From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <9910291811.AA21080@marc.watson.ibm.com> To: Gabriel Paubert Cc: Lou Langholtz , linuxppc-dev@lists.linuxppc.org, gdt@linuxppc.org, cort@cs.nmt.edu Subject: Re: linux-2.2.13pre15 stability w/ head.S patch In-Reply-To: Message from Gabriel Paubert of "Fri, 29 Oct 1999 12:34:30 +0200." Date: Fri, 29 Oct 1999 14:11:16 -0400 From: David Edelsohn Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: >>>>> Gabriel Paubert writes: Gabriel> OTOH when address translation is turned on (or when the its state is Gabriel> unknown) I would have put an isync _before_ the first mtdbatu to make Gabriel> sure that it does not interfere with previous instructions (this is Gabriel> required from the manuals AFAICT). You are correct, I mistyped the example. The isync's should go before the entire block of DBAT updates and after. The PowerPC Microprocessor Programming Environments book synchronization requirements state that a "context-synchronizing instruction" is REQUIRED PRIOR and REQUIRED AFTER a mtspr (DBAT) instruction. Context Synchronizing Instructions are "sc", "rfi", "rfid", and "isync". Disabling the valid bits by zeroing the upper BAT register before modifying the lower BAT register is necessary. If address translation is off, the context sychronization is unnecessary. David ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/