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Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not
set. This is because ftrace_function_trace is not always set to ftrace_stub
when function_graph is in use.
Do not skip checking of graph tracer functions when ftrace_function_trace
is set.
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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In a randconfig build I ran into this build error:
arch/arm64/kernel/entry-ftrace.S: Assembler messages:
arch/arm64/kernel/entry-ftrace.S:101: Error: unknown mnemonic `ldr_l' -- `ldr_l x2,ftrace_trace_function'
The macro is defined in asm/assembler.h, so we should include that file.
Fixes: 829d2bd13392 ("arm64: entry-ftrace.S: avoid open-coded {adr,ldr}_l")
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Some places in the kernel open-code sequences using ADRP for a symbol
another instruction using a :lo12: relocation for that same symbol.
These sequences are easy to get wrong, and more painful to read than is
necessary. For these reasons, it is preferable to use the
{adr,ldr,str}_l macros for these cases.
This patch makes use of these in entry-ftrace.S, removing open-coded
sequences using adrp. This results in a minor code change, since a
temporary register is not used when generating the address for some
symbols, but this is fine, as the value of the temporary register is not
used elsewhere.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Make HAVE_FUNCTION_GRAPH_FP_TEST a normal define, independent from
kconfig. This removes some config file pollution and simplifies the
checking for the fp test.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2c4e5f05054d6d367f702fd153af7a0109dd5c81.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When function graph tracer is enabled, the following operation
will trigger panic:
mount -t debugfs nodev /sys/kernel
echo next_tgid > /sys/kernel/tracing/set_ftrace_filter
echo function_graph > /sys/kernel/tracing/current_tracer
ls /proc/
------------[ cut here ]------------
[ 198.501417] Unable to handle kernel paging request at virtual address cb88537fdc8ba316
[ 198.506126] pgd = ffffffc008f79000
[ 198.509363] [cb88537fdc8ba316] *pgd=00000000488c6003, *pud=00000000488c6003, *pmd=0000000000000000
[ 198.517726] Internal error: Oops: 94000005 [#1] SMP
[ 198.518798] Modules linked in:
[ 198.520582] CPU: 1 PID: 1388 Comm: ls Tainted: G
[ 198.521800] Hardware name: linux,dummy-virt (DT)
[ 198.522852] task: ffffffc0fa9e8000 ti: ffffffc0f9ab0000 task.ti: ffffffc0f9ab0000
[ 198.524306] PC is at next_tgid+0x30/0x100
[ 198.525205] LR is at return_to_handler+0x0/0x20
[ 198.526090] pc : [<ffffffc0002a1070>] lr : [<ffffffc0000907c0>] pstate: 60000145
[ 198.527392] sp : ffffffc0f9ab3d40
[ 198.528084] x29: ffffffc0f9ab3d40 x28: ffffffc0f9ab0000
[ 198.529406] x27: ffffffc000d6a000 x26: ffffffc000b786e8
[ 198.530659] x25: ffffffc0002a1900 x24: ffffffc0faf16c00
[ 198.531942] x23: ffffffc0f9ab3ea0 x22: 0000000000000002
[ 198.533202] x21: ffffffc000d85050 x20: 0000000000000002
[ 198.534446] x19: 0000000000000002 x18: 0000000000000000
[ 198.535719] x17: 000000000049fa08 x16: ffffffc000242efc
[ 198.537030] x15: 0000007fa472b54c x14: ffffffffff000000
[ 198.538347] x13: ffffffc0fada84a0 x12: 0000000000000001
[ 198.539634] x11: ffffffc0f9ab3d70 x10: ffffffc0f9ab3d70
[ 198.540915] x9 : ffffffc0000907c0 x8 : ffffffc0f9ab3d40
[ 198.542215] x7 : 0000002e330f08f0 x6 : 0000000000000015
[ 198.543508] x5 : 0000000000000f08 x4 : ffffffc0f9835ec0
[ 198.544792] x3 : cb88537fdc8ba316 x2 : cb88537fdc8ba306
[ 198.546108] x1 : 0000000000000002 x0 : ffffffc000d85050
[ 198.547432]
[ 198.547920] Process ls (pid: 1388, stack limit = 0xffffffc0f9ab0020)
[ 198.549170] Stack: (0xffffffc0f9ab3d40 to 0xffffffc0f9ab4000)
[ 198.582568] Call trace:
[ 198.583313] [<ffffffc0002a1070>] next_tgid+0x30/0x100
[ 198.584359] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.585503] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.586574] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.587660] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70
[ 198.588896] Code: aa0003f5 2a0103f4 b4000102 91004043 (885f7c60)
[ 198.591092] ---[ end trace 6a346f8f20949ac8 ]---
This is because when using function graph tracer, if the traced
function return value is in multi regs ([x0-x7]), return_to_handler
may corrupt them. So in return_to_handler, the parameter regs should
be protected properly.
Cc: <stable@vger.kernel.org> # 3.18+
Signed-off-by: Li Bin <huawei.libin@huawei.com>
Acked-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Replace ldr xN, =<symbol> with adrp/add or adrp/ldr [as appropriate]
in the implementation of _mcount(), which may be called very often.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.
arm64 was broken anyway, as it had an ifdef testing
CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST which is only set if
the arch supports the code (which it obviously did not), and
it was testing a non existent ftrace_trace_stop instead of
function_trace_stop.
Link: http://lkml.kernel.org/r/20140627124421.GP26276@arm.com
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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This patch allows "dynamic ftrace" if CONFIG_DYNAMIC_FTRACE is enabled.
Here we can turn on and off tracing dynamically per-function base.
On arm64, this is done by patching single branch instruction to _mcount()
inserted by gcc -pg option. The branch is replaced to NOP initially at
kernel start up, and later on, NOP to branch to ftrace_caller() when
enabled or branch to NOP when disabled.
Please note that ftrace_caller() is a counterpart of _mcount() in case of
'static' ftrace.
More details on architecture specific requirements are described in
Documentation/trace/ftrace-design.txt.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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This patch implements arm64 specific part to support function tracers,
such as function (CONFIG_FUNCTION_TRACER), function_graph
(CONFIG_FUNCTION_GRAPH_TRACER) and function profiler
(CONFIG_FUNCTION_PROFILER).
With 'function' tracer, all the functions in the kernel are traced with
timestamps in ${sysfs}/tracing/trace. If function_graph tracer is
specified, call graph is generated.
The kernel must be compiled with -pg option so that _mcount() is inserted
at the beginning of functions. This function is called on every function's
entry as long as tracing is enabled.
In addition, function_graph tracer also needs to be able to probe function's
exit. ftrace_graph_caller() & return_to_handler do this by faking link
register's value to intercept function's return path.
More details on architecture specific requirements are described in
Documentation/trace/ftrace-design.txt.
Reviewed-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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