linux/arch/ppc
Marcelo Tosatti bb16574681 [PATCH] 8xx: avoid "dcbst" misbehaviour with unpopulated TLB
The proposed _tlbie call at update_mmu_cache() is safe because:

Addresses for which update_mmu_cache() gets invocated are never inside the
static kernel virtual mapping, meaning that there is no risk for the
_tlbie() here to be thrashing the pinned entry, as Dan suspected.

The intermediate TLB state in which this bug can be triggered is not
visible by userspace or any other contexts, except the page fault handling
path.  So there is no need to worry about userspace dcbxxx users.

The other solution to this is to avoid dcbst misbehaviour in the first
place, which involves changing in-kernel "dcbst" callers to use 8xx
specific SPR's.

Summary:

On 8xx, cache control instructions (particularly "dcbst" from
flush_dcache_icache) fault as write operation if there is an unpopulated
TLB entry for the address in question.  To workaround that, we invalidate
the TLB here, thus avoiding dcbst misbehaviour.

Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-27 15:11:42 -07:00
..
4xx_io Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
8xx_io Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
8260_io Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
amiga Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
boot [PATCH] update comment about gzip scratch size 2005-06-25 16:25:07 -07:00
configs [PATCH] ppc32: Added preliminary support for the MPC8548 CDS board 2005-06-21 18:46:23 -07:00
kernel [PATCH] Update cfq io scheduler to time sliced design 2005-06-27 14:33:29 -07:00
lib [PATCH] smp_processor_id() cleanup 2005-06-21 18:46:13 -07:00
math-emu Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
mm [PATCH] 8xx: avoid "dcbst" misbehaviour with unpopulated TLB 2005-06-27 15:11:42 -07:00
oprofile Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
platforms [PATCH] ppc32: Fix compiling of sandpoint platform 2005-06-27 15:11:41 -07:00
syslib [PATCH] ppc32: Fix MPC83xx IPIC external interrupt pending register offset 2005-06-26 08:43:19 -07:00
xmon [PATCH] ppc32: Kill embedded system.map, use kallsyms 2005-06-21 18:46:26 -07:00
Kconfig [PATCH] kexec: kexec ppc support 2005-06-25 16:24:51 -07:00
Kconfig.debug [PATCH] ppc32: Remove FSL OCP support 2005-06-25 16:24:27 -07:00
Makefile [PATCH] ppc32: Add support for Freescale e200 (Book-E) core 2005-06-25 16:24:26 -07:00