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LoongArch: Add kretprobes support

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

Tested-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Tiezhu Yang 2023-02-25 15:52:57 +08:00 committed by Huacai Chen
parent 6d4cc40fb5
commit 3f55368600
5 changed files with 128 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
arch/loongarch/Kconfig
View file

@ -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

3
arch/loongarch/include/asm/kprobes.h
View file

@ -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; }

2
arch/loongarch/kernel/Makefile
View file

@ -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)

27
arch/loongarch/kernel/kprobes.c
View file

@ -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);

96
arch/loongarch/kernel/kprobes_trampoline.S Normal file
View file

@ -0,0 +1,96 @@
/* 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)