Date: Mon, 04 Mar 2013 22:08:43 -0800 From: Thomas Skibo <ThomasSkibo@sbcglobal.net> To: freebsd-arm@freebsd.org Subject: Re: Weird kernel mode data abort panic on Zedboard. Message-ID: <51358BEB.50603@sbcglobal.net> In-Reply-To: <51354125.4060500@sbcglobal.net> References: <51354125.4060500@sbcglobal.net>
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Oleksandr Tymoshenko : > > Just a hunch here - looks like TLB entry is not update properly. Might > be missing > PTE_SYNC in pmap-v6.c. Or current PTE_SYNC implementation does not cover > all requirements for your platform. I'd say latter - but without proper > debugging > it's just guesswork. > Thanks. On my platform, PMAP_NEEDS_PTE_SYNC was 0 and I convinced myself earlier that the page tables were properly configured with write-through caching and didn't need PTE_SYNC() anyway. But, I just forced it use the run-time configurable pmap_needs_pte_sync variable which is set to 1 upon initialization and the problem went away. Setting pmap_needs_pte_sync to 0 subsequently didn't make the problem reappear so maybe it has something to do with early initialization of the page tables. I'll get more time to look at it later in the week. By the way, PTE_SYNC() doesn't properly write-back the level 2 cache on my platform because it needs physical addresses. But, it looks like that doesn't matter. --Thomas -- -------- Thomas Skibo ThomasSkibo@sbcglobal.net
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