Messages in this thread Patch in this message | | | Date | Fri, 24 Mar 2017 08:20:43 -0400 | From | Steven Rostedt <> | Subject | [PATCH 0/1 v6] [GIT PULL] ftrace/x86: Ftrace cleanup and add support for -mfentry on x86_32 |
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[ 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 It's based on 4.11-rc2 as I noticed that tip/x86/core is rather outdated, and Linus is fine with basing off of his tagged releases.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
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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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