On Mon, 16 Mar 2015 11:50:59 -0400, Anthony Jenkins wrote: > On 03/16/2015 11:00 AM, Anthony Jenkins wrote: > > On 03/16/2015 09:59 AM, Ian Smith wrote: > >> On Sat, 14 Mar 2015 23:40:34 -0400, Anthony Jenkins wrote: > >>> + if (!acpi_check_rtc_byteaccess(function == ACPI_READ, address)) > >>> + return AE_BAD_PARAMETER; > >> acpi_check_rtc_byteaccess() needs to be called per byte of 1, 2 or 4 > >> bytes - or pass it 'bytes' also, and loop over each of them within? > >> ======= > >> > >> Otherwise (for example) a 2 byte read from 0x0b or 4 byte read from > >> 0x09-0x0b will read 0x0c (clearing interrupts), or a 2 or 4 byte write > >> to (say) 0x01 will also write to 0x02 and 0x04 (clobbering the time). > > Right, this is an (incorrect) hybrid of a few attempts, probably from > > around the time I lost my SSD and only had a single backup copy of my > > work to go from. In one revision I had disallowed all multibyte > > accesses (width > 8) since IMHO it was more consistent/correct with the > > suggested locking. I wasn't ignoring your suggestion, just making one > > or a few changes at a time (generally the simpler ones). > > Okay now I remember why I was reluctant to do this - suppose ACPIBIOS > does a multibyte op on a set of bytes whose last byte fails > acpi_check_rtc_byteaccess(). I will have already performed n-1 > accesses. At one point I had a revision (acpi_check_rtc_access()?) that > permitted/denied the entire request (it took the starting address and > byte length), but I guess that got lost too. I'll just recreate it...
Yep, validating all access before doing any sounds like the way to go. Also, bytes = width >> 3 is ok, since you then affirm !(width & 0x07), so non-multiples of 8 bits are invalidated anyway. You should still check that width (or bytes) > 0, even if 0 should never be passed. I guess the Big Kids will start playing once this hits bugzilla? :) cheers, Ian _______________________________________________ freebsd-acpi@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-acpi To unsubscribe, send any mail to "freebsd-acpi-unsubscr...@freebsd.org"
