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