Hello,
most SPARC BSPs use current the following linker provided symbols to specify
the memory layout:
_PROM_SIZE = DEFINED (_PROM_SIZE) ? _PROM_SIZE : 2M;
_PROM_START = DEFINED (_PROM_START) ? _PROM_START : 0x00000000;
_RAM_SIZE = DEFINED (_RAM_SIZE) ? _RAM_SIZE : 4M;
_RAM_START = DEFINED (_RAM_START) ? _RAM_START : 0x40000000;
So it is possible to define them as command line parameters. There are two
problems with this approach.
Firstly start address must be consistent with the memory area definition. Due
to this reason the NGMP linker command file looks like this:
_PROM_SIZE = DEFINED (_PROM_SIZE) ? _PROM_SIZE : 0;
_RAM_SIZE = DEFINED (_RAM_SIZE) ? _RAM_SIZE : 64M;
MEMORY {
rom : ORIGIN = 0xC0000000, LENGTH = 256M
ram : ORIGIN = 0x00000000, LENGTH = 2048M
sram : ORIGIN = 0xD0000000, LENGTH = 256M
}
_PROM_START = ORIGIN (rom);
_RAM_START = ORIGIN (ram);
INCLUDE linkcmds.base
Secondly the size symbols don't allow region overflow checks by the linker.
A better approach would be to remove the ability to define these symbols on the
command line and use a memory map definition via memory regions only. For the
NGMP as an example this would look like:
MEMORY {
rom : ORIGIN = 0xC0000000, LENGTH = 8M
ram : ORIGIN = 0x00000000, LENGTH = 64M
}
INCLUDE linkcmds.base
This change makes it necessary to adopt user Makefiles to this new approach.
--
Sebastian Huber, embedded brains GmbH
Address : Dornierstr. 4, D-82178 Puchheim, Germany
Phone : +49 89 189 47 41-16
Fax : +49 89 189 47 41-09
E-Mail : sebastian.hu...@embedded-brains.de
PGP : Public key available on request.
Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
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