All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH 0/6 v5] [GIT PULL] ftrace/x86: Ftrace cleanup and add support for -mfentry on x86_32
@ 2017-03-23 14:33 Steven Rostedt
  2017-03-23 14:33 ` [PATCH 1/6 v5] ftrace/x86_64: Rename mcount_64.S to ftrace_64.S Steven Rostedt
                   ` (5 more replies)
  0 siblings, 6 replies; 37+ messages in thread
From: Steven Rostedt @ 2017-03-23 14:33 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Peter Zijlstra,
	Masami Hiramatsu, H. Peter Anvin, Andy Lutomirski,
	Josh Poimboeuf, Linus Torvalds

[
 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 as I noticed that tip/x86/core is rather outdated, and Linus is fine with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: fadff4e942659f37a2374438dbb12388a9518107


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 v4:

 * s/mcount_/ftrace_/ in comment header that states the name.
      (Namhyung Kim)

 * Added Masami's Reviewed-by tag to patch 3

 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} |   6 +-
 5 files changed, 251 insertions(+), 177 deletions(-)
 create mode 100644 arch/x86/kernel/ftrace_32.S
 rename arch/x86/kernel/{mcount_64.S => ftrace_64.S} (98%)


Diff against v4:

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index de50c9084d16..97ede82aeb8c 100644
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -1,5 +1,5 @@
 /*
- *  linux/arch/x86_64/mcount_64.S
+ *  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 b9c46919d4fc..aef2361e7f83 100644
--- a/arch/x86/kernel/ftrace_64.S
+++ b/arch/x86/kernel/ftrace_64.S
@@ -1,5 +1,5 @@
 /*
- *  linux/arch/x86_64/mcount_64.S
+ *  linux/arch/x86_64/ftrace_64.S
  *
  *  Copyright (C) 2014  Steven Rostedt, Red Hat Inc
  */

^ permalink raw reply related	[flat|nested] 37+ messages in thread
* [PATCH 0/5 v2] ftrace/x86_32: Ftrace cleanup and add support for -mfentry
@ 2017-03-16 17:20 Steven Rostedt
  2017-03-16 17:20 ` [PATCH 1/5 v2] x86/ftrace: Rename mcount_64.S to ftrace_64.S Steven Rostedt
                   ` (4 more replies)
  0 siblings, 5 replies; 37+ messages in thread
From: Steven Rostedt @ 2017-03-16 17:20 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ingo Molnar, Andrew Morton, Thomas Gleixner, Peter Zijlstra,
	Masami Hiramatsu, H. Peter Anvin, Andy Lutomirski,
	Josh Poimboeuf, Linus Torvalds

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).

Steven Rostedt (VMware) (5):
      x86/ftrace: 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

----
 Makefile                                     |  12 +-
 arch/x86/Kconfig                             |   2 +-
 arch/x86/entry/entry_32.S                    | 168 ------------------
 arch/x86/kernel/Makefile                     |   5 +-
 arch/x86/kernel/ftrace_32.S                  | 250 +++++++++++++++++++++++++++
 arch/x86/kernel/{mcount_64.S => ftrace_64.S} |   0
 6 files changed, 260 insertions(+), 177 deletions(-)
 create mode 100644 arch/x86/kernel/ftrace_32.S
 rename arch/x86/kernel/{mcount_64.S => ftrace_64.S} (100%)

Changes from v1:

  Removed MCOUNT_FRAME_SIZE macro, as it is not used.
    (Masami Hiramatsu)

  Fixed vertical alignment of args (Josh Poimboeuf)

  s/ndef USING_FRAME_POINTER/def CC_USING_FENTRY/ (Josh Poimboeuf)

  Fixed adding $0 into orig_ax and not ax. (Josh Poimboeuf)

  Updated some comments.

Here's the diff of v1 to v2:

diff --git a/arch/x86/kernel/ftrace_32.S b/arch/x86/kernel/ftrace_32.S
index 4bf8223..7ed4137 100644
--- a/arch/x86/kernel/ftrace_32.S
+++ b/arch/x86/kernel/ftrace_32.S
@@ -9,7 +9,6 @@
 #include <asm/export.h>
 #include <asm/ftrace.h>
 
-
 #ifdef CC_USING_FENTRY
 # define function_hook	__fentry__
 EXPORT_SYMBOL(__fentry__)
@@ -24,14 +23,8 @@ EXPORT_SYMBOL(mcount)
 #endif
 
 #ifdef USING_FRAME_POINTER
-# ifdef CC_USING_FENTRY
-#  define MCOUNT_FRAME_SIZE		(4*4)	/* bp,ip and parent's  */
-# else
-#  define MCOUNT_FRAME_SIZE		4	/* just the bp         */
-# endif
 # define MCOUNT_FRAME			1	/* using frame = true  */
 #else
-# define MCOUNT_FRAME_SIZE		0	/* no stack frame      */
 # define MCOUNT_FRAME			0	/* using frame = false */
 #endif
 
@@ -52,14 +45,14 @@ ENTRY(ftrace_caller)
 	 * parent-ip, function-ip. We need to add a frame with
 	 * parent-ip followed by ebp.
 	 */
-	pushl 4(%esp)				/* parent ip */
-	pushl %ebp
-	movl %esp, %ebp
-	pushl 2*4(%esp)				/* function ip */
+	pushl	4(%esp)				/* parent ip */
+	pushl	%ebp
+	movl	%esp, %ebp
+	pushl	2*4(%esp)			/* function ip */
 # endif
 	/* For mcount, the function ip is directly above */
-	pushl %ebp
-	movl %esp, %ebp
+	pushl	%ebp
+	movl	%esp, %ebp
 #endif
 	pushl	%eax
 	pushl	%ecx
@@ -131,8 +124,8 @@ ENTRY(ftrace_regs_caller)
 
 	/* move flags into the location of where the return ip was */
 	movl	5*4(%esp), %eax
-	movl	$0, (%esp)			/* Load 0 into orig_ax */
-	movl	%eax, 8*4(%esp)
+	movl	$0, 5*4(%esp)			/* Load 0 into orig_ax */
+	movl	%eax, 8*4(%esp)			/* Load flags in return ip */
 
 	pushl	%ebp
 	pushl	%edi
@@ -140,7 +133,7 @@ ENTRY(ftrace_regs_caller)
 	pushl	%edx
 	pushl	%ecx
 	pushl	%ebx
-#ifndef USING_FRAME_POINTER
+#ifdef CC_USING_FENTRY
 	/* Load 4 off of the parent ip addr into ebp */
 	lea	14*4(%esp), %ebp
 #endif
@@ -160,7 +153,7 @@ GLOBAL(ftrace_regs_call)
 	movl	14*4(%esp), %eax
 	movl	%eax, 13*4(%esp)
 
-	/* Move ip back to its original location */
+	/* Move return ip back to its original location */
 	movl	12*4(%esp), %eax
 	movl	%eax, 14*4(%esp)
 

^ permalink raw reply related	[flat|nested] 37+ messages in thread
end of thread, other threads:[~2017-03-24  9:27 UTC | newest]

Thread overview: 37+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-23 14:33 [PATCH 0/6 v5] [GIT PULL] ftrace/x86: Ftrace cleanup and add support for -mfentry on x86_32 Steven Rostedt
2017-03-23 14:33 ` [PATCH 1/6 v5] ftrace/x86_64: Rename mcount_64.S to ftrace_64.S Steven Rostedt
2017-03-24  9:19   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
2017-03-23 14:33 ` [PATCH 2/6 v5] ftrace/x86_32: Move the ftrace specific code out of entry_32.S Steven Rostedt
2017-03-23 18:19   ` Thomas Gleixner
2017-03-23 19:03     ` Steven Rostedt
2017-03-24  9:20   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
2017-03-23 14:33 ` [PATCH 3/6 v5] ftrace/x86_32: Add stack frame pointer to ftrace_caller Steven Rostedt
2017-03-24  9:20   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
2017-03-23 14:33 ` [PATCH 4/6 v5] ftrace/x86_32: Clean up ftrace_regs_caller Steven Rostedt
2017-03-24  9:21   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
2017-03-23 14:33 ` [PATCH 5/6 v5] ftrace/x86_32: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set Steven Rostedt
2017-03-24  9:21   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
2017-03-23 14:33 ` [PATCH 6/6 v5] ftrace/x86: Use Makefile logic instead of #ifdef for compiling ftrace_*.o Steven Rostedt
2017-03-24  9:22   ` [tip:x86/asm] x86/ftrace: " tip-bot for Steven Rostedt (VMware)
  -- strict thread matches above, loose matches on Subject: below --
2017-03-16 17:20 [PATCH 0/5 v2] ftrace/x86_32: Ftrace cleanup and add support for -mfentry Steven Rostedt
2017-03-16 17:20 ` [PATCH 1/5 v2] x86/ftrace: Rename mcount_64.S to ftrace_64.S Steven Rostedt
2017-03-16 17:20 ` [PATCH 2/5 v2] ftrace/x86-32: Move the ftrace specific code out of entry_32.S Steven Rostedt
2017-03-17 13:21   ` Steven Rostedt
2017-03-16 17:20 ` [PATCH 3/5 v2] ftrace/x86_32: Add stack frame pointer to ftrace_caller Steven Rostedt
2017-03-16 17:20 ` [PATCH 4/5 v2] ftrace/x86_32: Clean up ftrace_regs_caller Steven Rostedt
2017-03-16 17:40   ` Linus Torvalds
2017-03-16 17:55     ` Steven Rostedt
2017-03-16 18:09     ` [PATCH 4/5 v3] " Steven Rostedt
2017-03-16 18:19       ` Linus Torvalds
2017-03-16 19:19         ` Steven Rostedt
2017-03-16 19:24           ` Steven Rostedt
2017-03-16 19:30             ` Linus Torvalds
2017-03-16 19:50               ` Steven Rostedt
2017-03-16 19:28           ` Linus Torvalds
2017-03-16 19:49             ` Steven Rostedt
2017-03-16 20:14         ` [PATCH 4/5 v3.1] " Steven Rostedt
2017-03-16 17:20 ` [PATCH 5/5 v2] ftrace/x86-32: Add -mfentry support to x86_32 with DYNAMIC_FTRACE set Steven Rostedt
2017-03-16 20:40   ` [PATCH 5/5 v3] " Steven Rostedt
2017-03-16 21:00     ` Josh Poimboeuf
2017-03-16 21:25       ` Steven Rostedt
2017-03-17 10:38     ` Masami Hiramatsu

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.