On 2/15/22 03:10, Sami Tolvanen wrote:
On Fri, Feb 11, 2022 at 4:11 PM Nick Desaulniers
<ndesaulniers@xxxxxxxxxx> wrote:
+ Sami, Kees
Do you guys remember why we don't support
FTRACE_MCOUNT_USE_RECORDMCOUNT with LTO?
It's because recordmcount cannot distinguish between calls and other
references to mcount/fentry, which is a problem with LTO where we have
to process the entire vmlinux.o and cannot ignore individual
translation units. Instead of resorting to workarounds, Peter was kind
enough to implement a smarter mcount pass in objtool, which we now use
on x86_64 with LTO.
So can x86_64 have both FTRACE_MCOUNT_USE_RECORDMCOUNT and LTO?