Re: [1/3] PATCH Kprobes for x86_64- 2.6.9-final

From: Prasanna S Panchamukhi
Date: Thu Oct 28 2004 - 06:37:06 EST

[1/3] kprobes-arch-i386-changes.patch
Couple of routine's are modified to support kprobes porting to other
architectures.

Signed-off-by: Prasanna S Panchamukhi <prasanna@xxxxxxxxxx>
---


---

linux-2.6.9-final-prasanna/arch/i386/kernel/kprobes.c | 23 ++++++++++--------
linux-2.6.9-final-prasanna/include/asm-i386/kprobes.h | 7 +++++
linux-2.6.9-final-prasanna/include/linux/kprobes.h | 5 ++-
linux-2.6.9-final-prasanna/kernel/kprobes.c | 6 +++-
4 files changed, 29 insertions(+), 12 deletions(-)

diff -puN arch/i386/kernel/kprobes.c~kprobes-arch-i386-changes arch/i386/kernel/kprobes.c
--- linux-2.6.9-final/arch/i386/kernel/kprobes.c~kprobes-arch-i386-changes 2004-10-28 16:44:50.000000000 +0530
+++ linux-2.6.9-final-prasanna/arch/i386/kernel/kprobes.c 2004-10-28 16:44:50.000000000 +0530
@@ -58,9 +58,14 @@ static inline int is_IF_modifier(kprobe_
return 0;
}

-void arch_prepare_kprobe(struct kprobe *p)
+int arch_prepare_kprobe(struct kprobe *p)
+{
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ return 0;
+}
+
+void arch_remove_kprobe(struct kprobe *p)
{
- memcpy(p->insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
}

static inline void disarm_kprobe(struct kprobe *p, struct pt_regs *regs)
@@ -73,7 +78,7 @@ static inline void prepare_singlestep(st
{
regs->eflags |= TF_MASK;
regs->eflags &= ~IF_MASK;
- regs->eip = (unsigned long)&p->insn;
+ regs->eip = (unsigned long)&p->ainsn.insn;
}

/*
@@ -153,7 +158,7 @@ static inline int kprobe_handler(struct
* instruction. To avoid the SMP problems that can occur when we
* temporarily put back the original opcode to single-step, we
* single-stepped a copy of the instruction. The address of this
- * copy is p->insn.
+ * copy is p->ainsn.insn.
*
* This function prepares to return from the post-single-step
* interrupt. We have to fix up the stack as follows:
@@ -173,10 +178,10 @@ static void resume_execution(struct kpro
{
unsigned long *tos = (unsigned long *)&regs->esp;
unsigned long next_eip = 0;
- unsigned long copy_eip = (unsigned long)&p->insn;
+ unsigned long copy_eip = (unsigned long)&p->ainsn.insn;
unsigned long orig_eip = (unsigned long)p->addr;

- switch (p->insn[0]) {
+ switch (p->ainsn.insn[0]) {
case 0x9c: /* pushfl */
*tos &= ~(TF_MASK | IF_MASK);
*tos |= kprobe_old_eflags;
@@ -185,13 +190,13 @@ static void resume_execution(struct kpro
*tos = orig_eip + (*tos - copy_eip);
break;
case 0xff:
- if ((p->insn[1] & 0x30) == 0x10) {
+ if ((p->ainsn.insn[1] & 0x30) == 0x10) {
/* call absolute, indirect */
/* Fix return addr; eip is correct. */
next_eip = regs->eip;
*tos = orig_eip + (*tos - copy_eip);
- } else if (((p->insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
- ((p->insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
+ } else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
+ ((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
/* eip is correct. */
next_eip = regs->eip;
}
diff -puN include/asm-i386/kprobes.h~kprobes-arch-i386-changes include/asm-i386/kprobes.h
--- linux-2.6.9-final/include/asm-i386/kprobes.h~kprobes-arch-i386-changes 2004-10-28 16:44:50.000000000 +0530
+++ linux-2.6.9-final-prasanna/include/asm-i386/kprobes.h 2004-10-28 16:44:50.000000000 +0530
@@ -38,6 +38,13 @@ typedef u8 kprobe_opcode_t;
? (MAX_STACK_SIZE) \
: (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR)))

+/* Architecture specific copy of original instruction*/
+struct arch_specific_insn {
+ /* copy of the original instruction */
+ kprobe_opcode_t insn[MAX_INSN_SIZE];
+};
+
+
/* trap3/1 are intr gates for kprobes. So, restore the status of IF,
* if necessary, before executing the original int3/1 (trap) handler.
*/
diff -puN include/linux/kprobes.h~kprobes-arch-i386-changes include/linux/kprobes.h
--- linux-2.6.9-final/include/linux/kprobes.h~kprobes-arch-i386-changes 2004-10-28 16:44:50.000000000 +0530
+++ linux-2.6.9-final-prasanna/include/linux/kprobes.h 2004-10-28 16:44:50.000000000 +0530
@@ -64,7 +64,7 @@ struct kprobe {
kprobe_opcode_t opcode;

/* copy of the original instruction */
- kprobe_opcode_t insn[MAX_INSN_SIZE];
+ struct arch_specific_insn ainsn;
};

/*
@@ -94,7 +94,8 @@ static inline int kprobe_running(void)
return kprobe_cpu == smp_processor_id();
}

-extern void arch_prepare_kprobe(struct kprobe *p);
+extern int arch_prepare_kprobe(struct kprobe *p);
+extern void arch_remove_kprobe(struct kprobe *p);
extern void show_registers(struct pt_regs *regs);

/* Get the kprobe at this addr (if any). Must have called lock_kprobes */
diff -puN kernel/kprobes.c~kprobes-arch-i386-changes kernel/kprobes.c
--- linux-2.6.9-final/kernel/kprobes.c~kprobes-arch-i386-changes 2004-10-28 16:44:50.000000000 +0530
+++ linux-2.6.9-final-prasanna/kernel/kprobes.c 2004-10-28 16:44:50.000000000 +0530
@@ -84,10 +84,13 @@ int register_kprobe(struct kprobe *p)
ret = -EEXIST;
goto out;
}
+
+ if ((ret = arch_prepare_kprobe(p)) != 0) {
+ goto out;
+ }
hlist_add_head(&p->hlist,
&kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);

- arch_prepare_kprobe(p);
p->opcode = *p->addr;
*p->addr = BREAKPOINT_INSTRUCTION;
flush_icache_range((unsigned long) p->addr,
@@ -101,6 +104,7 @@ void unregister_kprobe(struct kprobe *p)
{
unsigned long flags;
spin_lock_irqsave(&kprobe_lock, flags);
+ arch_remove_kprobe(p);
*p->addr = p->opcode;
hlist_del(&p->hlist);
flush_icache_range((unsigned long) p->addr,

_
--
Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Ph: 91-80-25044636
<prasanna@xxxxxxxxxx>
-
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