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author | Alistair Francis <alistair.francis@xilinx.com> | 2016-10-04 13:28:09 +0100 |
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committer | Peter Maydell <peter.maydell@linaro.org> | 2016-10-04 13:28:09 +0100 |
commit | 03bf19535c2581937397e608335c111c03895ba8 (patch) | |
tree | 8c03c6050ec0ae9c50ae7c2e23aaee89843d0d30 /docs/generic-loader.txt | |
parent | e481a1f63c93344974f799a5e38df980ef5f7f9c (diff) |
docs: Add a generic loader explanation document
Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 9d991a2df990cf55e2630410a5a03ea48930af5d.1475195078.git.alistair.francis@xilinx.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs/generic-loader.txt')
-rw-r--r-- | docs/generic-loader.txt | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/docs/generic-loader.txt b/docs/generic-loader.txt new file mode 100644 index 0000000000..8fcb550414 --- /dev/null +++ b/docs/generic-loader.txt @@ -0,0 +1,84 @@ +Copyright (c) 2016 Xilinx Inc. + +This work is licensed under the terms of the GNU GPL, version 2 or later. See +the COPYING file in the top-level directory. + + +The 'loader' device allows the user to load multiple images or values into +QEMU at startup. + +Loading Data into Memory Values +--------------------- +The loader device allows memory values to be set from the command line. This +can be done by following the syntax below: + + -device loader,addr=<addr>,data=<data>,data-len=<data-len> + [,data-be=<data-be>][,cpu-num=<cpu-num>] + + <addr> - The address to store the data in. + <data> - The value to be written to the address. The maximum size of + the data is 8 bytes. + <data-len> - The length of the data in bytes. This argument must be + included if the data argument is. + <data-be> - Set to true if the data to be stored on the guest should be + written as big endian data. The default is to write little + endian data. + <cpu-num> - The number of the CPU's address space where the data should + be loaded. If not specified the address space of the first + CPU is used. + +All values are parsed using the standard QemuOps parsing. This allows the user +to specify any values in any format supported. By default the values +will be parsed as decimal. To use hex values the user should prefix the number +with a '0x'. + +An example of loading value 0x8000000e to address 0xfd1a0104 is: + -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4 + +Setting a CPU's Program Counter +--------------------- +The loader device allows the CPU's PC to be set from the command line. This +can be done by following the syntax below: + + -device loader,addr=<addr>,cpu-num=<cpu-num> + + <addr> - The value to use as the CPU's PC. + <cpu-num> - The number of the CPU whose PC should be set to the + specified value. + +All values are parsed using the standard QemuOps parsing. This allows the user +to specify any values in any format supported. By default the values +will be parsed as decimal. To use hex values the user should prefix the number +with a '0x'. + +An example of setting CPU 0's PC to 0x8000 is: + -device loader,addr=0x8000,cpu-num=0 + +Loading Files +--------------------- +The loader device also allows files to be loaded into memory. This can be done +similarly to setting memory values. The syntax is shown below: + + -device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>] + + <file> - A file to be loaded into memory + <addr> - The addr in memory that the file should be loaded. This is + ignored if you are using an ELF (unless force-raw is true). + This is required if you aren't loading an ELF. + <cpu-num> - This specifies the CPU that should be used. This is an + optional argument and will cause the CPU's PC to be set to + where the image is stored or in the case of an ELF file to + the value in the header. This option should only be used + for the boot image. + This will also cause the image to be written to the specified + CPU's address space. If not specified, the default is CPU 0. + <force-raw> - Forces the file to be treated as a raw image. This can be + used to specify the load address of ELF files. + +All values are parsed using the standard QemuOps parsing. This allows the user +to specify any values in any format supported. By default the values +will be parsed as decimal. To use hex values the user should prefix the number +with a '0x'. + +An example of loading an ELF file which CPU0 will boot is shown below: + -device loader,file=./images/boot.elf,cpu-num=0 |