Am 9. Januar 2021 22:23:01 MEZ schrieb Tom Rini trini@konsulko.com:
On Sat, Jan 09, 2021 at 08:59:01PM +0100, Heinrich Schuchardt wrote:
Am 9. Januar 2021 20:40:04 MEZ schrieb Tom Rini trini@konsulko.com:
On Sat, Jan 09, 2021 at 08:33:40PM +0100, Heinrich Schuchardt wrote:
On 1/9/21 7:58 PM, Tom Rini wrote:
On Sat, Jan 09, 2021 at 08:47:07PM +0200, Andy Shevchenko wrote:
On Sat, Jan 9, 2021 at 8:06 PM Heinrich Schuchardt
xypron.glpk@gmx.de wrote:
> > The comment for initrd_high in the coding and in README were
contradicting
> and neither fully described what the coding does. > > Clarify the usage of the special value ~0UL for the
environment
variable
> initrd_high.
All those F:s are hard to read in the comments and
documentation
and
typo prone. I would prefer to rephrase like "all 1:s value in
32-
or
64-bit format" or alike.
Who would understand that?
All 1s that is 111111111?
We need something a non-developer will grasp. Copying the exact value from the readme is the easiest thing to do and the least typo prone.
Best regards
Heinrich
If we're going to improve this we should also note it's
discouraged
unless you know for certain there will be no overlap and it's
strongly
discouraged in default environments.
What exactly is discouraged?
- setting initrd_high to a value != ~0? Here I would agree.
- setting intird_high to ~0? Why should we copy initrd to a different place? Is it for some outdated Linux release?
We should always default to allowing the initrd to be relocated
because
we can see (in many cases) overlap that will lead to failure to boot but this forces us to ignore that. Having good default load values
means
we don't have a problem here.
We have an initrd that is already in memory. What could it overlap with that is not already overwritten?
Having the kernel and initrd too close in memory has the kernel BSS overwrite the initrd. This has happened time and time again before I went around making some platforms have reasonable (ie kernel early, ramdisk in lowmem but beyond where a kernel+bss can be, etc) defaults and pushing others to do the same.
Can you provide the text you want to see here?
Off-hand, it should look more like the big comment block in include/configs/ti_armv7_common.h and reference the Linux booting on arm/arm64 documents while noting that other architectures have the same fundamental issues and their exact limits may or may not be as well documented.