From 3f5536860086d906b01ec5ed68cf50c7edcc40af Mon Sep 17 00:00:00 2001 From: Tiezhu Yang Date: Sat, 25 Feb 2023 15:52:57 +0800 Subject: [PATCH] LoongArch: Add kretprobes support Use the generic kretprobe trampoline handler to add kretprobes support for LoongArch. Tested-by: Jeff Xie Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen --- arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/kprobes.h | 3 + arch/loongarch/kernel/Makefile | 2 +- arch/loongarch/kernel/kprobes.c | 27 ++++++ arch/loongarch/kernel/kprobes_trampoline.S | 96 ++++++++++++++++++++++ 5 files changed, 128 insertions(+), 1 deletion(-) create mode 100644 arch/loongarch/kernel/kprobes_trampoline.S diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index bb538b68116d..d90bb47f1dc3 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -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 diff --git a/arch/loongarch/include/asm/kprobes.h b/arch/loongarch/include/asm/kprobes.h index 7b9fc3ed71c3..798020ae02c6 100644 --- a/arch/loongarch/include/asm/kprobes.h +++ b/arch/loongarch/include/asm/kprobes.h @@ -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; } diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 0a2f546216c0..78d4e3384305 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -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) diff --git a/arch/loongarch/kernel/kprobes.c b/arch/loongarch/kernel/kprobes.c index 73eddd76f37c..56c8c4b09a42 100644 --- a/arch/loongarch/kernel/kprobes.c +++ b/arch/loongarch/kernel/kprobes.c @@ -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); diff --git a/arch/loongarch/kernel/kprobes_trampoline.S b/arch/loongarch/kernel/kprobes_trampoline.S new file mode 100644 index 000000000000..af94b0d213fa --- /dev/null +++ b/arch/loongarch/kernel/kprobes_trampoline.S @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +#include +#include + + .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)