Re: cache flush

[manu%netbsd.org@localhost (Emmanuel Dreyfus)]

Matt Thomas <matt%3am-software.com@localhost> wrote:

> > What is the prefered way to flush caches from C code in the kernel? Is
> > there a routine to call in locore, or should I inline the necessary
> > instructions in asm? (and what are the necessary instructions?)
> 
> Why do you want to do this?

To support this Mach service:

vm_machine_attribute
     _________________________________________________________________

   Function - Get/set the target memory region's special attributes.

(...)

   attribute
          [in scalar] The name of the attribute to be get/set. Possible
          values are:
   
        MATTR_CACHE
                Cachability. Aside from the generic values listed below,
                the following special values are defined:
          
              MATTR_VAL_CACHE_FLUSH
                      Flush from all caches
   
              MATTR_VAL_DCACHE_FLUSH
                      Flush from data caches
          
              MATTR_VAL_ICACHE_FLUSH
                      Flush from instruction caches
(...)          

For a given range of memory (typically delimited by a uvm_map_entry), I
need to support the following operations:
 
- flush I cache
- flush D cache
- sync I cache
- sync D cache
- set cachability

-- 
Emmanuel Dreyfus
Il y a 10 sortes de personnes dans le monde: ceux qui comprennent 
le binaire et ceux qui ne le comprennent pas.
manu%netbsd.org@localhost