MIPS: mm: Panic if an XPA kernel is run without RIXI

XPA kernels hardcode for the presence of RIXI - the PTE format & its
handling presume RI & XI bits. Make this dependence explicit by panicing
if we run on a system that violates it.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13125/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c
index 0efa6211cc4094c3a7dd56f179ac6236edc7a91a..274da90adf0d682cb00f8811de9c19ba45fc3fa8 100644 (file)
--- a/arch/mips/mm/tlbex.c
+++ b/arch/mips/mm/tlbex.c
@@ -2508,6 +2508,9 @@ void build_tlb_refill_handler(void)
         */
        static int run_once = 0;
 
+       if (config_enabled(CONFIG_XPA) && !cpu_has_rixi)
+               panic("Kernels supporting XPA currently require CPUs with RIXI");
+
        output_pgtable_bits_defines();
        check_pabits();