linux.git/arch/csky/kernel/probes, branch v5.14

kprobes: Do not increment probe miss count in the fault handler

2021-06-03T13:47:26+00:00

Kprobes has a counter 'nmissed', that is used to count the number of
times a probe handler was not called. This generally happens when we hit
a kprobe while handling another kprobe.

However, if one of the probe handlers causes a fault, we are currently
incrementing 'nmissed'. The comment in fault handler indicates that this
can be used to account faults taken by the probe handlers. But, this has
never been the intention as is evident from the comment above 'nmissed'
in 'struct kprobe':

	/*count the number of times this probe was temporarily disarmed */
	unsigned long nmissed;

Signed-off-by: Naveen N. Rao 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com

kprobes: Remove kprobe::fault_handler

2021-06-01T14:00:08+00:00

The reason for kprobe::fault_handler(), as given by their comment:

 * We come here because instructions in the pre/post
 * handler caused the page_fault, this could happen
 * if handler tries to access user space by
 * copy_from_user(), get_user() etc. Let the
 * user-specified handler try to fix it first.

Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Christoph Hellwig 
Acked-by: Masami Hiramatsu 
Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org

ftrace: Fix spelling mistake "disabed" -> "disabled"

2021-03-17T04:19:40+00:00

There is a spelling mistake in a comment, fix it.

Signed-off-by: Colin Ian King 
Signed-off-by: Palmer Dabbelt

csky: kprobe: Fixup code in simulate without 'long'

2021-02-27T08:34:50+00:00

The type of 'val' is 'unsigned long' in simulate_blz32, so 'val < 0'
can't be true.

Cast 'val' to 'long' here to determine branch token or not,

Fixup instructions: bnezad32, bhsz32, bhz32, blsz32, blz32

Link: https://lore.kernel.org/linux-csky/CAJF2gTQjKXR9gpo06WAWG1aquiT87mATiMGorXs6ChxOxoe90Q@mail.gmail.com/T/#t
Signed-off-by: Guo Ren 
Co-developed-by: Menglong Dong 
Signed-off-by: Menglong Dong

ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs

2020-11-13T17:14:55+00:00

In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.

For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.

This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.

Acked-by: Peter Zijlstra (Intel) 
Reviewed-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

ftrace: Add recording of functions that caused recursion

2020-11-06T13:42:26+00:00

This adds CONFIG_FTRACE_RECORD_RECURSION that will record to a file
"recursed_functions" all the functions that caused recursion while a
callback to the function tracer was running.

Link: https://lkml.kernel.org/r/20201106023548.102375687@goodmis.org

Cc: Masami Hiramatsu 
Cc: Andrew Morton 
Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Guo Ren 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: Thomas Gleixner 
Cc: Borislav Petkov 
Cc: x86@kernel.org
Cc: "H. Peter Anvin" 
Cc: Kees Cook 
Cc: Anton Vorontsov 
Cc: Colin Cross 
Cc: Tony Luck 
Cc: Josh Poimboeuf 
Cc: Jiri Kosina 
Cc: Miroslav Benes 
Cc: Petr Mladek 
Cc: Joe Lawrence 
Cc: Kamalesh Babulal 
Cc: Mauro Carvalho Chehab 
Cc: Sebastian Andrzej Siewior 
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: live-patching@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware)

kprobes/ftrace: Add recursion protection to the ftrace callback

2020-11-06T13:35:44+00:00

If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.

The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.

Link: https://lkml.kernel.org/r/20201028115613.140212174@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.944907560@goodmis.org

Cc: Peter Zijlstra 
Cc: Ingo Molnar 
Cc: Josh  Poimboeuf 
Cc: Jiri Kosina 
Cc: Miroslav Benes 
Cc: Petr Mladek 
Cc: Andrew Morton 
Cc: Guo Ren 
Cc: "James E.J. Bottomley" 
Cc: Helge Deller 
Cc: Michael Ellerman 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mackerras 
Cc: Heiko Carstens 
Cc: Vasily Gorbik 
Cc: Christian Borntraeger 
Cc: Thomas Gleixner 
Cc: Borislav Petkov 
Cc: x86@kernel.org
Cc: "H. Peter Anvin" 
Cc: "Naveen N. Rao" 
Cc: Anil S Keshavamurthy 
Cc: "David S. Miller" 
Cc: linux-csky@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Acked-by: Masami Hiramatsu 
Signed-off-by: Steven Rostedt (VMware)

csky: kprobes: Use generic kretprobe trampoline handler

2020-09-08T09:52:33+00:00

Use the generic kretprobe trampoline handler. Don't use
framepointer verification.

Signed-off-by: Masami Hiramatsu 
Signed-off-by: Ingo Molnar 
Acked-by: Guo Ren 
Link: https://lore.kernel.org/r/159870605775.1229682.2627276871589951304.stgit@devnote2

csky: Fixup perf probe -x hungup

2020-05-13T09:55:05+00:00

case:
 # perf probe -x /lib/libc-2.28.9000.so memcpy
 # perf record -e probe_libc:memcpy -aR sleep 1

System hangup and cpu get in trap_c loop, because our hardware
singlestep state could still get interrupt signal. When we get in
uprobe_xol singlestep slot, we should disable irq in pt_regs->psr.

And is_swbp_insn() need a csky arch implementation with a low 16bit
mask.

Signed-off-by: Guo Ren 
Cc: Steven Rostedt (VMware)

csky: Add uprobes support

2020-04-03T03:37:51+00:00

This patch adds support for uprobes on csky architecture.

Just like kprobe, it support single-step and simulate instructions.

Signed-off-by: Guo Ren 
Cc: Arnd Bergmann 
Cc: Steven Rostedt (VMware)