Date: Fri, 18 Mar 2016 10:49:45 -0700 From: John Baldwin <jhb@freebsd.org> To: Justin Hibbits <jhibbits@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r297000 - in head: . sys/arm/xscale/ixp425 sys/arm/xscale/pxa sys/compat/ndis sys/dev/acpica sys/dev/advansys sys/dev/atkbdc sys/dev/bxe sys/dev/cardbus sys/dev/ctau sys/dev/ed sys/dev/... Message-ID: <2148463.8F4WoXScuZ@ralph.baldwin.cx> In-Reply-To: <201603180128.u2I1SfaM039505@repo.freebsd.org> References: <201603180128.u2I1SfaM039505@repo.freebsd.org>
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On Friday, March 18, 2016 01:28:41 AM Justin Hibbits wrote: > Author: jhibbits > Date: Fri Mar 18 01:28:41 2016 > New Revision: 297000 > URL: https://svnweb.freebsd.org/changeset/base/297000 > > Log: > Use uintmax_t (typedef'd to rman_res_t type) for rman ranges. > > On some architectures, u_long isn't large enough for resource definitions. > Particularly, powerpc and arm allow 36-bit (or larger) physical addresses, but > type `long' is only 32-bit. This extends rman's resources to uintmax_t. With > this change, any resource can feasibly be placed anywhere in physical memory > (within the constraints of the driver). > > Why uintmax_t and not something machine dependent, or uint64_t? Though it's > possible for uintmax_t to grow, it's highly unlikely it will become 128-bit on > 32-bit architectures. 64-bit architectures should have plenty of RAM to absorb > the increase on resource sizes if and when this occurs, and the number of > resources on memory-constrained systems should be sufficiently small as to not > pose a drastic overhead. That being said, uintmax_t was chosen for source > clarity. If it's specified as uint64_t, all printf()-like calls would either > need casts to uintmax_t, or be littered with PRI*64 macros. Casts to uintmax_t > aren't horrible, but it would also bake into the API for > resource_list_print_type() either a hidden assumption that entries get cast to > uintmax_t for printing, or these calls would need the PRI*64 macros. Since > source code is meant to be read more often than written, I chose the clearest > path of simply using uintmax_t. > > Tested on a PowerPC p5020-based board, which places all device resources in > 0xfxxxxxxxx, and has 8GB RAM. > Regression tested on qemu-system-i386 > Regression tested on qemu-system-mips (malta profile) > > Tested PAE and devinfo on virtualbox (live CD) > > Special thanks to bz for his testing on ARM. > > Reviewed By: bz, jhb (previous) > Relnotes: Yes > Sponsored by: Alex Perez/Inertial Computing > Differential Revision: https://reviews.freebsd.org/D4544 Thank you for chasing this down to completion. It removes quite a few hacks from the PAE case. Thank you also for being patient when I asked you to split the changes up, rearrange things, etc. :) -- John Baldwin
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