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authorTom Rini <trini@ti.com>2013-03-18 12:31:00 -0400
committerTom Rini <trini@ti.com>2013-03-18 14:37:18 -0400
commit0ce033d2582129243aca10d3072a221386bbba44 (patch)
tree6e50a3f4eed22007549dc740d0fa647a6c8cec5b /doc/README.commands
parentb5bec88434adb52413f1bc33fa63d7642cb8fd35 (diff)
parentb27673ccbd3d5435319b5c09c3e7061f559f925d (diff)
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Merge branch 'master' of git://git.denx.de/u-boot-arm
Albert's rework of the linker scripts conflicted with Simon's making everyone use __bss_end. We also had a minor conflict over README.scrapyard being added to in mainline and enhanced in u-boot-arm/master with proper formatting. Conflicts: arch/arm/cpu/ixp/u-boot.lds arch/arm/cpu/u-boot.lds arch/arm/lib/Makefile board/actux1/u-boot.lds board/actux2/u-boot.lds board/actux3/u-boot.lds board/dvlhost/u-boot.lds board/freescale/mx31ads/u-boot.lds doc/README.scrapyard include/configs/tegra-common.h Build tested for all of ARM and run-time tested on am335x_evm. Signed-off-by: Tom Rini <trini@ti.com>
Diffstat (limited to 'doc/README.commands')
-rw-r--r--doc/README.commands18
1 files changed, 8 insertions, 10 deletions
diff --git a/doc/README.commands b/doc/README.commands
index 923418b..9eb3671 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_list_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_list_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
3 lines:
.u_boot_list : {
- #include "u-boot.lst";
+ KEEP(*(SORT(.u_boot_list*)));
}