arch/c6x/kernel/ptrace.c

   1 /*
   2  *  Port on Texas Instruments TMS320C6x architecture
   3  *
   4  *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
   5  *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
   6  *
   7  *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License version 2 as
  11  *  published by the Free Software Foundation.
  12  */
  13 #include <linux/ptrace.h>
  14 #include <linux/tracehook.h>
  15 #include <linux/regset.h>
  16 #include <linux/elf.h>
  17 #include <linux/sched/task_stack.h>
  18
  19 #include <asm/cacheflush.h>
  20
  21 #define PT_REG_SIZE       (sizeof(struct pt_regs))
  22
  23 /*
  24  * Called by kernel/ptrace.c when detaching.
  25  */
  26 void ptrace_disable(struct task_struct *child)
  27 {
  28         /* nothing to do */
  29 }
  30
  31 /*
  32  * Get a register number from live pt_regs for the specified task.
  33  */
  34 static inline long get_reg(struct task_struct *task, int regno)
  35 {
  36         long *addr = (long *)task_pt_regs(task);
  37
  38         if (regno == PT_TSR || regno == PT_CSR)
  39                 return 0;
  40
  41         return addr[regno];
  42 }
  43
  44 /*
  45  * Write contents of register REGNO in task TASK.
  46  */
  47 static inline int put_reg(struct task_struct *task,
  48                           int regno,
  49                           unsigned long data)
  50 {
  51         unsigned long *addr = (unsigned long *)task_pt_regs(task);
  52
  53         if (regno != PT_TSR && regno != PT_CSR)
  54                 addr[regno] = data;
  55
  56         return 0;
  57 }
  58
  59 /* regset get/set implementations */
  60
  61 static int gpr_get(struct task_struct *target,
  62                    const struct user_regset *regset,
  63                    unsigned int pos, unsigned int count,
  64                    void *kbuf, void __user *ubuf)
  65 {
  66         struct pt_regs *regs = task_pt_regs(target);
  67
  68         return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
  69                                    regs,
  70                                    0, sizeof(*regs));
  71 }
  72
  73 enum c6x_regset {
  74         REGSET_GPR,
  75 };
  76
  77 static const struct user_regset c6x_regsets[] = {
  78         [REGSET_GPR] = {
  79                 .core_note_type = NT_PRSTATUS,
  80                 .n = ELF_NGREG,
  81                 .size = sizeof(u32),
  82                 .align = sizeof(u32),
  83                 .get = gpr_get,
  84         },
  85 };
  86
  87 static const struct user_regset_view user_c6x_native_view = {
  88         .name           = "tic6x",
  89         .e_machine      = EM_TI_C6000,
  90         .regsets        = c6x_regsets,
  91         .n              = ARRAY_SIZE(c6x_regsets),
  92 };
  93
  94 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  95 {
  96         return &user_c6x_native_view;
  97 }
  98
  99 /*
 100  * Perform ptrace request
 101  */
 102 long arch_ptrace(struct task_struct *child, long request,
 103                  unsigned long addr, unsigned long data)
 104 {
 105         int ret = 0;
 106
 107         switch (request) {
 108                 /*
 109                  * write the word at location addr.
 110                  */
 111         case PTRACE_POKETEXT:
 112                 ret = generic_ptrace_pokedata(child, addr, data);
 113                 if (ret == 0 && request == PTRACE_POKETEXT)
 114                         flush_icache_range(addr, addr + 4);
 115                 break;
 116         default:
 117                 ret = ptrace_request(child, request, addr, data);
 118                 break;
 119         }
 120
 121         return ret;
 122 }
 123
 124 /*
 125  * handle tracing of system call entry
 126  * - return the revised system call number or ULONG_MAX to cause ENOSYS
 127  */
 128 asmlinkage unsigned long syscall_trace_entry(struct pt_regs *regs)
 129 {
 130         if (tracehook_report_syscall_entry(regs))
 131                 /* tracing decided this syscall should not happen, so
 132                  * We'll return a bogus call number to get an ENOSYS
 133                  * error, but leave the original number in
 134                  * regs->orig_a4
 135                  */
 136                 return ULONG_MAX;
 137
 138         return regs->b0;
 139 }
 140
 141 /*
 142  * handle tracing of system call exit
 143  */
 144 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 145 {
 146         tracehook_report_syscall_exit(regs, 0);
 147 }