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Re: [Qemu-devel] [PATCH v8 5/5] docs: Add a generic loader explanation d
From: |
Alistair Francis |
Subject: |
Re: [Qemu-devel] [PATCH v8 5/5] docs: Add a generic loader explanation document |
Date: |
Wed, 13 Jul 2016 10:48:37 -0700 |
On Tue, Jul 12, 2016 at 9:31 AM, Peter Maydell <address@hidden> wrote:
> On 2 July 2016 at 02:07, Alistair Francis <address@hidden> wrote:
>> Signed-off-by: Alistair Francis <address@hidden>
>> ---
>> V8:
>> - Improve documentation
>> V6:
>> - Fixup documentation
>> V4:
>> - Re-write to be more comprehensive
>>
>> docs/generic-loader.txt | 60
>> +++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 60 insertions(+)
>> create mode 100644 docs/generic-loader.txt
>
>> diff --git a/docs/generic-loader.txt b/docs/generic-loader.txt
>> new file mode 100644
>> index 0000000..34684fc
>> --- /dev/null
>> +++ b/docs/generic-loader.txt
>> @@ -0,0 +1,60 @@
>> +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.
>> +
>> +
>> +The 'loader' device allows the user to load multiple images or values into
>> +QEMU at startup.
>> +
>> +Loading 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=<addr>,data=<data>,data-len=<len>
>> + -device loader,addr=<addr>,cpu-num=<cpu-num>
>> +
>> + <addr> - The address to store the data or the value to use as the
>> + CPU's PC.
>> + <data> - The value to be written to the address. The maximum size
>> of
>> + the data is 8 bytes.
>> + <data-len> - The length of the data in bytes. This argument must be
>> + included if the data argument is.
>> + <data-be> - 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.
>> + <cpu-num> - This will cause the CPU to be reset and the PC to be set
>> to
>> + the value of addr.
>> +
>> +For all values both hex and decimal values are allowed. 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
>> +
>> +Loading Files
>> +-------------
>> +The loader device also allows files to be loaded into memory. This can be
>> done
>> +similarly to setting memory values. The syntax is shown below:
>> +
>> + -device loader,file=<file>,addr=<addr>,cpu-num=<cpu-num>,force-raw=<raw>
>> +
>> + <file> - A file to be loaded into memory
>> + <addr> - The addr in memory that the file should be loaded. This is
>> + ignored if you are using an ELF (unless force-raw is
>> true).
>> + This is required if you aren't loading an ELF.
>> + <cpu-num> - This specifies the CPU that should be used. This is an
>> + optional argument and will cause the CPU's PC to be set to
>> + where the image is stored. This option should only be used
>> + for the boot image.
>
> For an ELF file we use the start address specified in the ELF header, right?
Yes, I have specified that now in the docs.
>
> We also end up writing to that CPU's address space, but only for ELF files.
Yes, this will apply to all images in the next version.
>
>> + <force-raw> - Forces the file to be treated as a raw image. This can be
>> + used to specify the load address of ELF files.
>
> Presumably it results in the ELF file being dumped into memory as a raw
> image without any regard to what the segment headers say about loading,
> offsets, etc?
Correct, I have made that more clear.
Thanks,
Alistair
>
>> +
>> +For all values both hex and decimal values are allowed. 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
>
> thanks
> -- PMM
>
- [Qemu-devel] [PATCH v8 3/5] loader: Add AddressSpace loading support to ELFs, (continued)
- [Qemu-devel] [PATCH v8 3/5] loader: Add AddressSpace loading support to ELFs, Alistair Francis, 2016/07/01
- [Qemu-devel] [PATCH v8 2/5] loader: All a custom SddressSpace when loading ROMs, Alistair Francis, 2016/07/01
- [Qemu-devel] [PATCH v8 4/5] generic-loader: Add a generic loader, Alistair Francis, 2016/07/01
- [Qemu-devel] [PATCH v8 5/5] docs: Add a generic loader explanation document, Alistair Francis, 2016/07/01
- Re: [Qemu-devel] [PATCH v8 0/5] Add a generic loader, Peter Maydell, 2016/07/04
- Re: [Qemu-devel] [PATCH v8 0/5] Add a generic loader, Christian Borntraeger, 2016/07/04