Bah, I forgot to add the "v4" in the subject (like I did for this
email).
-- Steve
On Tue, 21 Mar 2017 21:35:02 -0400
Steven Rostedt <rost...@goodmis.org> wrote:
> [
> Ingo, Thomas or H.Peter,
>
> I believe this is all set to go now. I updated those patches that
> Linus commented on and I don't believe there are any more issues. I
> ran this through several tests (although some of my tests are failing
> due to bugs introduced by others in 4.11-rc2). You can take this as a
> patch series, or you can pull from my tree defined below. It's based
> on 4.11-rc2 as I noticed that tip/x86/core is rather outdated, and
> Linus is fine with basing off of his tagged releases.
> ]
>
>
> With the issues of gcc screwing around with the mcount stack frame
> causing function graph tracer to panic on x86_32, and with Linus
> saying that we should start deprecating mcount (at least on x86), I
> figured that x86_32 needs to support fentry.
>
> First, I renamed mcount_64.S to ftrace_64.S. As we want to get away
> from mcount, having the ftrace code in a file called mcount seems
> rather backwards.
>
> Next I moved the ftrace code out of entry_32.S. It's not in entry_64.S
> and it does not belong in entry_32.S.
>
> I noticed that the x86_32 code has the same issue as the x86_64 did
> in the past with respect to a stack frame. I fixed that just for the
> main ftrace_caller. The ftrace_regs_caller is rather special, and so
> is function graph tracing.
>
> I realized the ftrace_regs_caller code was complex due to me
> aggressively saving flags, even though I could still do push, lea and
> mov without changing them. That made the logic a little nicer.
>
> Finally I added the fentry code.
>
> I tested this with an older compiler (for mcount) with and without
> FRAME_POINTER set. I also did it with a new compiler (with fentry),
> with and without FRAME_POINTER. I tested function tracing, stack
> tracing, function_graph tracing, and kprobes (as that uses the
> ftrace_regs_caller).
>
> Please pull (or take the patch series) from:
>
>
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
> tip/x86/ftrace
>
> Head SHA1: e086b1da846b8e53f4de11e38d02d05b1ec5db58
>
>
> Steven Rostedt (VMware) (6):
> ftrace/x86_64: Rename mcount_64.S to ftrace_64.S
> ftrace/x86_32: Move the ftrace specific code out of entry_32.S
> ftrace/x86_32: Add stack frame pointer to ftrace_caller
> ftrace/x86_32: Clean up ftrace_regs_caller
> ftrace/x86_32: Add -mfentry support to x86_32 with
> DYNAMIC_FTRACE set ftrace/x86: Use Makefile logic instead of #ifdef
> for compiling ftrace_*.o
>
> ----
> Changes since v3:
>
> * Changed comment about regs being skipped (Josh Poimboeuf)
>
> * Change subject line to fix typo (Josh Poimboeuf)
>
>
> arch/x86/Kconfig | 2 +-
> arch/x86/entry/entry_32.S | 169 ------------------
> arch/x86/kernel/Makefile | 5 +-
> arch/x86/kernel/ftrace_32.S | 246
> +++++++++++++++++++++++++++ arch/x86/kernel/{mcount_64.S =>
> ftrace_64.S} | 4 - 5 files changed, 250 insertions(+), 176
> deletions(-) create mode 100644 arch/x86/kernel/ftrace_32.S
> rename arch/x86/kernel/{mcount_64.S => ftrace_64.S} (99%)
>
> Diff against v3:
>
>
> diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
> index 4d52e0d49e26..de50c9084d16 100644
> --- a/arch/x86/kernel/ftrace_32.S
> +++ b/arch/x86/kernel/ftrace_32.S
> @@ -167,7 +167,7 @@ GLOBAL(ftrace_regs_call)
> popl %gs
>
> /* use lea to not affect flags */
> - lea 3*4(%esp), %esp /* Skip
> orig_ax, ip and flags */
> + lea 3*4(%esp), %esp /* Skip
> orig_ax, ip and cs */
> jmp .Lftrace_ret
> #else /* ! CONFIG_DYNAMIC_FTRACE */
