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 <cmetcalf@tilera.com>
Pull tile arch changes from Chris Metcalf:
"These are some minor new feature work and other changes that didn't
merit getting pushed up after the 3.9 merge window closed.
There should be a lot more activity in the 3.11 merge window"
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
arch/tile: Fix syscall return value passed to tracepoint
tile: comment assumption about __insn_mtspr for <asm/irqflags.h>
tile: ns2cycles should use __raw_get_cpu_var
arch: remove KCORE_ELF again [tile]
tile: remove two outdated Kconfig entries
tile: support atomic64_dec_if_positive()
tile: support TIF_SYSCALL_TRACEPOINT; select HAVE_SYSCALL_TRACEPOINTS
tile: Add definition of NR_syscalls
tile: move declaration of sys_call_table to <asm/syscall.h>
arch/tile: Enable HAVE_ARCH_TRACEHOOK
arch/tile: Call tracehook_report_syscall_{entry,exit} in syscall trace
Move it to a common place. Preparatory patch for implementing
set/clear for the idle need_resched poll implementation.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.446034505@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This patch adds support for the TIF_SYSCALL_TRACEPOINT on the tile
architecture. Basically, it calls the appropriate tracepoints on syscall
entry and exit.
Signed-off-by: Simon Marchi <simon.marchi@polymtl.ca>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This routine isn't used unless CONFIG_HOMECACHE is enabled, which
isn't even available as a public configuration option yet.
Since it no longer links correctly in 3.4, just remove it for now.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Pull smp hotplug cleanups from Thomas Gleixner:
"This series is merily a cleanup of code copied around in arch/* and
not changing any of the real cpu hotplug horrors yet. I wish I'd had
something more substantial for 3.5, but I underestimated the lurking
horror..."
Fix up trivial conflicts in arch/{arm,sparc,x86}/Kconfig and
arch/sparc/include/asm/thread_info_32.h
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits)
um: Remove leftover declaration of alloc_task_struct_node()
task_allocator: Use config switches instead of magic defines
sparc: Use common threadinfo allocator
score: Use common threadinfo allocator
sh-use-common-threadinfo-allocator
mn10300: Use common threadinfo allocator
powerpc: Use common threadinfo allocator
mips: Use common threadinfo allocator
hexagon: Use common threadinfo allocator
m32r: Use common threadinfo allocator
frv: Use common threadinfo allocator
cris: Use common threadinfo allocator
x86: Use common threadinfo allocator
c6x: Use common threadinfo allocator
fork: Provide kmemcache based thread_info allocator
tile: Use common threadinfo allocator
fork: Provide weak arch_release_[task_struct|thread_info] functions
fork: Move thread info gfp flags to header
fork: Remove the weak insanity
sh: Remove cpu_idle_wait()
...
First, we were at risk of handling thread-info flags, in particular
do_signal(), when returning from kernel space. This could happen
after a failed kernel_execve(), or when forking a kernel thread.
The fix is to test in do_work_pending() for user_mode() and return
immediately if so; we already had this test for one of the flags,
so I just hoisted it to the top of the function.
Second, if a ptraced process updated the callee-saved registers
in the ptregs struct and then processed another thread-info flag, we
would overwrite the modifications with the original callee-saved
registers. To fix this, we add a register to note if we've already
saved the registers once, and skip doing it on additional passes
through the loop. To avoid a performance hit from the couple of
extra instructions involved, I modified the GET_THREAD_INFO() macro
to be guaranteed to be one instruction, then bundled it with adjacent
instructions, yielding an overall net savings.
Reported-By: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This support is required for CONFIG_KEYS, NFSv4 kernel DNS, etc.
The change is slightly more complex than the minimal thing, since
I took advantage of having to go into the assembly code to just
move a bunch of stuff into C code: specifically, the schedule(),
do_async_page_fault(), do_signal(), and single_step_once() support,
in addition to the TIF_NOTIFY_RESUME support.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Add a node parameter to alloc_thread_info(), and change its name to
alloc_thread_info_node()
This change is needed to allow NUMA aware kthread_create_on_cpu()
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Tilera architecture traditionally supports 64KB page sizes
to improve TLB utilization and improve performance when the
hardware is being used primarily to run a single application.
For more generic server scenarios, it can be beneficial to run
with 4KB page sizes, so this commit allows that to be specified
(by modifying the arch/tile/include/hv/pagesize.h header).
As part of this change, we also re-worked the PTE management
slightly so that PTE writes all go through a __set_pte() function
where we can do some additional validation. The set_pte_order()
function was eliminated since the "order" argument wasn't being used.
One bug uncovered was in the PCI DMA code, which wasn't properly
flushing the specified range. This was benign with 64KB pages,
but with 4KB pages we were getting some larger flushes wrong.
The per-cpu memory reservation code also needed updating to
conform with the newer percpu stuff; before it always chose 64KB,
and that was always correct, but with 4KB granularity we now have
to pay closer attention and reserve the amount of memory that will
be requested when the percpu code starts allocating.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
None of these changes fix any actual bugs, but are just various cleanups
that fell out along the way. In particular, some unused #defines and
includes are removed, PREFETCH_STRIDE is added (the default is right for
our shipping chips, but wrong for our next generation), our tile-specific
prefetching code is removed so the (identical) generic prefetching code
can be used instead, a comment is fixed to be proper GPL and not just a
"paste GPL here" token, a "//" comment is converted to "/* */", etc.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This commit is primarily changes caused by reviewing "sparse"
and "checkpatch" output on our sources, so is somewhat noisy, since
things like "printk() -> pr_err()" (or whatever) throughout the
codebase tend to get tedious to read. Rather than trying to tease
apart precisely which things changed due to which type of code
review, this commit includes various cleanups in the code:
- sparse: Add declarations in headers for globals.
- sparse: Fix __user annotations.
- sparse: Using gfp_t consistently instead of int.
- sparse: removing functions not actually used.
- checkpatch: Clean up printk() warnings by using pr_info(), etc.;
also avoid partial-line printks except in bootup code.
- checkpatch: Use exposed structs rather than typedefs.
- checkpatch: Change some C99 comments to C89 comments.
In addition, a couple of minor other changes are rolled in
to this commit:
- Add support for a "raise" instruction to cause SIGFPE, etc., to be raised.
- Remove some compat code that is unnecessary when we fully eliminate
some of the deprecated syscalls from the generic syscall ABI.
- Update the tile_defconfig to reflect current config contents.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
This change is the core kernel support for TILEPro and TILE64 chips.
No driver support (except the console driver) is included yet.
This includes the relevant Linux headers in asm/; the low-level
low-level "Tile architecture" headers in arch/, which are
shared with the hypervisor, etc., and are build-system agnostic;
and the relevant hypervisor headers in hv/.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reviewed-by: Paul Mundt <lethal@linux-sh.org>
Chris Metcalf
Linus Torvalds
Thomas Gleixner
Simon Marchi
Al Viro
Eric Dumazet