diff options
| 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/include/asm/ftrace.h | |
| parent | 819e50e25d0ce8a75f5cba815416a6a8573655c4 (diff) | |
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/include/asm/ftrace.h')
| -rw-r--r-- | arch/arm64/include/asm/ftrace.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 58ea5951b198..ed5c448ece99 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -18,6 +18,21 @@ #ifndef __ASSEMBLY__ extern void _mcount(unsigned long); + +struct dyn_arch_ftrace { + /* No extra data needed for arm64 */ +}; + +extern unsigned long ftrace_graph_call; + +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + /* + * addr is the address of the mcount call instruction. + * recordmcount does the necessary offset calculation. + */ + return addr; +} #endif /* __ASSEMBLY__ */ #endif /* __ASM_FTRACE_H */ |