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>
This commit is contained in:
Steven J. Hill
2015-02-26 18:16:38 -06:00
committed by Ralf Baechle
parent be0c37c985
commit c5b367835c
11 changed files with 173 additions and 44 deletions

View File

@@ -96,7 +96,7 @@ static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
vaddr = __fix_to_virt(FIX_CMAP_END - idx);
pte = mk_pte(page, prot);
#if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32)
entrylo = pte.pte_high;
entrylo = pte_to_entrylo(pte.pte_high);
#else
entrylo = pte_to_entrylo(pte_val(pte));
#endif
@@ -106,6 +106,11 @@ static void *__kmap_pgprot(struct page *page, unsigned long addr, pgprot_t prot)
write_c0_entryhi(vaddr & (PAGE_MASK << 1));
write_c0_entrylo0(entrylo);
write_c0_entrylo1(entrylo);
#ifdef CONFIG_XPA
entrylo = (pte.pte_low & _PFNX_MASK);
writex_c0_entrylo0(entrylo);
writex_c0_entrylo1(entrylo);
#endif
tlbidx = read_c0_wired();
write_c0_wired(tlbidx + 1);
write_c0_index(tlbidx);