linux/arch
David Daney 9e0f162a36 MIPS: tlbex: Properly fix HUGE TLB Refill exception handler
In commit 8393c524a2 (MIPS: tlbex: Fix a missing statement for
HUGETLB), the TLB Refill handler was fixed so that non-OCTEON targets
would work properly with huge pages.  The change was incorrect in that
it broke the OCTEON case.

The problem is shown here:

    xxx0:	df7a0000 	ld	k0,0(k1)
    .
    .
    .
    xxxc0:	df610000 	ld	at,0(k1)
    xxxc4:	335a0ff0 	andi	k0,k0,0xff0
    xxxc8:	e825ffcd 	bbit1	at,0x5,0x0
    xxxcc:	003ad82d 	daddu	k1,at,k0
    .
    .
    .

In the non-octeon case there is a destructive test for the huge PTE
bit, and then at 0, $k0 is reloaded (that is what the 8393c524a2
patch added).

In the octeon case, we modify k1 in the branch delay slot, but we
never need k0 again, so the new load is not needed, but since k1 is
modified, if we do the load, we load from a garbage location and then
get a nested TLB Refill, which is seen in userspace as either SIGBUS
or SIGSEGV (depending on the garbage).

The real fix is to only do this reloading if it is needed, and never
where it is harmful.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Fuxin Zhang <zhangfx@lemote.com>
Cc: Zhangjin Wu <wuzhangjin@gmail.com>
Cc: stable@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8151/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-10-22 19:29:08 +02:00
..
alpha Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
arc Merge branch 'locking-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:48:00 +02:00
arm ARM: SoC fixes for -rc1 2014-10-19 17:43:06 -07:00
arm64 Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
avr32 Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma 2014-10-18 18:11:04 -07:00
blackfin Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2014-10-15 07:48:18 +02:00
c6x irq_work: Introduce arch_irq_work_has_interrupt() 2014-09-13 18:38:07 +02:00
cris Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 16:23:15 +02:00
frv frv: remove unused declarations of __start___ex_table and __stop___ex_table 2014-10-14 02:18:28 +02:00
hexagon Merge branch 'locking-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:48:00 +02:00
ia64 Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
m32r Merge branch 'locking-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:48:00 +02:00
m68k Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2014-10-14 03:51:22 +02:00
metag Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2014-10-15 07:48:18 +02:00
microblaze Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
mips MIPS: tlbex: Properly fix HUGE TLB Refill exception handler 2014-10-22 19:29:08 +02:00
mn10300 Merge branch 'locking-arch-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-10-13 15:48:00 +02:00
openrisc Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
parisc Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
powerpc Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
s390 Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
score score: use Kbuild logic to include <asm-generic/sections.h> 2014-10-09 22:25:46 -04:00
sh Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
sparc Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
tile Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2014-10-15 07:48:18 +02:00
um Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
unicore32 nosave: consolidate __nosave_{begin,end} in <asm/sections.h> 2014-10-09 22:26:04 -04:00
x86 Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
xtensa Merge git://git.infradead.org/users/eparis/audit 2014-10-19 16:25:56 -07:00
.gitignore
Kconfig seccomp: Document two-phase seccomp and arch-provided seccomp_data 2014-09-03 14:58:17 -07:00