MIPS: Add support for XPA.
Add support for extended physical addressing (XPA) so that
32-bit platforms can access equal to or greater than 40 bits
of physical addresses.
NOTE:
1) XPA and EVA are not the same and cannot be used
simultaneously.
2) If you configure your kernel for XPA, the PTEs
and all address sizes become 64-bit.
3) Your platform MUST have working HIGHMEM support.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9355/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index b2afa49..c2500f4 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -333,9 +333,17 @@
ptep = pte_offset_map(pmdp, address);
#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
+#ifdef CONFIG_XPA
+ write_c0_entrylo0(pte_to_entrylo(ptep->pte_high));
+ writex_c0_entrylo0(ptep->pte_low & _PFNX_MASK);
+ ptep++;
+ write_c0_entrylo1(pte_to_entrylo(ptep->pte_high));
+ writex_c0_entrylo1(ptep->pte_low & _PFNX_MASK);
+#else
write_c0_entrylo0(ptep->pte_high);
ptep++;
write_c0_entrylo1(ptep->pte_high);
+#endif
#else
write_c0_entrylo0(pte_to_entrylo(pte_val(*ptep++)));
write_c0_entrylo1(pte_to_entrylo(pte_val(*ptep)));
@@ -355,6 +363,9 @@
void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
unsigned long entryhi, unsigned long pagemask)
{
+#ifdef CONFIG_XPA
+ panic("Broken for XPA kernels");
+#else
unsigned long flags;
unsigned long wired;
unsigned long old_pagemask;
@@ -383,6 +394,7 @@
write_c0_pagemask(old_pagemask);
local_flush_tlb_all();
local_irq_restore(flags);
+#endif
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE