linux/arch/csky/kernel/probes/kprobes_trampoline.S

/* SPDX-License-Identifier: GPL-2.0+ */

#include <linux/linkage.h>

#include <abi/entry.h>

ENTRY(kretprobe_trampoline)
	SAVE_REGS_FTRACE

	mov	a0, sp /* pt_regs */

	jbsr	trampoline_probe_handler

	/* use the result as the return-address */
	mov	lr, a0

	RESTORE_REGS_FTRACE
	rts
ENDPROC(kretprobe_trampoline)
csky: Add kprobes supported This patch enable kprobes, kretprobes, ftrace interface. It utilized software breakpoint and single step debug exceptions, instructions simulation on csky. We use USR_BKPT replace origin instruction, and the kprobe handler prepares an excutable memory slot for out-of-line execution with a copy of the original instruction being probed. Most of instructions could be executed by single-step, but some instructions need origin pc value to execute and we need software simulate these instructions. Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> 2020-04-01 09:17:02 +08:00			`/* SPDX-License-Identifier: GPL-2.0+ */`

			`#include <linux/linkage.h>`

			`#include <abi/entry.h>`

			`ENTRY(kretprobe_trampoline)`
			`SAVE_REGS_FTRACE`

			`mov a0, sp /* pt_regs */`

			`jbsr trampoline_probe_handler`

			`/* use the result as the return-address */`
			`mov lr, a0`

			`RESTORE_REGS_FTRACE`
			`rts`
			`ENDPROC(kretprobe_trampoline)`