On Wed, 21 Aug 2019, Ed Maste wrote:
Author: emaste
Date: Wed Aug 21 01:45:29 2019
New Revision: 351319
URL: https://svnweb.freebsd.org/changeset/base/351319
Log:
makefs: use `char *` not `void *` for buf b_data, drop casts in msdos
(The kernel uses caddr_t.)
This is much better than churning the copy of the working code.
However, the kernel type is still bogus. caddr_t should not exist, and
should have been more like vm_offset_t to begin with. void * is no good
as an opaque type for it, since void * is only good for C addresses within
a single address space, but caddr_t is supposed to be able to represent
anything in a (possibly multiple) "core" address space. [u]intptr_t has
the same problem. Bus space addresses are also withing a single address
space and in general need a tag for uniqueness.
caddr_t has been char * for too long, so too much code including buf b_data
depends on it being precisely char * or u_char * to work. char * is an
honestly broken variant of void *. It is similarly limited to a single
address space. This is hard to fix. It works for [Free]BSD since no arches
with more than a single address space are supported (i386 with PAE or
pae_mode=1 or pae_mode has a larger physical address space where addresses
aren't unique, but only the kernel can see this).
Bruce
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