Xen devel - Mar 2011 - [PATCH 3/12] VTPM mini-os: Add ioread() and iowrite() functions to mini-os

Mini-os currently doesn''t have very many facilities for reading and 
writing to hardware io memory. This patch addes  a new header file 
iorw.h which when included gives access to
the ioread8(), iread32(), iowrite8(), iowrite32() family of functions. 
Each has a separate implementation
for each architecture supported by mini-os.

Currently only x86 has been implemented. ia64 is stubbed out for now.

Signed off by: Matthew Fioravante <matthew.fioravante@jhuapl.edu>



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Matthew Fioravante, le Fri 11 Mar 2011 17:38:32 -0500, a écrit
:
> Mini-os currently doesn''t have very many facilities for reading
and
> writing to hardware io memory. This patch addes  a new header file 
> iorw.h which when included gives access to
> the ioread8(), iread32(), iowrite8(), iowrite32() family of functions. 
> +void iowrite8(void* addr, uint8_t val)
> +{
> +   *((uint8_t*)addr) = val;
> +}
> +void iowrite32(void* addr, uint32_t val)
> +{
> +   *((uint32_t*)addr) = val;
> +}
Don''t you need a volatile qualifier on the cast pointer to not let the
compiler optimize it away?

Samuel

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Yeah your right, sorry about that! Heres a patch that applies on top of 
the previous one to add volatile.

Signed off by: Matthew Fioravante <matthew.fioravante@jhuapl.edu>

On 03/11/2011 07:29 PM, Samuel Thibault wrote:
> Matthew Fioravante, le Fri 11 Mar 2011 17:38:32 -0500, a écrit :
>> Mini-os currently doesn''t have very many facilities for
reading and
>> writing to hardware io memory. This patch addes  a new header file
>> iorw.h which when included gives access to
>> the ioread8(), iread32(), iowrite8(), iowrite32() family of functions.
>
>> +void iowrite8(void* addr, uint8_t val)
>> +{
>> +   *((uint8_t*)addr) = val;
>> +}
>> +void iowrite32(void* addr, uint32_t val)
>> +{
>> +   *((uint32_t*)addr) = val;
>> +}
> Don''t you need a volatile qualifier on the cast pointer to not let
the
> compiler optimize it away?
>
> Samuel



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Matthew Fioravante, le Mon 14 Mar 2011 13:10:54 -0400, a écrit
:
> Yeah your right, sorry about that! Heres a patch that applies on top of 
> the previous one to add volatile.
Ok, but you''ll rather have to submit an updated patch instead.

Samuel

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