The boot_fdt_add_mem_rsv_regions() function can be called twice, e.g.
first time during the board init (as a part of LMB init), and then when
booting the OS with 'booti' command:
lmb_add_region_flags
lmb_reserve_flags
boot_fdt_reserve_region
boot_fdt_add_mem_rsv_regions
^
|
+-----------------------+
| (1) | (2)
lmb_reserve_common image_setup_linux
lmb_init ...
initr_lmb do_booti
board_init_r 'booti'
That consequently leads to the attempt of reserving the same memory
areas (described in the 'reserved-memory' dts node) in LMB. The
lmb_add_region_flags() returns -EEXIST error code in such cases, but
boot_fdt_reserve_region() handles all negative error codes as a failure
to reserve fdt memory region, printing corresponding error messages,
which are essentially harmless, but misleading. For example, this is the
output of 'booti' command on E850-96 board:
=> booti $loadaddr - $fdtaddr
...
ERROR: reserving fdt memory region failed
(addr=bab00000 size=5500000 flags=2)
ERROR: reserving fdt memory region failed
(addr=f0000000 size=200000 flags=4)
...
Starting kernel ...
The mentioned false positive error messages are observed starting with
commit 1d9aa4a283 ("lmb: Fix the allocation of overlapping memory
areas with !LMB_NONE"), which removes the check for the already added
memory regions in lmb_add_region_flags(), making it return -1 for
!LMB_NONE cases. Another commit 827dee587b ("fdt: lmb: add reserved
regions as no-overwrite") changes flags used for reserving memory in
boot_fdt_add_mem_rsv_regions() from LMB_NONE to LMB_NOOVERWRITE. So
together with the patch mentioned earlier, it makes
lmb_add_region_flags() return -1 when called from
boot_fdt_reserve_region().
Since then, the different patch was implemented, returning -EEXIST error
code in described cases, which is:
lmb: Return -EEXIST in lmb_add_region_flags() if region already added
Handle -EEXIST error code as a normal (successful) case in
lmb_reserve_flags() and don't print any messages.
Fixes: 1d9aa4a283 ("lmb: Fix the allocation of overlapping memory areas with !LMB_NONE")
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Michal Simek <michal.simek@amd.com>
5a6aa7d591