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authorBernd Schmidt <bernds_cb1@t-online.de>2009-01-07 23:14:38 +0800
committerBryan Wu <cooloney@kernel.org>2009-01-07 23:14:38 +0800
commitdbdf20db537a5369c65330f878ad4905020a8bfa (patch)
treec7fa553755e2d75a6e98d3f32fbe41fab9f72609 /README
parent6651ece9e257302ee695ee76e69a4427f7033235 (diff)
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op-kernel-dev-dbdf20db537a5369c65330f878ad4905020a8bfa.tar.gz
Blackfin arch: Faster C implementation of no-MPU CPLB handler
This is a mixture ofcMichael McTernan's patch and the existing cplb-mpu code. We ditch the old cplb-nompu implementation, which is a good example of why a good algorithm in a HLL is preferrable to a bad algorithm written in assembly. Rather than try to construct a table of all posible CPLBs and search it, we just create a (smaller) table of memory regions and their attributes. Some of the data structures are now unified for both the mpu and nompu cases. A lot of needless complexity in cplbinit.c is removed. Further optimizations: * compile cplbmgr.c with a lot of -ffixed-reg options, and omit saving these registers on the stack when entering a CPLB exception. * lose cli/nop/nop/sti sequences for some workarounds - these don't * make sense in an exception context Additional code unification should be possible after this. [Mike Frysinger <vapier.adi@gmail.com>: - convert CPP if statements to C if statements - remove redundant statements - use a do...while loop rather than a for loop to get slightly better optimization and to avoid gcc "may be used uninitialized" warnings ... we know that the [id]cplb_nr_bounds variables will never be 0, so this is OK - the no-mpu code was the last user of MAX_MEM_SIZE and with that rewritten, we can punt it - add some BUG_ON() checks to make sure we dont overflow the small cplb_bounds array - add i/d cplb entries for the bootrom because there is functions/data in there we want to access - we do not need a NULL trailing entry as any time we access the bounds arrays, we use the nr_bounds variable ] Signed-off-by: Michael McTernan <mmcternan@airvana.com> Signed-off-by: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de> Signed-off-by: Bryan Wu <cooloney@kernel.org>
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