bcf48274ba
This patch does three things: - It adds a list of restrictions and ToDos - It corrects the header --- lines to match the length of the header - It clarifies the force-raw option Signed-off-by: Alistair Francis <alistair.francis@xilinx.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Message-id: e75d1d285cf8f45037c41ebe1bc3f68120f09cb9.1475702918.git.alistair.francis@xilinx.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
93 lines
4.2 KiB
Plaintext
93 lines
4.2 KiB
Plaintext
Copyright (c) 2016 Xilinx Inc.
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This work is licensed under the terms of the GNU GPL, version 2 or later. See
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the COPYING file in the top-level directory.
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The 'loader' device allows the user to load multiple images or values into
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QEMU at startup.
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Loading Data into Memory Values
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-------------------------------
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The loader device allows memory values to be set from the command line. This
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can be done by following the syntax below:
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-device loader,addr=<addr>,data=<data>,data-len=<data-len>
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[,data-be=<data-be>][,cpu-num=<cpu-num>]
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<addr> - The address to store the data in.
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<data> - The value to be written to the address. The maximum size of
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the data is 8 bytes.
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<data-len> - The length of the data in bytes. This argument must be
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included if the data argument is.
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<data-be> - Set to true if the data to be stored on the guest should be
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written as big endian data. The default is to write little
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endian data.
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<cpu-num> - The number of the CPU's address space where the data should
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be loaded. If not specified the address space of the first
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CPU is used.
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All values are parsed using the standard QemuOps parsing. This allows the user
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to specify any values in any format supported. By default the values
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will be parsed as decimal. To use hex values the user should prefix the number
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with a '0x'.
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An example of loading value 0x8000000e to address 0xfd1a0104 is:
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-device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4
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Setting a CPU's Program Counter
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-------------------------------
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The loader device allows the CPU's PC to be set from the command line. This
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can be done by following the syntax below:
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-device loader,addr=<addr>,cpu-num=<cpu-num>
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<addr> - The value to use as the CPU's PC.
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<cpu-num> - The number of the CPU whose PC should be set to the
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specified value.
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All values are parsed using the standard QemuOps parsing. This allows the user
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to specify any values in any format supported. By default the values
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will be parsed as decimal. To use hex values the user should prefix the number
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with a '0x'.
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An example of setting CPU 0's PC to 0x8000 is:
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-device loader,addr=0x8000,cpu-num=0
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Loading Files
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-------------
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The loader device also allows files to be loaded into memory. It can load raw
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files and ELF executable files. Raw files are loaded verbatim. ELF executable
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files are loaded by an ELF loader. The syntax is shown below:
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-device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>]
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<file> - A file to be loaded into memory
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<addr> - The addr in memory that the file should be loaded. This is
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ignored if you are using an ELF (unless force-raw is true).
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This is required if you aren't loading an ELF.
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<cpu-num> - This specifies the CPU that should be used. This is an
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optional argument and will cause the CPU's PC to be set to
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where the image is stored or in the case of an ELF file to
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the value in the header. This option should only be used
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for the boot image.
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This will also cause the image to be written to the specified
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CPU's address space. If not specified, the default is CPU 0.
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<force-raw> - Setting force-raw=on forces the file to be treated as a raw
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image. This can be used to load ELF files as if they were raw.
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All values are parsed using the standard QemuOps parsing. This allows the user
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to specify any values in any format supported. By default the values
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will be parsed as decimal. To use hex values the user should prefix the number
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with a '0x'.
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An example of loading an ELF file which CPU0 will boot is shown below:
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-device loader,file=./images/boot.elf,cpu-num=0
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Restrictions and ToDos
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----------------------
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- At the moment it is just assumed that if you specify a cpu-num then you
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want to set the PC as well. This might not always be the case. In future
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the internal state 'set_pc' (which exists in the generic loader now) should
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be exposed to the user so that they can choose if the PC is set or not.
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