arch/c6x/kernel/ptrace.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Port on Texas Instruments TMS320C6x architecture
   4  *
   5  *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
   6  *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
   7  *
   8  *  Updated for 2.6.34: Mark Salter <msalter@redhat.com>
   9  */
  10 #include <linux/ptrace.h>
  11 #include <linux/tracehook.h>
  12 #include <linux/regset.h>
  13 #include <linux/elf.h>
  14 #include <linux/sched/task_stack.h>
  15
  16 #include <asm/cacheflush.h>
  17
  18 #define PT_REG_SIZE       (sizeof(struct pt_regs))
  19
  20 /*
  21  * Called by kernel/ptrace.c when detaching.
  22  */
  23 void ptrace_disable(struct task_struct *child)
  24 {
  25         /* nothing to do */
  26 }
  27
  28 /*
  29  * Get a register number from live pt_regs for the specified task.
  30  */
  31 static inline long get_reg(struct task_struct *task, int regno)
  32 {
  33         long *addr = (long *)task_pt_regs(task);
  34
  35         if (regno == PT_TSR || regno == PT_CSR)
  36                 return 0;
  37
  38         return addr[regno];
  39 }
  40
  41 /*
  42  * Write contents of register REGNO in task TASK.
  43  */
  44 static inline int put_reg(struct task_struct *task,
  45                           int regno,
  46                           unsigned long data)
  47 {
  48         unsigned long *addr = (unsigned long *)task_pt_regs(task);
  49
  50         if (regno != PT_TSR && regno != PT_CSR)
  51                 addr[regno] = data;
  52
  53         return 0;
  54 }
  55
  56 /* regset get/set implementations */
  57
  58 static int gpr_get(struct task_struct *target,
  59                    const struct user_regset *regset,
  60                    struct membuf to)
  61 {
  62         return membuf_write(&to, task_pt_regs(target), sizeof(struct pt_regs));
  63 }
  64
  65 enum c6x_regset {
  66         REGSET_GPR,
  67 };
  68
  69 static const struct user_regset c6x_regsets[] = {
  70         [REGSET_GPR] = {
  71                 .core_note_type = NT_PRSTATUS,
  72                 .n = ELF_NGREG,
  73                 .size = sizeof(u32),
  74                 .align = sizeof(u32),
  75                 .regset_get = gpr_get,
  76         },
  77 };
  78
  79 static const struct user_regset_view user_c6x_native_view = {
  80         .name           = "tic6x",
  81         .e_machine      = EM_TI_C6000,
  82         .regsets        = c6x_regsets,
  83         .n              = ARRAY_SIZE(c6x_regsets),
  84 };
  85
  86 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
  87 {
  88         return &user_c6x_native_view;
  89 }
  90
  91 /*
  92  * Perform ptrace request
  93  */
  94 long arch_ptrace(struct task_struct *child, long request,
  95                  unsigned long addr, unsigned long data)
  96 {
  97         int ret = 0;
  98
  99         switch (request) {
 100                 /*
 101                  * write the word at location addr.
 102                  */
 103         case PTRACE_POKETEXT:
 104                 ret = generic_ptrace_pokedata(child, addr, data);
 105                 if (ret == 0 && request == PTRACE_POKETEXT)
 106                         flush_icache_range(addr, addr + 4);
 107                 break;
 108         default:
 109                 ret = ptrace_request(child, request, addr, data);
 110                 break;
 111         }
 112
 113         return ret;
 114 }
 115
 116 /*
 117  * handle tracing of system call entry
 118  * - return the revised system call number or ULONG_MAX to cause ENOSYS
 119  */
 120 asmlinkage unsigned long syscall_trace_entry(struct pt_regs *regs)
 121 {
 122         if (tracehook_report_syscall_entry(regs))
 123                 /* tracing decided this syscall should not happen, so
 124                  * We'll return a bogus call number to get an ENOSYS
 125                  * error, but leave the original number in
 126                  * regs->orig_a4
 127                  */
 128                 return ULONG_MAX;
 129
 130         return regs->b0;
 131 }
 132
 133 /*
 134  * handle tracing of system call exit
 135  */
 136 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 137 {
 138         tracehook_report_syscall_exit(regs, 0);
 139 }