Often all is needed is these small helpers, instead of compiler.h or a
full kprobes.h. This is important for asm helpers, in fact even some
asm/kprobes.h make use of these helpers... instead just keep a generic
asm file with helpers useful for asm code with the least amount of
clutter as possible.
Likewise we need now to also address what to do about this file for both
when architectures have CONFIG_HAVE_KPROBES, and when they do not. Then
for when architectures have CONFIG_HAVE_KPROBES but have disabled
CONFIG_KPROBES.
Right now most asm/kprobes.h do not have guards against CONFIG_KPROBES,
this means most architecture code cannot include asm/kprobes.h safely.
Correct this and add guards for architectures missing them.
Additionally provide architectures that not have kprobes support with
the default asm-generic solution. This lets us force asm/kprobes.h on
the header include/linux/kprobes.h always, but most importantly we can
now safely include just asm/kprobes.h on architecture code without
bringing the full kitchen sink of header files.
Two architectures already provided a guard against CONFIG_KPROBES on its
kprobes.h: sh, arch. The rest of the architectures needed gaurds added.
We avoid including any not-needed headers on asm/kprobes.h unless
kprobes have been enabled.
In a subsequent atomic change we can try now to remove compiler.h from
include/linux/kprobes.h.
During this sweep I've also identified a few architectures defining a
common macro needed for both kprobes and ftrace, that of the definition
of the breakput instruction up. Some refer to this as
BREAKPOINT_INSTRUCTION. This must be kept outside of the #ifdef
CONFIG_KPROBES guard.
[mcgrof@kernel.org: fix arm64 build]
Link: http://lkml.kernel.org/r/CAB=NE6X1WMByuARS4mZ1g9+W=LuVBnMDnh_5zyN0CLADaVh=Jw@mail.gmail.com
[sfr@canb.auug.org.au: fixup for kprobes declarations moving]
Link: http://lkml.kernel.org/r/20170214165933.13ebd4f4@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170203233139.32682-1-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is a superfluous '*' in the definition of kprobe_decode_insn_t
which on older versions of GCC (4.2.4) causes the compilation error:
In file included from arch/arm/probes/kprobes/core.c:37:
arch/arm/probes/kprobes/core.h:43: error: '[*]' not allowed in other than a declaration
Fix this by removing the unneeded character.
Reported-by: Janusz Użycki <j.uzycki@elproma.com.pl>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch removes software emulation or simulation for most of probed
instructions. If the instruction doesn't use PC relative addressing,
it will be translated into following instructions in the restore code
in code template:
ldmia {r0 - r14} // restore all instruction except PC
<instruction> // direct execute the probed instruction
b next_insn // branch to next instruction.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch utilizes the previously introduced checker to check
register usage for probed ARM instruction and saves it in a mask.
A further patch will use such information to avoid simulation or
emulation.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
For the instruction 'mrs Rn, cpsr' the resulting value of Rn can vary due to
external factors we can't control. So get the test code to mask out these
indeterminate bits.
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch introduce kprobeopt for ARM 32.
Limitations:
- Currently only kernel compiled with ARM ISA is supported.
- Offset between probe point and optinsn slot must not larger than
32MiB. Masami Hiramatsu suggests replacing 2 words, it will make
things complex. Futher patch can make such optimization.
Kprobe opt on ARM is relatively simpler than kprobe opt on x86 because
ARM instruction is always 4 bytes aligned and 4 bytes long. This patch
replace probed instruction by a 'b', branch to trampoline code and then
calls optimized_callback(). optimized_callback() calls opt_pre_handler()
to execute kprobe handler. It also emulate/simulate replaced instruction.
When unregistering kprobe, the deferred manner of unoptimizer may leave
branch instruction before optimizer is called. Different from x86_64,
which only copy the probed insn after optprobe_template_end and
reexecute them, this patch call singlestep to emulate/simulate the insn
directly. Futher patch can optimize this behavior.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Jon Medhurst (Tixy) <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
These have extra 'checker' functions associated with them so lets make
sure those get covered by testing. As they may create uninitialised
space on the stack we also update the test code to ensure such space is
consistent between test runs. This is done by disabling interrupts in
setup_test_context().
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch prohibits probing instructions for which the stack
requirements are unable to be determined statically. Some test cases
are found not work again after the modification, this patch also
removes them.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch uses the previously introduced checker functionality on
store instructions to record their stack consumption information to
arch_probes_insn.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This patch introdces 'checker' to decoding phase, and calls checkers
when instruction decoding. This allows further decoding for specific
instructions. This patch introduces a stub call of checkers in kprobe
arch_prepare_kprobe() as an example and for further expansion.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reviewed-by: Jon Medhurst <tixy@linaro.org>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jon Medhurst <tixy@linaro.org>
This doesn't correct any bugs when probing these instructions but makes
MOVW slightly faster and makes everything more symmetric with the Thumb
instruction cases.
We can also remove the now redundant PROBES_EMULATE_NONE and
PROBES_SIMULATE_NOP actions.
Signed-off-by: Jon Medhurst <tixy@linaro.org>
Luis R. Rodriguez