#include <linux/uaccess.h>
#include <asm/bootinfo.h>
#include <asm/reg.h>
+#include <asm/branch.h>
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
+#include "probes-common.h"
+
+#define BREAKINST 0x0000000d
+
/*
* Called by kernel/ptrace.c when detaching..
*
{
/* Don't load the watchpoint registers for the ex-child. */
clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
+ user_disable_single_step(child);
}
/*
#endif
}
+static int read_insn(struct task_struct *task, unsigned long addr, unsigned int *insn)
+{
+ int copied = access_process_vm(task, addr, insn,
+ sizeof(unsigned int), FOLL_FORCE);
+
+ if (copied != sizeof(unsigned int)) {
+ pr_err("failed to read instruction from 0x%lx\n", addr);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int write_insn(struct task_struct *task, unsigned long addr, unsigned int insn)
+{
+ int copied = access_process_vm(task, addr, &insn,
+ sizeof(unsigned int), FOLL_FORCE | FOLL_WRITE);
+
+ if (copied != sizeof(unsigned int)) {
+ pr_err("failed to write instruction to 0x%lx\n", addr);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int insn_has_delayslot(union mips_instruction insn)
+{
+ return __insn_has_delay_slot(insn);
+}
+
+static void ptrace_set_bpt(struct task_struct *child)
+{
+ union mips_instruction mips_insn = { 0 };
+ struct pt_regs *regs;
+ unsigned long pc;
+ unsigned int insn;
+ int i, ret, nsaved = 0;
+
+ regs = task_pt_regs(child);
+ pc = regs->cp0_epc;
+
+ ret = read_insn(child, pc, &insn);
+ if (ret < 0)
+ return;
+
+ if (insn_has_delayslot(mips_insn)) {
+ pr_info("executing branch insn\n");
+ ret = __compute_return_epc(regs);
+ if (ret < 0)
+ return;
+ task_thread_info(child)->bpt_addr[nsaved++] = regs->cp0_epc;
+ } else {
+ pr_info("executing normal insn\n");
+ task_thread_info(child)->bpt_addr[nsaved++] = pc + 4;
+ }
+
+ /* install breakpoints */
+ for (i = 0; i < nsaved; i++) {
+ ret = read_insn(child, task_thread_info(child)->bpt_addr[i], &insn);
+ if (ret < 0)
+ return;
+
+ task_thread_info(child)->bpt_insn[i] = insn;
+
+ ret = write_insn(child, task_thread_info(child)->bpt_addr[i], BREAKINST);
+ if (ret < 0)
+ return;
+ }
+
+ task_thread_info(child)->bpt_nsaved = nsaved;
+}
+
+static void ptrace_cancel_bpt(struct task_struct *child)
+{
+ int i, nsaved = task_thread_info(child)->bpt_nsaved;
+
+ task_thread_info(child)->bpt_nsaved = 0;
+
+ if (nsaved > 1) {
+ pr_info("%s: bogus nsaved: %d!\n", __func__, nsaved);
+ nsaved = 1;
+ }
+
+ for (i = 0; i < nsaved; i++) {
+ write_insn(child, task_thread_info(child)->bpt_addr[i],
+ task_thread_info(child)->bpt_insn[i]);
+ }
+}
+
+void user_enable_single_step(struct task_struct *child)
+{
+ set_tsk_thread_flag(child, TIF_SINGLESTEP);
+ ptrace_set_bpt(child);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+ clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+ ptrace_cancel_bpt(child);
+}
+
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{