From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 0/4] Nop out the preceding mflr with -mprofile-kernel
Date: Sat, 18 May 2019 00:32:44 +0530 [thread overview]
Message-ID: <cover.1558115654.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
On powerpc64, -mprofile-kernel results in two instructions being
emitted: 'mflr r0' and 'bl _mcount'. So far, we were only nop'ing out
the branch to _mcount(). This series implements an approach to also nop
out the preceding mflr.
Patches 1-3 are generic changes. Patch 2 is a fix for x86, but has not
been tested. Patch 4 implements the changes for powerpc64.
- Naveen
Naveen N. Rao (4):
ftrace: Expose flags used for ftrace_replace_code()
x86/ftrace: Fix use of flags in ftrace_replace_code()
ftrace: Expose __ftrace_replace_code()
powerpc/ftrace: Additionally nop out the preceding mflr with
-mprofile-kernel
arch/powerpc/kernel/trace/ftrace.c | 188 +++++++++++++++++++++++++----
arch/x86/kernel/ftrace.c | 3 +-
include/linux/ftrace.h | 6 +
kernel/trace/ftrace.c | 13 +-
4 files changed, 178 insertions(+), 32 deletions(-)
--
2.21.0
next reply other threads:[~2019-05-17 19:04 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-17 19:02 Naveen N. Rao [this message]
2019-05-17 19:02 ` [RFC PATCH 1/4] ftrace: Expose flags used for ftrace_replace_code() Naveen N. Rao
2019-05-20 13:08 ` Steven Rostedt
2019-05-17 19:02 ` [RFC PATCH 2/4] x86/ftrace: Fix use of flags in ftrace_replace_code() Naveen N. Rao
2019-05-20 13:13 ` Steven Rostedt
2019-05-20 13:44 ` Steven Rostedt
2019-05-20 14:42 ` Naveen N. Rao
2019-05-20 14:55 ` Steven Rostedt
2019-05-17 19:02 ` [RFC PATCH 3/4] ftrace: Expose __ftrace_replace_code() Naveen N. Rao
2019-05-17 19:02 ` [RFC PATCH 4/4] powerpc/ftrace: Additionally nop out the preceding mflr with -mprofile-kernel Naveen N. Rao
2019-05-18 2:08 ` Nicholas Piggin
2019-05-20 8:57 ` Naveen N. Rao
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