Commit Graph

2157 Commits

Author SHA1 Message Date
Jon Frosdick
b46373e0d4 sh: Use internal watchdog timer to perform reset
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>
2009-08-24 16:20:44 +09:00
Giuseppe Cavallaro
27a30f53bb sh: kgdb: do not reload VBR while handling debugger breackpoint
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>
2009-08-24 16:14:03 +09:00
David McKay
15444a8973 sh: Allow use of GENERIC_IOMAP
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>
2009-08-24 16:10:40 +09:00
Carl Shaw
2fc742f8d6 sh: Improve unwind info for signals
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>
2009-08-24 15:07:08 +09:00
Andre Draszik
5a0ab35e43 sh: cleanup of do_address_error()
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>
2009-08-24 15:01:10 +09:00
Andre Draszik
7436cde6b2 sh: Allow user control over misaligned fixup handling
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>
2009-08-24 14:53:46 +09:00
Andre Draszik
9a4af027a0 sh: ratelimit unaligned fixups
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>
2009-08-24 14:38:27 +09:00
Paul Mundt
c3144fc46f Merge branches 'sh/hwblk' and 'sh/pm-runtime' 2009-08-23 18:04:07 +09:00
Magnus Damm
cc58f597af sh: drop static UIO clocks for sh7722, sh7723 and sh7724
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>
2009-08-23 18:03:21 +09:00
Magnus Damm
ac2c596b57 sh: let ARCH_SHMOBILE select PM and PM_RUNTIME
With the Runtime PM driver changes in place, we must have
Runtime PM support in place. Otherwise there is no way to
enable clocks to the Runtime PM enabled hardware blocks.
This patch makes Runtime PM mandatory on SuperH Mobile.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-23 18:03:20 +09:00
Paul Mundt
a62926fe4b sh: Fix section mismatch in platform bus notifier.
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>
2009-08-23 18:03:20 +09:00
Magnus Damm
6a93dde1e8 sh: Runtime PM for SuperH Mobile platform bus devices
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>
2009-08-23 18:03:17 +09:00
Paul Mundt
4f896ffca2 sh: unwinder: cacheline align slab cache objects.
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>
2009-08-22 19:03:25 +09:00
Paul Mundt
fa9d3b4da5 Merge branch 'sh/dwarf-unwinder'
Conflicts:
	arch/sh/kernel/cpu/sh3/entry.S
2009-08-22 05:37:14 +09:00
Paul Mundt
74db2479c1 sh64: dummy unwinder BUG wrappers.
sh64 does not yet support GENERIC_BUG, but still wants unwinder support.
Alias UNWINDER_BUG and UNWINDER_BUG_ON to their BUG counterparts until
the conversion to GENERIC_BUG is completed.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-22 05:31:45 +09:00
Paul Mundt
e115f2c17c sh: unwinder: Use a special bug flag for unwinder traps.
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>
2009-08-22 05:28:25 +09:00
Paul Mundt
c153a58e71 Merge branch 'sh/dwarf-unwinder' of git://github.com/mfleming/linux-2.6 into sh/dwarf-unwinder 2009-08-22 03:49:58 +09:00
Paul Mundt
4ab8f241f6 sh: Export unwind_stack() to satisfy modular oprofile.
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>
2009-08-22 03:43:15 +09:00
Matt Fleming
5580e9044d sh: Handle the DWARF op, DW_CFA_undefined
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>
2009-08-21 13:04:11 +01:00
Matt Fleming
5480675dc6 sh: Fix bug calculating the end of the FDE instructions
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>
2009-08-21 13:04:10 +01:00
Matt Fleming
fe98dd31eb sh: Setup the frame pointer in handle_interrupt
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>
2009-08-21 13:04:10 +01:00
Matt Fleming
b344e24a8e sh: unwinder: Introduce UNWINDER_BUG() and UNWINDER_BUG_ON()
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>
2009-08-21 13:02:44 +01:00
Matt Fleming
97efbbd588 sh: unwinder: Set the flags for DW_CFA_val_offset ops as DWARF_VAL_OFFSET
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>
2009-08-21 13:02:44 +01:00
Matt Fleming
fb3f3e7fc6 sh: unwinder: Fix memory leak and create our own kmem cache
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>
2009-08-21 13:02:43 +01:00
Yoshihiro Shimoda
c01f0f1a4a sh: Add initial support for SH7757 CPU subtype
Signed-off-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 17:25:47 +09:00
Magnus Damm
a81bec7653 sh: update kfr2r09 defconfig
Update the kfr2r09 defconfig with support for LCDC and USB gadget.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 08:32:16 +09:00
Magnus Damm
e498dab4bb sh: add kfr2r09 romimage defconfig
Add romImage defconfig for the kfr2r09 board. This defconfig
should be used to build the kernel based boot loader.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 08:32:15 +09:00
Magnus Damm
673b74be85 sh: jump to p1 during boot on kfr2r09
Add a P1 jump to the the kfr2r09 romimage code. With this
patch applied the initial zImage assembly code will run
with instruction cache enabled.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 08:32:15 +09:00
Magnus Damm
7c328e476b sh: invalidate icache and tlbs during boot on kfr2r09
Add instruction cache and TLB invalidation code for the
the kfr2r09 romimage target.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 08:32:15 +09:00
Magnus Damm
045a4b7ee7 sh: i2c compile fix for kfr2r09
Fix the kfr2r09 board code so it compiles if CONFIG_I2C=n.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-21 08:32:14 +09:00
Paul Mundt
e89561cf49 sh: enable rtc-ds1302 in snapgear_defconfig.
This is the only board that presently supports this rtc, so make sure it
is enabled by default to get some build coverage.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 15:06:47 +09:00
Paul Mundt
485f0720c3 sh: DSP save/restore ordering and a0 sign extension fixups.
As an excellent indicator of how much testing the DSP code gets, a couple
of rather glaring bugs in the DSP save/restore paths were found:

- In the DSP restore case a0 needs to be popped off before a0g,
  or the value of a0g is clobbered by the MSB of a0 in the case
  of sign extension.

- Beyond that, the save and restore orders were out of sync,
  so this fixes that up as well. At the same time, we switch over
  to using movs.l for both the save and restore of the general DSP
  registers as opposed to using sts.l (which was initially put in
  place to work around a bug in ancient binutils versions which
  the kernel no longer supports).

Reported-by: Chee Soon Yip <yip.cheesoon@renesas.com>
Cc: Chu Lih Kwek <kwek.chulih@renesas.com>,
Cc: General Lai <general.lai@renesas.com>,
Cc: Robert Cozens <Robert.Cozens@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 14:02:20 +09:00
Michael Trimarchi
6503fe4a65 sh: Better description of SH-4 PTEA register update.
Signed-off-by: Michael Trimarchi <trimarchimichael@yahoo.it>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 13:27:44 +09:00
Paul Mundt
307646c958 sh: Fix up the CONFIG_FTRACE_SYSCALLS=n build.
-tip can't be bothered keeping interfaces stable long enough for anyone
to use them without having their builds broken without notification, so
just ifdef around the problematic symbols until the new interfaces become
available upstream.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 12:07:46 +09:00
Paul Mundt
65603789db Merge branch 'sh/r8a66597-udc' 2009-08-20 11:54:38 +09:00
Magnus Damm
f8f8c0797d sh: add r8a66597 usb1 gadget to the se7724 board
Add USB gadget support for port CN26 on the Solution Engine 7724
board. The r8a66597-udc driver is hooked up as a platform device
and some registers are configured to enable the USB in gadget mode.
The hardware driving the USB port is the on-chip USB1 block in
the sh7724 processor configured as USB gadget controller.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 10:32:18 +09:00
Magnus Damm
5a1c4cb5bc sh: add r8a66597 usb0 gadget to the kfr2r09 board
Add USB gadget support for port YC301 on the KFR2R09 board.

The r8a66597-udc driver is hooked up as a platform device,
clocks are enabled via I2C and some registers are configured
to enable the USB in gadget mode. The hardware driving the
USB port is the on-chip USB0 block in the sh7724 processor
configured as USB gadget controller.

This board is using external hardware to detect USB hotplug
events and allows the processor to dynamically start and stop
clocks. This well thought out hardware feature is unused at
this point and plug and play is unfortunately unsupported.
To properly support all hardware features the USB gadget
stack may need some adjustment.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 10:32:17 +09:00
Paul Mundt
e638fab91e sh: Add mach-types entry for EcoVec board.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 10:14:29 +09:00
Kuninori Morimoto
4138b74066 sh: Add EcoVec (SH7724) board support
This adds preliminary support for the EcoVec board.

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-20 10:13:16 +09:00
Kuninori Morimoto
24d76195d1 sh: Add SH7724 support to NR_ONCHIP_DMA_CHANNELS
This patch also update help comment

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-19 19:28:40 +09:00
Kuninori Morimoto
1bc265d06c sh: USB0 resource area fix for ms7724se
Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-19 19:28:40 +09:00
Kuninori Morimoto
e174d13010 sh: Prevent heartbeat from scribbling over non-LED bits.
While most platforms implement LED banks in sets of 8/16/32, some use
different configurations. This adds a LED mask to the heartbeat platform
data to allow platforms to constrain the bitmap, which is otherwise
derived from the register size.

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 21:16:29 +09:00
Kuninori Morimoto
b2ea8b4215 sh: clkfwk: Support additional IFC divisor on SH7724.
This patch updates the FRQCRA.IFC divisor values for SH7724. Despite
not being initially documented, the / 3 mode is also support for the IFC
division.

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 21:16:29 +09:00
Kuninori Morimoto
7a01be28ba sh: mach-kfr2409: add FLLFRQ value for PLL correction.
FLLFRQ setting is needed to use correct PLL clock for kfr2409.

Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 21:16:29 +09:00
Matt Fleming
f3a8308864 sh: Add a few missing irqflags tracing markers.
save_regs contains an SR modification without an irqflags annotation,
which resulted in a missing TRACE_IRQS_OFF in the interrupt exception
path on SH-3/SH4.

I've also moved the TRACE_IRQS_OFF/ON annotation when returning from the
interrupt to just before we call __restore_all. This seems like the most
logical place to put this because the annotation is for when we restore
the SR register so we should delay the annotation until as last as
possible.

We were also missing a TRACE_IRQS_OFF in resume_kernel when
CONFIG_PREEMPT is enabled.

The end result is that this fixes up the lockdep engine debugging support
with CONFIG_PREEMPT enabled on all SH-3/4 parts.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 11:35:09 +09:00
Magnus Damm
63cd91dfd4 sh: SuperH Mobile Software Standby support for cpuidle
This patch adds "SuperH Mobile Standby Mode [SF]" to the list
of cpuidle sleep modes. If the software latency requirements
from cpuidle are met together with fulfilled hardware
requirements then deep sleep modes can be entered.

Tested on sh7722 and sh7724 with "Sleep Mode", "Sleep Mode + SF"
and "Software Standby Mode + SF" together with a multimedia
work load and flood ping without packet drop.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 10:17:32 +09:00
Magnus Damm
309214af53 sh: rework SuperH Mobile sleep code exception handling
This patch updates the exception handling in the sleep code
for SuperH Mobile. With the patch applied the sleep code
always rewrites the VBR and resumes from the exception vector,
re-initializes hardware and jumps straight to the original
interrupt vector.

Tested on sh7722 and sh7724 with "Sleep Mode", "Sleep Mode + SF"
and "Software Standby Mode + SF" with CONFIG_SUSPEND.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-18 10:17:29 +09:00
Paul Mundt
97f361e249 sh: unwinder: Move initialization to early_initcall() and tidy up locking.
This moves the initialization over to an early_initcall(). This fixes up
some lockdep interaction issues. At the same time, kill off some
superfluous locking in the init path.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-17 05:07:38 +09:00
Matt Fleming
cd7246f0e2 sh: Add support for DWARF GNU extensions
Also, remove the "fix" to DW_CFA_def_cfa_register where we reset the
frame's cfa_offset to 0. This action is incorrect when handling
DW_CFA_def_cfa_register as the DWARF spec specifically states that the
previous contents of cfa_offset should be used with the new
register. The reason that I thought cfa_offset should be reset to 0 was
because it was being assigned a bogus value prior to executing the
DW_CFA_def_cfa_register op. It turns out that the bogus cfa_offset value
came from interpreting .cfi_escape pseudo-ops (those used by the GNU
extensions) as CFA_DW_def_cfa ops.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
2009-08-16 12:48:53 +01:00
Matt Fleming
b955873bf5 sh: Try again at getting the initial return address for an unwind
The previous hack for calculating the return address for the first frame
we unwind (dwarf_unwinder_dump) didn't always work. The problem was that
it assumed once it read the rule for calculating the return address,
there would be no new rules for calculating it. This isn't true because
the way in which the CFA is calculated can change as you progress
through a function and the return address is figured out using the
CFA. Therefore, the way to calculate the return address can change.

So, instead of using some offset from the beginning of
dwarf_unwind_stack which is just a flakey approach, and instead of
executing instructions from the FDE until the return address is setup,
we now figure out the pc in dwarf_unwind_stack() just before we call
dwarf_cfa_execute_insns().

Signed-off-by: Matt Fleming <matt@console-pimps.org>
2009-08-16 12:48:53 +01:00