Date: Wed, 25 Feb 2004 21:15:23 +0000 From: Bruce Cran <bruce@cran.org.uk> To: freebsd-current@freebsd.org Subject: 64-bit values in sysctl Message-ID: <20040225211523.GA3031@box1.cran>
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After investigating whether FreeBSD will be able to show the correct speed of a 4.3GHz CPU (http://www.theinquirer.net/?article=14319), I found that the sysctl infrastructure doesn't currently have support for 64-bit integers, on a 32-bit platform at least. The only type pertaining to 64-bits is CTLTYPE_QUAD, but since there's no corresponding sysctl_handle_quad, it's still handled as a 32-bit integer. I found PR kern/39681 which explains that it's apparently not as simple as adding a sysctl_handle_quad function. With CPUs getting faster and a few people adding more then 4GB RAM to their machines, there's a need for some sort of solution IMO. In addition, the only place a CTLTYPE_QUAD is used is in sys/i386/i386/tsc.c, and then it mixed CTLTYPE_QUAD and sizeof(u_int). I've also noticed that the machdep.[i8254_freq, tsc_freq, acpi_timer_freq] are all writable, whereas I think they should probably be read-only, as should kern.bootfile. One last thing I've noticed during my look into the kernel code is that a lot of the sysctls are defined as signed integers - wouldn't it be better if these were converted to be unsigned, so that it would be impossible for the writable ones to be set to negative values and thus avoid possible foot-shooting? I already have some diffs, so I could put together a PR if some of these changes (such as making some sysctls read-only) are valid. -- Bruce Cran
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