From 70f20110150ec60d112bbbc9a6f8b100cd203701 Mon Sep 17 00:00:00 2001 From: Alex Bennée Date: Wed, 3 Mar 2021 17:36:40 +0000 Subject: docs: move generic-loader documentation into the main manual 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 Reviewed-by: Alistair Francis Message-Id: <20210303173642.3805-6-alex.bennee@linaro.org> --- docs/system/generic-loader.rst | 117 +++++++++++++++++++++++++++++++++++++++++ docs/system/index.rst | 1 + 2 files changed, 118 insertions(+) create mode 100644 docs/system/generic-loader.rst (limited to 'docs/system') diff --git a/docs/system/generic-loader.rst b/docs/system/generic-loader.rst new file mode 100644 index 0000000000..6bf8a4eb48 --- /dev/null +++ b/docs/system/generic-loader.rst @@ -0,0 +1,117 @@ +.. + 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. + +Generic Loader +-------------- + +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=,data=,data-len= \ + [,data-be=][,cpu-num=] + +```` + The address to store the data in. + +```` + The value to be written to the address. The maximum size of the data + is 8 bytes. + +```` + The length of the data in bytes. This argument must be included if + the data argument is. + +```` + 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. + +```` + 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=,cpu-num= + +```` + The value to use as the CPU's PC. + +```` + The number of the CPU whose PC should be set to the specified value. + +All values are parsed using the standard QemuOpts 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. It can load ELF, +U-Boot, and Intel HEX executable formats as well as raw images. The syntax is +shown below: + + -device loader,file=[,addr=][,cpu-num=][,force-raw=] + +```` + A file to be loaded into memory + +```` + The memory address where the file should be loaded. This is required + for raw images and ignored for non-raw files. + +```` + This specifies the CPU that should be used. This is an + optional argument and will cause the CPU's PC to be set to the + memory address where the raw file is loaded or the entry point + specified in the executable format 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. - Setting force-raw=on forces the file + to be treated as a raw image. This can be used to load supported + executable formats as if they were raw. + +All values are parsed using the standard QemuOpts 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 + +Restrictions and ToDos +^^^^^^^^^^^^^^^^^^^^^^ + +At the moment it is just assumed that if you specify a cpu-num then +you want to set the PC as well. This might not always be the case. In +future the internal state 'set_pc' (which exists in the generic loader +now) should be exposed to the user so that they can choose if the PC +is set or not. + + diff --git a/docs/system/index.rst b/docs/system/index.rst index 625b494372..cee1c83540 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -25,6 +25,7 @@ Contents: usb ivshmem linuxboot + generic-loader vnc-security tls gdb -- cgit v1.2.3-55-g7522