提交 d38f1220 编写于 作者: D David S. Miller 提交者: David S. Miller

[SPARC64]: Add kretprobe support.

Passes the smoke tests at least, powerpc implementation was used
as a guide.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 13fa14e1
......@@ -480,8 +480,117 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
return 0;
}
/* architecture specific initialization */
int arch_init_kprobes(void)
/* Called with kretprobe_lock held. The value stored in the return
* address register is actually 2 instructions before where the
* callee will return to. Sequences usually look something like this
*
* call some_function <--- return register points here
* nop <--- call delay slot
* whatever <--- where callee returns to
*
* To keep trampoline_probe_handler logic simpler, we normalize the
* value kept in ri->ret_addr so we don't need to keep adjusting it
* back and forth.
*/
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
ri->ret_addr = (kprobe_opcode_t *)(regs->u_regs[UREG_RETPC] + 8);
/* Replace the return addr with trampoline addr */
regs->u_regs[UREG_RETPC] =
((unsigned long)kretprobe_trampoline) - 8;
}
/*
* Called when the probe at kretprobe trampoline is hit
*/
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
/*
* It is possible to have multiple instances associated with a given
* task either because an multiple functions in the call path
* have a return probe installed on them, and/or more then one return
* return probe was registered for a target function.
*
* We can handle this because:
* - instances are always inserted at the head of the list
* - when multiple return probes are registered for the same
* function, the first instance's ret_addr will point to the
* real return address, and all the rest will point to
* kretprobe_trampoline
*/
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task != current)
/* another task is sharing our hash bucket */
continue;
if (ri->rp && ri->rp->handler)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
* This is the real return address. Any other
* instances associated with this task are for
* other calls deeper on the call stack
*/
break;
}
kretprobe_assert(ri, orig_ret_address, trampoline_address);
regs->tpc = orig_ret_address;
regs->tnpc = orig_ret_address + 4;
reset_current_kprobe();
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
* to run (and have re-enabled preemption)
*/
return 1;
}
void kretprobe_trampoline_holder(void)
{
asm volatile(".global kretprobe_trampoline\n"
"kretprobe_trampoline:\n"
"\tnop\n"
"\tnop\n");
}
static struct kprobe trampoline_p = {
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
.pre_handler = trampoline_probe_handler
};
int __init arch_init_kprobes(void)
{
return register_kprobe(&trampoline_p);
}
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
{
if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
return 1;
return 0;
}
......@@ -14,11 +14,15 @@ typedef u32 kprobe_opcode_t;
#define arch_remove_kprobe(p) do {} while (0)
#define ARCH_SUPPORTS_KRETPROBES
#define flush_insn_slot(p) \
do { flushi(&(p)->ainsn.insn[0]); \
flushi(&(p)->ainsn.insn[1]); \
} while (0)
void kretprobe_trampoline(void);
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
/* copy of the original instruction */
......
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