x86/ftrace: Remove mcount support from x86_32 with DYNAMIC_FTRACE enabled
Now that the oldest compiler to build the Linux kernel is gcc 4.6, we no
longer need to support mcount (-pg without -mfentry) as the fentry caller
takes precedence. The build process checks if -mfentry is supported by the
compiler and will use that if it is. The -mfentry option was added to gcc
4.6 for x86_32, and since 4.6 is the oldest compiler to build the Linux
kernel, it will only be build with -mfentry support for x86_32.
Note, the fentry code was only ported to x86_32 for DYNAMIC_FTRACE, as
static ftrace is only there to make sure static ftrace works (for other
archs that don't support DYNAMIC_FTRACE). The mcount code needs to still
exist for x86_32 with DYNAMIC_FTRACE disabled. But we can remove it for all
the places that DYNAMIC_FTRACE is enabled.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
1 file changed
