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@imgtec.com>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10691/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Paul Burton 2015-07-13 17:12:44 +01:00 committed by Ralf Baechle
parent 8961b28f09
commit 091bc3a404

View File

@ -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 ||