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author | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2013-02-25 00:59:00 +0000 |
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committer | Albert ARIBAUD <albert.u.boot@aribaud.net> | 2013-03-12 23:28:40 +0100 |
commit | ef123c525370463254a6f8e67563fdb0b0b46412 (patch) | |
tree | e4c49bfa2efe3608b5e65fc6a10f02176637ceea /doc | |
parent | 3ebd1cbc49f0005092d69cf0d9a6e64d7a1c300b (diff) | |
download | u-boot-imx-ef123c525370463254a6f8e67563fdb0b0b46412.zip u-boot-imx-ef123c525370463254a6f8e67563fdb0b0b46412.tar.gz u-boot-imx-ef123c525370463254a6f8e67563fdb0b0b46412.tar.bz2 |
Refactor linker-generated arrays
Refactor linker-generated array code so that symbols
which were previously linker-generated are now compiler-
generated. This causes relocation records of type
R_ARM_ABS32 to become R_ARM_RELATIVE, which makes
code which uses LGA able to run before relocation as
well as after.
Note: this affects more than ARM targets, as linker-
lists span possibly all target architectures, notably
PowerPC.
Conflicts:
arch/arm/cpu/arm926ejs/mxs/u-boot-spl.lds
arch/arm/cpu/arm926ejs/spear/u-boot-spl.lds
arch/arm/cpu/armv7/omap-common/u-boot-spl.lds
board/ait/cam_enc_4xx/u-boot-spl.lds
board/davinci/da8xxevm/u-boot-spl-da850evm.lds
board/davinci/da8xxevm/u-boot-spl-hawk.lds
board/vpac270/u-boot-spl.lds
Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/README.commands | 18 |
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*))); } |