Hi Albert, On Tue, 2015-01-20 at 08:07 +0100, Albert ARIBAUD wrote: > Hello Alexey, > > On Mon, 19 Jan 2015 20:55:03 +0300, Alexey Brodkin > <alexey.brod...@synopsys.com> wrote: > > In case of CONFIG_SYS_MALLOC_F_LEN "malloc_base" is used for early > > start-up code and is set very early, typically in "start.S" or "crt1.S". > > There is no "crt1.S" in U-Boot. Did you mean "crt0.S"?
Indeed I meant "crt0.S" > > In current implementation in case of CONFIG_SYS_GENERIC_GLOBAL_DATA all > > global data gets zeroed on "board_init_f" entry. But by that time > > "malloc_base" could have been set already, which means it will be zeroed > > and subsequent C-code will be executed improperly (if executed at all - > > if there's no memory mapped to 0 or it is read-only then on some arches > > there will be an exception and others will quetly die). > > > > To work-around described situation we just need to make sure > > "malloc_base" is saved prior zeroing global data and recovered > > afterwards. > > Keeping data from being zeroed etc is usually done through GD. Could > malloc_base be placed there instead of creating a specific exemption > for it? Unfortunately I didn't understand your suggestion here. "malloc_base" is already in global data structure. But the point is global data structure also requires zeroing sometime on early start-up. This is required to make sure we don't have any garbage in GD (for example left-overs from lower-level bootloader or previously executed kernel etc). So other option is to zero GD earlier in start-up code. This is essentially doable but it will be done on per-architecture or even per-CPU basis in their "start.S" - which means we'll have duplication of the same functionality and maintenance will be difficult then. Probably I just didn't get you point so then could you please clarify what did you mean. -Alexey _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
