[PATCH 09/11] csky: Add kprobes supported

From: guoren
Date: Fri Apr 03 2020 - 00:42:36 EST

From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
arch/csky/Kconfig | 3 +
arch/csky/include/asm/Kbuild | 1 -
arch/csky/include/asm/kprobes.h | 48 ++
arch/csky/include/asm/probes.h | 24 +
arch/csky/include/asm/ptrace.h | 2 +
arch/csky/kernel/Makefile | 1 +
arch/csky/kernel/probes/Makefile | 6 +
arch/csky/kernel/probes/decode-insn.c | 49 ++
arch/csky/kernel/probes/decode-insn.h | 20 +
arch/csky/kernel/probes/ftrace.c | 66 +++
arch/csky/kernel/probes/kprobes.c | 499 +++++++++++++++++++
arch/csky/kernel/probes/kprobes_trampoline.S | 19 +
arch/csky/kernel/probes/simulate-insn.c | 398 +++++++++++++++
arch/csky/kernel/probes/simulate-insn.h | 49 ++
arch/csky/kernel/traps.c | 10 +-
arch/csky/mm/fault.c | 4 +
16 files changed, 1197 insertions(+), 2 deletions(-)
create mode 100644 arch/csky/include/asm/kprobes.h
create mode 100644 arch/csky/include/asm/probes.h
create mode 100644 arch/csky/kernel/probes/Makefile
create mode 100644 arch/csky/kernel/probes/decode-insn.c
create mode 100644 arch/csky/kernel/probes/decode-insn.h
create mode 100644 arch/csky/kernel/probes/ftrace.c
create mode 100644 arch/csky/kernel/probes/kprobes.c
create mode 100644 arch/csky/kernel/probes/kprobes_trampoline.S
create mode 100644 arch/csky/kernel/probes/simulate-insn.c
create mode 100644 arch/csky/kernel/probes/simulate-insn.h

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 998188f44fd7..f76c333758ca 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -46,6 +46,9 @@ config CSKY
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO
select HAVE_KERNEL_LZMA
+ select HAVE_KPROBES if !CPU_CK610
+ select HAVE_KPROBES_ON_FTRACE if !CPU_CK610
+ select HAVE_KRETPROBES if !CPU_CK610
select HAVE_PERF_EVENTS
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index 4130e3eaa766..59d3186578fd 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -20,7 +20,6 @@ generic-y += irq_regs.h
generic-y += irq_work.h
generic-y += kdebug.h
generic-y += kmap_types.h
-generic-y += kprobes.h
generic-y += kvm_para.h
generic-y += linkage.h
generic-y += local.h
diff --git a/arch/csky/include/asm/kprobes.h b/arch/csky/include/asm/kprobes.h
new file mode 100644
index 000000000000..b647bbde4d6d
--- /dev/null
+++ b/arch/csky/include/asm/kprobes.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __ASM_CSKY_KPROBES_H
+#define __ASM_CSKY_KPROBES_H
+
+#include <asm-generic/kprobes.h>
+
+#ifdef CONFIG_KPROBES
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/percpu.h>
+
+#define __ARCH_WANT_KPROBES_INSN_SLOT
+#define MAX_INSN_SIZE 1
+
+#define flush_insn_slot(p) do { } while (0)
+#define kretprobe_blacklist_size 0
+
+#include <asm/probes.h>
+
+struct prev_kprobe {
+ struct kprobe *kp;
+ unsigned int status;
+};
+
+/* Single step context for kprobe */
+struct kprobe_step_ctx {
+ unsigned long ss_pending;
+ unsigned long match_addr;
+};
+
+/* per-cpu kprobe control block */
+struct kprobe_ctlblk {
+ unsigned int kprobe_status;
+ unsigned long saved_sr;
+ struct prev_kprobe prev_kprobe;
+ struct kprobe_step_ctx ss_ctx;
+};
+
+void arch_remove_kprobe(struct kprobe *p);
+int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
+int kprobe_breakpoint_handler(struct pt_regs *regs);
+int kprobe_single_step_handler(struct pt_regs *regs);
+void kretprobe_trampoline(void);
+void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
+
+#endif /* CONFIG_KPROBES */
+#endif /* __ASM_CSKY_KPROBES_H */
diff --git a/arch/csky/include/asm/probes.h b/arch/csky/include/asm/probes.h
new file mode 100644
index 000000000000..5e526334e6f9
--- /dev/null
+++ b/arch/csky/include/asm/probes.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_CSKY_PROBES_H
+#define __ASM_CSKY_PROBES_H
+
+typedef u32 probe_opcode_t;
+typedef void (probes_handler_t) (u32 opcode, long addr, struct pt_regs *);
+
+/* architecture specific copy of original instruction */
+struct arch_probe_insn {
+ probe_opcode_t *insn;
+ probes_handler_t *handler;
+ /* restore address after simulation */
+ unsigned long restore;
+};
+
+#ifdef CONFIG_KPROBES
+typedef u32 kprobe_opcode_t;
+struct arch_specific_insn {
+ struct arch_probe_insn api;
+};
+#endif
+
+#endif /* __ASM_CSKY_PROBES_H */
diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h
index f16ca256e007..aae5aa96cf54 100644
--- a/arch/csky/include/asm/ptrace.h
+++ b/arch/csky/include/asm/ptrace.h
@@ -13,6 +13,8 @@

#define PS_S 0x80000000 /* Supervisor Mode */

+#define USR_BKPT 0x1464
+
#define arch_has_single_step() (1)
#define current_pt_regs() \
({ (struct pt_regs *)((char *)current_thread_info() + THREAD_SIZE) - 1; })
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 071d659f37b7..fd6d9dc8b7f3 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -4,6 +4,7 @@ extra-y := head.o vmlinux.lds
obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o
obj-y += power.o syscall.o syscall_table.o setup.o
obj-y += process.o cpu-probe.o ptrace.o dumpstack.o
+obj-y += probes/

obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_SMP) += smp.o
diff --git a/arch/csky/kernel/probes/Makefile b/arch/csky/kernel/probes/Makefile
new file mode 100644
index 000000000000..3a857d081958
--- /dev/null
+++ b/arch/csky/kernel/probes/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_KPROBES) += kprobes.o decode-insn.o simulate-insn.o
+obj-$(CONFIG_KPROBES) += kprobes_trampoline.o
+obj-$(CONFIG_KPROBES_ON_FTRACE) += ftrace.o
+
+CFLAGS_REMOVE_simulate-insn.o = $(CC_FLAGS_FTRACE)
diff --git a/arch/csky/kernel/probes/decode-insn.c b/arch/csky/kernel/probes/decode-insn.c
new file mode 100644
index 000000000000..bbc4edc25dc9
--- /dev/null
+++ b/arch/csky/kernel/probes/decode-insn.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <asm/sections.h>
+
+#include "decode-insn.h"
+#include "simulate-insn.h"
+
+/* Return:
+ * INSN_REJECTED If instruction is one not allowed to kprobe,
+ * INSN_GOOD_NO_SLOT If instruction is supported but doesn't use its slot.
+ */
+enum probe_insn __kprobes
+csky_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *api)
+{
+ probe_opcode_t insn = le32_to_cpu(*addr);
+
+ CSKY_INSN_SET_SIMULATE(br16, insn);
+ CSKY_INSN_SET_SIMULATE(bt16, insn);
+ CSKY_INSN_SET_SIMULATE(bf16, insn);
+ CSKY_INSN_SET_SIMULATE(jmp16, insn);
+ CSKY_INSN_SET_SIMULATE(jsr16, insn);
+ CSKY_INSN_SET_SIMULATE(lrw16, insn);
+ CSKY_INSN_SET_SIMULATE(pop16, insn);
+
+ CSKY_INSN_SET_SIMULATE(br32, insn);
+ CSKY_INSN_SET_SIMULATE(bt32, insn);
+ CSKY_INSN_SET_SIMULATE(bf32, insn);
+ CSKY_INSN_SET_SIMULATE(jmp32, insn);
+ CSKY_INSN_SET_SIMULATE(jsr32, insn);
+ CSKY_INSN_SET_SIMULATE(lrw32, insn);
+ CSKY_INSN_SET_SIMULATE(pop32, insn);
+
+ CSKY_INSN_SET_SIMULATE(bez32, insn);
+ CSKY_INSN_SET_SIMULATE(bnez32, insn);
+ CSKY_INSN_SET_SIMULATE(bnezad32, insn);
+ CSKY_INSN_SET_SIMULATE(bhsz32, insn);
+ CSKY_INSN_SET_SIMULATE(bhz32, insn);
+ CSKY_INSN_SET_SIMULATE(blsz32, insn);
+ CSKY_INSN_SET_SIMULATE(blz32, insn);
+ CSKY_INSN_SET_SIMULATE(bsr32, insn);
+ CSKY_INSN_SET_SIMULATE(jmpi32, insn);
+ CSKY_INSN_SET_SIMULATE(jsri32, insn);
+
+ return INSN_GOOD;
+}
diff --git a/arch/csky/kernel/probes/decode-insn.h b/arch/csky/kernel/probes/decode-insn.h
new file mode 100644
index 000000000000..9c4ad48fee0d
--- /dev/null
+++ b/arch/csky/kernel/probes/decode-insn.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef __CSKY_KERNEL_KPROBES_DECODE_INSN_H
+#define __CSKY_KERNEL_KPROBES_DECODE_INSN_H
+
+#include <asm/sections.h>
+#include <asm/kprobes.h>
+
+enum probe_insn {
+ INSN_REJECTED,
+ INSN_GOOD_NO_SLOT,
+ INSN_GOOD,
+};
+
+#define is_insn32(insn) ((insn & 0xc000) == 0xc000)
+
+enum probe_insn __kprobes
+csky_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *asi);
+
+#endif /* __CSKY_KERNEL_KPROBES_DECODE_INSN_H */
diff --git a/arch/csky/kernel/probes/ftrace.c b/arch/csky/kernel/probes/ftrace.c
new file mode 100644
index 000000000000..5264763d05be
--- /dev/null
+++ b/arch/csky/kernel/probes/ftrace.c
@@ -0,0 +1,66 @@
+// 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 pt_regs *regs)
+{
+ bool lr_saver = false;
+ struct kprobe *p;
+ struct kprobe_ctlblk *kcb;
+
+ /* Preempt is disabled by ftrace */
+ 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))
+ return;
+ 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);
+ }
+}
+NOKPROBE_SYMBOL(kprobe_ftrace_handler);
+
+int arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+ p->ainsn.api.insn = NULL;
+ return 0;
+}
diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
new file mode 100644
index 000000000000..f0f733b7ac5a
--- /dev/null
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -0,0 +1,499 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/kprobes.h>
+#include <linux/extable.h>
+#include <linux/slab.h>
+#include <linux/stop_machine.h>
+#include <asm/ptrace.h>
+#include <linux/uaccess.h>
+#include <asm/sections.h>
+#include <asm/cacheflush.h>
+
+#include "decode-insn.h"
+
+DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
+DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+
+static void __kprobes
+post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
+
+struct csky_insn_patch {
+ kprobe_opcode_t *addr;
+ u32 opcode;
+ atomic_t cpu_count;
+};
+
+static int __kprobes patch_text_cb(void *priv)
+{
+ struct csky_insn_patch *param = priv;
+ unsigned int addr = (unsigned int)param->addr;
+
+ if (atomic_inc_return(&param->cpu_count) == 1) {
+ *(u16 *) addr = cpu_to_le16(param->opcode);
+ dcache_wb_range(addr, addr + 2);
+ atomic_inc(&param->cpu_count);
+ } else {
+ while (atomic_read(&param->cpu_count) <= num_online_cpus())
+ cpu_relax();
+ }
+
+ icache_inv_range(addr, addr + 2);
+
+ return 0;
+}
+
+static int __kprobes patch_text(kprobe_opcode_t *addr, u32 opcode)
+{
+ struct csky_insn_patch param = { addr, opcode, ATOMIC_INIT(0) };
+
+ return stop_machine_cpuslocked(patch_text_cb, &param, cpu_online_mask);
+}
+
+static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
+{
+ unsigned long offset = is_insn32(p->opcode) ? 4 : 2;
+
+ p->ainsn.api.restore = (unsigned long)p->addr + offset;
+
+ patch_text(p->ainsn.api.insn, p->opcode);
+}
+
+static void __kprobes arch_prepare_simulate(struct kprobe *p)
+{
+ p->ainsn.api.restore = 0;
+}
+
+static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if (p->ainsn.api.handler)
+ p->ainsn.api.handler((u32)p->opcode, (long)p->addr, regs);
+
+ post_kprobe_handler(kcb, regs);
+}
+
+int __kprobes arch_prepare_kprobe(struct kprobe *p)
+{
+ unsigned long probe_addr = (unsigned long)p->addr;
+
+ if (probe_addr & 0x1) {
+ pr_warn("Address not aligned.\n");
+ return -EINVAL;
+ }
+
+ /* copy instruction */
+ p->opcode = le32_to_cpu(*p->addr);
+
+ /* decode instruction */
+ switch (csky_probe_decode_insn(p->addr, &p->ainsn.api)) {
+ case INSN_REJECTED: /* insn not supported */
+ return -EINVAL;
+
+ case INSN_GOOD_NO_SLOT: /* insn need simulation */
+ p->ainsn.api.insn = NULL;
+ break;
+
+ case INSN_GOOD: /* instruction uses slot */
+ p->ainsn.api.insn = get_insn_slot();
+ if (!p->ainsn.api.insn)
+ return -ENOMEM;
+ break;
+ }
+
+ /* prepare the instruction */
+ if (p->ainsn.api.insn)
+ arch_prepare_ss_slot(p);
+ else
+ arch_prepare_simulate(p);
+
+ return 0;
+}
+
+/* install breakpoint in text */
+void __kprobes arch_arm_kprobe(struct kprobe *p)
+{
+ patch_text(p->addr, USR_BKPT);
+}
+
+/* remove breakpoint from text */
+void __kprobes arch_disarm_kprobe(struct kprobe *p)
+{
+ patch_text(p->addr, p->opcode);
+}
+
+void __kprobes arch_remove_kprobe(struct kprobe *p)
+{
+}
+
+static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ kcb->prev_kprobe.kp = kprobe_running();
+ kcb->prev_kprobe.status = kcb->kprobe_status;
+}
+
+static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+{
+ __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
+ kcb->kprobe_status = kcb->prev_kprobe.status;
+}
+
+static void __kprobes set_current_kprobe(struct kprobe *p)
+{
+ __this_cpu_write(current_kprobe, p);
+}
+
+/*
+ * Interrupts need to be disabled before single-step mode is set, and not
+ * reenabled until after single-step mode ends.
+ * Without disabling interrupt on local CPU, there is a chance of
+ * interrupt occurrence in the period of exception return and start of
+ * out-of-line single-step, that result in wrongly single stepping
+ * into the interrupt handler.
+ */
+static void __kprobes kprobes_save_local_irqflag(struct kprobe_ctlblk *kcb,
+ struct pt_regs *regs)
+{
+ kcb->saved_sr = regs->sr;
+ regs->sr &= ~BIT(6);
+}
+
+static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb,
+ struct pt_regs *regs)
+{
+ regs->sr = kcb->saved_sr;
+}
+
+static void __kprobes
+set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr, struct kprobe *p)
+{
+ unsigned long offset = is_insn32(p->opcode) ? 4 : 2;
+
+ kcb->ss_ctx.ss_pending = true;
+ kcb->ss_ctx.match_addr = addr + offset;
+}
+
+static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb)
+{
+ kcb->ss_ctx.ss_pending = false;
+ kcb->ss_ctx.match_addr = 0;
+}
+
+#define TRACE_MODE_SI BIT(14)
+#define TRACE_MODE_MASK ~(0x3 << 14)
+#define TRACE_MODE_RUN 0
+
+static void __kprobes setup_singlestep(struct kprobe *p,
+ struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb, int reenter)
+{
+ unsigned long slot;
+
+ if (reenter) {
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p);
+ kcb->kprobe_status = KPROBE_REENTER;
+ } else {
+ kcb->kprobe_status = KPROBE_HIT_SS;
+ }
+
+ if (p->ainsn.api.insn) {
+ /* prepare for single stepping */
+ slot = (unsigned long)p->ainsn.api.insn;
+
+ set_ss_context(kcb, slot, p); /* mark pending ss */
+
+ /* IRQs and single stepping do not mix well. */
+ kprobes_save_local_irqflag(kcb, regs);
+ regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_SI;
+ instruction_pointer_set(regs, slot);
+ } else {
+ /* insn simulation */
+ arch_simulate_insn(p, regs);
+ }
+}
+
+static int __kprobes reenter_kprobe(struct kprobe *p,
+ struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SSDONE:
+ case KPROBE_HIT_ACTIVE:
+ kprobes_inc_nmissed_count(p);
+ setup_singlestep(p, regs, kcb, 1);
+ break;
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ pr_warn("Unrecoverable kprobe detected.\n");
+ dump_kprobe(p);
+ BUG();
+ break;
+ default:
+ WARN_ON(1);
+ return 0;
+ }
+
+ return 1;
+}
+
+static void __kprobes
+post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs)
+{
+ struct kprobe *cur = kprobe_running();
+
+ if (!cur)
+ return;
+
+ /* return addr restore if non-branching insn */
+ if (cur->ainsn.api.restore != 0)
+ regs->pc = cur->ainsn.api.restore;
+
+ /* restore back original saved kprobe variables and continue */
+ if (kcb->kprobe_status == KPROBE_REENTER) {
+ restore_previous_kprobe(kcb);
+ return;
+ }
+
+ /* call post handler */
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
+ if (cur->post_handler) {
+ /* post_handler can hit breakpoint and single step
+ * again, so we enable D-flag for recursive exception.
+ */
+ cur->post_handler(cur, regs, 0);
+ }
+
+ reset_current_kprobe();
+}
+
+int __kprobes kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr)
+{
+ struct kprobe *cur = kprobe_running();
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SS:
+ case KPROBE_REENTER:
+ /*
+ * We are here because the instruction being single
+ * stepped caused a page fault. We reset the current
+ * kprobe and the ip points back to the probe address
+ * and allow the page fault handler to continue as a
+ * normal page fault.
+ */
+ regs->pc = (unsigned long) cur->addr;
+ if (!instruction_pointer(regs))
+ BUG();
+
+ if (kcb->kprobe_status == KPROBE_REENTER)
+ restore_previous_kprobe(kcb);
+ else
+ reset_current_kprobe();
+
+ break;
+ case KPROBE_HIT_ACTIVE:
+ case KPROBE_HIT_SSDONE:
+ /*
+ * We increment the nmissed count for accounting,
+ * we can also use npre/npostfault count for accounting
+ * these specific fault cases.
+ */
+ kprobes_inc_nmissed_count(cur);
+
+ /*
+ * We come here because instructions in the pre/post
+ * handler caused the page_fault, this could happen
+ * if handler tries to access user space by
+ * copy_from_user(), get_user() etc. Let the
+ * user-specified handler try to fix it first.
+ */
+ if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
+ return 1;
+
+ /*
+ * In case the user-specified fault handler returned
+ * zero, try to fix up.
+ */
+ if (fixup_exception(regs))
+ return 1;
+ }
+ return 0;
+}
+
+int __kprobes
+kprobe_breakpoint_handler(struct pt_regs *regs)
+{
+ struct kprobe *p, *cur_kprobe;
+ struct kprobe_ctlblk *kcb;
+ unsigned long addr = instruction_pointer(regs);
+
+ kcb = get_kprobe_ctlblk();
+ cur_kprobe = kprobe_running();
+
+ p = get_kprobe((kprobe_opcode_t *) addr);
+
+ if (p) {
+ if (cur_kprobe) {
+ if (reenter_kprobe(p, regs, kcb))
+ return 1;
+ } else {
+ /* Probe hit */
+ set_current_kprobe(p);
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+
+ /*
+ * If we have no pre-handler or it returned 0, we
+ * continue with normal processing. If we have a
+ * pre-handler and it returned non-zero, it will
+ * modify the execution path and no need to single
+ * stepping. Let's just reset current kprobe and exit.
+ *
+ * pre_handler can hit a breakpoint and can step thru
+ * before return.
+ */
+ if (!p->pre_handler || !p->pre_handler(p, regs))
+ setup_singlestep(p, regs, kcb, 0);
+ else
+ reset_current_kprobe();
+ }
+ return 1;
+ }
+
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Return back to original instruction, and continue.
+ */
+ return 0;
+}
+
+int __kprobes
+kprobe_single_step_handler(struct pt_regs *regs)
+{
+ struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
+
+ if ((kcb->ss_ctx.ss_pending)
+ && (kcb->ss_ctx.match_addr == instruction_pointer(regs))) {
+ clear_ss_context(kcb); /* clear pending ss */
+
+ kprobes_restore_local_irqflag(kcb, regs);
+ regs->sr = (regs->sr & TRACE_MODE_MASK) | TRACE_MODE_RUN;
+
+ post_kprobe_handler(kcb, regs);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Provide a blacklist of symbols identifying ranges which cannot be kprobed.
+ * This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
+ */
+int __init arch_populate_kprobe_blacklist(void)
+{
+ int ret;
+
+ ret = kprobe_add_area_blacklist((unsigned long)__irqentry_text_start,
+ (unsigned long)__irqentry_text_end);
+ return ret;
+}
+
+void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
+{
+ struct kretprobe_instance *ri = NULL;
+ struct hlist_head *head, empty_rp;
+ struct hlist_node *tmp;
+ unsigned long flags, orig_ret_address = 0;
+ unsigned long trampoline_address =
+ (unsigned long)&kretprobe_trampoline;
+ kprobe_opcode_t *correct_ret_addr = NULL;
+
+ INIT_HLIST_HEAD(&empty_rp);
+ kretprobe_hash_lock(current, &head, &flags);
+
+ /*
+ * It is possible to have multiple instances associated with a given
+ * task either because multiple functions in the call path have
+ * return probes installed on them, and/or more than one
+ * return probe was registered for a target function.
+ *
+ * We can handle this because:
+ * - instances are always pushed into the head of the list
+ * - when multiple return probes are registered for the same
+ * function, the (chronologically) first instance's ret_addr
+ * will be the real return address, and all the rest will
+ * point to kretprobe_trampoline.
+ */
+ hlist_for_each_entry_safe(ri, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_assert(ri, orig_ret_address, trampoline_address);
+
+ correct_ret_addr = ri->ret_addr;
+ hlist_for_each_entry_safe(ri, tmp, head, hlist) {
+ if (ri->task != current)
+ /* another task is sharing our hash bucket */
+ continue;
+
+ orig_ret_address = (unsigned long)ri->ret_addr;
+ if (ri->rp && ri->rp->handler) {
+ __this_cpu_write(current_kprobe, &ri->rp->kp);
+ get_kprobe_ctlblk()->kprobe_status = KPROBE_HIT_ACTIVE;
+ ri->ret_addr = correct_ret_addr;
+ ri->rp->handler(ri, regs);
+ __this_cpu_write(current_kprobe, NULL);
+ }
+
+ recycle_rp_inst(ri, &empty_rp);
+
+ if (orig_ret_address != trampoline_address)
+ /*
+ * This is the real return address. Any other
+ * instances associated with this task are for
+ * other calls deeper on the call stack
+ */
+ break;
+ }
+
+ kretprobe_hash_unlock(current, &flags);
+
+ hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
+ hlist_del(&ri->hlist);
+ kfree(ri);
+ }
+ return (void *)orig_ret_address;
+}
+
+void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
+ struct pt_regs *regs)
+{
+ ri->ret_addr = (kprobe_opcode_t *)regs->lr;
+ regs->lr = (unsigned long) &kretprobe_trampoline;
+}
+
+int __kprobes arch_trampoline_kprobe(struct kprobe *p)
+{
+ return 0;
+}
+
+int __init arch_init_kprobes(void)
+{
+ return 0;
+}
diff --git a/arch/csky/kernel/probes/kprobes_trampoline.S b/arch/csky/kernel/probes/kprobes_trampoline.S
new file mode 100644
index 000000000000..b1fe3af24f03
--- /dev/null
+++ b/arch/csky/kernel/probes/kprobes_trampoline.S
@@ -0,0 +1,19 @@
+/* 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)
diff --git a/arch/csky/kernel/probes/simulate-insn.c b/arch/csky/kernel/probes/simulate-insn.c
new file mode 100644
index 000000000000..4e464fed52ec
--- /dev/null
+++ b/arch/csky/kernel/probes/simulate-insn.c
@@ -0,0 +1,398 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+
+#include "decode-insn.h"
+#include "simulate-insn.h"
+
+static inline bool csky_insn_reg_get_val(struct pt_regs *regs,
+ unsigned long index,
+ unsigned long *ptr)
+{
+ if (index < 14)
+ *ptr = *(&regs->a0 + index);
+
+ if (index > 15 && index < 31)
+ *ptr = *(&regs->exregs[0] + index - 16);
+
+ switch (index) {
+ case 14:
+ *ptr = regs->usp;
+ break;
+ case 15:
+ *ptr = regs->lr;
+ break;
+ case 31:
+ *ptr = regs->tls;
+ break;
+ default:
+ goto fail;
+ }
+
+ return true;
+fail:
+ return false;
+}
+
+static inline bool csky_insn_reg_set_val(struct pt_regs *regs,
+ unsigned long index,
+ unsigned long val)
+{
+ if (index < 14)
+ *(&regs->a0 + index) = val;
+
+ if (index > 15 && index < 31)
+ *(&regs->exregs[0] + index - 16) = val;
+
+ switch (index) {
+ case 14:
+ regs->usp = val;
+ break;
+ case 15:
+ regs->lr = val;
+ break;
+ case 31:
+ regs->tls = val;
+ break;
+ default:
+ goto fail;
+ }
+
+ return true;
+fail:
+ return false;
+}
+
+void __kprobes
+simulate_br16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0x3ff) << 1, 9));
+}
+
+void __kprobes
+simulate_br32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+}
+
+void __kprobes
+simulate_bt16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ if (regs->sr & 1)
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0x3ff) << 1, 9));
+ else
+ instruction_pointer_set(regs, addr + 2);
+}
+
+void __kprobes
+simulate_bt32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ if (regs->sr & 1)
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ else
+ instruction_pointer_set(regs, addr + 4);
+}
+
+void __kprobes
+simulate_bf16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ if (!(regs->sr & 1))
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0x3ff) << 1, 9));
+ else
+ instruction_pointer_set(regs, addr + 2);
+}
+
+void __kprobes
+simulate_bf32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ if (!(regs->sr & 1))
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ else
+ instruction_pointer_set(regs, addr + 4);
+}
+
+void __kprobes
+simulate_jmp16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = (opcode >> 2) & 0xf;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ instruction_pointer_set(regs, tmp & 0xfffffffe);
+}
+
+void __kprobes
+simulate_jmp32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ instruction_pointer_set(regs, tmp & 0xfffffffe);
+}
+
+void __kprobes
+simulate_jsr16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = (opcode >> 2) & 0xf;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ regs->lr = addr + 2;
+
+ instruction_pointer_set(regs, tmp & 0xfffffffe);
+}
+
+void __kprobes
+simulate_jsr32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ regs->lr = addr + 4;
+
+ instruction_pointer_set(regs, tmp & 0xfffffffe);
+}
+
+void __kprobes
+simulate_lrw16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long val;
+ unsigned long tmp = (opcode & 0x300) >> 3;
+ unsigned long offset = ((opcode & 0x1f) | tmp) << 2;
+
+ tmp = (opcode & 0xe0) >> 5;
+
+ val = *(unsigned int *)(instruction_pointer(regs) + offset);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_lrw32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long val;
+ unsigned long offset = (opcode & 0xffff0000) >> 14;
+ unsigned long tmp = opcode & 0x0000001f;
+
+ val = *(unsigned int *)
+ ((instruction_pointer(regs) + offset) & 0xfffffffc);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_pop16(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long *tmp = (unsigned long *)regs->usp;
+ int i;
+
+ for (i = 0; i < (opcode & 0xf); i++) {
+ csky_insn_reg_set_val(regs, i + 4, *tmp);
+ tmp += 1;
+ }
+
+ if (opcode & 0x10) {
+ csky_insn_reg_set_val(regs, 15, *tmp);
+ tmp += 1;
+ }
+
+ regs->usp = (unsigned long)tmp;
+
+ instruction_pointer_set(regs, regs->lr);
+}
+
+void __kprobes
+simulate_pop32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long *tmp = (unsigned long *)regs->usp;
+ int i;
+
+ for (i = 0; i < ((opcode & 0xf0000) >> 16); i++) {
+ csky_insn_reg_set_val(regs, i + 4, *tmp);
+ tmp += 1;
+ }
+
+ if (opcode & 0x100000) {
+ csky_insn_reg_set_val(regs, 15, *tmp);
+ tmp += 1;
+ }
+
+ for (i = 0; i < ((opcode & 0xe00000) >> 21); i++) {
+ csky_insn_reg_set_val(regs, i + 16, *tmp);
+ tmp += 1;
+ }
+
+ if (opcode & 0x1000000) {
+ csky_insn_reg_set_val(regs, 29, *tmp);
+ tmp += 1;
+ }
+
+ regs->usp = (unsigned long)tmp;
+
+ instruction_pointer_set(regs, regs->lr);
+}
+
+void __kprobes
+simulate_bez32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ if (tmp == 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+}
+
+void __kprobes
+simulate_bnez32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+
+ csky_insn_reg_get_val(regs, tmp, &tmp);
+
+ if (tmp != 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+}
+
+void __kprobes
+simulate_bnezad32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+ unsigned long val;
+
+ csky_insn_reg_get_val(regs, tmp, &val);
+
+ val -= 1;
+
+ if (val > 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_bhsz32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+ unsigned long val;
+
+ csky_insn_reg_get_val(regs, tmp, &val);
+
+ if (val >= 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_bhz32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+ unsigned long val;
+
+ csky_insn_reg_get_val(regs, tmp, &val);
+
+ if (val > 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_blsz32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+ unsigned long val;
+
+ csky_insn_reg_get_val(regs, tmp, &val);
+
+ if (val <= 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_blz32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp = opcode & 0x1f;
+ unsigned long val;
+
+ csky_insn_reg_get_val(regs, tmp, &val);
+
+ if (val < 0) {
+ instruction_pointer_set(regs,
+ addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
+ } else
+ instruction_pointer_set(regs, addr + 4);
+
+ csky_insn_reg_set_val(regs, tmp, val);
+}
+
+void __kprobes
+simulate_bsr32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long tmp;
+
+ tmp = (opcode & 0xffff) << 16;
+ tmp |= (opcode & 0xffff0000) >> 16;
+
+ instruction_pointer_set(regs,
+ addr + sign_extend32((tmp & 0x3ffffff) << 1, 15));
+
+ regs->lr = addr + 4;
+}
+
+void __kprobes
+simulate_jmpi32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long val;
+ unsigned long offset = ((opcode & 0xffff0000) >> 14);
+
+ val = *(unsigned int *)
+ ((instruction_pointer(regs) + offset) & 0xfffffffc);
+
+ instruction_pointer_set(regs, val);
+}
+
+void __kprobes
+simulate_jsri32(u32 opcode, long addr, struct pt_regs *regs)
+{
+ unsigned long val;
+ unsigned long offset = ((opcode & 0xffff0000) >> 14);
+
+ val = *(unsigned int *)
+ ((instruction_pointer(regs) + offset) & 0xfffffffc);
+
+ regs->lr = addr + 4;
+
+ instruction_pointer_set(regs, val);
+}
diff --git a/arch/csky/kernel/probes/simulate-insn.h b/arch/csky/kernel/probes/simulate-insn.h
new file mode 100644
index 000000000000..ba4cb7ef062e
--- /dev/null
+++ b/arch/csky/kernel/probes/simulate-insn.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef __CSKY_KERNEL_PROBES_SIMULATE_INSN_H
+#define __CSKY_KERNEL_PROBES_SIMULATE_INSN_H
+
+#define __CSKY_INSN_FUNCS(name, mask, val) \
+static __always_inline bool csky_insn_is_##name(probe_opcode_t code) \
+{ \
+ BUILD_BUG_ON(~(mask) & (val)); \
+ return (code & (mask)) == (val); \
+} \
+void simulate_##name(u32 opcode, long addr, struct pt_regs *regs);
+
+#define CSKY_INSN_SET_SIMULATE(name, code) \
+ do { \
+ if (csky_insn_is_##name(code)) { \
+ api->handler = simulate_##name; \
+ return INSN_GOOD_NO_SLOT; \
+ } \
+ } while (0)
+
+__CSKY_INSN_FUNCS(br16, 0xfc00, 0x0400)
+__CSKY_INSN_FUNCS(bt16, 0xfc00, 0x0800)
+__CSKY_INSN_FUNCS(bf16, 0xfc00, 0x0c00)
+__CSKY_INSN_FUNCS(jmp16, 0xffc3, 0x7800)
+__CSKY_INSN_FUNCS(jsr16, 0xffc3, 0x7801)
+__CSKY_INSN_FUNCS(lrw16, 0xfc00, 0x1000)
+__CSKY_INSN_FUNCS(pop16, 0xffe0, 0x1480)
+
+__CSKY_INSN_FUNCS(br32, 0x0000ffff, 0x0000e800)
+__CSKY_INSN_FUNCS(bt32, 0x0000ffff, 0x0000e860)
+__CSKY_INSN_FUNCS(bf32, 0x0000ffff, 0x0000e840)
+__CSKY_INSN_FUNCS(jmp32, 0xffffffe0, 0x0000e8c0)
+__CSKY_INSN_FUNCS(jsr32, 0xffffffe0, 0x0000e8e0)
+__CSKY_INSN_FUNCS(lrw32, 0x0000ffe0, 0x0000ea80)
+__CSKY_INSN_FUNCS(pop32, 0xfe00ffff, 0x0000ebc0)
+
+__CSKY_INSN_FUNCS(bez32, 0x0000ffe0, 0x0000e900)
+__CSKY_INSN_FUNCS(bnez32, 0x0000ffe0, 0x0000e920)
+__CSKY_INSN_FUNCS(bnezad32, 0x0000ffe0, 0x0000e820)
+__CSKY_INSN_FUNCS(bhsz32, 0x0000ffe0, 0x0000e9a0)
+__CSKY_INSN_FUNCS(bhz32, 0x0000ffe0, 0x0000e940)
+__CSKY_INSN_FUNCS(blsz32, 0x0000ffe0, 0x0000e960)
+__CSKY_INSN_FUNCS(blz32, 0x0000ffe0, 0x0000e980)
+__CSKY_INSN_FUNCS(bsr32, 0x0000fc00, 0x0000e000)
+__CSKY_INSN_FUNCS(jmpi32, 0x0000ffff, 0x0000eac0)
+__CSKY_INSN_FUNCS(jsri32, 0x0000ffff, 0x0000eae0)
+
+#endif /* __CSKY_KERNEL_PROBES_SIMULATE_INSN_H */
diff --git a/arch/csky/kernel/traps.c b/arch/csky/kernel/traps.c
index 63715cb90ee9..c6a40806977f 100644
--- a/arch/csky/kernel/traps.c
+++ b/arch/csky/kernel/traps.c
@@ -14,6 +14,7 @@
#include <linux/kallsyms.h>
#include <linux/rtc.h>
#include <linux/uaccess.h>
+#include <linux/kprobes.h>

#include <asm/setup.h>
#include <asm/traps.h>
@@ -109,7 +110,6 @@ void buserr(struct pt_regs *regs)
force_sig_fault(SIGSEGV, 0, (void __user *)regs->pc);
}

-#define USR_BKPT 0x1464
asmlinkage void trap_c(struct pt_regs *regs)
{
int sig;
@@ -126,11 +126,19 @@ asmlinkage void trap_c(struct pt_regs *regs)
break;
/* ptrace */
case VEC_TRACE:
+#ifdef CONFIG_KPROBES
+ if (kprobe_single_step_handler(regs))
+ return;
+#endif
info.si_code = TRAP_TRACE;
sig = SIGTRAP;
break;
case VEC_ILLEGAL:
tsk->thread.trap_no = vector;
+#ifdef CONFIG_KPROBES
+ if (kprobe_breakpoint_handler(regs))
+ return;
+#endif
die_if_kernel("Kernel mode ILLEGAL", regs, vector);
#ifndef CONFIG_CPU_NO_USER_BKPT
if (*(uint16_t *)instruction_pointer(regs) != USR_BKPT)
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 562c7f708749..d3c61b83e195 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -18,6 +18,7 @@
#include <linux/extable.h>
#include <linux/uaccess.h>
#include <linux/perf_event.h>
+#include <linux/kprobes.h>

#include <asm/hardirq.h>
#include <asm/mmu_context.h>
@@ -53,6 +54,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
int fault;
unsigned long address = mmu_meh & PAGE_MASK;

+ if (kprobe_page_fault(regs, tsk->thread.trap_no))
+ return;
+
si_code = SEGV_MAPERR;

#ifndef CONFIG_CPU_HAS_TLBI
--
2.17.0