lkml.org 
[lkml]   [2015]   [Jan]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 03/11] x86: kprobes: directly modify code if kprobe is not initialized.
Date
When registering early kprobes, SMP should has not been enabled, so
doesn't require synchronization in text_poke_bp(). Simply memcpy is
enough.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
---
arch/x86/kernel/kprobes/opt.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 0dd8d08..dc5fccb 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -397,8 +397,11 @@ void arch_optimize_kprobes(struct list_head *oplist)
insn_buf[0] = RELATIVEJUMP_OPCODE;
*(s32 *)(&insn_buf[1]) = rel;

- text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE,
- op->optinsn.insn);
+ if (unlikely(!kprobes_initialized))
+ memcpy(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE);
+ else
+ text_poke_bp(op->kp.addr, insn_buf, RELATIVEJUMP_SIZE,
+ op->optinsn.insn);

list_del_init(&op->list);
}
--
1.8.4


\
 
 \ /
  Last update: 2015-01-07 09:21    [W:0.100 / U:0.072 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site