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authorStuart Menefy <stuart.menefy@st.com>2007-11-30 10:05:18 +0100
committerPaul Mundt <lethal@linux-sh.org>2008-01-28 05:18:59 +0100
commitfc55888f83c1c0ac09abe4680f9a94fc0662677f (patch)
treede8a32166ac3fa5e0a52f43fd080cec53341e547 /include/asm-sh
parentsh: Populate swapper_pg_dir with fixmap range. (diff)
downloadlinux-fc55888f83c1c0ac09abe4680f9a94fc0662677f.tar.xz
linux-fc55888f83c1c0ac09abe4680f9a94fc0662677f.zip
sh: Document PTEL 31:29 use on PTEA-wielding parts.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'include/asm-sh')
-rw-r--r--include/asm-sh/pgtable_32.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/include/asm-sh/pgtable_32.h b/include/asm-sh/pgtable_32.h
index 7efc95404c64..3e3557c53c55 100644
--- a/include/asm-sh/pgtable_32.h
+++ b/include/asm-sh/pgtable_32.h
@@ -22,8 +22,9 @@
* - Bits 10 and 11 are low bits of the PPN that are reserved on >= 4K pages.
* Bit 10 is used for _PAGE_ACCESSED, bit 11 remains unused.
*
- * - Bits 31, 30, and 29 remain unused by everyone and can be used for future
- * software flags, although care must be taken to update _PAGE_CLEAR_FLAGS.
+ * - On 29 bit platforms, bits 31 to 29 are used for the space attributes
+ * and timing control which (together with bit 0) are moved into the
+ * old-style PTEA on the parts that support it.
*
* XXX: Leave the _PAGE_FILE and _PAGE_WT overhaul for a rainy day.
*