[bootlin/training-materials updates] master: embedded-linux: on stm32, don't load kernel right at start of RAM (ea17e44e)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/ea17e44ee872123092400052e53999bcf2411fd4

>---------------------------------------------------------------

commit ea17e44ee872123092400052e53999bcf2411fd4
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Fri Feb 17 16:45:57 2023 +0100

    embedded-linux: on stm32, don't load kernel right at start of RAM
    
    That's not recommended practise, as the compressed kernel would
    overlap with the uncompressed kernel, as explained on
    https://people.kernel.org/linusw/how-the-arm32-linux-kernel-decompresses
    
    As a consequence, the kernel bootstrap code has to make a copy of the
    compressed kernel far enough in RAM so there is no such overlap.
    
    Tests on stm32mp157a-dk1 show a 107 ms boot time reduction
    (observed consistently on 2 series of 5 tests).
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


>---------------------------------------------------------------

ea17e44ee872123092400052e53999bcf2411fd4
 common/embedded-linux-labs-vars.tex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/common/embedded-linux-labs-vars.tex b/common/embedded-linux-labs-vars.tex
index f0270fbb..aeb9fe86 100644
--- a/common/embedded-linux-labs-vars.tex
+++ b/common/embedded-linux-labs-vars.tex
@@ -3,7 +3,7 @@
 \def\labboard{stm32mp1}
 \newcommand*{\workingkernel}{5.15}
 \newcommand*{\labboarddescription}{STM32MP157D-DK1 Discovery kit}
-\newcommand*{\zimageboardaddr}{0xc0000000}
+\newcommand*{\zimageboardaddr}{0xc2000000}
 \newcommand*{\dtbboardaddr}{0xc4000000}
 \newcommand*{\dtname}{stm32mp157a-dk1}
 \newcommand*{\hosttty}{/dev/ttyACM0}