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Date:      Fri, 10 Jul 2009 09:54:07 -0500 (CDT)
From:      Mark Tinguely <tinguely@casselton.net>
To:        mih@semihalf.com, tinguely@casselton.net
Cc:        freebsd-arm@freebsd.org
Subject:   Re: pmap problem in FreeBSD current - PS
Message-ID:  <200907101454.n6AEs7nJ087492@casselton.net>
In-Reply-To: <200907101307.n6AD7lZT081110@casselton.net>

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PS. sorry to even question your cpu_(l2)idcache_wbinv_range() implemetation.
    the cpu_idcache_wbinv_range() in bus_dmamem_alloc() is wrong.
    arm_remap_nocache() should wb/inv the entire page especially if the
    buffer that uses the page is less than a page size or non-page aligned. 
    The cache lines NOT in the buffer is the data that can be lost if
    used while the nocache shadow mapping is in effect.

   As an open question to the group: should we add an explict page
   cpu_(l2)idcache_wbinv_range() in the arm_remap_nocache() routine,
   so we know that it happens rather than a side effect of the new
   managing of kernel pages?

   For freebsd-9, I will rewrite arm_remap_nocache() to get rid of the
   shadow map.

Did your lock problems go away?

Good work.

--Mark Tinguely



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