Insert version information into a boot stream

Hi Roberto,

On 8/19/2011 10:52 AM, Roberto Waltman wrote:
>
> Another way, (which I don't like, but it works.)
> You can enbedd the version info in the flash image surrounded by
> "markers" that will allow you to search and locate it anywhere.
>
> #pragma pack()
>
> struct version
> {
>      char before[35];
>      int  v_major;
>      int  v_minor;
>      char date[11];
>      int  checksum;  // to reduce the likelihood of false possitives

I figured the string "Vassilevsky" probably stands a greater chance
of reducing those sorts of hits!  (there are advantages to having
"unique" surnames!  :> )

>      char after[35];
> };	
>
> struct version this_version =
> {
>      "find version after this ##########",
>      0,
>      0,                    /* to be updated after build */
>      "--/--/----",
>      0,
>      "######### find version before this"
> };	
>
> Of curse, if the boot image includes any checksums to detect corrupted
> files they will need to be updated after modifying the structure
> above.

Or, ensure the struct's contents are "checksum neutral"
(not possible with all checksum algorithms)

Hi Rob,

On 8/19/2011 11:02 AM, Rob Gaddi wrote:

>> Instead of requiring a "predefined location" (admittedly, easier to
>> *find*), could you wrap the information with a unique signature
>> such that anything else is unlikely to be (erroneously) recognized
>> as having that signature IN THAT REGION OF MEMORY?
>>
>> E.g., add to the flash image:
>>
>> "Copyright 08192011 Vladimir Vassilevsky, Build 12.3.4, v9A03"
>>
>> (assuming this *context* is unlikely to randomly appear elsewhere
>> in your code image :> )
>
> Surprisingly, on the Blackfin, that actually disassembles to code that
> erases the entire flash and then sets the chip on fire.

Ah, my bad.  :<

Then, instead, store:

"30A9v ,4.3.21 dliuB ,yksvelissaV rimidalV 11029180 thgirypoC"

which, theoretically, should *program* the entire chip and spray
water (halon?) on anyone nearby!!

Roberto Waltman wrote:

> Another way, (which I don't like, but it works.)
> You can enbedd the version info in the flash image surrounded by
> "markers" that will allow you to search and locate it anywhere.

That idea almost works... but the maker string could be occasionally 
broken into two chunks in the boot sequence. So, the flash stream should 
be interpreted rather then simply searched. If the flash stream has to 
be interpreted, then I can put a version structure to a predefined 
location in the target memory map, and everything is simple. Oh, but I 
don't like writing an interpretor, that's the only problem :-)


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

Rob Gaddi wrote:

> On 8/19/2011 10:49 AM, Don Y wrote:
> 

>> E.g., add to the flash image:
>>
>> "Copyright 08192011 Vladimir Vassilevsky, Build 12.3.4, v9A03"
>>
>> (assuming this *context* is unlikely to randomly appear elsewhere
>> in your code image :> )
> 
> 
> Surprisingly, on the Blackfin, that actually disassembles to code that 
> erases the entire flash and then sets the chip on fire.

Does the "(c)Rob Gaddi" string put an ARM processor into an idle mode ?

Actually, I can remember piece of code that started with a text string 
"Hello my dear friend". That was a computer game for Sinclair Spectrum. 
IIRC, that translated to a harmless series of relative jumps on Z80 cpu.


VLV