Commit Graph

360751 Commits

Author SHA1 Message Date
James Hogan
9fb4aa8723 metag: move traps.c exports out of metag_ksyms.c
It's less error prone to have function symbols exported immediately
after the function rather than in metag_ksyms.c. Move each EXPORT_SYMBOL
in metag_ksyms.c for symbols defined in traps.c into traps.c

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:11:14 +00:00
James Hogan
fa771d029a metag: move irq enable out of irqflags.h on SMP
The SMP version of arch_local_irq_enable() uses preempt_disable(), but
<asm/irqflags.h> doesn't include <linux/preempt.h> causing the following
errors on SMP when pstore/ftrace is enabled (caught by buildbot smp
allyesconfig):

In file included from include/linux/irqflags.h:15,
                 from fs/pstore/ftrace.c:16:
arch/metag/include/asm/irqflags.h: In function 'arch_local_irq_enable':
arch/metag/include/asm/irqflags.h:84: error: implicit declaration of function 'preempt_disable'
arch/metag/include/asm/irqflags.h:86: error: implicit declaration of function 'preempt_enable_no_resched'

However <linux/preempt.h> cannot be easily included from
<asm/irqflags.h> as it can cause circular include dependencies in the
!SMP case, and potentially in the SMP case in the future. Therefore move
the SMP implementation of arch_local_irq_enable() into traps.c and use
an inline version of get_trigger_mask() which is also defined in traps.c
for SMP.

This adds an extra layer of function call / stack push when
preempt_disable needs to call other functions, however in the
non-preemptive SMP case it should be about as fast, as it was already
calling the get_trigger_mask() function which is now used inline.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:11:14 +00:00
James Hogan
97c3ec6308 genksyms: fix metag symbol prefix on crc symbols
Meta uses symbol prefixes, so add "metag" to the list of architectures
to set the mod_prefix to "_" for. This fixes __crc_* symbols to add the
extra underscore to match _CRC_SYMBOL macro in <linux/export.h> and so
that modpost finds them.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:11:13 +00:00
James Hogan
f75c28d896 metag: hugetlb: convert to vm_unmapped_area()
Convert hugetlb_get_unmapped_area_new_pmd() to use vm_unmapped_area()
rather than searching the virtual address space itself. This fixes the
following errors in linux-next due to the specified members being
removed after other architectures have already been converted:

arch/metag/mm/hugetlbpage.c: In function 'hugetlb_get_unmapped_area_new_pmd':
arch/metag/mm/hugetlbpage.c:199: error: 'struct mm_struct' has no member named 'cached_hole_size'
arch/metag/mm/hugetlbpage.c:200: error: 'struct mm_struct' has no member named 'free_area_cache'
arch/metag/mm/hugetlbpage.c:215: error: 'struct mm_struct' has no member named 'cached_hole_size'

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Michel Lespinasse <walken@google.com>
2013-03-02 20:11:13 +00:00
James Hogan
c838e72a35 metag: export clear_page and copy_page
Various file systems use clear_page() and copy_page(), so when they're
built as modules we get build errors like the following:

ERROR: "clear_page" [fs/ntfs/ntfs.ko] undefined!
ERROR: "copy_page" [fs/nilfs2/nilfs2.ko] undefined!

Therefore export these functions to modules from metag_ksyms.c to fix
the errors. This was hit by a randconfig build.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:11:13 +00:00
James Hogan
f626dc704e metag: export metag_code_cache_flush_all
Various file systems indirectly use metag_code_cache_flush_all(), so
when they're built as modules we get build errors like the following:

ERROR: "metag_code_cache_flush_all" [fs/xfs/xfs.ko] undefined!

Therefore export this function to modules to fix the errors. This was
hit by a randconfig build.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:11:12 +00:00
James Hogan
3d6b7bb0a2 metag: protect more non-MMU memory regions
Rename setup_txprivext() to setup_priv() and add initialisation of some
more per-thread privilege protection registers:

 - TxPRIVSYSR: 0x04400000-0x047fffff
               0x05000000-0x07ffffff
               0x84000000-0x87ffffff
 - TxPIOREG:   0x02000000-0x02ffffff
               0x04800000-0x048fffff
 - TxSYREG:    0x04000000-0x04000fff (except write fetch system event)

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:58 +00:00
James Hogan
c787c2d62f metag: make TXPRIVEXT bits explicit
Define PRIV_BITS using explicit constants from <asm/metag_regs.h> rather
than with a hard coded value. This also adds a couple of missing
definitions for the TXPRIVEXT priv bits for protecting writes to TXTIMER
and the trace registers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:58 +00:00
James Hogan
82f0167aa4 metag: kernel/setup.c: sort includes
Sort includes in kernel/setup.c.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:57 +00:00
James Hogan
1bea5b8188 perf: Enable building perf tools for Meta
Define rmb(), cpu_relax(), and CPUINFO_PROC for Meta so that the perf
tools can be built for Meta.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
2013-03-02 20:09:57 +00:00
James Hogan
883a635591 metag: add boot time LNKGET/LNKSET check
Add boot time check for whether LNKGET/LNKSET go through or around the
cache. Depending on the configuration an info message (no harm), warning
(technically wrong but no harm), or big WARN (expect failure in either
kernel or userland) may be emitted if the behaviour is not as expected:

Configuration                                Hardware   Response
------------------------------------------   --------   --------
AROUND_CACHE                                 through    pr_info
!AROUND_CACHE && ATOMICITY_LNKGET            around     WARN (kernel)
     "        && !ATOMICITY_LNKGET && SMP    around     WARN (user)
     "                   "         && !SMP   around     pr_warn

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:56 +00:00
James Hogan
0a38a8adc5 metag: add __init to metag_cache_probe()
metag_cache_probe() is only called from setup_arch(), so add the __init
attribute to it.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:56 +00:00
James Hogan
ae85ac71b7 metag: Add JTAG Debug Adapter (DA) support
Add basic JTAG Debug Adapter (DA) support so that drivers which
communicate with the DA can detect whether one is actually present
(otherwise the target will halt indefinitely).

This allows the metag_da TTY driver and imgdafs filesystem driver to be
built, updates defconfigs, and sets up the metag_da console early if
it's configured in.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:56 +00:00
James Hogan
690998b629 scripts/checkstack.pl: Add metag support
Adapt checkstack.pl so that it works for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:55 +00:00
James Hogan
00512bdd45 metag: ftrace support
Add ftrace support for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-02 20:09:55 +00:00
James Hogan
903b20ad68 metag: Perf
Add Perf support for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
2013-03-02 20:09:54 +00:00
James Hogan
5633004cc2 metag: Build infrastructure
Add metag build infrastructure.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:54 +00:00
James Hogan
79f83c0294 Kconfig.debug: add METAG to dependency lists
Add [!]METAG to a couple of Kconfig dependencies in lib/Kconfig.debug.
Don't allow stack utilization instrumentation on metag, and allow
building with frame pointers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Paul E. McKenney" <paul.mckenney@linaro.org>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
2013-03-02 20:09:53 +00:00
James Hogan
9ca52ed979 mm: define VM_GROWSUP for CONFIG_METAG
Commit cc2383ec06 ("mm: introduce
arch-specific vma flag VM_ARCH_1") merged in v3.7-rc1.

The above commit combined several arch-specific vma flags into one, and
in the process it changed the VM_GROWSUP definition to depend on
specific architectures rather than CONFIG_STACK_GROWSUP. Therefore add
an ifdef for CONFIG_METAG to also set VM_GROWSUP.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michel Lespinasse <walken@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-mm@kvack.org
2013-03-02 20:09:53 +00:00
James Hogan
1e57372eac metag: Various other headers
Add the remaining metag header files:
 - byteorder.h, swab.h (byte order and swapping)
 - barrier.h, cpu.h. hwthread.h, processor.h (hardware thread related)
 - bug.h, elf.h, gpio.h, linkage.h, resource.h (other)

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:52 +00:00
James Hogan
e8de3486a4 metag: Stack unwinding
Add stack unwinding support for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:52 +00:00
James Hogan
086e9dc0e2 metag: Optimised library functions
Add optimised library functions for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:52 +00:00
James Hogan
f507758ccb metag: DMA
Add DMA mapping code.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:51 +00:00
James Hogan
42682c6c42 metag: SMP support
Add SMP support for metag. This allows Linux to take control of multiple
hardware threads on a single Meta core, treating them as separate Linux
CPUs.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:51 +00:00
James Hogan
fdabf525b4 metag: Basic documentation
Add basic metag documentation. This includes an outline description of
the ABIs (including syscall ABI) and calling conventions, similar to the
one in Documentation/frv/.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Rob Landley <rob@landley.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: linux-doc@vger.kernel.org
2013-03-02 20:09:50 +00:00
James Hogan
6006c0d8ce metag: Atomics, locks and bitops
Add header files to implement Meta hardware thread locks (used by some
other atomic operations), atomics, spinlocks, and bitops.

There are 2 main types of atomic primitives for metag (in addition to
IRQs off on UP):
 - LOCK instructions provide locking between hardware threads.
 - LNKGET/LNKSET instructions provide load-linked/store-conditional
   operations allowing for lighter weight atomics on Meta2

LOCK instructions allow for hardware threads to acquire voluntary or
exclusive hardware thread locks:
 - LOCK0 releases exclusive and voluntary lock from the running hardware
   thread.
 - LOCK1 acquires the voluntary hardware lock, blocking until it becomes
   available.
 - LOCK2 implies LOCK1, and additionally acquires the exclusive hardware
   lock, blocking all other hardware threads from executing.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:50 +00:00
James Hogan
9b802d1f43 metag: Module support
Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:49 +00:00
James Hogan
44dea393cf metag: Scheduling/Process management
Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:49 +00:00
James Hogan
26025bbfbb metag: System Calls
Add metag system call and gateway page interfaces. The metag
architecture port uses the generic system call numbers from
asm-generic/unistd.h, as well as a user gateway page mapped at
0x6ffff000 which contains fast atomic primitives (depending on SMP) and
a fast method of accessing TLS data.

System calls use the SWITCH instruction with the immediate 0x440001 to
signal a system call.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:49 +00:00
James Hogan
5698c50d9d metag: Internal and external irqchips
Meta core internal interrupts (from HWSTATMETA and friends) are vectored
onto the TR1 core trigger for the current thread. This is demultiplexed
in irq-metag.c to individual Linux IRQs for each internal interrupt.

External SoC interrupts (from HWSTATEXT and friends) are vectored onto
the TR2 core trigger for the current thread. This is demultiplexed in
irq-metag-ext.c to individual Linux IRQs for each external SoC interrupt.
The external irqchip has devicetree bindings for configuring the number
of irq banks and the type of masking available.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Rob Landley <rob@landley.net>
Cc: Dom Cobley <popcornmix@gmail.com>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: linux-doc@vger.kernel.org
2013-03-02 20:09:48 +00:00
James Hogan
63047ea360 metag: IRQ handling
Add core IRQ handling for metag. The code in irq.c exposes the TBX
signal numbers as Linux IRQs.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:48 +00:00
James Hogan
ac919f0883 metag: Traps
Add trap code for metag. At the lowest level Meta traps (and return from
interrupt instruction - RTI) simply swap the PC and PCX registers and
optionally toggle the interrupt status bit (ISTAT). Low level TBX code
in tbipcx.S handles the core context save, determine the TBX signal
number based on the core trigger that fired (using the TXSTATI status
register), and call TBX signal handlers (mostly in traps.c) via a vector
table.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2013-03-02 20:09:45 +00:00
James Hogan
a2c5d4ed92 metag: Time keeping
Add time keeping code for metag. Meta hardware threads have 2 timers.
The background timer (TXTIMER) is used as a free-running time base, and
the interrupt timer (TXTIMERI) is used for the timer interrupt. Both
counters traditionally count at approximately 1MHz.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-03-02 20:09:22 +00:00
James Hogan
bc3966bf15 metag: ptrace
The ptrace interface for metag provides access to some core register
sets using the PTRACE_GETREGSET and PTRACE_SETREGSET operations. The
details of the internal context structures is abstracted into user API
structures to both ease use and allow flexibility to change the internal
context layouts. Copyin and copyout functions for these register sets
are exposed to allow signal handling code to use them to copy to and
from the signal context.

struct user_gp_regs (NT_PRSTATUS) provides access to the core general
purpose register context.

struct user_cb_regs (NT_METAG_CBUF) provides access to the TXCATCH*
registers which contains information abuot a memory fault, unaligned
access error or watchpoint. This can be modified to alter the way the
fault is replayed on resume ("catch replay"), or to prevent the replay
taking place.

struct user_rp_state (NT_METAG_RPIPE) provides access to the state of
the Meta read pipeline which can be used to hide memory latencies in
hand optimised data loops.

Extended DSP register state, DSP RAM, and hardware breakpoint registers
aren't yet exposed through ptrace.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
2013-03-02 20:09:22 +00:00
James Hogan
29dd78cf0b metag: Device tree
Add device tree files to arch/metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Vineet Gupta <vgupta@synopsys.com>
2013-03-02 20:09:22 +00:00
James Hogan
262d96b0de metag: Signal handling
Add signal handling code for metag.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
2013-03-02 20:09:21 +00:00
James Hogan
c438b58e65 metag: TCM support
Add some TCM support

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:21 +00:00
James Hogan
bbc17704d5 metag: Highmem support
Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:20 +00:00
James Hogan
e624e95bd8 metag: Huge TLB
Add huge TLB support to the metag architecture.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:20 +00:00
James Hogan
373cd784d0 metag: Memory handling
Meta has instructions for accessing:
 - bytes        - GETB (1 byte)
 - words        - GETW (2 bytes)
 - doublewords  - GETD (4 bytes)
 - longwords    - GETL (8 bytes)

All accesses must be aligned. Unaligned accesses can be detected and
made to fault on Meta2, however it isn't possible to fix up unaligned
writes so we don't bother fixing up reads either.

This patch adds metag memory handling code including:
 - I/O memory (io.h, ioremap.c): Actually any virtual memory can be
   accessed with these helpers. A part of the non-MMUable address space
   is used for memory mapped I/O. The ioremap() function is implemented
   one to one for non-MMUable addresses.
 - User memory (uaccess.h, usercopy.c): User memory is directly
   accessible from privileged code.
 - Kernel memory (maccess.c): probe_kernel_write() needs to be
   overwridden to use the I/O functions when doing a simple aligned
   write to non-writecombined memory, otherwise the write may be split
   by the generic version.

Note that due to the fact that a portion of the virtual address space is
non-MMUable, and therefore always maps directly to the physical address
space, metag specific I/O functions are made available (metag_in32,
metag_out32 etc). These cast the address argument to a pointer so that
they can be used with raw physical addresses. These accessors are only
to be used for accessing fixed core Meta architecture registers in the
non-MMU region, and not for any SoC/peripheral registers.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:19 +00:00
James Hogan
f5df8e268f metag: Memory management
Add memory management files for metag.

Meta's 32bit virtual address space is split into two halves:
 - local (0x08000000-0x7fffffff): traditionally local to a hardware
   thread and incoherent between hardware threads. Each hardware thread
   has it's own local MMU table. On Meta2 the local space can be
   globally coherent (GCOn) if the cache partitions coincide.
 - global (0x88000000-0xffff0000): coherent and traditionally global
   between hardware threads. On Meta2, each hardware thread has it's own
   global MMU table.

The low 128MiB of each half is non-MMUable and maps directly to the
physical address space:
 - 0x00010000-0x07ffffff: contains Meta core registers and maps SoC bus
 - 0x80000000-0x87ffffff: contains low latency global core memories

Linux usually further splits the local virtual address space like this:
 - 0x08000000-0x3fffffff: user mappings
 - 0x40000000-0x7fffffff: kernel mappings

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:19 +00:00
James Hogan
99ef7c2ac1 metag: Cache/TLB handling
Add cache and TLB handling code for metag, including the required
callbacks used by MM switches and DMA operations. Caches can be
partitioned between the hardware threads and the global space, however
this is usually configured by the bootloader so Linux doesn't make any
changes to this configuration. TLBs aren't configurable, so only need
consideration to flush them.

On Meta1 the L1 cache was VIVT which required a full flush on MM switch.
Meta2 has a VIPT L1 cache so it doesn't require the full flush on MM
switch. Meta2 can also have a writeback L2 with hardware prefetch which
requires some special handling. Support is optional, and the L2 can be
detected and initialised by Linux.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:19 +00:00
James Hogan
027f891f76 metag: TBX source
Add source files from the Thread Binary Interface (TBI) library which
provides useful low level operations and traps/context management.

Among other things it handles interrupt/exception/syscall entry (in
tbipcx.S).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:18 +00:00
James Hogan
4ca151b208 metag: TBX header
Add the main header for the Thread Binary Interface (TBI) library which
provides useful low level operations and trap/context management.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:18 +00:00
James Hogan
85d9d7a920 metag: Boot
Add boot code for metag. Due to the multi-threaded nature of Meta it is
not uncommon for an RTOS or bare metal application to be started on
other hardware threads by the bootloader. Since there is a single MMU
switch which affects all threads, the MMU is traditionally configured by
the bootloader prior to starting Linux. The bootloader passes a
structure to Linux which among other things contains information about
memory regions which have been mapped. Linux then assumes control of the
local heap memory region.

A kernel arguments string pointer or a flattened device tree pointer can
be provided in the third argument.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:17 +00:00
James Hogan
87aa1328f2 metag: Header for core memory mapped registers
Add the header <asm/metag_mem.h> describing addresses, fields, and bits
of various core memory mapped registers in the low non-MMU region.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:17 +00:00
James Hogan
af8a10493e metag: Headers for core arch constants
Add a couple of header files containing core architecture constants.

The first (<asm/metag_isa.h>) contains some constants relating to the
instruction set, such as values to give to the CACHEW and CACHER
instructions.

The second (<asm/metag_regs.h>) contains constants for the core register
units directly accessible to various instructions, and for the
registers, fields, and bits in those units. The main units described are
the control unit (CT.*), the trigger unit (TR.*), and the run-time trace
unit (TT.*).

Signed-off-by: James Hogan <james.hogan@imgtec.com>
2013-03-02 20:09:16 +00:00
James Hogan
1228594528 metag: Add MAINTAINERS entry
Add MAINTAINERS entry for the metag architecture port.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Cesar Eduardo Barros <cesarb@cesarb.net>
Cc: Joe Perches <joe@perches.com>
Cc: "David S. Miller" <davem@davemloft.net>
2013-03-02 20:09:16 +00:00
James Hogan
649508f684 trace/ring_buffer: handle 64bit aligned structs
Some 32 bit architectures require 64 bit values to be aligned (for
example Meta which has 64 bit read/write instructions). These require 8
byte alignment of event data too, so use
!CONFIG_HAVE_64BIT_ALIGNED_ACCESS instead of !CONFIG_64BIT ||
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to decide alignment, and align
buffer_data_page::data accordingly.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org> (previous version subtly different)
2013-03-02 20:09:16 +00:00
James Hogan
c19fa94a8f Add HAVE_64BIT_ALIGNED_ACCESS
On 64 bit architectures with no efficient unaligned access, padding and
explicit alignment must be added in various places to prevent unaligned
64bit accesses (such as taskstats and trace ring buffer).

However this also needs to apply to 32 bit architectures with 64 bit
accesses requiring alignment such as metag.

This is solved by adding a new Kconfig symbol HAVE_64BIT_ALIGNED_ACCESS
which defaults to 64BIT && !HAVE_EFFICIENT_UNALIGNED_ACCESS, and can be
explicitly selected by METAG and any other relevant architectures. This
can be used in various places to determine whether 64bit alignment is
required.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: Will Drewry <wad@chromium.org>
2013-03-02 20:09:15 +00:00