diff options
Diffstat (limited to 'arch/powerpc/mm/nohash/40x.c')
| -rw-r--r-- | arch/powerpc/mm/nohash/40x.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/arch/powerpc/mm/nohash/40x.c b/arch/powerpc/mm/nohash/40x.c index 3684d6e570fb..e835e80c09db 100644 --- a/arch/powerpc/mm/nohash/40x.c +++ b/arch/powerpc/mm/nohash/40x.c @@ -48,20 +48,25 @@ */ void __init MMU_init_hw(void) { + int i; + unsigned long zpr; + /* * The Zone Protection Register (ZPR) defines how protection will - * be applied to every page which is a member of a given zone. At - * present, we utilize only two of the 4xx's zones. + * be applied to every page which is a member of a given zone. * The zone index bits (of ZSEL) in the PTE are used for software - * indicators, except the LSB. For user access, zone 1 is used, - * for kernel access, zone 0 is used. We set all but zone 1 - * to zero, allowing only kernel access as indicated in the PTE. - * For zone 1, we set a 01 binary (a value of 10 will not work) + * indicators. We use the 4 upper bits of virtual address to select + * the zone. We set all zones above TASK_SIZE to zero, allowing + * only kernel access as indicated in the PTE. For zones below + * TASK_SIZE, we set a 01 binary (a value of 10 will not work) * to allow user access as indicated in the PTE. This also allows * kernel access as indicated in the PTE. */ - mtspr(SPRN_ZPR, 0x10000000); + for (i = 0, zpr = 0; i < TASK_SIZE >> 28; i++) + zpr |= 1 << (30 - i * 2); + + mtspr(SPRN_ZPR, zpr); flush_instruction_cache(); |