d19ad0775d
In preparation to have arguments of a function passed to callbacks attached to functions as default, change the default callback prototype to receive a struct ftrace_regs as the forth parameter instead of a pt_regs. For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they will now need to get the pt_regs via a ftrace_get_regs() helper call. If this is called by a callback that their ftrace_ops did not have a FL_SAVE_REGS flag set, it that helper function will return NULL. This will allow the ftrace_regs to hold enough just to get the parameters and stack pointer, but without the worry that callbacks may have a pt_regs that is not completely filled. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
77 lines
1.9 KiB
C
77 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
|
|
#include <linux/kprobes.h>
|
|
|
|
int arch_check_ftrace_location(struct kprobe *p)
|
|
{
|
|
if (ftrace_location((unsigned long)p->addr))
|
|
p->flags |= KPROBE_FLAG_FTRACE;
|
|
return 0;
|
|
}
|
|
|
|
/* Ftrace callback handler for kprobes -- called under preepmt disabed */
|
|
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
|
|
struct ftrace_ops *ops, struct ftrace_regs *fregs)
|
|
{
|
|
int bit;
|
|
bool lr_saver = false;
|
|
struct kprobe *p;
|
|
struct kprobe_ctlblk *kcb;
|
|
struct pt_regs *regs;
|
|
|
|
bit = ftrace_test_recursion_trylock(ip, parent_ip);
|
|
if (bit < 0)
|
|
return;
|
|
|
|
regs = ftrace_get_regs(fregs);
|
|
preempt_disable_notrace();
|
|
p = get_kprobe((kprobe_opcode_t *)ip);
|
|
if (!p) {
|
|
p = get_kprobe((kprobe_opcode_t *)(ip - MCOUNT_INSN_SIZE));
|
|
if (unlikely(!p) || kprobe_disabled(p))
|
|
goto out;
|
|
lr_saver = true;
|
|
}
|
|
|
|
kcb = get_kprobe_ctlblk();
|
|
if (kprobe_running()) {
|
|
kprobes_inc_nmissed_count(p);
|
|
} else {
|
|
unsigned long orig_ip = instruction_pointer(regs);
|
|
|
|
if (lr_saver)
|
|
ip -= MCOUNT_INSN_SIZE;
|
|
instruction_pointer_set(regs, ip);
|
|
__this_cpu_write(current_kprobe, p);
|
|
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
|
|
if (!p->pre_handler || !p->pre_handler(p, regs)) {
|
|
/*
|
|
* Emulate singlestep (and also recover regs->pc)
|
|
* as if there is a nop
|
|
*/
|
|
instruction_pointer_set(regs,
|
|
(unsigned long)p->addr + MCOUNT_INSN_SIZE);
|
|
if (unlikely(p->post_handler)) {
|
|
kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
|
p->post_handler(p, regs, 0);
|
|
}
|
|
instruction_pointer_set(regs, orig_ip);
|
|
}
|
|
/*
|
|
* If pre_handler returns !0, it changes regs->pc. We have to
|
|
* skip emulating post_handler.
|
|
*/
|
|
__this_cpu_write(current_kprobe, NULL);
|
|
}
|
|
out:
|
|
preempt_enable_notrace();
|
|
ftrace_test_recursion_unlock(bit);
|
|
}
|
|
NOKPROBE_SYMBOL(kprobe_ftrace_handler);
|
|
|
|
int arch_prepare_kprobe_ftrace(struct kprobe *p)
|
|
{
|
|
p->ainsn.api.insn = NULL;
|
|
return 0;
|
|
}
|