diff options
Diffstat (limited to 'arch/v850/kernel/ptrace.c')
| -rw-r--r-- | arch/v850/kernel/ptrace.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/arch/v850/kernel/ptrace.c b/arch/v850/kernel/ptrace.c new file mode 100644 index 000000000000..8fa780757dcd --- /dev/null +++ b/arch/v850/kernel/ptrace.c @@ -0,0 +1,282 @@ +/* + * arch/v850/kernel/ptrace.c -- `ptrace' system call + * + * Copyright (C) 2002,03,04 NEC Electronics Corporation + * Copyright (C) 2002,03,04 Miles Bader <miles@gnu.org> + * + * Derived from arch/mips/kernel/ptrace.c: + * + * Copyright (C) 1992 Ross Biro + * Copyright (C) Linus Torvalds + * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle + * Copyright (C) 1996 David S. Miller + * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com + * Copyright (C) 1999 MIPS Technologies, Inc. + * + * 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. + */ + +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/smp_lock.h> +#include <linux/ptrace.h> + +#include <asm/errno.h> +#include <asm/ptrace.h> +#include <asm/processor.h> +#include <asm/uaccess.h> + +/* Returns the address where the register at REG_OFFS in P is stashed away. */ +static v850_reg_t *reg_save_addr (unsigned reg_offs, struct task_struct *t) +{ + struct pt_regs *regs; + + /* Three basic cases: + + (1) A register normally saved before calling the scheduler, is + available in the kernel entry pt_regs structure at the top + of the kernel stack. The kernel trap/irq exit path takes + care to save/restore almost all registers for ptrace'd + processes. + + (2) A call-clobbered register, where the process P entered the + kernel via [syscall] trap, is not stored anywhere; that's + OK, because such registers are not expected to be preserved + when the trap returns anyway (so we don't actually bother to + test for this case). + + (3) A few registers not used at all by the kernel, and so + normally never saved except by context-switches, are in the + context switch state. */ + + if (reg_offs == PT_CTPC || reg_offs == PT_CTPSW || reg_offs == PT_CTBP) + /* Register saved during context switch. */ + regs = thread_saved_regs (t); + else + /* Register saved during kernel entry (or not available). */ + regs = task_regs (t); + + return (v850_reg_t *)((char *)regs + reg_offs); +} + +/* Set the bits SET and clear the bits CLEAR in the v850e DIR + (`debug information register'). Returns the new value of DIR. */ +static inline v850_reg_t set_dir (v850_reg_t set, v850_reg_t clear) +{ + register v850_reg_t rval asm ("r10"); + register v850_reg_t arg0 asm ("r6") = set; + register v850_reg_t arg1 asm ("r7") = clear; + + /* The dbtrap handler has exactly this functionality when called + from kernel mode. 0xf840 is a `dbtrap' insn. */ + asm (".short 0xf840" : "=r" (rval) : "r" (arg0), "r" (arg1)); + + return rval; +} + +/* Makes sure hardware single-stepping is (globally) enabled. + Returns true if successful. */ +static inline int enable_single_stepping (void) +{ + static int enabled = 0; /* Remember whether we already did it. */ + if (! enabled) { + /* Turn on the SE (`single-step enable') bit, 0x100, in the + DIR (`debug information register'). This may fail if a + processor doesn't support it or something. We also try + to clear bit 0x40 (`INI'), which is necessary to use the + debug stuff on the v850e2; on the v850e, clearing 0x40 + shouldn't cause any problem. */ + v850_reg_t dir = set_dir (0x100, 0x40); + /* Make sure it really got set. */ + if (dir & 0x100) + enabled = 1; + } + return enabled; +} + +/* Try to set CHILD's single-step flag to VAL. Returns true if successful. */ +static int set_single_step (struct task_struct *t, int val) +{ + v850_reg_t *psw_addr = reg_save_addr(PT_PSW, t); + if (val) { + /* Make sure single-stepping is enabled. */ + if (! enable_single_stepping ()) + return 0; + /* Set T's single-step flag. */ + *psw_addr |= 0x800; + } else + *psw_addr &= ~0x800; + return 1; +} + +int sys_ptrace(long request, long pid, long addr, long data) +{ + struct task_struct *child; + int rval; + + lock_kernel(); + + if (request == PTRACE_TRACEME) { + /* are we already being traced? */ + if (current->ptrace & PT_PTRACED) { + rval = -EPERM; + goto out; + } + /* set the ptrace bit in the process flags. */ + current->ptrace |= PT_PTRACED; + rval = 0; + goto out; + } + rval = -ESRCH; + read_lock(&tasklist_lock); + child = find_task_by_pid(pid); + if (child) + get_task_struct(child); + read_unlock(&tasklist_lock); + if (!child) + goto out; + + rval = -EPERM; + if (pid == 1) /* you may not mess with init */ + goto out_tsk; + + if (request == PTRACE_ATTACH) { + rval = ptrace_attach(child); + goto out_tsk; + } + rval = ptrace_check_attach(child, request == PTRACE_KILL); + if (rval < 0) + goto out_tsk; + + switch (request) { + unsigned long val, copied; + + case PTRACE_PEEKTEXT: /* read word at location addr. */ + case PTRACE_PEEKDATA: + copied = access_process_vm(child, addr, &val, sizeof(val), 0); + rval = -EIO; + if (copied != sizeof(val)) + break; + rval = put_user(val, (unsigned long *)data); + goto out; + + case PTRACE_POKETEXT: /* write the word at location addr. */ + case PTRACE_POKEDATA: + rval = 0; + if (access_process_vm(child, addr, &data, sizeof(data), 1) + == sizeof(data)) + break; + rval = -EIO; + goto out; + + /* Read/write the word at location ADDR in the registers. */ + case PTRACE_PEEKUSR: + case PTRACE_POKEUSR: + rval = 0; + if (addr >= PT_SIZE && request == PTRACE_PEEKUSR) { + /* Special requests that don't actually correspond + to offsets in struct pt_regs. */ + if (addr == PT_TEXT_ADDR) + val = child->mm->start_code; + else if (addr == PT_DATA_ADDR) + val = child->mm->start_data; + else if (addr == PT_TEXT_LEN) + val = child->mm->end_code + - child->mm->start_code; + else + rval = -EIO; + } else if (addr >= 0 && addr < PT_SIZE && (addr & 0x3) == 0) { + v850_reg_t *reg_addr = reg_save_addr(addr, child); + if (request == PTRACE_PEEKUSR) + val = *reg_addr; + else + *reg_addr = data; + } else + rval = -EIO; + + if (rval == 0 && request == PTRACE_PEEKUSR) + rval = put_user (val, (unsigned long *)data); + goto out; + + /* Continue and stop at next (return from) syscall */ + case PTRACE_SYSCALL: + /* Restart after a signal. */ + case PTRACE_CONT: + /* Execute a single instruction. */ + case PTRACE_SINGLESTEP: + rval = -EIO; + if ((unsigned long) data > _NSIG) + break; + + /* Turn CHILD's single-step flag on or off. */ + if (! set_single_step (child, request == PTRACE_SINGLESTEP)) + break; + + if (request == PTRACE_SYSCALL) + set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + else + clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); + + child->exit_code = data; + wake_up_process(child); + rval = 0; + break; + + /* + * make the child exit. Best I can do is send it a sigkill. + * perhaps it should be put in the status that it wants to + * exit. + */ + case PTRACE_KILL: + rval = 0; + if (child->exit_state == EXIT_ZOMBIE) /* already dead */ + break; + child->exit_code = SIGKILL; + wake_up_process(child); + break; + + case PTRACE_DETACH: /* detach a process that was attached. */ + set_single_step (child, 0); /* Clear single-step flag */ + rval = ptrace_detach(child, data); + break; + + default: + rval = -EIO; + goto out; + } + +out_tsk: + put_task_struct(child); +out: + unlock_kernel(); + return rval; +} + +asmlinkage void syscall_trace(void) +{ + if (!test_thread_flag(TIF_SYSCALL_TRACE)) + return; + if (!(current->ptrace & PT_PTRACED)) + return; + /* The 0x80 provides a way for the tracing parent to distinguish + between a syscall stop and SIGTRAP delivery */ + ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) + ? 0x80 : 0)); + /* + * this isn't the same as continuing with a signal, but it will do + * for normal use. strace only continues with a signal if the + * stopping signal is not SIGTRAP. -brl + */ + if (current->exit_code) { + send_sig(current->exit_code, current, 1); + current->exit_code = 0; + } +} + +void ptrace_disable (struct task_struct *child) +{ + /* nothing to do */ +} |