Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.
Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.
All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)
The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.
Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.
User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)
This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILES
for N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
done
FILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\<event\>/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES
... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.
Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.
( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )
Suggested-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: (262 commits)
sh: mach-ecovec24: Add user debug switch support
sh: Kill off unused se_skipped in alignment trap notification code.
sh: Wire up HAVE_SYSCALL_TRACEPOINTS.
video: sh_mobile_lcdcfb: use both register sets for display panning
video: sh_mobile_lcdcfb: implement display panning
sh: Fix up sh7705 flush_dcache_page() build.
sh: kfr2r09: document the PLL/FLL <-> RF relationship.
sh: mach-ecovec24: need asm/clock.h.
sh: mach-ecovec24: deassert usb irq on boot.
sh: Add KEYSC support for EcoVec24
sh: add kycr2_delay for sh_keysc
sh: cpufreq: Include CPU id in info messages.
sh: multi-evt support for SH-X3 proto CPU.
sh: clkfwk: remove bogus set_bus_parent() from SH7709.
sh: Fix the indication point of the liquid crystal of AP-325RXA(AP3300)
sh: Add EcoVec24 romImage defconfig
sh: USB disable process is needed if romImage boot for EcoVec24
sh: EcoVec24: add HIZA setting for LED
sh: EcoVec24: write MAC address in boot
sh: Add romImage support for EcoVec24
...
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (34 commits)
time: Prevent 32 bit overflow with set_normalized_timespec()
clocksource: Delay clocksource down rating to late boot
clocksource: clocksource_select must be called with mutex locked
clocksource: Resolve cpu hotplug dead lock with TSC unstable, fix crash
timers: Drop a function prototype
clocksource: Resolve cpu hotplug dead lock with TSC unstable
timer.c: Fix S/390 comments
timekeeping: Fix invalid getboottime() value
timekeeping: Fix up read_persistent_clock() breakage on sh
timekeeping: Increase granularity of read_persistent_clock(), build fix
time: Introduce CLOCK_REALTIME_COARSE
x86: Do not unregister PIT clocksource on PIT oneshot setup/shutdown
clocksource: Avoid clocksource watchdog circular locking dependency
clocksource: Protect the watchdog rating changes with clocksource_mutex
clocksource: Call clocksource_change_rating() outside of watchdog_lock
timekeeping: Introduce read_boot_clock
timekeeping: Increase granularity of read_persistent_clock()
timekeeping: Update clocksource with stop_machine
timekeeping: Add timekeeper read_clock helper functions
timekeeping: Move NTP adjusted clock multiplier to struct timekeeper
...
Fix trivial conflict due to MIPS lemote -> loongson renaming.
This is necessary to get ftrace syscall tracing working again.. a fairly
trivial and mechanical change. The one benefit is that this can also be
enabled on sh64, despite not having its own ftrace port.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits)
powerpc64: convert to dynamic percpu allocator
sparc64: use embedding percpu first chunk allocator
percpu: kill lpage first chunk allocator
x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA
percpu: update embedding first chunk allocator to handle sparse units
percpu: use group information to allocate vmap areas sparsely
vmalloc: implement pcpu_get_vm_areas()
vmalloc: separate out insert_vmalloc_vm()
percpu: add chunk->base_addr
percpu: add pcpu_unit_offsets[]
percpu: introduce pcpu_alloc_info and pcpu_group_info
percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward
percpu: add @align to pcpu_fc_alloc_fn_t
percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()
percpu: drop @static_size from first chunk allocators
percpu: generalize first chunk allocator selection
percpu: build first chunk allocators selectively
percpu: rename 4k first chunk allocator to page
percpu: improve boot messages
percpu: fix pcpu_reclaim() locking
...
Fix trivial conflict as by Tejun Heo in kernel/sched.c
This tidies up the printks when running on SMP, and aids in debugging
when certain cores are unable to be scaled.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This fixes up broken clock re-parenting undertaken by the SH7709 clock
framework code, which is currently in conflict with the legacy CPG
framework. With this change in place, the legacy CPG ancestry is used,
and we manage to avoid contending on the clock_list_sem mutex, which is
already held under the legacy registration path, resulting in livelock.
In order for SH7709 to fully support the varying clock modes, it needs to
implement a more complete clock framework. After this change it is in
sync with legacy CPG mode, which ends up being the default configuration
for this CPU anyways.
Signed-off-by: Rafael Ignacio Zurita <rizurita@yahoo.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Add a keyctl to install a process's session keyring onto its parent. This
replaces the parent's session keyring. Because the COW credential code does
not permit one process to change another process's credentials directly, the
change is deferred until userspace next starts executing again. Normally this
will be after a wait*() syscall.
To support this, three new security hooks have been provided:
cred_alloc_blank() to allocate unset security creds, cred_transfer() to fill in
the blank security creds and key_session_to_parent() - which asks the LSM if
the process may replace its parent's session keyring.
The replacement may only happen if the process has the same ownership details
as its parent, and the process has LINK permission on the session keyring, and
the session keyring is owned by the process, and the LSM permits it.
Note that this requires alteration to each architecture's notify_resume path.
This has been done for all arches barring blackfin, m68k* and xtensa, all of
which need assembly alteration to support TIF_NOTIFY_RESUME. This allows the
replacement to be performed at the point the parent process resumes userspace
execution.
This allows the userspace AFS pioctl emulation to fully emulate newpag() and
the VIOCSETTOK and VIOCSETTOK2 pioctls, all of which require the ability to
alter the parent process's PAG membership. However, since kAFS doesn't use
PAGs per se, but rather dumps the keys into the session keyring, the session
keyring of the parent must be replaced if, for example, VIOCSETTOK is passed
the newpag flag.
This can be tested with the following program:
#include <stdio.h>
#include <stdlib.h>
#include <keyutils.h>
#define KEYCTL_SESSION_TO_PARENT 18
#define OSERROR(X, S) do { if ((long)(X) == -1) { perror(S); exit(1); } } while(0)
int main(int argc, char **argv)
{
key_serial_t keyring, key;
long ret;
keyring = keyctl_join_session_keyring(argv[1]);
OSERROR(keyring, "keyctl_join_session_keyring");
key = add_key("user", "a", "b", 1, keyring);
OSERROR(key, "add_key");
ret = keyctl(KEYCTL_SESSION_TO_PARENT);
OSERROR(ret, "KEYCTL_SESSION_TO_PARENT");
return 0;
}
Compiled and linked with -lkeyutils, you should see something like:
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
355907932 --alswrv 4043 -1 \_ keyring: _uid.4043
[dhowells@andromeda ~]$ /tmp/newpag
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: _ses
1055658746 --alswrv 4043 4043 \_ user: a
[dhowells@andromeda ~]$ /tmp/newpag hello
[dhowells@andromeda ~]$ keyctl show
Session Keyring
-3 --alswrv 4043 4043 keyring: hello
340417692 --alswrv 4043 4043 \_ user: a
Where the test program creates a new session keyring, sticks a user key named
'a' into it and then installs it on its parent.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
The kgdb stub has traditionally tied in to the NMI slot, and manually
handled debounce. Now that we have a generic way to do this instead, all
of the stub-specific debounce silliness can be killed off.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This implements support for NMI debugging that was shamelessly copied
from the avr32 port. A bit of special magic is needed in the interrupt
exception path given that the NMI exception handler is stubbed in to the
regular exception handling table despite being reported in INTEVT. So we
mangle the lookup and kick off an EXPEVT-style exception dispatch from
the INTEVT path for exceptions that do_IRQ() has no chance of handling.
As a result, we also drop the evt2irq() conversion from the do_IRQ() path
and just do it in assembly.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Some unaligned accesses are completely expected. For example, the
trapped_io code uses the unaligned access fixup code path so there's no
need to warn about having to fixup the unaligned access.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The recent commit "timekeeping: Increase granularity of
read_persistent_clock()" introduced read_persistent_clock()
rework which inadvertently broke the sh conversion:
arch/sh/kernel/time.c:45: error: passing argument 1 of 'rtc_sh_get_time' from incompatible pointer type
distcc[13470] ERROR: compile arch/sh/kernel/time.c on sprygo/32 failed
make[2]: *** [arch/sh/kernel/time.o] Error 1
This trivial fix gets it working again.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
LKML-Reference: <20090824223239.GB20832@linux-sh.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch changes the way in which "multi-evt" interrups are handled.
The intc_evt2irq_table and related intc_evt2irq() have been removed and
the "redirecting" handler is installed for the coupled interrupts.
Thanks to that the do_IRQ() function don't have to use another level
of indirection for all the interrupts...
Signed-off-by: Pawel Moll <pawel.moll@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
sys_cacheflush should return with EINVAL if the cache parameter is not
one of ICACHE, DCACHE or BCACHE.
So, we need to include 0 in the first check.
It also adds the three definitions above as wrapper of the existent macros.
PS: ltp cacheflush01 test now passes.
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
It is possible for the CPU to re-enable it's interrupt block bit
before the write to the interrupt controller has actually masked out
the external interupt at the controller. We get around this by
reading back from the interrupt controller which will ensure the
write has happened.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Adds a system call to allow user code to flush code from the cache.
You can use instructions for the data side, but the iside can
only be done by a flush ROM which really only works with a direct
mapped cache. The later SH4's have 2 way Iside, so this call allows
a portable way to flush the cache.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Optimise memcpy_to/fromio. This is used extensivly by MTD, so is a
worthwhile performance gain. The main savings come from not repeatedly
calling readl/writel, and doing word instead of byte at a time
transfers. Also using "movca.l" on SH4 gives a small performance win.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
After performing the port2addr conversion, and checking that the data is
correctly aligned, simply call __raw_readsX/writesX. These have already been
optimised.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The SH instruction set has several instructions which accept an 8 bit
immediate operand. For logical instructions this operand is zero extended,
for arithmetic instructions the operand is sign extended. After adding an
option to the assembler to check this, it was found that several pieces
of assembly code were assuming this behaviour, and in one case
getting it wrong.
So this patch explicitly sign extends any immediate operands, which makes
it obvious what is happening, and fixes the one case which got it wrong.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
So far kernel command line arguments could be passed in by a bootloader
or defined as CONFIG_CMDLINE, which completely overwriting the first one.
This change allows a developer to declare selected kernel parameters in
a kernel configuration (eg. project-specific defconfig), retaining
possibility of passing others by a bootloader.
The obvious examples of the first type are MTD partition or
bigphysarea-like region definitions, while "debug" option or network
configuration should be given by a bootloader or a JTAG boot script.
Signed-off-by: Pawel Moll <pawel.moll@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patches will trigger a reboot using the watchdog
timer instead of double fault. Unlike the previous
method, this one actually works in 32 bit mode.
Reset should also be cleaner.
Signed-off-by: Jon Frosdick <jon.frosdick@st.com>
Signed-off-by: Carl Shaw <carl.shaw@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Save the VBR allowing GDB to dump full registers set but do not reload it
as soon as the kgdb_handle_exception is invoked.
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The synopsys PCI cell used in the later STMicro chips requires code to
be run in order to do IO cycles, rather than just memory mapping the IO
space. Rather than extending the existing SH infrastructure to allow
this, use the GENERIC_IOMAP implmentation to save re-inventing the
wheel.
This set of changes allows the SH to be built with GENERIC_IOMAP
enabled, it just ifdef's out the functions provided by the GENERIC_IOMAP
implementation, and provides a few required missing functions.
Signed-off-by: David McKay <david.mckay@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
GCC does not issue unwind information for function epilogues.
Unfortunately we can catch a signal during an epilogue. The signal
handler writes the current context and signal return code onto the stack
overwriting previous contents. During unwinding, libgcc can try to
restore registers from the stack and restores corrupted ones. This can
lead to segmentation, misaligned access and sigbus faults.
For example, consider the following code:
mov.l r12,@-r15
mov.l r14,@-r15
sts.l pr,@-r15
mov r15,r14
<do stuff>
mov r14, r15
lds.l @r15+, pr
<<< SIGNAL HERE
mov.l @r15+, r14
mov.l @r15+, r12
rts
Unwind is aware that pr was pushed to stack in prolog, so tries to
restore it. Unfortunately it restores the last word of the signal
handler code placed on the stack by the kernel.
This patch tries to avoid the problem by adding a guard region on the
stack between where the function pushes data and where the signal handler
pushes its return code. We probably don't see this problem often because
exception handling unwinding in an epilogue only occurs due to a pthread
cancel signal. Also the kernel signal stack handler alignment of 8 bytes
could hide the occurance of this problem sometimes as the stack may not
be trampled at a particular required word.
This is not guaranteed to always work. It relies on a frame pointer
existing for the function (so it can get the correct sp value) which is
not always the case for the SH4.
Modifications will also be made to libgcc for the case where there is no
fp.
Signed-off-by: Carl Shaw <carl.shaw@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch fixes a few problems with the existing code in do_address_error().
a) the variable used to printk()d the offending instruction wasn't
initialized correctly. This is a fix to bug 5727
b) behaviour for CONFIG_CPU_SH2A wasn't correct
c) the 'ignore address error' behaviour didn't update the PC, causing an
infinite loop.
Signed-off-by: Andre Draszik <andre.draszik@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch brings the SH4 misaligned trap handler in line with what
happens on ARM:
Add a /proc/cpu/alignment which can be read from to get alignment
trap statistics and written to to influence the behaviour of the
alignment trap handling. The value to write is a bitfield, which
has the following meaning: 1 warn, 2 fixup, 4 signal
In addition, we add a /proc/cpu/kernel_alignment, to enable or
disable warnings in case of kernel code causing alignment errors.
Signed-off by: Andre Draszik <andre.draszik@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch makes sure we see messages about unaligned access fixups
every now and then. Else especially userspace apps suffering from
bad programming won't ever be noticed...
Signed-off by: Andre Draszik <andre.draszik@st.com>
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The Runtime PM patch for UIO driver implements coarse grained
dynamic power management for UIO devices. With that patch in
place we can get rid of the static clock configuration. Which
in turn makes it possible for cpuidle to enter deeper sleep.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The runtime PM for SH-Mobile code had platform_bus_notify() as __devinit,
which is rather bogus. Kill off the annotation, which subsequently
silences the section mismatch warnings.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch is V3 of the SuperH Mobile Runtime PM platform bus
implentation matching Rafael's Runtime PM v16.
The code gets invoked from the SuperH specific Runtime PM
platform bus functions that override the weak symbols for:
- platform_pm_runtime_suspend()
- platform_pm_runtime_resume()
- platform_pm_runtime_idle()
This Runtime PM implementation performs two levels of power
management. At the time of platform bus runtime suspend the
clock to the device is stopped instantly. Later on if all
devices within the power domain has their clocks stopped
then the device driver ->runtime_suspend() callbacks are
used to save hardware register state for each device.
Device driver ->runtime_suspend() calls are scheduled from
cpuidle context using platform_pm_runtime_suspend_idle().
When all devices have been fully suspended the processor
is allowed to enter deep sleep from cpuidle.
The runtime resume operation turns on clocks and also
restores registers if needed. It is worth noting that the
devices start in a suspended state and the device driver
is responsible for calling runtime resume before accessing
the actual hardware.
In this particular platform bus implementation runtime
resume is not allowed from interrupt context. Runtime
suspend is however allowed from interrupt context as
long as the synchronous functions are avoided.
[ updated for v17 -- PFM. ]
Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
The CIE and FDE structs are big enough and accessed regularly enough in
certain configurations to make cacheline alignment useful.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This simplifies the unwinder trap handling, dropping the use of the
special trapa vector and simply piggybacking on top of the BUG support. A
new BUGFLAG_UNWINDER is added for flagging the unwinder fault, before
continuing on with regular BUG dispatch.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
If the oprofile code is built as a module, unwind_stack() as used by the
oprofile backtrace code is not available, causing build breakage.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Allow a DWARF register to have an undefined value. When applied to the
DWARF return address register this lets lets us label a function as
having no direct caller, e.g. kernel_thread_helper().
Signed-off-by: Matt Fleming <matt@console-pimps.org>
The 'end' member of struct dwarf_fde denotes one byte past the end of
the CFA instruction stream for an FDE. The value of 'end' was being
calcualted incorrectly, it was being set too high. This resulted in
dwarf_cfa_execute_insns() interpreting data past the end of valid
instructions, thus causing all sorts of weird crashes.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
When CONFIG_DWARF_UNWINDER is enabled setup r14 in handle_interrupt, so
that we can figure out what function was running when we were
interrupted.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
We can't assume that if we execute the unwinder code and the unwinder
was already running that it has faulted. Clearly two kernel threads can
invoke the unwinder at the same time and may be running simultaneously.
The previous approach used BUG() and BUG_ON() in the unwinder code to
detect whether the unwinder was incapable of unwinding the stack, and
that the next available unwinder should be used instead. A better
approach is to explicitly invoke a trap handler to switch unwinders when
the current unwinder cannot continue.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
The handling of DW_CFA_val_offset ops was incorrectly using the
DWARF_REG_OFFSET flag but the register's value cannot be calculated
using the DWARF_REG_OFFSET method. Create a new flag to indicate that a
different method must be used to calculate the register's value even
though there is no implementation for DWARF_VAL_OFFSET yet; it's mainly
just a place holder.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Plug a memory leak in dwarf_unwinder_dump() where we didn't free the
memory that we had previously allocated for the DWARF frames and DWARF
registers.
Now is also a opportune time to implement our own mempool and kmem
cache. It's a good idea to have a certain number of frame and register
objects in reserve at all times, so that we are guaranteed to have our
allocation satisfied even when memory is scarce. Since we have pools to
allocate from we can implement the registers for each frame as a linked
list as opposed to a sparsely populated array. Whilst it's true that the
lookup time for a linked list is larger than for arrays, there's only
usually a maximum of 8 registers per frame. So the overhead isn't that
much of a concern.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
