[POWERPC] Use 1TB segments
This makes the kernel use 1TB segments for all kernel mappings and for
user addresses of 1TB and above, on machines which support them
(currently POWER5+, POWER6 and PA6T).
We detect that the machine supports 1TB segments by looking at the
ibm,processor-segment-sizes property in the device tree.
We don't currently use 1TB segments for user addresses < 1T, since
that would effectively prevent 32-bit processes from using huge pages
unless we also had a way to revert to using 256MB segments. That
would be possible but would involve extra complications (such as
keeping track of which segment size was used when HPTEs were inserted)
and is not addressed here.
Parts of this patch were originally written by Ben Herrenschmidt.
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-powerpc/cputable.h b/include/asm-powerpc/cputable.h
index d913f46..ae093ef 100644
--- a/include/asm-powerpc/cputable.h
+++ b/include/asm-powerpc/cputable.h
@@ -164,6 +164,7 @@
#define CPU_FTR_CELL_TB_BUG LONG_ASM_CONST(0x0000800000000000)
#define CPU_FTR_SPURR LONG_ASM_CONST(0x0001000000000000)
#define CPU_FTR_DSCR LONG_ASM_CONST(0x0002000000000000)
+#define CPU_FTR_1T_SEGMENT LONG_ASM_CONST(0x0004000000000000)
#ifndef __ASSEMBLY__
@@ -374,7 +375,7 @@
#define CPU_FTRS_POSSIBLE \
(CPU_FTRS_POWER3 | CPU_FTRS_RS64 | CPU_FTRS_POWER4 | \
CPU_FTRS_PPC970 | CPU_FTRS_POWER5 | CPU_FTRS_POWER6 | \
- CPU_FTRS_CELL | CPU_FTRS_PA6T)
+ CPU_FTRS_CELL | CPU_FTRS_PA6T | CPU_FTR_1T_SEGMENT)
#else
enum {
CPU_FTRS_POSSIBLE =