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Subject[PATCH 0/1 v6] [GIT PULL] ftrace/x86: Ftrace cleanup and add support for -mfentry on x86_32
[
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as I noticed that tip/x86/core is rather outdated, and Linus is fine with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: 71a281dd0356fb7cb207e3387c2716b887b646de


[ Note, all is the same from v5 but patch 2, so I'm only posting that one ]

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 from v5:

Removed file name from header comment. (Thomas Gleixner)

arch/x86/Kconfig | 2 +-
arch/x86/entry/entry_32.S | 169 -------------------
arch/x86/kernel/Makefile | 5 +-
arch/x86/kernel/ftrace_32.S | 244 +++++++++++++++++++++++++++
arch/x86/kernel/{mcount_64.S => ftrace_64.S} | 6 -
5 files changed, 248 insertions(+), 178 deletions(-)
create mode 100644 arch/x86/kernel/ftrace_32.S
rename arch/x86/kernel/{mcount_64.S => ftrace_64.S} (98%)

Diff against v5:

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index 97ede82aeb8c..07f40359c9ea 100644
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -1,6 +1,4 @@
/*
- * linux/arch/x86_64/ftrace_32.S
- *
* Copyright (C) 2017 Steven Rostedt, VMware Inc.
*/

diff --git a/arch/x86/kernel/ftrace_64.S b/arch/x86/kernel/ftrace_64.S
index aef2361e7f83..1dfac634bbf7 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -1,6 +1,4 @@
/*
- * linux/arch/x86_64/ftrace_64.S
- *
* Copyright (C) 2014 Steven Rostedt, Red Hat Inc
*/

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