This introduces CONFIG_DEBUG_RODATA, making kernel text and rodata
read-only. Additionally, this splits rodata from text so that rodata can
also be NX, which may lead to wasted memory when aligning to SECTION_SIZE.
The read-only areas are made writable during ftrace updates and kexec.
Signed-off-by: NKees Cook <keescook@chromium.org>
Tested-by: NLaura Abbott <lauraa@codeaurora.org>
Acked-by: NNicolas Pitre <nico@linaro.org>

Make ftrace work with CONFIG_DEBUG_SET_MODULE_RONX by making module text
writable around the place where ftrace does its work, like it is done on
x86 in the patch which introduced CONFIG_DEBUG_SET_MODULE_RONX,
84e1c6bb ("x86: Add RO/NX protection for loadable kernel modules").
Tested-by: NMitchel Humpherys <mitchelh@codeaurora.org>
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As the data parameter is not really used by any ftrace_dyn_arch_init,
remove that from ftrace_dyn_arch_init. This also removes the addr
local variable from ftrace_init which is now unused.

Note the documentation was imprecise as it did not suggest to set
(*data) to 0.

Link: http://lkml.kernel.org/r/1393268401-24379-4-git-send-email-jslaby@suse.cz

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.

Note there is also "return 0" in every ftrace_dyn_arch_init.  So it is
enough to check the retval and remove all the indirect sets of data on
all archs.

Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz

Cc: linux-arch@vger.kernel.org
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Commit 722b3c74 modified x86 ftrace to
avoid tracing all functions called from irqs when function graph was
used with a filter.  Port the same fix to ARM.
Acked-by: NSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: NColin Cross <ccross@android.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Extract out the instruction generation code so that it can be used
for jump labels too.
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

As commit 592201a9 (ARM: Thumb-2: Support Thumb-2 in undefined
instruction handler) says:

    32-bit Thumb instructions are specified in the form:
        ((first_half << 16 ) | second_half)
    which matches the layout used by the ARM ARM.

Convert the ftrace code to use the same format to avoid the usage of
different formats in kernel code.
Acked-by: NDave Martin <dave.martin@linaro.org>
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Before replacing an instruction, the ftrace code determines what the old
instruction should be and verifies that that's what's really there in
memory before replacing it.  This is useful if for example a bug in
mcountrecord causes it to record wrong locations.

However, in cases where we replace call sites in entry-common.S, these
checks are not needed.  For these, we currently just memcpy() the memory
content and then "verify" it -- this is quite useless and can be
removed.
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Support the graph tracer + dynamic ftrace combination on ARM.
Signed-off-by: NRabin Vincent <rabin@rab.in>

Cc: Tim Bird <tim.bird@am.sony.com>
[rabin@rab.in: rebase on top of latest code,
	       keep code in ftrace.c instead of separate file,
	       check for ftrace_graph_entry also]
Signed-off-by: NRabin Vincent <rabin@rab.in>

Handle the different nop and call instructions for Thumb-2.  Also, we
need to adjust the recorded mcount_loc addresses because they have the
lsb set.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change]
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This adds mcount recording and updates dynamic ftrace for ARM to work
with the new ftrace dyamic tracing implementation.  It also adds support
for the mcount format used by newer ARM compilers.

With dynamic tracing, mcount() is implemented as a nop.  Callsites are
patched on startup with nops, and dynamically patched to call to the
ftrace_caller() routine as needed.

Acked-by: Steven Rostedt <rostedt@goodmis.org> [recordmcount.pl change]
Signed-off-by: NRabin Vincent <rabin@rab.in>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

/tmp/ccJ3ssZW.s: Assembler messages:
/tmp/ccJ3ssZW.s:1952: Error: can't resolve `.text' {.text section} - `.LFB1077'

This is caused because:

	.section .data
	.section .text
	.section .text
	.previous

does not return us to the .text section, but the .data section; this
makes use of .previous dangerous if the ordering of previous sections
is not known.

Fix up the other users of .previous; .pushsection and .popsection are
a safer pairing to use than .section and .previous.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

... not kstop_machine.  Add a note that irqs are disabled.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>

The arch dependent function ftrace_mcount_set was only used by the daemon
start up code. This patch removes it.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Record the address of the mcount call-site. Currently all archs except sparc64
record the address of the instruction following the mcount call-site. Some
general cleanups are entailed. Storing mcount addresses in rec->ip enables
looking them up in the kprobe hash table later on to check if they're kprobe'd.
Signed-off-by: NAbhishek Sagar <sagar.abhishek@gmail.com>
Cc: davem@davemloft.net
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Remove the unneeded function ftrace_ip_converted().
Signed-off-by: NAbhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Core ftrace support for the ARM architecture, which includes support
for dynamic function tracing.
Signed-off-by: NAbhishek Sagar <sagar.abhishek@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>