| Message ID | 20191225172836.7f381759@xhacker.debian (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: implement KPROBES_ON_FTRACE | expand |
On Wed, 25 Dec 2019 09:42:52 +0000 Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > On some architectures, the DYNAMIC_FTRACE_WITH_REGS is implemented by > gcc's -fpatchable-function-entry option. Take arm64 for example, arm64 > makes use of GCC -fpatchable-function-entry=2 option to insert two > nops. When the function is traced, the first nop will be modified to > the LR saver, then the second nop to "bl <ftrace-entry>". we need to > update ftrace_location() to recognise these two instructions as being > part of ftrace. To do this, we introduce FTRACE_IP_EXTENSION to let > ftrace_location search IP, IP + FTRACE_IP_EXTENSION range. > Looks good to me. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Thanks! > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> > --- > include/linux/ftrace.h | 4 ++++ > kernel/trace/ftrace.c | 2 +- > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index 7247d35c3d16..05a03b2a2f39 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -20,6 +20,10 @@ > > #include <asm/ftrace.h> > > +#ifndef FTRACE_IP_EXTENSION > +#define FTRACE_IP_EXTENSION 0 > +#endif > + > /* > * If the arch supports passing the variable contents of > * function_trace_op as the third parameter back from the > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 74439ab5c2b6..a8cfea502369 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -1590,7 +1590,7 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) > */ > unsigned long ftrace_location(unsigned long ip) > { > - return ftrace_location_range(ip, ip); > + return ftrace_location_range(ip, ip + FTRACE_IP_EXTENSION); > } > > /** > -- > 2.24.1 >
On Wed, 25 Dec 2019 09:42:52 +0000 Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > On some architectures, the DYNAMIC_FTRACE_WITH_REGS is implemented by > gcc's -fpatchable-function-entry option. Take arm64 for example, arm64 > makes use of GCC -fpatchable-function-entry=2 option to insert two > nops. When the function is traced, the first nop will be modified to > the LR saver, then the second nop to "bl <ftrace-entry>". we need to > update ftrace_location() to recognise these two instructions as being > part of ftrace. To do this, we introduce FTRACE_IP_EXTENSION to let > ftrace_location search IP, IP + FTRACE_IP_EXTENSION range. > > Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> > Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> You can also add: Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> and when Masami is happy with your patches, it should go through the tip tree. Thanks! -- Steve > --- > include/linux/ftrace.h | 4 ++++ > kernel/trace/ftrace.c | 2 +- > 2 files changed, 5 insertions(+), 1 deletion(-) > > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index 7247d35c3d16..05a03b2a2f39 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -20,6 +20,10 @@ > > #include <asm/ftrace.h> > > +#ifndef FTRACE_IP_EXTENSION > +#define FTRACE_IP_EXTENSION 0 > +#endif > + > /* > * If the arch supports passing the variable contents of > * function_trace_op as the third parameter back from the > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > index 74439ab5c2b6..a8cfea502369 100644 > --- a/kernel/trace/ftrace.c > +++ b/kernel/trace/ftrace.c > @@ -1590,7 +1590,7 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) > */ > unsigned long ftrace_location(unsigned long ip) > { > - return ftrace_location_range(ip, ip); > + return ftrace_location_range(ip, ip + FTRACE_IP_EXTENSION); > } > > /**
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7247d35c3d16..05a03b2a2f39 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -20,6 +20,10 @@ #include <asm/ftrace.h> +#ifndef FTRACE_IP_EXTENSION +#define FTRACE_IP_EXTENSION 0 +#endif + /* * If the arch supports passing the variable contents of * function_trace_op as the third parameter back from the diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 74439ab5c2b6..a8cfea502369 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1590,7 +1590,7 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end) */ unsigned long ftrace_location(unsigned long ip) { - return ftrace_location_range(ip, ip); + return ftrace_location_range(ip, ip + FTRACE_IP_EXTENSION); } /**
On some architectures, the DYNAMIC_FTRACE_WITH_REGS is implemented by gcc's -fpatchable-function-entry option. Take arm64 for example, arm64 makes use of GCC -fpatchable-function-entry=2 option to insert two nops. When the function is traced, the first nop will be modified to the LR saver, then the second nop to "bl <ftrace-entry>". we need to update ftrace_location() to recognise these two instructions as being part of ftrace. To do this, we introduce FTRACE_IP_EXTENSION to let ftrace_location search IP, IP + FTRACE_IP_EXTENSION range. Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> --- include/linux/ftrace.h | 4 ++++ kernel/trace/ftrace.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-)