From: Paul Burton <paul.burton@imgtec.com>
Date: Tue, 19 Apr 2016 08:25:11 +0000 (+0100)
Subject: MIPS: mm: Panic if an XPA kernel is run without RIXI
X-Git-Tag: v4.7-rc1~6^2~96
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e56c7e18818dd721179f9ca95c77dd941a360384;p=platform%2Fkernel%2Flinux-exynos.git

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 0efa621..274da90 100644
--- 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();