linux-kernel - [PATCH] MIPS: tlb-r4k: panic if the MMU doesn't support PAGE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1436803964-29820-1-git-send-email-paul.burton@imgtec.com>
Date:	Mon, 13 Jul 2015 17:12:44 +0100
From:	Paul Burton <paul.burton@...tec.com>
To:	<linux-mips@...ux-mips.org>
CC:	Paul Burton <paul.burton@...tec.com>,
	"Steven J. Hill" <Steven.Hill@...tec.com>,
	Joshua Kinard <kumba@...too.org>,
	<linux-kernel@...r.kernel.org>,
	Rafał Miłecki <zajec5@...il.com>,
	James Hogan <james.hogan@...tec.com>,
	Markos Chandras <markos.chandras@...tec.com>,
	Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH] MIPS: tlb-r4k: panic if the MMU doesn't support PAGE_SIZE

After writing the appropriate mask to the cop0 PageMask register, read
the register back & check it matches what we want. If it doesn't then
the MMU does not support the page size the kernel is configured for and
we're better off bailing than continuing to do odd things with TLB
exceptions.

Signed-off-by: Paul Burton <paul.burton@...tec.com>
---

 arch/mips/mm/tlb-r4k.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index 08318ec..4330315 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -19,6 +19,7 @@
 #include <asm/cpu.h>
 #include <asm/cpu-type.h>
 #include <asm/bootinfo.h>
+#include <asm/hazards.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/tlb.h>
@@ -486,6 +487,10 @@ static void r4k_tlb_configure(void)
 	 *     be set to fixed-size pages.
 	 */
 	write_c0_pagemask(PM_DEFAULT_MASK);
+	back_to_back_c0_hazard();
+	if (read_c0_pagemask() != PM_DEFAULT_MASK)
+		panic("MMU doesn't support PAGE_SIZE=0x%lx", PAGE_SIZE);
+
 	write_c0_wired(0);
 	if (current_cpu_type() == CPU_R10000 ||
 	    current_cpu_type() == CPU_R12000 ||
-- 
2.4.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/