X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=doc%2FREADME.commands;h=afd5577b0a9ce66b86c52f7cae595eb7d914e556;hb=f85764cc1f6ab01ffc60dd78de9c4de4cff2b5ce;hp=125f077c08ffc03f7cf549e6c54480e3a6a41b87;hpb=cec2655c3b3b86f14a6a5c2cbb01833f7e3974be;p=u-boot diff --git a/doc/README.commands b/doc/README.commands index 125f077c08..afd5577b0a 100644 --- a/doc/README.commands +++ b/doc/README.commands @@ -15,24 +15,22 @@ help: Long description. This is a string **** Behind the scene ****** -The structure created is named with a special prefix (__u_boot_cmd_) -and placed by the linker in a special section. +The structure created is named with a special prefix and placed by +the linker in a special section using the linker lists mechanism +(see include/linker_lists.h) This makes it possible for the final link to extract all commands compiled into any object code and construct a static array so the -command can be found in an array starting at __u_boot_cmd_start. +command array can be iterated over using the linker lists macros. -To ensure that the linker does not discard these symbols when linking -full U-Boot we generate a list of all the commands we have built (based -on the sections mentioned above) and use that to force the linker to -first enter the symbol as undefined in the output object so that there -is then a need for the symbol to be kept (this is the UNDEF_SYM logic in -the Makefile). +The linker lists feature ensures that the linker does not discard +these symbols when linking full U-Boot even though they are not +referenced in the source code as such. If a new board is defined do not forget to define the command section -by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these +by writing in u-boot.lds ($(srctree)/board/boardname/u-boot.lds) these 3 lines: - __u_boot_cmd_start = .; - .u_boot_cmd : { *(.u_boot_cmd) } - __u_boot_cmd_end = .; + .u_boot_list : { + KEEP(*(SORT(.u_boot_list*))); + }