MIPS: Add uprobes support.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 7e18242..7a9a255 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1,6 +1,7 @@
config MIPS
bool
default y
+ select ARCH_SUPPORTS_UPROBES
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
select ARCH_USE_CMPXCHG_LOCKREF if 64BIT
@@ -1041,6 +1042,9 @@
config ARCH_DMA_ADDR_T_64BIT
def_bool (HIGHMEM && ARCH_PHYS_ADDR_T_64BIT) || 64BIT
+config ARCH_SUPPORTS_UPROBES
+ bool
+
config DMA_MAYBE_COHERENT
select DMA_NONCOHERENT
bool
diff --git a/arch/mips/include/asm/kdebug.h b/arch/mips/include/asm/kdebug.h
index cba22ab..8e3d08e 100644
--- a/arch/mips/include/asm/kdebug.h
+++ b/arch/mips/include/asm/kdebug.h
@@ -11,7 +11,9 @@
DIE_PAGE_FAULT,
DIE_BREAK,
DIE_SSTEPBP,
- DIE_MSAFP
+ DIE_MSAFP,
+ DIE_UPROBE,
+ DIE_UPROBE_XOL,
};
#endif /* _ASM_MIPS_KDEBUG_H */
diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index ffc3203..f6fc6aa 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -14,11 +14,16 @@
#include <linux/linkage.h>
#include <linux/types.h>
#include <asm/isadep.h>
+#include <asm/page.h>
+#include <asm/thread_info.h>
#include <uapi/asm/ptrace.h>
/*
* This struct defines the way the registers are stored on the stack during a
* system call/exception. As usual the registers k0/k1 aren't being saved.
+ *
+ * If you add a register here, also add it to regoffset_table[] in
+ * arch/mips/kernel/ptrace.c.
*/
struct pt_regs {
#ifdef CONFIG_32BIT
@@ -43,8 +48,83 @@
unsigned long long mpl[6]; /* MTM{0-5} */
unsigned long long mtp[6]; /* MTP{0-5} */
#endif
+ unsigned long __last[0];
} __aligned(8);
+static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+{
+ return regs->regs[31];
+}
+
+/*
+ * Don't use asm-generic/ptrace.h it defines FP accessors that don't make
+ * sense on MIPS. We rather want an error if they get invoked.
+ */
+
+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->cp0_epc = val;
+}
+
+/* Query offset/name of register from its name/offset */
+extern int regs_query_register_offset(const char *name);
+#define MAX_REG_OFFSET (offsetof(struct pt_regs, __last))
+
+/**
+ * regs_get_register() - get register value from its offset
+ * @regs: pt_regs from which register value is gotten.
+ * @offset: offset number of the register.
+ *
+ * regs_get_register returns the value of a register. The @offset is the
+ * offset of the register in struct pt_regs address which specified by @regs.
+ * If @offset is bigger than MAX_REG_OFFSET, this returns 0.
+ */
+static inline unsigned long regs_get_register(struct pt_regs *regs,
+ unsigned int offset)
+{
+ if (unlikely(offset > MAX_REG_OFFSET))
+ return 0;
+
+ return *(unsigned long *)((unsigned long)regs + offset);
+}
+
+/**
+ * regs_within_kernel_stack() - check the address in the stack
+ * @regs: pt_regs which contains kernel stack pointer.
+ * @addr: address which is checked.
+ *
+ * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
+ * If @addr is within the kernel stack, it returns true. If not, returns false.
+ */
+static inline int regs_within_kernel_stack(struct pt_regs *regs,
+ unsigned long addr)
+{
+ return ((addr & ~(THREAD_SIZE - 1)) ==
+ (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
+}
+
+/**
+ * regs_get_kernel_stack_nth() - get Nth entry of the stack
+ * @regs: pt_regs which contains kernel stack pointer.
+ * @n: stack entry number.
+ *
+ * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
+ * is specified by @regs. If the @n th entry is NOT in the kernel stack,
+ * this returns 0.
+ */
+static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs,
+ unsigned int n)
+{
+ unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
+
+ addr += n;
+ if (regs_within_kernel_stack(regs, (unsigned long)addr))
+ return *addr;
+ else
+ return 0;
+}
+
struct task_struct;
extern int ptrace_getregs(struct task_struct *child,
diff --git a/arch/mips/include/asm/thread_info.h b/arch/mips/include/asm/thread_info.h
index 9c0014e..e309d8f 100644
--- a/arch/mips/include/asm/thread_info.h
+++ b/arch/mips/include/asm/thread_info.h
@@ -99,6 +99,7 @@
#define TIF_SYSCALL_AUDIT 3 /* syscall auditing active */
#define TIF_SECCOMP 4 /* secure computing */
#define TIF_NOTIFY_RESUME 5 /* callback before returning to user */
+#define TIF_UPROBE 6 /* breakpointed or singlestepping */
#define TIF_RESTORE_SIGMASK 9 /* restore signal mask in do_signal() */
#define TIF_USEDFPU 16 /* FPU was used by this task this quantum (SMP) */
#define TIF_MEMDIE 18 /* is terminating due to OOM killer */
@@ -122,6 +123,7 @@
#define _TIF_SYSCALL_AUDIT (1<<TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1<<TIF_SECCOMP)
#define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME)
+#define _TIF_UPROBE (1<<TIF_UPROBE)
#define _TIF_USEDFPU (1<<TIF_USEDFPU)
#define _TIF_NOHZ (1<<TIF_NOHZ)
#define _TIF_FIXADE (1<<TIF_FIXADE)
@@ -146,7 +148,8 @@
/* work to do on interrupt/exception return */
#define _TIF_WORK_MASK \
- (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME)
+ (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_NOTIFY_RESUME | \
+ _TIF_UPROBE)
/* work to do on any return to u-space */
#define _TIF_ALLWORK_MASK (_TIF_NOHZ | _TIF_WORK_MASK | \
_TIF_WORK_SYSCALL_EXIT | \
diff --git a/arch/mips/include/asm/uprobes.h b/arch/mips/include/asm/uprobes.h
new file mode 100644
index 0000000..34c325c
--- /dev/null
+++ b/arch/mips/include/asm/uprobes.h
@@ -0,0 +1,58 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#ifndef __ASM_UPROBES_H
+#define __ASM_UPROBES_H
+
+#include <linux/notifier.h>
+#include <linux/types.h>
+
+#include <asm/break.h>
+#include <asm/inst.h>
+
+/*
+ * We want this to be defined as union mips_instruction but that makes the
+ * generic code blow up.
+ */
+typedef u32 uprobe_opcode_t;
+
+/*
+ * Classic MIPS (note this implementation doesn't consider microMIPS yet)
+ * instructions are always 4 bytes but in order to deal with branches and
+ * their delay slots, we treat instructions as having 8 bytes maximum.
+ */
+#define MAX_UINSN_BYTES 8
+#define UPROBE_XOL_SLOT_BYTES 128 /* Max. cache line size */
+
+#define UPROBE_BRK_UPROBE 0x000d000d /* break 13 */
+#define UPROBE_BRK_UPROBE_XOL 0x000e000d /* break 14 */
+
+#define UPROBE_SWBP_INSN UPROBE_BRK_UPROBE
+#define UPROBE_SWBP_INSN_SIZE 4
+
+struct arch_uprobe {
+ unsigned long resume_epc;
+ u32 insn[2];
+ u32 ixol[2];
+ union mips_instruction orig_inst[MAX_UINSN_BYTES / 4];
+};
+
+struct arch_uprobe_task {
+ unsigned long saved_trap_nr;
+};
+
+extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup,
+ struct mm_struct *mm, unsigned long addr);
+extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
+extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
+extern int arch_uprobe_exception_notify(struct notifier_block *self,
+ unsigned long val, void *data);
+extern void arch_uprobe_abort_xol(struct arch_uprobe *aup,
+ struct pt_regs *regs);
+extern unsigned long arch_uretprobe_hijack_return_addr(
+ unsigned long trampoline_vaddr, struct pt_regs *regs);
+
+#endif /* __ASM_UPROBES_H */
diff --git a/arch/mips/include/uapi/asm/break.h b/arch/mips/include/uapi/asm/break.h
index 002c39e..9c4265c 100644
--- a/arch/mips/include/uapi/asm/break.h
+++ b/arch/mips/include/uapi/asm/break.h
@@ -21,6 +21,8 @@
#define BRK_DIVZERO 7 /* Divide by zero check */
#define BRK_RANGE 8 /* Range error check */
#define BRK_BUG 12 /* Used by BUG() */
+#define BRK_UPROBE 13 /* See <asm/uprobes.h> */
+#define BRK_UPROBE_XOL 14 /* See <asm/uprobes.h> */
#define BRK_MEMU 514 /* Used by FPU emulator */
#define BRK_KPROBE_BP 515 /* Kprobe break */
#define BRK_KPROBE_SSTEPBP 516 /* Kprobe single step software implementation */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 3f5cf8a..a61435b 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -100,6 +100,7 @@
obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_mipsxx.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_UPROBES) += uprobes.o
obj-$(CONFIG_MIPS_CM) += mips-cm.o
obj-$(CONFIG_MIPS_CPC) += mips-cpc.o
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index e933a30..4f0ac78 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -25,6 +25,7 @@
#include <linux/regset.h>
#include <linux/smp.h>
#include <linux/security.h>
+#include <linux/stddef.h>
#include <linux/tracehook.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
@@ -490,6 +491,93 @@
REGSET_FPR,
};
+struct pt_regs_offset {
+ const char *name;
+ int offset;
+};
+
+#define REG_OFFSET_NAME(reg, r) { \
+ .name = #reg, \
+ .offset = offsetof(struct pt_regs, r) \
+}
+
+#define REG_OFFSET_END { \
+ .name = NULL, \
+ .offset = 0 \
+}
+
+static const struct pt_regs_offset regoffset_table[] = {
+ REG_OFFSET_NAME(r0, regs[0]),
+ REG_OFFSET_NAME(r1, regs[1]),
+ REG_OFFSET_NAME(r2, regs[2]),
+ REG_OFFSET_NAME(r3, regs[3]),
+ REG_OFFSET_NAME(r4, regs[4]),
+ REG_OFFSET_NAME(r5, regs[5]),
+ REG_OFFSET_NAME(r6, regs[6]),
+ REG_OFFSET_NAME(r7, regs[7]),
+ REG_OFFSET_NAME(r8, regs[8]),
+ REG_OFFSET_NAME(r9, regs[9]),
+ REG_OFFSET_NAME(r10, regs[10]),
+ REG_OFFSET_NAME(r11, regs[11]),
+ REG_OFFSET_NAME(r12, regs[12]),
+ REG_OFFSET_NAME(r13, regs[13]),
+ REG_OFFSET_NAME(r14, regs[14]),
+ REG_OFFSET_NAME(r15, regs[15]),
+ REG_OFFSET_NAME(r16, regs[16]),
+ REG_OFFSET_NAME(r17, regs[17]),
+ REG_OFFSET_NAME(r18, regs[18]),
+ REG_OFFSET_NAME(r19, regs[19]),
+ REG_OFFSET_NAME(r20, regs[20]),
+ REG_OFFSET_NAME(r21, regs[21]),
+ REG_OFFSET_NAME(r22, regs[22]),
+ REG_OFFSET_NAME(r23, regs[23]),
+ REG_OFFSET_NAME(r24, regs[24]),
+ REG_OFFSET_NAME(r25, regs[25]),
+ REG_OFFSET_NAME(r26, regs[26]),
+ REG_OFFSET_NAME(r27, regs[27]),
+ REG_OFFSET_NAME(r28, regs[28]),
+ REG_OFFSET_NAME(r29, regs[29]),
+ REG_OFFSET_NAME(r30, regs[30]),
+ REG_OFFSET_NAME(r31, regs[31]),
+ REG_OFFSET_NAME(c0_status, cp0_status),
+ REG_OFFSET_NAME(hi, hi),
+ REG_OFFSET_NAME(lo, lo),
+#ifdef CONFIG_CPU_HAS_SMARTMIPS
+ REG_OFFSET_NAME(acx, acx),
+#endif
+ REG_OFFSET_NAME(c0_badvaddr, cp0_badvaddr),
+ REG_OFFSET_NAME(c0_cause, cp0_cause),
+ REG_OFFSET_NAME(c0_epc, cp0_epc),
+#ifdef CONFIG_MIPS_MT_SMTC
+ REG_OFFSET_NAME(c0_tcstatus, cp0_tcstatus),
+#endif
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+ REG_OFFSET_NAME(mpl0, mpl[0]),
+ REG_OFFSET_NAME(mpl1, mpl[1]),
+ REG_OFFSET_NAME(mpl2, mpl[2]),
+ REG_OFFSET_NAME(mtp0, mtp[0]),
+ REG_OFFSET_NAME(mtp1, mtp[1]),
+ REG_OFFSET_NAME(mtp2, mtp[2]),
+#endif
+ REG_OFFSET_END,
+};
+
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name: the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+ const struct pt_regs_offset *roff;
+ for (roff = regoffset_table; roff->name != NULL; roff++)
+ if (!strcmp(roff->name, name))
+ return roff->offset;
+ return -EINVAL;
+}
+
#if defined(CONFIG_32BIT) || defined(CONFIG_MIPS32_O32)
static const struct user_regset mips_regsets[] = {
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index fa13a52..2fec67b 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -21,6 +21,7 @@
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
+#include <linux/uprobes.h>
#include <linux/compiler.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
@@ -856,6 +857,9 @@
user_exit();
+ if (thread_info_flags & _TIF_UPROBE)
+ uprobe_notify_resume(regs);
+
/* deal with pending signal delivery */
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index cea964d..fdb392b 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -984,6 +984,18 @@
* pertain to them.
*/
switch (bcode) {
+ case BRK_UPROBE:
+ if (notify_die(DIE_UPROBE, "uprobe", regs, bcode,
+ current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ goto out;
+ else
+ break;
+ case BRK_UPROBE_XOL:
+ if (notify_die(DIE_UPROBE_XOL, "uprobe_xol", regs, bcode,
+ current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
+ goto out;
+ else
+ break;
case BRK_KPROBE_BP:
if (notify_die(DIE_BREAK, "debug", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
diff --git a/arch/mips/kernel/uprobes.c b/arch/mips/kernel/uprobes.c
new file mode 100644
index 0000000..8452d93
--- /dev/null
+++ b/arch/mips/kernel/uprobes.c
@@ -0,0 +1,341 @@
+#include <linux/highmem.h>
+#include <linux/kdebug.h>
+#include <linux/types.h>
+#include <linux/notifier.h>
+#include <linux/sched.h>
+#include <linux/uprobes.h>
+
+#include <asm/branch.h>
+#include <asm/cpu-features.h>
+#include <asm/ptrace.h>
+#include <asm/inst.h>
+
+static inline int insn_has_delay_slot(const union mips_instruction insn)
+{
+ switch (insn.i_format.opcode) {
+ /*
+ * jr and jalr are in r_format format.
+ */
+ case spec_op:
+ switch (insn.r_format.func) {
+ case jalr_op:
+ case jr_op:
+ return 1;
+ }
+ break;
+
+ /*
+ * This group contains:
+ * bltz_op, bgez_op, bltzl_op, bgezl_op,
+ * bltzal_op, bgezal_op, bltzall_op, bgezall_op.
+ */
+ case bcond_op:
+ switch (insn.i_format.rt) {
+ case bltz_op:
+ case bltzl_op:
+ case bgez_op:
+ case bgezl_op:
+ case bltzal_op:
+ case bltzall_op:
+ case bgezal_op:
+ case bgezall_op:
+ case bposge32_op:
+ return 1;
+ }
+ break;
+
+ /*
+ * These are unconditional and in j_format.
+ */
+ case jal_op:
+ case j_op:
+ case beq_op:
+ case beql_op:
+ case bne_op:
+ case bnel_op:
+ case blez_op: /* not really i_format */
+ case blezl_op:
+ case bgtz_op:
+ case bgtzl_op:
+ return 1;
+
+ /*
+ * And now the FPA/cp1 branch instructions.
+ */
+ case cop1_op:
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+ case lwc2_op: /* This is bbit0 on Octeon */
+ case ldc2_op: /* This is bbit032 on Octeon */
+ case swc2_op: /* This is bbit1 on Octeon */
+ case sdc2_op: /* This is bbit132 on Octeon */
+#endif
+ return 1;
+ }
+
+ return 0;
+}
+
+/**
+ * arch_uprobe_analyze_insn - instruction analysis including validity and fixups.
+ * @mm: the probed address space.
+ * @arch_uprobe: the probepoint information.
+ * @addr: virtual address at which to install the probepoint
+ * Return 0 on success or a -ve number on error.
+ */
+int arch_uprobe_analyze_insn(struct arch_uprobe *aup,
+ struct mm_struct *mm, unsigned long addr)
+{
+ union mips_instruction inst;
+
+ /*
+ * For the time being this also blocks attempts to use uprobes with
+ * MIPS16 and microMIPS.
+ */
+ if (addr & 0x03)
+ return -EINVAL;
+
+ inst.word = aup->insn[0];
+ aup->ixol[0] = aup->insn[insn_has_delay_slot(inst)];
+ aup->ixol[1] = UPROBE_BRK_UPROBE_XOL; /* NOP */
+
+ return 0;
+}
+
+/**
+ * is_trap_insn - check if the instruction is a trap variant
+ * @insn: instruction to be checked.
+ * Returns true if @insn is a trap variant.
+ *
+ * This definition overrides the weak definition in kernel/events/uprobes.c.
+ * and is needed for the case where an architecture has multiple trap
+ * instructions (like PowerPC or MIPS). We treat BREAK just like the more
+ * modern conditional trap instructions.
+ */
+bool is_trap_insn(uprobe_opcode_t *insn)
+{
+ union mips_instruction inst;
+
+ inst.word = *insn;
+
+ switch (inst.i_format.opcode) {
+ case spec_op:
+ switch (inst.r_format.func) {
+ case break_op:
+ case teq_op:
+ case tge_op:
+ case tgeu_op:
+ case tlt_op:
+ case tltu_op:
+ case tne_op:
+ return 1;
+ }
+ break;
+
+ case bcond_op: /* Yes, really ... */
+ switch (inst.u_format.rt) {
+ case teqi_op:
+ case tgei_op:
+ case tgeiu_op:
+ case tlti_op:
+ case tltiu_op:
+ case tnei_op:
+ return 1;
+ }
+ break;
+ }
+
+ return 0;
+}
+
+#define UPROBE_TRAP_NR ULONG_MAX
+
+/*
+ * arch_uprobe_pre_xol - prepare to execute out of line.
+ * @auprobe: the probepoint information.
+ * @regs: reflects the saved user state of current task.
+ */
+int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+ union mips_instruction insn;
+
+ /*
+ * Now find the EPC where to resume after the breakpoint has been
+ * dealt with. This may require emulation of a branch.
+ */
+ aup->resume_epc = regs->cp0_epc + 4;
+ if (insn_has_delay_slot((union mips_instruction) aup->insn[0])) {
+ unsigned long epc;
+
+ epc = regs->cp0_epc;
+ __compute_return_epc_for_insn(regs, insn);
+ aup->resume_epc = regs->cp0_epc;
+ }
+
+ utask->autask.saved_trap_nr = current->thread.trap_nr;
+ current->thread.trap_nr = UPROBE_TRAP_NR;
+ regs->cp0_epc = current->utask->xol_vaddr;
+
+ return 0;
+}
+
+int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ current->thread.trap_nr = utask->autask.saved_trap_nr;
+ regs->cp0_epc = aup->resume_epc;
+
+ return 0;
+}
+
+/*
+ * If xol insn itself traps and generates a signal(Say,
+ * SIGILL/SIGSEGV/etc), then detect the case where a singlestepped
+ * instruction jumps back to its own address. It is assumed that anything
+ * like do_page_fault/do_trap/etc sets thread.trap_nr != -1.
+ *
+ * arch_uprobe_pre_xol/arch_uprobe_post_xol save/restore thread.trap_nr,
+ * arch_uprobe_xol_was_trapped() simply checks that ->trap_nr is not equal to
+ * UPROBE_TRAP_NR == -1 set by arch_uprobe_pre_xol().
+ */
+bool arch_uprobe_xol_was_trapped(struct task_struct *tsk)
+{
+ if (tsk->thread.trap_nr != UPROBE_TRAP_NR)
+ return true;
+
+ return false;
+}
+
+int arch_uprobe_exception_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct die_args *args = data;
+ struct pt_regs *regs = args->regs;
+
+ /* regs == NULL is a kernel bug */
+ if (WARN_ON(!regs))
+ return NOTIFY_DONE;
+
+ /* We are only interested in userspace traps */
+ if (!user_mode(regs))
+ return NOTIFY_DONE;
+
+ switch (val) {
+ case DIE_BREAK:
+ if (uprobe_pre_sstep_notifier(regs))
+ return NOTIFY_STOP;
+ break;
+ case DIE_UPROBE_XOL:
+ if (uprobe_post_sstep_notifier(regs))
+ return NOTIFY_STOP;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * This function gets called when XOL instruction either gets trapped or
+ * the thread has a fatal signal. Reset the instruction pointer to its
+ * probed address for the potential restart or for post mortem analysis.
+ */
+void arch_uprobe_abort_xol(struct arch_uprobe *aup,
+ struct pt_regs *regs)
+{
+ struct uprobe_task *utask = current->utask;
+
+ instruction_pointer_set(regs, utask->vaddr);
+}
+
+unsigned long arch_uretprobe_hijack_return_addr(
+ unsigned long trampoline_vaddr, struct pt_regs *regs)
+{
+ unsigned long ra;
+
+ ra = regs->regs[31];
+
+ /* Replace the return address with the trampoline address */
+ regs->regs[31] = ra;
+
+ return ra;
+}
+
+/**
+ * set_swbp - store breakpoint at a given address.
+ * @auprobe: arch specific probepoint information.
+ * @mm: the probed process address space.
+ * @vaddr: the virtual address to insert the opcode.
+ *
+ * For mm @mm, store the breakpoint instruction at @vaddr.
+ * Return 0 (success) or a negative errno.
+ *
+ * This version overrides the weak version in kernel/events/uprobes.c.
+ * It is required to handle MIPS16 and microMIPS.
+ */
+int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm,
+ unsigned long vaddr)
+{
+ return uprobe_write_opcode(mm, vaddr, UPROBE_SWBP_INSN);
+}
+
+/**
+ * set_orig_insn - Restore the original instruction.
+ * @mm: the probed process address space.
+ * @auprobe: arch specific probepoint information.
+ * @vaddr: the virtual address to insert the opcode.
+ *
+ * For mm @mm, restore the original opcode (opcode) at @vaddr.
+ * Return 0 (success) or a negative errno.
+ *
+ * This overrides the weak version in kernel/events/uprobes.c.
+ */
+int set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,
+ unsigned long vaddr)
+{
+ return uprobe_write_opcode(mm, vaddr,
+ *(uprobe_opcode_t *)&auprobe->orig_inst[0].word);
+}
+
+void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,
+ void *src, unsigned long len)
+{
+ void *kaddr;
+
+ /* Initialize the slot */
+ kaddr = kmap_atomic(page);
+ memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
+ kunmap_atomic(kaddr);
+
+ /*
+ * The MIPS version of flush_icache_range will operate safely on
+ * user space addresses and more importantly, it doesn't require a
+ * VMA argument.
+ */
+ flush_icache_range(vaddr, vaddr + len);
+}
+
+/**
+ * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs
+ * @regs: Reflects the saved state of the task after it has hit a breakpoint
+ * instruction.
+ * Return the address of the breakpoint instruction.
+ *
+ * This overrides the weak version in kernel/events/uprobes.c.
+ */
+unsigned long uprobe_get_swbp_addr(struct pt_regs *regs)
+{
+ return instruction_pointer(regs);
+}
+
+/*
+ * See if the instruction can be emulated.
+ * Returns true if instruction was emulated, false otherwise.
+ *
+ * For now we always emulate so this function just returns 0.
+ */
+bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ return 0;
+}
