| Message ID | 1449195519-17901-2-git-send-email-huawei.libin@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 4 Dec 2015 10:18:38 +0800 Li Bin <huawei.libin@huawei.com> wrote: > For ftrace on arm64, kstop_machine which is hugely disruptive > to a running system is not needed to convert nops to ftrace calls > or back, because that to be modified instrucions, that NOP, B or BL, > are all safe instructions which called "concurrent modification > and execution of instructions", that can be executed by one > thread of execution as they are being modified by another thread > of execution without requiring explicit synchronization. > > Signed-off-by: Li Bin <huawei.libin@huawei.com> > --- > arch/arm64/kernel/ftrace.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-) > > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index c851be7..9669b33 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -93,6 +93,11 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, > return ftrace_modify_code(pc, old, new, true); > } > > +void arch_ftrace_update_code(int command) > +{ > + ftrace_modify_all_code(command); Hmm, I wonder why I haven't done this for powerpc. I probably should. Anyway, Reviewed-by: Steven Rostedt <rostedt@goodmis.org> If it is indeed safe not to do any special handling. -- Steve > +} > + > int __init ftrace_dyn_arch_init(void) > { > return 0;
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index c851be7..9669b33 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -93,6 +93,11 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, return ftrace_modify_code(pc, old, new, true); } +void arch_ftrace_update_code(int command) +{ + ftrace_modify_all_code(command); +} + int __init ftrace_dyn_arch_init(void) { return 0;
For ftrace on arm64, kstop_machine which is hugely disruptive to a running system is not needed to convert nops to ftrace calls or back, because that to be modified instrucions, that NOP, B or BL, are all safe instructions which called "concurrent modification and execution of instructions", that can be executed by one thread of execution as they are being modified by another thread of execution without requiring explicit synchronization. Signed-off-by: Li Bin <huawei.libin@huawei.com> --- arch/arm64/kernel/ftrace.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)