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linux/arch/mips/kernel/ptrace.c

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/*
* 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.
*
* 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.
* Copyright (C) 2000 Ulf Carlsson
*
* At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
* binaries.
*/
#include <linux/config.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/audit.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/signal.h>
#include <asm/cpu.h>
#include <asm/fpu.h>
#include <asm/mipsregs.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/bootinfo.h>
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* Nothing to do.. */
}
asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
int ret;
#if 0
printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
(int) request, (int) pid, (unsigned long) addr,
(unsigned long) data);
#endif
lock_kernel();
ret = -EPERM;
if (request == PTRACE_TRACEME) {
/* are we already being traced? */
if (current->ptrace & PT_PTRACED)
goto out;
if ((ret = security_ptrace(current->parent, current)))
goto out;
/* set the ptrace bit in the process flags. */
current->ptrace |= PT_PTRACED;
ret = 0;
goto out;
}
ret = -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;
ret = -EPERM;
if (pid == 1) /* you may not mess with init */
goto out_tsk;
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
goto out_tsk;
}
ret = ptrace_check_attach(child, request == PTRACE_KILL);
if (ret < 0)
goto out_tsk;
switch (request) {
/* when I and D space are separate, these will need to be fixed. */
case PTRACE_PEEKTEXT: /* read word at location addr. */
case PTRACE_PEEKDATA: {
unsigned long tmp;
int copied;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
ret = -EIO;
if (copied != sizeof(tmp))
break;
ret = put_user(tmp,(unsigned long *) data);
break;
}
/* Read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
struct pt_regs *regs;
unsigned long tmp = 0;
regs = (struct pt_regs *) ((unsigned long) child->thread_info +
THREAD_SIZE - 32 - sizeof(struct pt_regs));
ret = 0; /* Default return value. */
switch (addr) {
case 0 ... 31:
tmp = regs->regs[addr];
break;
case FPR_BASE ... FPR_BASE + 31:
if (tsk_used_math(child)) {
fpureg_t *fregs = get_fpu_regs(child);
#ifdef CONFIG_MIPS32
/*
* The odd registers are actually the high
* order bits of the values stored in the even
* registers - unless we're using r2k_switch.S.
*/
if (addr & 1)
tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
else
tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
#endif
#ifdef CONFIG_MIPS64
tmp = fregs[addr - FPR_BASE];
#endif
} else {
tmp = -1; /* FP not yet used */
}
break;
case PC:
tmp = regs->cp0_epc;
break;
case CAUSE:
tmp = regs->cp0_cause;
break;
case BADVADDR:
tmp = regs->cp0_badvaddr;
break;
case MMHI:
tmp = regs->hi;
break;
case MMLO:
tmp = regs->lo;
break;
case FPC_CSR:
if (cpu_has_fpu)
tmp = child->thread.fpu.hard.fcr31;
else
tmp = child->thread.fpu.soft.fcr31;
break;
case FPC_EIR: { /* implementation / version register */
unsigned int flags;
if (!cpu_has_fpu)
break;
flags = read_c0_status();
__enable_fpu();
__asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
write_c0_status(flags);
break;
}
default:
tmp = 0;
ret = -EIO;
goto out_tsk;
}
ret = put_user(tmp, (unsigned long *) data);
break;
}
/* when I and D space are separate, this will have to be fixed. */
case PTRACE_POKETEXT: /* write the word at location addr. */
case PTRACE_POKEDATA:
ret = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1)
== sizeof(data))
break;
ret = -EIO;
break;
case PTRACE_POKEUSR: {
struct pt_regs *regs;
ret = 0;
regs = (struct pt_regs *) ((unsigned long) child->thread_info +
THREAD_SIZE - 32 - sizeof(struct pt_regs));
switch (addr) {
case 0 ... 31:
regs->regs[addr] = data;
break;
case FPR_BASE ... FPR_BASE + 31: {
fpureg_t *fregs = get_fpu_regs(child);
if (!tsk_used_math(child)) {
/* FP not yet used */
memset(&child->thread.fpu.hard, ~0,
sizeof(child->thread.fpu.hard));
child->thread.fpu.hard.fcr31 = 0;
}
#ifdef CONFIG_MIPS32
/*
* The odd registers are actually the high order bits
* of the values stored in the even registers - unless
* we're using r2k_switch.S.
*/
if (addr & 1) {
fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
} else {
fregs[addr - FPR_BASE] &= ~0xffffffffLL;
fregs[addr - FPR_BASE] |= data;
}
#endif
#ifdef CONFIG_MIPS64
fregs[addr - FPR_BASE] = data;
#endif
break;
}
case PC:
regs->cp0_epc = data;
break;
case MMHI:
regs->hi = data;
break;
case MMLO:
regs->lo = data;
break;
case FPC_CSR:
if (cpu_has_fpu)
child->thread.fpu.hard.fcr31 = data;
else
child->thread.fpu.soft.fcr31 = data;
break;
default:
/* The rest are not allowed. */
ret = -EIO;
break;
}
break;
}
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
ret = -EIO;
if (!valid_signal(data))
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);
ret = 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:
ret = 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. */
ret = ptrace_detach(child, data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
out_tsk:
put_task_struct(child);
out:
unlock_kernel();
return ret;
}
static inline int audit_arch(void)
{
#ifdef CONFIG_CPU_LITTLE_ENDIAN
#ifdef CONFIG_MIPS64
if (!(current->thread.mflags & MF_32BIT_REGS))
return AUDIT_ARCH_MIPSEL64;
#endif /* MIPS64 */
return AUDIT_ARCH_MIPSEL;
#else /* big endian... */
#ifdef CONFIG_MIPS64
if (!(current->thread.mflags & MF_32BIT_REGS))
return AUDIT_ARCH_MIPS64;
#endif /* MIPS64 */
return AUDIT_ARCH_MIPS;
#endif /* endian */
}
/*
* Notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit)
{
if (unlikely(current->audit_context) && entryexit)
audit_syscall_exit(current, AUDITSC_RESULT(regs->regs[2]), regs->regs[2]);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
goto out;
if (!(current->ptrace & PT_PTRACED))
goto out;
/* 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;
}
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(current, audit_arch(), regs->regs[2],
regs->regs[4], regs->regs[5],
regs->regs[6], regs->regs[7]);
}
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