This is a full implementation of Kprobes including Jprobes and
Kretprobes support.
This ARM implementation does not follow the usual kprobes double-
exception model. The traditional model is where the initial kprobes
breakpoint calls kprobe_handler(), which returns from exception to
execute the instruction in its original context, then immediately
re-enters after a second breakpoint (or single-stepping exception)
into post_kprobe_handler(), each time the probe is hit.. The ARM
implementation only executes one kprobes exception per hit, so no
post_kprobe_handler() phase. All side-effects from the kprobe'd
instruction are resolved before returning from the initial exception.
As a result, all instructions are _always_ effectively boosted
regardless of the type of instruction, and even regardless of whether
or not there is a post-handler for the probe.
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: Quentin Barnes <qbarnes@gmail.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
This is the code implementing instruction single-stepping for kprobes
on ARM.
To get around the limitation of no Next-PC and no hardware single-
stepping, all kprobe'd instructions are split into three camps:
simulation, emulation, and rejected. "Simulated" instructions are
those instructions which behavior is reproduced by straight C code.
"Emulated" instructions are ones that are copied, slightly altered
and executed directly in the instruction slot to reproduce their
behavior. "Rejected" instructions are ones that could be simulated,
but work hasn't been put into simulating them. These instructions
should be very rare, if not unencountered, in the kernel. If ever
needed, code could be added to simulate them.
One might wonder why this and the ptrace singlestep facility are not
sharing some code. Both approaches are fundamentally different because
the ptrace code regains control after the stepped instruction by installing
a breakpoint after the instruction itself, and possibly at the location
where the instruction might be branching to, instead of simulating or
emulating the target instruction.
The ptrace approach isn't suitable for kprobes because the breakpoints
would have to be moved back, and the icache flushed, everytime the
probe is hit to let normal code execution resume, which would have a
significant performance impact. It is also racy on SMP since another
CPU could, with the right timing, sail through the probe point without
being caught. Because ptrace single-stepping always result in a
different process to be scheduled, the concern for performance is much
less significant.
On the other hand, the kprobes approach isn't (currently) suitable for
ptrace because it has no provision for proper user space memory
protection and translation, and even if that was implemented, the gain
wouldn't be worth the added complexity in the ptrace path compared to
the current approach.
So, until kprobes does support user space, both kprobes and ptrace are
best kept independent and separate.
Signed-off-by: Quentin Barnes <qbarnes@gmail.com>
Signed-off-by: Abhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Add support for stacktrace. Use the new stacktrace code with
oprofile instead of it's version; there's no point having
multiple versions of stacktracing in the kernel.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (117 commits)
[ARM] 4058/2: iop32x: set ->broken_parity_status on n2100 onboard r8169 ports
[ARM] 4140/1: AACI stability add ac97 timeout and retries
[ARM] 4139/1: AACI record support
[ARM] 4138/1: AACI: multiple channel support for IRQ handling
[ARM] 4211/1: Provide a defconfig for ns9xxx
[ARM] 4210/1: base for new machine type "NetSilicon NS9360"
[ARM] 4222/1: S3C2443: Remove reference to missing S3C2443_PM
[ARM] 4221/1: S3C2443: DMA support
[ARM] 4220/1: S3C24XX: DMA system initialised from sysdev
[ARM] 4219/1: S3C2443: DMA source definitions
[ARM] 4218/1: S3C2412: fix CONFIG_CPU_S3C2412_ONLY wrt to S3C2443
[ARM] 4217/1: S3C24XX: remove the dma channel show at startup
[ARM] 4090/2: avoid clash between PXA and SA1111 defines
[ARM] 4216/1: add .gitignore entries for ARM specific files
[ARM] 4214/2: S3C2410: Add Armzone QT2410
[ARM] 4215/1: s3c2410 usb device: per-platform vbus_draw
[ARM] 4213/1: S3C2410 - Update definition of ADCTSC_XY_PST
[ARM] 4098/1: ARM: rtc_lock only used with rtc_cmos
[ARM] 4137/1: Add kexec support
[ARM] 4201/1: SMP barriers pair needed for the secondary boot process
...
Fix up conflict due to typedef removal in sound/arm/aaci.h
Add kexec support to ARM.
Improvements like commandline handling could be made but this patch gives
basic functional support. It uses the next available syscall number, 347.
Once the syscall number is known, userspace support will be
finalised/submitted to kexec-tools, various patches already exist.
Originally based on a patch by Maxim Syrchin but updated and forward
ported by various people.
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
XScale cores either have a DSP coprocessor (which contains a single
40 bit accumulator register), or an iWMMXt coprocessor (which contains
eight 64 bit registers.)
Because of the small amount of state in the DSP coprocessor, access to
the DSP coprocessor (CP0) is always enabled, and DSP context switching
is done unconditionally on every task switch. Access to the iWMMXt
coprocessor (CP0/CP1) is enabled only when an iWMMXt instruction is
first issued, and iWMMXt context switching is done lazily.
CONFIG_IWMMXT is supposed to mean 'the cpu we will be running on will
have iWMMXt support', but boards are supposed to select this config
symbol by hand, and at least one pxa27x board doesn't get this right,
so on that board, proc-xscale.S will incorrectly assume that we have a
DSP coprocessor, enable CP0 on boot, and we will then only save the
first iWMMXt register (wR0) on context switches, which is Bad.
This patch redefines CONFIG_IWMMXT as 'the cpu we will be running on
might have iWMMXt support, and we will enable iWMMXt context switching
if it does.' This means that with this patch, running a CONFIG_IWMMXT=n
kernel on an iWMMXt-capable CPU will no longer potentially corrupt iWMMXt
state over context switches, and running a CONFIG_IWMMXT=y kernel on a
non-iWMMXt capable CPU will still do DSP context save/restore.
These changes should make iWMMXt work on PXA3xx, and as a side effect,
enable proper acc0 save/restore on non-iWMMXt capable xsc3 cores such
as IOP13xx and IXP23xx (which will not have CONFIG_CPU_XSCALE defined),
as well as setting and using HWCAP_IWMMXT properly.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add the necessary call to register_isa_ports() so that glibc knows
where these are found on Integrator platforms.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
This patch makes the iWMMXt context switch hook use the generic
thread notifier infrastructure that was recently merged in commit
d6551e884c.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Lennert Buytenhek
Add the necessary kernel bits for crunch task switching.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fix compilation problem of start-up codes.
(head-nommu.S, arch/arm/kernel/Makefile)
Signed-off-by: Hyok S. Choi <hyok.choi@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre
The difference between EABI and the legacy ABI may affect either
structure member alignment and/or argument register selection.
The patch has the details.
Included are wrappers for the following syscalls:
sys_stat64
sys_lstat64
sys_fstat64
sys_fcntl64
sys_epoll_ctl
sys_epoll_wait
sys_ipc
sys_semop
sys_semtimedop
sys_pread64
sys_pwrite64
sys_truncate64
sys_ftruncate64
sys_readahead
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ISA_DMA_API tells the rest of the kernel if the ISA DMA API is
available. Select this symbol only on machine types which make
use of the ISA DMA API.
Make building of arch/arm/kernel/dma.c depend on this symbol -
if a machine does not support the ISA DMA API, it's pointless
building this file.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We are coding the kernel link address into the makefiles, which is
invisibly dependent on PAGE_OFFSET. If PAGE_OFFSET is changed, the
makefiles also need to be changed.
Make adjustments such that the makefiles encode just the offset from
PAGE_OFFSET for the kernel link address, and use PAGE_OFFSET in the
linker scripts directly.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch from Nicolas Pitre
Since vmlinux.lds.S is preprocessed, we can use the defines already
present in asm/memory.h (allowed by patch #3060) for the XIP kernel link
address instead of relying on a duplicated Makefile hardcoded value, and
also get rid of its dependency on awk to handle it at the same time.
While at it let's clean XIP stuff even further and make things clearer
in head.S with a nice code reduction.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Abhishek Sagar