Re: [Qemu-devel] Better Cortex-M support?

[Liviu Ionescu]

On 28 Oct 2014, at 16:18, Peter Maydell <address@hidden> wrote:

> Thanks. I've identified what's happening here, and
> it's not a bug in QEMU as such. The 'lm3s6965evb'
> model is of a microcontroller with 64KB of SRAM,
> so valid RAM is only from 0x20000000 to 0x20010000,
> but your binary is trying to use the area beyond that
> as RAM as well, and is therefore misbehaving.

outch! 

actually my application is not for lm3s6965evb at all, it is a generic 
Cortex-M3 application, and in the past I could use 'qemu-system-arm -cpu 
cortex-m3' to run it, but now I got an error and had to enter one of the 
Cortex-M boards.

> (We ignore any attempt to specify RAM size via the
> command line -m switch, so your '-m 513M' has no effect).

that explains it. my linker script assumes 1MB of flash and 1MB of RAM.

what would be the recommended solution for a generic Cortex-M3 emulation, make 
it back work with '-cpu cortex-m3' or do you mandate to use add a generic 
'-machine cortex-m3'?

> I suggest you relink your binary to fit in the 64K
> of RAM this board has. (There's also flash at address
> zero.)

yeah, the flash issue is another item on my features list.

the behaviour that I expect is to have the flash as a read only area, where gdb 
will be allowed to write in a similar way as when writing the physical flash 
(same as J-Link does).

is this supported by the current version?


regards,

Liviu