From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: masami.hiramatsu.pt@hitachi.com, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org
Subject: [PATCH] kprobes: Mark OPTPROBES n/a for powerpc
Date: Thu, 16 Jul 2015 16:26:39 +0530 [thread overview]
Message-ID: <20150716105639.9151.75671.stgit@thinktux.in.ibm.com> (raw)
Kprobes uses a breakpoint instruction to trap into execution flow
and the probed instruction is single-stepped from an alternate location.
On some architectures like x86, under certain conditions, the OPTPROBES
feature enables replacing the probed instruction with a jump instead,
resulting in a significant perfomance boost (one single-step exception
is bypassed for each kprobe).
Powerpc has an in-kernel instruction emulator. Kprobes on powerpc uses
this emulator already and bypasses the single-step exception, with a
lot less complexity.
Hence, mark OPTPROBES n/a for powerpc.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
---
.../features/debug/optprobes/arch-support.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/features/debug/optprobes/arch-support.txt b/Documentation/features/debug/optprobes/arch-support.txt
index b8999d8..0a3ca33 100644
--- a/Documentation/features/debug/optprobes/arch-support.txt
+++ b/Documentation/features/debug/optprobes/arch-support.txt
@@ -27,7 +27,7 @@
| nios2: | TODO |
| openrisc: | TODO |
| parisc: | TODO |
- | powerpc: | TODO |
+ | powerpc: | n/a |
| s390: | TODO |
| score: | TODO |
| sh: | TODO |
next reply other threads:[~2015-07-16 10:57 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-16 10:56 Ananth N Mavinakayanahalli [this message]
2015-07-19 2:21 ` [PATCH] kprobes: Mark OPTPROBES n/a for powerpc Masami Hiramatsu
2015-07-20 10:38 ` Ananth N Mavinakayanahalli
2015-07-21 2:53 ` Michael Ellerman
2015-07-21 4:34 ` Ananth N Mavinakayanahalli
2015-07-21 10:26 ` Masami Hiramatsu
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