linux-toradex.git/arch/powerpc/kernel/ftrace.c, branch v4.2.7

Merge tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

2014-12-12T01:48:14+00:00

Pull powerpc updates from Michael Ellerman:
"Some nice cleanups like removing bootmem, and removal of
__get_cpu_var().

There is one patch to mm/gup.c. This is the generic GUP
implementation, but is only used by us and arm(64). We have an ack
from Steve Capper, and although we didn't get an ack from Andrew he
told us to take the patch through the powerpc tree.

There's one cxl patch. This is in drivers/misc, but Greg said he was
happy for us to manage fixes for it.

There is an infrastructure patch to support an IPMI driver for OPAL.

There is also an RTC driver for OPAL. We weren't able to get any
response from the RTC maintainer, Alessandro Zummo, so in the end we
just merged the driver.

The usual batch of Freescale updates from Scott"

* tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits)
powerpc/powernv: Return to cpu offline loop when finished in KVM guest
powerpc/book3s: Fix partial invalidation of TLBs in MCE code.
powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
powerpc/xmon: Cleanup the breakpoint flags
powerpc/xmon: Enable HW instruction breakpoint on POWER8
powerpc/mm/thp: Use tlbiel if possible
powerpc/mm/thp: Remove code duplication
powerpc/mm/hugetlb: Sanity check gigantic hugepage count
powerpc/oprofile: Disable pagefaults during user stack read
powerpc/mm: Check for matching hpte without taking hpte lock
powerpc: Drop useless warning in eeh_init()
powerpc/powernv: Cleanup unused MCE definitions/declarations.
powerpc/eeh: Dump PHB diag-data early
powerpc/eeh: Recover EEH error on ownership change for BCM5719
powerpc/eeh: Set EEH_PE_RESET on PE reset
powerpc/eeh: Refactor eeh_reset_pe()
powerpc: Remove more traces of bootmem
powerpc/pseries: Initialise nvram_pstore_info's buf_lock
cxl: Name interrupts in /proc/interrupt
cxl: Return error to PSL if IRQ demultiplexing fails & print clearer warning
...

ftrace: Add more information to ftrace_bug() output

2014-11-11T17:42:13+00:00

With the introduction of the dynamic trampolines, it is useful that if
things go wrong that ftrace_bug() produces more information about what
the current state is. This can help debug issues that may arise.

Ftrace has lots of checks to make sure that the state of the system it
touchs is exactly what it expects it to be. When it detects an abnormality
it calls ftrace_bug() and disables itself to prevent any further damage.
It is crucial that ftrace_bug() produces sufficient information that
can be used to debug the situation.

Cc: Benjamin Herrenschmidt 
Acked-by: Borislav Petkov 
Tested-by: Masami Hiramatsu 
Tested-by: Jiri Kosina 
Signed-off-by: Steven Rostedt

powerpc/ftrace: simplify prepare_ftrace_return

2014-11-09T22:59:28+00:00

Instead of passing in the stack address of the link register
to be modified, just pass in the old value and return the
new value and rely on ftrace_graph_caller to do the
modification.

This removes the exception handling around the stack update -
it isn't needed and we weren't consistent about it. Later on
we would do an unprotected modification:

       if (!ftrace_graph_entry(&trace)) {
               *parent = old;

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc/ftrace: Remove mod_return_to_handler

2014-11-09T22:59:27+00:00

mod_return_to_handler is the same as return_to_handler, except
it handles the change of the TOC (r2). Add this into
return_to_handler and remove mod_return_to_handler.

Signed-off-by: Anton Blanchard 
Signed-off-by: Michael Ellerman

powerpc/ftrace: Add call to ftrace_graph_is_dead() in function graph code

2014-07-18T17:56:56+00:00

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Cc: Anton Blanchard 
Acked-by: Benjamin Herrenschmidt 
Signed-off-by: Steven Rostedt

powerpc/ftrace: Use pr_fmt() to namespace error messages

2014-06-24T04:05:50+00:00

The printks() in our ftrace code have no prefix, so they appear on the
console with very little context, eg:

  Branch out of range

Use pr_fmt() & pr_err() to add a prefix. While we're at it, collapse a
few split lines that don't need to be, and add a missing newline to one
message.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix nop of modules on 64bit LE (ABIv2)

2014-06-24T04:05:46+00:00

There is a bug in the handling of the function entry when we are nopping
out a branch from a module in ftrace.

We compare the result of module_trampoline_target() with the value of
ppc_function_entry(), and expect them to be true. But they never will
be.

module_trampoline_target() will always return the global entry point of
the function, whereas ppc_function_entry() will always return the local.

Fix it by using the newly added ppc_global_function_entry().

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix inverted check of create_branch()

2014-06-24T04:05:41+00:00

In commit 24a1bdc35, "Fix ABIv2 issues with __ftrace_make_call", Anton
changed the logic that creates and patches the branch, and added a
thinko in the check of create_branch(). create_branch() returns the
instruction that was generated, so if we get zero then it succeeded.

The result is we can't ftrace modules:

  Branch out of range
  WARNING: at ../kernel/trace/ftrace.c:1638
  ftrace failed to modify [] fuse_req_init_context+0x1c/0x90 [fuse]

We should probably fix patch_instruction() to do that check and make the
API saner, but that's a separate patch. For now just invert the test.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix typo in mask of opcode

2014-06-24T04:05:37+00:00

In commit 24a1bdc35, "Fix ABIv2 issues with __ftrace_make_call", Anton
changed the logic that checks for the expected code sequence when
patching a module.

We missed the typo in the mask, 0xffff00000 should be 0xffff0000, which
has the effect of making the test always true.

That makes it impossible to ftrace against modules, eg:

  Unexpected call sequence: 48000008 e8410018
  WARNING: at ../kernel/trace/ftrace.c:1638
  ftrace failed to modify [] rng_dev_open+0x1c/0x70 [rng_core]

Reported-by: David Binderman 
Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc/ftrace: Fix ABIv2 issues with __ftrace_make_call

2014-04-23T00:05:35+00:00

__ftrace_make_call assumed ABIv1 TOC stack offsets, so it
broke on ABIv2.

While we are here, we can simplify the instruction modification
code. Since we always update one instruction there is no need to
probe_kernel_write and flush_icache_range, just use patch_branch.

Signed-off-by: Anton Blanchard