70f2011015
We might as well surface this useful information in the manual so users can find it easily. It is a fairly simple conversion to rst with the only textual fixes being QemuOps to QemuOpts. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20210303173642.3805-6-alex.bennee@linaro.org>
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3.9 KiB
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118 lines
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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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Generic Loader
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--------------
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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>``
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The address to store the data in.
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``<data>``
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The value to be written to the address. The maximum size of the data
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is 8 bytes.
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``<data-len>``
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The length of the data in bytes. This argument must be included if
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the data argument is.
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``<data-be>``
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Set to true if the data to be stored on the guest should be written
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as big endian data. The default is to write little endian data.
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``<cpu-num>``
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The number of the CPU's address space where the data should be
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loaded. If not specified the address space of the first 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>``
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The value to use as the CPU's PC.
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``<cpu-num>``
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The number of the CPU whose PC should be set to the specified value.
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All values are parsed using the standard QemuOpts 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 ELF,
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U-Boot, and Intel HEX executable formats as well as raw images. The syntax is
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shown below:
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-device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>]
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``<file>``
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A file to be loaded into memory
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``<addr>``
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The memory address where the file should be loaded. This is required
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for raw images and ignored for non-raw files.
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``<cpu-num>``
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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 the
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memory address where the raw file is loaded or the entry point
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specified in the executable format header. This option should only
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be used for the boot image. This will also cause the image to be
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written to the specified CPU's address space. If not specified, the
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default is CPU 0. <force-raw> - Setting force-raw=on forces the file
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to be treated as a raw image. This can be used to load supported
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executable formats as if they were raw.
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All values are parsed using the standard QemuOpts 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
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you want to set the PC as well. This might not always be the case. In
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future the internal state 'set_pc' (which exists in the generic loader
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now) should be exposed to the user so that they can choose if the PC
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is set or not.
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