[PATCH] Revert "arm: bootm: Disable LMB reservation for command line and board info on arm64"

Wolfgang Denk wd at denx.de
Mon Aug 9 08:44:58 CEST 2021


Dear Marek,

In message <03720507-5ea4-0fb9-0549-37df3128be2b at denx.de> you wrote:
>
> The IMX thing is odd indeed and raises a bigger question -- what is the 
> "right" amount of stack to reserve ?

In the original U-Boot design (which is still documented in the
README, see section "Memory Management", start reading at "typical
memory configuration") The stack was located below the lowest
reserved address range, so it could grow downward, only limited by
available memory size.  And yes, it was the responsibility of the
user to make sure not to overwrite it for example by loading images
at too high addresses or running "mw" with unsuitable address or
size.

What I want to point out is: there are probably a number of areas in
U-Boot which are based on this assumption, as reserving buffers or
the like on the stack is a much cheaper operation with much less
potential for memory leaks etc. than using malloc().

Any assumption that a stack size of 4 kB or 16 kB or such will be
sufficient is ... optimistic at best.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
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