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| author | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2014-04-30 10:54:34 +0100 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2014-05-29 09:08:33 +0100 |
| commit | bd7d38dbdf356e75eb3b1699158c9b8021fd6784 (patch) | |
| tree | edad0afa91c1774cfaba6319b319d65db244123d /arch/arm64/Kconfig | |
| parent | 819e50e25d0ce8a75f5cba815416a6a8573655c4 (diff) | |
| download | lwn-bd7d38dbdf356e75eb3b1699158c9b8021fd6784.tar.gz lwn-bd7d38dbdf356e75eb3b1699158c9b8021fd6784.zip | |
arm64: ftrace: Add dynamic ftrace support
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>
Diffstat (limited to 'arch/arm64/Kconfig')
| -rw-r--r-- | arch/arm64/Kconfig | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8a25a4ad3159..4e689ad5f27c 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -36,6 +36,7 @@ config ARM64 select HAVE_DMA_API_DEBUG select HAVE_DMA_ATTRS select HAVE_DMA_CONTIGUOUS + select HAVE_DYNAMIC_FTRACE select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_TRACER |