On Thu, Oct 5, 2017 at 6:06 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Wed, 4 Oct 2017 14:19:56 -0700 > Thomas Garnier <thgarnie@xxxxxxxxxx> wrote: > >> When using -fPIE/PIC with function tracing, the compiler generates a >> call through the GOT (call *__fentry__@GOTPCREL). This instruction >> takes 6 bytes instead of 5 on the usual relative call. >> >> With this change, function tracing supports 6 bytes on traceable >> function and can still replace relative calls on the ftrace assembly >> functions. >> >> Position Independent Executable (PIE) support will allow to extended the >> KASLR randomization range below the -2G memory limit. > > Question: This 6 bytes is only the initial call that gcc creates. When > function tracing is enabled, the calls are back to the normal call to > the ftrace trampoline? That is correct. > > -- Steve > -- Thomas _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
