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authorPrasanna S Panchamukhi <prasanna@in.ibm.com>2006-02-24 13:04:08 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-02-24 14:31:37 -0800
commit124d90be62343f71bbb7a6b4a907b5584181e6d5 (patch)
tree6e9a53f6bee52bb551724ec29e7710a656fbb187
parentd1521260f57d70d0ba86d2a309ec1ce7979be2fc (diff)
downloadlinux-linaro-124d90be62343f71bbb7a6b4a907b5584181e6d5.tar.gz
[PATCH] Kprobes causes NX protection fault on i686 SMP
Fix a problem seen on i686 machine with NX support where the instruction could not be single stepped because of NX bit set on the memory pages allocated by kprobes module. This patch provides allocation of instruction solt so that the processor can execute the instruction from that location similar to x86_64 architecture. Thanks to Bibo and Masami for testing this patch. Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/kprobes.c16
-rw-r--r--include/asm-i386/kprobes.h7
2 files changed, 19 insertions, 4 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 6483eeb1a4e..694a1399763 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -58,6 +58,11 @@ static inline int is_IF_modifier(kprobe_opcode_t opcode)
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
+ /* insn: must be on special executable page on i386. */
+ p->ainsn.insn = get_insn_slot();
+ if (!p->ainsn.insn)
+ return -ENOMEM;
+
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr;
return 0;
@@ -77,6 +82,13 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
(unsigned long) p->addr + sizeof(kprobe_opcode_t));
}
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+ down(&kprobe_mutex);
+ free_insn_slot(p->ainsn.insn);
+ up(&kprobe_mutex);
+}
+
static inline void save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
@@ -111,7 +123,7 @@ static inline void prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
if (p->opcode == BREAKPOINT_INSTRUCTION)
regs->eip = (unsigned long)p->addr;
else
- regs->eip = (unsigned long)&p->ainsn.insn;
+ regs->eip = (unsigned long)p->ainsn.insn;
}
/* Called with kretprobe_lock held */
@@ -351,7 +363,7 @@ static void __kprobes resume_execution(struct kprobe *p,
{
unsigned long *tos = (unsigned long *)&regs->esp;
unsigned long next_eip = 0;
- unsigned long copy_eip = (unsigned long)&p->ainsn.insn;
+ unsigned long copy_eip = (unsigned long)p->ainsn.insn;
unsigned long orig_eip = (unsigned long)p->addr;
switch (p->ainsn.insn[0]) {
diff --git a/include/asm-i386/kprobes.h b/include/asm-i386/kprobes.h
index 27cac050a60..a0d2d74a7dd 100644
--- a/include/asm-i386/kprobes.h
+++ b/include/asm-i386/kprobes.h
@@ -27,6 +27,9 @@
#include <linux/types.h>
#include <linux/ptrace.h>
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+
+struct kprobe;
struct pt_regs;
typedef u8 kprobe_opcode_t;
@@ -40,14 +43,14 @@ typedef u8 kprobe_opcode_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
-#define arch_remove_kprobe(p) do {} while (0)
+void arch_remove_kprobe(struct kprobe *p);
void kretprobe_trampoline(void);
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
/* copy of the original instruction */
- kprobe_opcode_t insn[MAX_INSN_SIZE];
+ kprobe_opcode_t *insn;
};
struct prev_kprobe {