Hi Alexey, On 20 January 2015 at 06:06, Alexey Brodkin <alexey.brod...@synopsys.com> wrote: > 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.
This should be done before board_init_f(). See for example this patch: http://patchwork.ozlabs.org/patch/421210/ There is no need for it to be SOC- or even arch-specific. We can clean this up fairly soon. But we should not set up global_data in board_init_f(). This is a hang-over from previous code. It needs to be removed. Perhaps in addition to my comments above you could add a comment that the code at the top of board_init_f() is deprecated and will soon be removed? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
