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| author | Bin Meng <bmeng.cn@gmail.com> | 2019-07-23 21:29:58 -0700 |
|---|---|---|
| committer | Anup Patel <anup.patel@wdc.com> | 2019-07-25 09:11:49 +0530 |
| commit | c90009aa2087eb690e6cb6e7d6d73e3c63de87c3 (patch) | |
| tree | de365262d6fdb4f71423ca660ce4fb412f28b995 | |
| parent | bf2ee7bcdc9b94aa4c62f197adeb71bab20bcfa3 (diff) | |
README: Document 32-bit / 64-bit images build
At present the exact details of building 32-bit or 64-bit OpenSBI
images are missing in the docs. This adds the missing part.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Acked-by: Anup Patel <anup.patel@wdc.com>
| -rw-r--r-- | README.md | 19 |
1 files changed, 19 insertions, 0 deletions
@@ -131,6 +131,25 @@ top-level make command line. These options, such as *PLATFORM_<xyz>* or *docs/platform/<platform_name>.md* files and *docs/firmware/<firmware_name>.md* files. +Building 32-bit / 64-bit OpenSBI Images +--------------------------------------- +By default, building OpenSBI generates 32-bit or 64-bit images based on the +supplied RISC-V cross-compile toolchain. For example if *CROSS_COMPILE* is set +to *riscv64-unknown-elf-*, 64-bit OpenSBI images will be generated. If building +32-bit OpenSBI images, *CROSS_COMPILE* should be set to a toolchain that is +pre-configured to generate 32-bit RISC-V codes, like *riscv32-unknown-elf-*. + +However it's possible to explicitly specify the image bits we want to build with +a given RISC-V toolchain. This can be done by setting the environment variable +*PLATFORM_RISCV_XLEN* to the desired width, for example: + +``` +export CROSS_COMPILE=riscv64-unknown-elf- +export PLATFORM_RISCV_XLEN=32 +``` + +will generate 32-bit OpenSBI images. And vice vesa. + License ------- |