[RFC PATCH 02/11] ARM: kprobes: introduce early kprobes related code area.

[Wang Nan]

In arm's vmlinux.lds, introduces code area inside text section.
Executable area used by early kprobes will be allocated from there.

Signed-off-by: Wang Nan <wangnan0 at huawei.com>
---
 arch/arm/include/asm/kprobes.h | 29 +++++++++++++++++++++++++++--
 arch/arm/kernel/vmlinux.lds.S  |  2 ++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/kprobes.h b/arch/arm/include/asm/kprobes.h
index 3ea9be5..99f16dc 100644
--- a/arch/arm/include/asm/kprobes.h
+++ b/arch/arm/include/asm/kprobes.h
@@ -17,16 +17,40 @@
 #define _ARM_KPROBES_H
 
 #include <linux/types.h>
-#include <linux/ptrace.h>
-#include <linux/notifier.h>
 
 #define __ARCH_WANT_KPROBES_INSN_SLOT
 #define MAX_INSN_SIZE			2
 
+#ifdef __ASSEMBLY__
+
+#define KPROBE_OPCODE_SIZE	4
+#define MAX_OPTINSN_SIZE (optprobe_template_end - optprobe_template_entry)
+
+#ifdef CONFIG_EARLY_KPROBES
+#define EARLY_KPROBES_CODES_AREA					\
+	. = ALIGN(8);							\
+	VMLINUX_SYMBOL(__early_kprobes_code_area_start) = .;		\
+	. = . + MAX_OPTINSN_SIZE * CONFIG_NR_EARLY_KPROBES_SLOTS;	\
+	VMLINUX_SYMBOL(__early_kprobes_code_area_end) = .;		\
+	. = ALIGN(8);							\
+	VMLINUX_SYMBOL(__early_kprobes_insn_slot_start) = .;		\
+	. = . + MAX_INSN_SIZE * KPROBE_OPCODE_SIZE * CONFIG_NR_EARLY_KPROBES_SLOTS;\
+	VMLINUX_SYMBOL(__early_kprobes_insn_slot_end) = .;
+
+#else
+#define EARLY_KPROBES_CODES_AREA
+#endif
+
+#else
+
+#include <linux/ptrace.h>
+#include <linux/notifier.h>
+
 #define flush_insn_slot(p)		do { } while (0)
 #define kretprobe_blacklist_size	0
 
 typedef u32 kprobe_opcode_t;
+#define KPROBE_OPCODE_SIZE	sizeof(kprobe_opcode_t)
 struct kprobe;
 #include <asm/probes.h>
 
@@ -83,4 +107,5 @@ struct arch_optimized_insn {
 	 */
 };
 
+#endif /* __ASSEMBLY__ */
 #endif /* _ARM_KPROBES_H */
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index b31aa73..12ff76d 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -11,6 +11,7 @@
 #ifdef CONFIG_ARM_KERNMEM_PERMS
 #include <asm/pgtable.h>
 #endif
+#include <asm/kprobes.h>
 	
 #define PROC_INFO							\
 	. = ALIGN(4);							\
@@ -108,6 +109,7 @@ SECTIONS
 			SCHED_TEXT
 			LOCK_TEXT
 			KPROBES_TEXT
+			EARLY_KPROBES_CODES_AREA
 			IDMAP_TEXT
 #ifdef CONFIG_MMU
 			*(.fixup)
-- 
1.8.4