From: wangnan0@huawei.com (Wang Nan)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v3 03/26] kprobes: x86: mark 2 bytes NOP as boostable.
Date: Fri, 13 Feb 2015 13:40:24 +0800 [thread overview]
Message-ID: <1423806024-61617-1-git-send-email-wangnan0@huawei.com> (raw)
In-Reply-To: <1423805941-61407-1-git-send-email-wangnan0@huawei.com>
Currently, x86 kprobes is unable to boost 2 bytes nop like:
nopl 0x0(%rax,%rax,1)
which is 0x0f 0x1f 0x44 0x00 0x00.
Such nops have exactly 5 bytes which is able to hold a relative jmp
instruction. Boosting them should be obviously safe.
This patch enable boosting such nops by simply updating
twobyte_is_boostable[] array.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
---
arch/x86/kernel/kprobes/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 98f654d..6a1146e 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -84,7 +84,7 @@ static volatile u32 twobyte_is_boostable[256 / 32] = {
/* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
/* ---------------------------------------------- */
W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
- W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
+ W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */
W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
--
1.8.4
next prev parent reply other threads:[~2015-02-13 5:40 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-13 5:39 [RFC PATCH v3 00/26] Early kprobe: enable kprobes at very early booting stage Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 01/26] kprobes: set kprobes_all_disarmed earlier to enable re-optimization Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 02/26] kprobes: makes kprobes/enabled works correctly for optimized kprobes Wang Nan
2015-02-13 5:40 ` Wang Nan [this message]
2015-02-13 5:40 ` [RFC PATCH v3 04/26] ftrace: don't update record flags if code modification fail Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 05/26] ftrace/x86: Ensure rec->flags no change when failure occures Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 06/26] ftrace: sort ftrace entries earlier Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 07/26] ftrace: allow search ftrace addr before ftrace fully inited Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 08/26] ftrace: enable make ftrace nop before ftrace_init() Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 09/26] ftrace: allow fixing code update failure by notifier chain Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 10/26] ftrace: x86: try to fix ftrace when ftrace_replace_code Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 11/26] early kprobes: introduce kprobe_is_early for futher early kprobe use Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 12/26] early kprobes: Add an KPROBE_FLAG_EARLY for early kprobe Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 13/26] early kprobes: ARM: directly modify code Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 14/26] early kprobes: ARM: introduce early kprobes related code area Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 15/26] early kprobes: x86: directly modify code Wang Nan
2015-02-20 4:00 ` Masami Hiramatsu
2015-02-13 5:40 ` [RFC PATCH v3 16/26] early kprobes: x86: introduce early kprobes related code area Wang Nan
2015-02-13 5:40 ` [RFC PATCH v3 17/26] early kprobes: introduces macros for allocing early kprobe resources Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 18/26] early kprobes: allows __alloc_insn_slot() from early kprobes slots Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 19/26] early kprobes: perhibit probing at early kprobe reserved area Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 20/26] early kprobes: core logic of eraly kprobes Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 21/26] early kprobes: add CONFIG_EARLY_KPROBES option Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 22/26] early kprobes: introduce arch_fix_ftrace_early_kprobe() Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 23/26] early kprobes: x86: arch_restore_optimized_kprobe() Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 24/26] early kprobes: core logic to support early kprobe on ftrace Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 25/26] early kprobes: introduce kconfig option " Wang Nan
2015-02-13 5:41 ` [RFC PATCH v3 26/26] kprobes: enable 'ekprobe=' cmdline option for early kprobes Wang Nan
2015-02-20 3:59 ` [RFC PATCH v3 00/26] Early kprobe: enable kprobes at very early booting stage Masami Hiramatsu
2015-02-25 11:11 ` Wang Nan
2015-02-25 11:46 ` Wang Nan
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