generic-loader.rst (4003B)
1 .. 2 Copyright (c) 2016, Xilinx Inc. 3 4 This work is licensed under the terms of the GNU GPL, version 2 or later. See 5 the COPYING file in the top-level directory. 6 7 Generic Loader 8 -------------- 9 10 The 'loader' device allows the user to load multiple images or values into 11 QEMU at startup. 12 13 Loading Data into Memory Values 14 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 15 The loader device allows memory values to be set from the command line. This 16 can be done by following the syntax below:: 17 18 -device loader,addr=<addr>,data=<data>,data-len=<data-len> \ 19 [,data-be=<data-be>][,cpu-num=<cpu-num>] 20 21 ``<addr>`` 22 The address to store the data in. 23 24 ``<data>`` 25 The value to be written to the address. The maximum size of the data 26 is 8 bytes. 27 28 ``<data-len>`` 29 The length of the data in bytes. This argument must be included if 30 the data argument is. 31 32 ``<data-be>`` 33 Set to true if the data to be stored on the guest should be written 34 as big endian data. The default is to write little endian data. 35 36 ``<cpu-num>`` 37 The number of the CPU's address space where the data should be 38 loaded. If not specified the address space of the first CPU is used. 39 40 All values are parsed using the standard QemuOps parsing. This allows the user 41 to specify any values in any format supported. By default the values 42 will be parsed as decimal. To use hex values the user should prefix the number 43 with a '0x'. 44 45 An example of loading value 0x8000000e to address 0xfd1a0104 is:: 46 47 -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4 48 49 Setting a CPU's Program Counter 50 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 51 52 The loader device allows the CPU's PC to be set from the command line. This 53 can be done by following the syntax below:: 54 55 -device loader,addr=<addr>,cpu-num=<cpu-num> 56 57 ``<addr>`` 58 The value to use as the CPU's PC. 59 60 ``<cpu-num>`` 61 The number of the CPU whose PC should be set to the specified value. 62 63 All values are parsed using the standard QemuOpts parsing. This allows the user 64 to specify any values in any format supported. By default the values 65 will be parsed as decimal. To use hex values the user should prefix the number 66 with a '0x'. 67 68 An example of setting CPU 0's PC to 0x8000 is:: 69 70 -device loader,addr=0x8000,cpu-num=0 71 72 Loading Files 73 ^^^^^^^^^^^^^ 74 75 The loader device also allows files to be loaded into memory. It can load ELF, 76 U-Boot, and Intel HEX executable formats as well as raw images. The syntax is 77 shown below: 78 79 -device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>] 80 81 ``<file>`` 82 A file to be loaded into memory 83 84 ``<addr>`` 85 The memory address where the file should be loaded. This is required 86 for raw images and ignored for non-raw files. 87 88 ``<cpu-num>`` 89 This specifies the CPU that should be used. This is an 90 optional argument and will cause the CPU's PC to be set to the 91 memory address where the raw file is loaded or the entry point 92 specified in the executable format header. This option should only 93 be used for the boot image. This will also cause the image to be 94 written to the specified CPU's address space. If not specified, the 95 default is CPU 0. 96 97 ``<force-raw>`` 98 Setting 'force-raw=on' forces the file to be treated as a raw image. 99 This can be used to load supported executable formats as if they 100 were raw. 101 102 All values are parsed using the standard QemuOpts parsing. This allows the user 103 to specify any values in any format supported. By default the values 104 will be parsed as decimal. To use hex values the user should prefix the number 105 with a '0x'. 106 107 An example of loading an ELF file which CPU0 will boot is shown below:: 108 109 -device loader,file=./images/boot.elf,cpu-num=0 110 111 Restrictions and ToDos 112 ^^^^^^^^^^^^^^^^^^^^^^ 113 114 At the moment it is just assumed that if you specify a cpu-num then 115 you want to set the PC as well. This might not always be the case. In 116 future the internal state 'set_pc' (which exists in the generic loader 117 now) should be exposed to the user so that they can choose if the PC 118 is set or not. 119 120