Ralf Baechle wrote:
> On Tue, Jan 02, 2001 at 04:52:22PM -0800, Jun Sun wrote:
> > Someone reported this bug to me. I think it is a valid one. Basically
> > trap_init() installs the vectors through kseg0 address and then flushes
> > icache. It is possible that the vectors are still in the data cache and not
> > written back to memory yet. If an exception happens it may get the
> > corrupted
> > the vector value.
> > The following patch should fix it. I am not sure if I can use
> > flush_cache_range() to have potentially better performance.
> Flush_icache_range is correct; the function is expected to do any dcache
> writebacks etc. to make dcache / icache / memory coherent.
> Is it possible that you're using a CPU with additional vectors that aren't
> flushed by this flush_icache_call or?
You are right - flush_icache_range() practically flushes both caches in the
current implementation. There might be some other problems.
Aside of that, the name of flush_icache_range() seems to be misleading. Also
in general how does it know which part of dcache to flush() without a given
process mm struct? If it does not know, the only choice is to flush the whole
dcache, which seems to make this function very close to flush_all().
Is this function introduced by other CPU platforms? How would it make a
difference there? I am just curious ...