linux-toradex.git/arch/tile/mm/fault.c, branch v3.12.15

tile: remove HUGE_VMAP dead code

2013-09-13T15:15:24+00:00

A config option to allow a variant vmap() using huge pages that was never
upstreamed had some bits of code related to it scattered around the tile
architecture; the config option was removed downstream and this commit
cleans up the scattered evidence of it from the upstream as well.

Signed-off-by: Chris Metcalf

arch: mm: pass userspace fault flag to generic fault handler

2013-09-12T22:38:01+00:00

Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.

Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Cc: David Rientjes 
Cc: KAMEZAWA Hiroyuki 
Cc: azurIt 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arch: mm: remove obsolete init OOM protection

2013-09-12T22:38:01+00:00

The memcg code can trap tasks in the context of the failing allocation
until an OOM situation is resolved.  They can hold all kinds of locks
(fs, mm) at this point, which makes it prone to deadlocking.

This series converts memcg OOM handling into a two step process that is
started in the charge context, but any waiting is done after the fault
stack is fully unwound.

Patches 1-4 prepare architecture handlers to support the new memcg
requirements, but in doing so they also remove old cruft and unify
out-of-memory behavior across architectures.

Patch 5 disables the memcg OOM handling for syscalls, readahead, kernel
faults, because they can gracefully unwind the stack with -ENOMEM.  OOM
handling is restricted to user triggered faults that have no other
option.

Patch 6 reworks memcg's hierarchical OOM locking to make it a little
more obvious wth is going on in there: reduce locked regions, rename
locking functions, reorder and document.

Patch 7 implements the two-part OOM handling such that tasks are never
trapped with the full charge stack in an OOM situation.

This patch:

Back before smart OOM killing, when faulting tasks were killed directly on
allocation failures, the arch-specific fault handlers needed special
protection for the init process.

Now that all fault handlers call into the generic OOM killer (see commit
609838cfed97: "mm: invoke oom-killer from remaining unconverted page
fault handlers"), which already provides init protection, the
arch-specific leftovers can be removed.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Acked-by: KOSAKI Motohiro 
Cc: David Rientjes 
Cc: KAMEZAWA Hiroyuki 
Cc: azurIt 
Acked-by: Vineet Gupta 	[arch/arc bits]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tile: remove support for TILE64

2013-09-03T18:53:29+00:00

This chip is no longer being actively developed for (it was superceded
by the TILEPro64 in 2008), and in any case the existing compiler and
toolchain in the community do not support it.  It's unlikely that the
kernel works with TILE64 at this point as the configuration has not been
tested in years.  The support is also awkward as it requires maintaining
a significant number of ifdefs.  So, just remove it altogether.

Signed-off-by: Chris Metcalf

tile: don't assume user privilege is zero

2013-09-03T18:45:52+00:00

Technically, user privilege is anything less than kernel
privilege.  We modify the existing user_mode() macro to have
this semantic (and use it in a couple of places it wasn't being
used before), and add an IS_KERNEL_EX1() macro to the assembly
code as well.

Signed-off-by: Chris Metcalf

tile: support kprobes on tilegx

2013-08-30T15:55:53+00:00

This change includes support for Kprobes, Jprobes and Return Probes.

Reviewed-by: Masami Hiramatsu 
Signed-off-by: Tony Lu 
Signed-off-by: Chris Metcalf

tile: remove calls to arch_flush_lazy_mmu_mode()

2013-08-13T20:25:56+00:00

Since it's a no-op on tile anyway, there's no reason to be calling
it in tile-specific code.

Signed-off-by: Chris Metcalf

tile: fast-path unaligned memory access for tilegx

2013-08-13T20:04:10+00:00

This change enables unaligned userspace memory access via a kernel
fast path on tilegx.  The kernel tracks user PC/instruction pairs
per-thread using a direct-mapped cache in userspace.  The cache
maps those PC/instruction pairs to JIT'ed instruction sequences that
load or store using byte-wide load store intructions and then
synthesize 2-, 4- or 8-byte load or store results.  Once an
instruction has been seen to generate an unaligned access once,
subsequent hits on that instruction typically require overhead
of only around 50 cycles if cache and TLB is hot.

We support the prctl() PR_GET_UNALIGN / PR_SET_UNALIGN sys call to
enable or disable unaligned fixups on a per-process basis.

To do this we pull some of the tilepro unaligned support out of the
single_step.c file; tilepro uses instruction disassembly for both
single-step and unaligned access support.  Since tilegx actually has
hardware singlestep support, though, it's cleaner to keep the tilegx
unaligned access code in a separate file.  While we're at it,
properly rename the tilepro-specific types, etc., to have tilepro
suffixes instead of generic tile suffixes.

Signed-off-by: Chris Metcalf

tile: fix tilegx vmalloc_sync_all BUG_ON

2013-08-12T18:46:51+00:00

As specified, the test wasn't correct, and in any case it should
be a BUILD_BUG_ON.

Signed-off-by: Chris Metcalf

mm: invoke oom-killer from remaining unconverted page fault handlers

2013-07-09T17:33:20+00:00

A few remaining architectures directly kill the page faulting task in an
out of memory situation.  This is usually not a good idea since that
task might not even use a significant amount of memory and so may not be
the optimal victim to resolve the situation.

Since 2.6.29's 1c0fe6e ("mm: invoke oom-killer from page fault") there
is a hook that architecture page fault handlers are supposed to call to
invoke the OOM killer and let it pick the right task to kill.  Convert
the remaining architectures over to this hook.

To have the previous behavior of simply taking out the faulting task the
vm.oom_kill_allocating_task sysctl can be set to 1.

Signed-off-by: Johannes Weiner 
Reviewed-by: Michal Hocko 
Cc: KAMEZAWA Hiroyuki 
Acked-by: David Rientjes 
Acked-by: Vineet Gupta    [arch/arc bits]
Cc: James Hogan 
Cc: David Howells 
Cc: Jonas Bonn 
Cc: Chen Liqin 
Cc: Lennox Wu 
Cc: Chris Metcalf 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds