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From: Masami Hiramatsu <mhiramat@kernel.org>
To: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
	"David S . Miller" <davem@davemloft.net>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Ye Xiaolong <xiaolong.ye@intel.com>,
	mhiramat@kernel.org
Subject: [RFC PATCH tip/master V2 2/8] kprobes/x86: Fix the description of __copy_instruction()
Date: Mon, 27 Mar 2017 16:51:07 +0900	[thread overview]
Message-ID: <149060105771.12303.7863098798043032622.stgit@devbox> (raw)
In-Reply-To: <149060091581.12303.13449343279538504544.stgit@devbox>

Fix the description comment of __copy_instruction() function
since it has already been changed to return the length of
copied instruction.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/x86/kernel/kprobes/core.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 9eae5a6..81d4dc7 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -350,11 +350,10 @@ static int is_IF_modifier(kprobe_opcode_t *insn)
 }
 
 /*
- * Copy an instruction and adjust the displacement if the instruction
- * uses the %rip-relative addressing mode.
- * If it does, Return the address of the 32-bit displacement word.
- * If not, return null.
- * Only applicable to 64-bit x86.
+ * Copy an instruction with recovering modified instruction by kprobes
+ * and adjust the displacement if the instruction uses the %rip-relative
+ * addressing mode.
+ * This returns the length of copied instruction, or 0 if it has an error.
  */
 int __copy_instruction(u8 *dest, u8 *src)
 {
@@ -376,6 +375,7 @@ int __copy_instruction(u8 *dest, u8 *src)
 	memcpy(dest, insn.kaddr, length);
 
 #ifdef CONFIG_X86_64
+	/* Only x86_64 has RIP relative instructions */
 	if (insn_rip_relative(&insn)) {
 		s64 newdisp;
 		u8 *disp;

  parent reply	other threads:[~2017-03-27  7:52 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-27  7:48 [RFC PATCH tip/master V2 0/8] kprobes/x86: Make kprobes instruction buffers read-only Masami Hiramatsu
2017-03-27  7:49 ` [RFC PATCH tip/master V2 1/8] kprobes/x86: Fix not to boost call far instruction Masami Hiramatsu
2017-03-27  7:51 ` Masami Hiramatsu [this message]
2017-03-27  7:52 ` [RFC PATCH tip/master V2 3/8] kprobes/x86: Use instruction decoder for booster Masami Hiramatsu
2017-03-27  7:53 ` [RFC PATCH tip/master V2 4/8] kprobes/x86: Do not modify singlestep buffer while resuming Masami Hiramatsu
2017-03-28  7:04   ` Ingo Molnar
2017-03-28 15:28     ` Masami Hiramatsu
2017-03-27  7:54 ` [RFC PATCH tip/master V2 5/8] kprobes/x86: Make boostable flag boolean Masami Hiramatsu
2017-03-27  7:56 ` [RFC PATCH tip/master V2 6/8] kprobes/x86: Set kprobes pages readonly Masami Hiramatsu
2017-03-27  7:57 ` [RFC PATCH tip/master V2 7/8] kprobes/x86: Use probe_kernel_read instead of memcpy Masami Hiramatsu
2017-03-27  7:58 ` [RFC PATCH tip/master V2 8/8] kprobes/x86: Consolidate insn decoder users for copying code Masami Hiramatsu

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