[lkml]   [2004]   [Sep]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Subject[vm 0/76] convert remap_page_range() to remap_pfn_range() vs. 2.6.9-rc2-mm3
This series resolves a physical address overflow issue in the
remap_page_range() API by replacing it with remap_pfn_range(), which
accepts its physical address argument as a pfn, hence allowing the use
of a single-precision physical address argument without the risk of
overflow at the API boundary. The above issue has hobbled support for
various 32-bit architectures, including some embedded systems (ppc440
IIRC), caused persistent portability issues for sound drivers for
legacy systems (sparc32; unfortunately this patch alone does not fully
resolve those), and according to John Fusco's reports, made drivers for
some PCI-X hardware infeasible to port to recent ia32 PAE enterprise
systems. With this patch series applied, physical address overflows on
32-bit systems caused directly by remap_page_range() are gone forever,
and ca. 100LOC of cut-and-waste driver code are swept out of existence
alongside them.

vs. 2.6.9-rc2-mm3 and the scheduler header cleanups. The parts touching
mm.h should apply with just offsets if those aren't applied beforehand.
Successfully tested on x86-64.

-- wli

P.S.: The existing solution to the sparc32 issue was to pass a double
precision representation of the physical address as 2 single-
precision arguments in an API (io_remap_page_range()) whose
argument corresponding to those two was a single single-
precision argument on most/all other architectures. The
sparc32-specific issue requires more work beyond these patches
to rectify. The most apparent consequence of the API skew is
that drivers don't compile on sparc32 when they use
io_remap_page_range() due to passing insufficient arguments,
or vice-versa for drivers originally written for sparc32.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 14:06    [W:0.032 / U:12.312 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site