Commit 3f553686 authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Huacai Chen
Browse files

LoongArch: Add kretprobes support 



Use the generic kretprobe trampoline handler to add kretprobes support
for LoongArch.

Tested-by: default avatarJeff Xie <xiehuan09@gmail.com>
Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 6d4cc40f

arch/loongarch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -107,6 +107,7 @@ config LOONGARCH 
	select HAVE_IRQ_EXIT_ON_IRQ_STACK

	select HAVE_IRQ_TIME_ACCOUNTING

	select HAVE_KPROBES

	select HAVE_KRETPROBES

	select HAVE_MOD_ARCH_SPECIFIC

	select HAVE_NMI

	select HAVE_PCI

arch/loongarch/include/asm/kprobes.h

+3 −0
Original line number Diff line number Diff line
@@ -49,6 +49,9 @@ bool kprobe_fault_handler(struct pt_regs *regs, int trapnr); 
bool kprobe_breakpoint_handler(struct pt_regs *regs);

bool kprobe_singlestep_handler(struct pt_regs *regs);



void __kretprobe_trampoline(void);

void *trampoline_probe_handler(struct pt_regs *regs);



#else /* !CONFIG_KPROBES */



static inline bool kprobe_breakpoint_handler(struct pt_regs *regs) { return false; }

arch/loongarch/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -52,6 +52,6 @@ obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o 
obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o perf_regs.o

obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o



obj-$(CONFIG_KPROBES)		+= kprobes.o

obj-$(CONFIG_KPROBES)		+= kprobes.o kprobes_trampoline.o



CPPFLAGS_vmlinux.lds		:= $(KBUILD_CFLAGS)

arch/loongarch/kernel/kprobes.c

+27 −0
Original line number Diff line number Diff line
@@ -377,3 +377,30 @@ int __init arch_init_kprobes(void) 
{

	return 0;

}



/* ASM function that handles the kretprobes must not be probed */

NOKPROBE_SYMBOL(__kretprobe_trampoline);



/* Called from __kretprobe_trampoline */

void __used *trampoline_probe_handler(struct pt_regs *regs)

{

	return (void *)kretprobe_trampoline_handler(regs, NULL);

}

NOKPROBE_SYMBOL(trampoline_probe_handler);



void arch_prepare_kretprobe(struct kretprobe_instance *ri,

			    struct pt_regs *regs)

{

	ri->ret_addr = (kprobe_opcode_t *)regs->regs[1];

	ri->fp = NULL;



	/* Replace the return addr with trampoline addr */

	regs->regs[1] = (unsigned long)&__kretprobe_trampoline;

}

NOKPROBE_SYMBOL(arch_prepare_kretprobe);



int arch_trampoline_kprobe(struct kprobe *p)

{

	return 0;

}

NOKPROBE_SYMBOL(arch_trampoline_kprobe);

arch/loongarch/kernel/kprobes_trampoline.S

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0+ */

#include <linux/linkage.h>

#include <asm/stackframe.h>



	.text



	.macro save_all_base_regs

	cfi_st  ra, PT_R1

	cfi_st	tp, PT_R2

	cfi_st	a0, PT_R4

	cfi_st	a1, PT_R5

	cfi_st	a2, PT_R6

	cfi_st	a3, PT_R7

	cfi_st	a4, PT_R8

	cfi_st	a5, PT_R9

	cfi_st	a6, PT_R10

	cfi_st	a7, PT_R11

	cfi_st	t0, PT_R12

	cfi_st	t1, PT_R13

	cfi_st	t2, PT_R14

	cfi_st	t3, PT_R15

	cfi_st	t4, PT_R16

	cfi_st	t5, PT_R17

	cfi_st	t6, PT_R18

	cfi_st	t7, PT_R19

	cfi_st	t8, PT_R20

	cfi_st	u0, PT_R21

	cfi_st	fp, PT_R22

	cfi_st	s0, PT_R23

	cfi_st	s1, PT_R24

	cfi_st	s2, PT_R25

	cfi_st	s3, PT_R26

	cfi_st	s4, PT_R27

	cfi_st	s5, PT_R28

	cfi_st	s6, PT_R29

	cfi_st	s7, PT_R30

	cfi_st	s8, PT_R31

	csrrd	t0, LOONGARCH_CSR_CRMD

	andi	t0, t0, 0x7 /* extract bit[1:0] PLV, bit[2] IE */

	LONG_S	t0, sp, PT_CRMD

	.endm



	.macro restore_all_base_regs

	cfi_ld	tp, PT_R2

	cfi_ld	a0, PT_R4

	cfi_ld	a1, PT_R5

	cfi_ld	a2, PT_R6

	cfi_ld	a3, PT_R7

	cfi_ld	a4, PT_R8

	cfi_ld	a5, PT_R9

	cfi_ld	a6, PT_R10

	cfi_ld	a7, PT_R11

	cfi_ld	t0, PT_R12

	cfi_ld	t1, PT_R13

	cfi_ld	t2, PT_R14

	cfi_ld	t3, PT_R15

	cfi_ld	t4, PT_R16

	cfi_ld	t5, PT_R17

	cfi_ld	t6, PT_R18

	cfi_ld	t7, PT_R19

	cfi_ld	t8, PT_R20

	cfi_ld	u0, PT_R21

	cfi_ld	fp, PT_R22

	cfi_ld	s0, PT_R23

	cfi_ld	s1, PT_R24

	cfi_ld	s2, PT_R25

	cfi_ld	s3, PT_R26

	cfi_ld	s4, PT_R27

	cfi_ld	s5, PT_R28

	cfi_ld	s6, PT_R29

	cfi_ld	s7, PT_R30

	cfi_ld	s8, PT_R31

	LONG_L  t0, sp, PT_CRMD

	li.d	t1, 0x7 /* mask bit[1:0] PLV, bit[2] IE */

	csrxchg t0, t1, LOONGARCH_CSR_CRMD

	.endm



SYM_CODE_START(__kretprobe_trampoline)

	addi.d	sp, sp, -PT_SIZE

	save_all_base_regs



	addi.d	t0, sp, PT_SIZE

	LONG_S	t0, sp, PT_R3



	move a0, sp /* pt_regs */



	bl trampoline_probe_handler



	/* use the result as the return-address */

	move ra, a0



	restore_all_base_regs

	addi.d	sp, sp, PT_SIZE



	jr ra

SYM_CODE_END(__kretprobe_trampoline)