.org>
This patch series adds support for ZFS listing and load to u-boot.
To Enable zfs ls and load commands, modify the board specific config file with
#define CONFIG_CMD_ZFS
Steps to test:
1. After applying the patch, zfs specific commands can be seen
in the boot loader prompt using
UBOOT #help
zfsload- load binary file from a ZFS file system
zfsls - list files in a directory (default /)
2. To list the files in zfs pool, device or partition, execute
zfsls <interface> <dev[:part]> [POOL/@/dir/file]
For example:
UBOOT #zfsls mmc 0:5 /rpool/@/usr/bin/
3. To read and load a file from an ZFS formatted partition to RAM, execute
zfsload <interface> <dev[:part]> [addr] [filename] [bytes]
For example:
UBOOT #zfsload mmc 2:2 0x30007fc0 /rpool/@/boot/uImage
References :
-- ZFS GRUB sources from Solaris GRUB-0.97
-- GRUB Bazaar repository
Jorgen Lundman <lundman at lundman.net> 2012.
0b2fa98aa5