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linux/arch/x86/kernel/ptrace_64.c

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/* By Ross Biro 1/23/92 */
/*
* Pentium III FXSR, SSE support
* Gareth Hughes <gareth@valinux.com>, May 2000
*
* x86-64 port 2000-2002 Andi Kleen
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/signal.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/prctl.h>
#include <asm/i387.h>
#include <asm/debugreg.h>
#include <asm/ldt.h>
#include <asm/desc.h>
#include <asm/proto.h>
#include <asm/ia32.h>
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Determines which flags the user has access to [1 = access, 0 = no access].
* Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9).
* Also masks reserved bits (63-22, 15, 5, 3, 1).
*/
#define FLAG_MASK 0x54dd5UL
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
user_disable_single_step(child);
}
static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
{
BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
return &regs->r15 + (offset / sizeof(regs->r15));
}
static int putreg(struct task_struct *child,
unsigned long regno, unsigned long value)
{
struct pt_regs *regs = task_pt_regs(child);
switch (regno) {
case offsetof(struct user_regs_struct,fs):
if (value && (value & 3) != 3)
return -EIO;
child->thread.fsindex = value & 0xffff;
return 0;
case offsetof(struct user_regs_struct,gs):
if (value && (value & 3) != 3)
return -EIO;
child->thread.gsindex = value & 0xffff;
return 0;
case offsetof(struct user_regs_struct,ds):
if (value && (value & 3) != 3)
return -EIO;
child->thread.ds = value & 0xffff;
return 0;
case offsetof(struct user_regs_struct,es):
if (value && (value & 3) != 3)
return -EIO;
child->thread.es = value & 0xffff;
return 0;
case offsetof(struct user_regs_struct,ss):
if ((value & 3) != 3)
return -EIO;
value &= 0xffff;
return 0;
case offsetof(struct user_regs_struct,fs_base):
if (value >= TASK_SIZE_OF(child))
return -EIO;
/*
* When changing the segment base, use do_arch_prctl
* to set either thread.fs or thread.fsindex and the
* corresponding GDT slot.
*/
if (child->thread.fs != value)
return do_arch_prctl(child, ARCH_SET_FS, value);
return 0;
case offsetof(struct user_regs_struct,gs_base):
/*
* Exactly the same here as the %fs handling above.
*/
if (value >= TASK_SIZE_OF(child))
return -EIO;
if (child->thread.gs != value)
return do_arch_prctl(child, ARCH_SET_GS, value);
return 0;
case offsetof(struct user_regs_struct, eflags):
value &= FLAG_MASK;
/*
* If the user value contains TF, mark that
* it was not "us" (the debugger) that set it.
* If not, make sure it stays set if we had.
*/
if (value & X86_EFLAGS_TF)
clear_tsk_thread_flag(child, TIF_FORCED_TF);
else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
value |= X86_EFLAGS_TF;
value |= regs->eflags & ~FLAG_MASK;
break;
case offsetof(struct user_regs_struct,cs):
if ((value & 3) != 3)
return -EIO;
value &= 0xffff;
break;
}
*pt_regs_access(regs, regno) = value;
return 0;
}
static unsigned long getreg(struct task_struct *child, unsigned long regno)
{
struct pt_regs *regs = task_pt_regs(child);
unsigned long val;
switch (regno) {
case offsetof(struct user_regs_struct, fs):
return child->thread.fsindex;
case offsetof(struct user_regs_struct, gs):
return child->thread.gsindex;
case offsetof(struct user_regs_struct, ds):
return child->thread.ds;
case offsetof(struct user_regs_struct, es):
return child->thread.es;
case offsetof(struct user_regs_struct, fs_base):
/*
* do_arch_prctl may have used a GDT slot instead of
* the MSR. To userland, it appears the same either
* way, except the %fs segment selector might not be 0.
*/
if (child->thread.fs != 0)
return child->thread.fs;
if (child->thread.fsindex != FS_TLS_SEL)
return 0;
return get_desc_base(&child->thread.tls_array[FS_TLS]);
case offsetof(struct user_regs_struct, gs_base):
/*
* Exactly the same here as the %fs handling above.
*/
if (child->thread.gs != 0)
return child->thread.gs;
if (child->thread.gsindex != GS_TLS_SEL)
return 0;
return get_desc_base(&child->thread.tls_array[GS_TLS]);
case offsetof(struct user_regs_struct, eflags):
/*
* If the debugger set TF, hide it from the readout.
*/
val = regs->eflags;
if (test_tsk_thread_flag(child, TIF_IA32))
val &= 0xffffffff;
if (test_tsk_thread_flag(child, TIF_FORCED_TF))
val &= ~X86_EFLAGS_TF;
return val;
default:
val = *pt_regs_access(regs, regno);
if (test_tsk_thread_flag(child, TIF_IA32))
val &= 0xffffffff;
return val;
}
}
unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
{
switch (n) {
case 0: return child->thread.debugreg0;
case 1: return child->thread.debugreg1;
case 2: return child->thread.debugreg2;
case 3: return child->thread.debugreg3;
case 6: return child->thread.debugreg6;
case 7: return child->thread.debugreg7;
}
return 0;
}
int ptrace_set_debugreg(struct task_struct *child, int n, unsigned long data)
{
int i;
if (n < 4) {
int dsize = test_tsk_thread_flag(child, TIF_IA32) ? 3 : 7;
if (unlikely(data >= TASK_SIZE_OF(child) - dsize))
return -EIO;
}
switch (n) {
case 0: child->thread.debugreg0 = data; break;
case 1: child->thread.debugreg1 = data; break;
case 2: child->thread.debugreg2 = data; break;
case 3: child->thread.debugreg3 = data; break;
case 6:
if (data >> 32)
return -EIO;
child->thread.debugreg6 = data;
break;
case 7:
/*
* See ptrace_32.c for an explanation of this awkward check.
*/
data &= ~DR_CONTROL_RESERVED;
for (i = 0; i < 4; i++)
if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
return -EIO;
child->thread.debugreg7 = data;
if (data)
set_tsk_thread_flag(child, TIF_DEBUG);
else
clear_tsk_thread_flag(child, TIF_DEBUG);
break;
}
return 0;
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
long ret;
unsigned ui;
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:
ret = generic_ptrace_peekdata(child, addr, data);
break;
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & 7) ||
addr > sizeof(struct user) - 7)
break;
tmp = 0;
if (addr < sizeof(struct user_regs_struct))
tmp = getreg(child, addr);
else if (addr >= offsetof(struct user, u_debugreg[0])) {
addr -= offsetof(struct user, u_debugreg[0]);
tmp = ptrace_get_debugreg(child, addr / sizeof(long));
}
ret = put_user(tmp,(unsigned long __user *) 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 = generic_ptrace_pokedata(child, addr, data);
break;
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & 7) ||
addr > sizeof(struct user) - 7)
break;
if (addr < sizeof(struct user_regs_struct))
ret = putreg(child, addr, data);
else if (addr >= offsetof(struct user, u_debugreg[0])) {
addr -= offsetof(struct user, u_debugreg[0]);
ret = ptrace_set_debugreg(child,
addr / sizeof(long), data);
}
break;
#ifdef CONFIG_IA32_EMULATION
/* This makes only sense with 32bit programs. Allow a
64bit debugger to fully examine them too. Better
don't use it against 64bit processes, use
PTRACE_ARCH_PRCTL instead. */
case PTRACE_GET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_get_thread_area(child, addr,
(struct user_desc __user *) data);
break;
case PTRACE_SET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_set_thread_area(child, addr,
(struct user_desc __user *) data, 0);
break;
#endif
/* normal 64bit interface to access TLS data.
Works just like arch_prctl, except that the arguments
are reversed. */
case PTRACE_ARCH_PRCTL:
ret = do_arch_prctl(child, data, addr);
break;
case PTRACE_GETREGS: { /* Get all gp regs from the child. */
if (!access_ok(VERIFY_WRITE, (unsigned __user *)data,
sizeof(struct user_regs_struct))) {
ret = -EIO;
break;
}
ret = 0;
for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) {
ret |= __put_user(getreg(child, ui),(unsigned long __user *) data);
data += sizeof(long);
}
break;
}
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
unsigned long tmp;
if (!access_ok(VERIFY_READ, (unsigned __user *)data,
sizeof(struct user_regs_struct))) {
ret = -EIO;
break;
}
ret = 0;
for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) {
ret = __get_user(tmp, (unsigned long __user *) data);
if (ret)
break;
ret = putreg(child, ui, tmp);
if (ret)
break;
data += sizeof(long);
}
break;
}
case PTRACE_GETFPREGS: { /* Get the child extended FPU state. */
if (!access_ok(VERIFY_WRITE, (unsigned __user *)data,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
ret = get_fpregs((struct user_i387_struct __user *)data, child);
break;
}
case PTRACE_SETFPREGS: { /* Set the child extended FPU state. */
if (!access_ok(VERIFY_READ, (unsigned __user *)data,
sizeof(struct user_i387_struct))) {
ret = -EIO;
break;
}
set_stopped_child_used_math(child);
ret = set_fpregs(child, (struct user_i387_struct __user *)data);
break;
}
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
static void syscall_trace(struct pt_regs *regs)
{
#if 0
printk("trace %s rip %lx rsp %lx rax %d origrax %d caller %lx tiflags %x ptrace %x\n",
current->comm,
regs->rip, regs->rsp, regs->rax, regs->orig_rax, __builtin_return_address(0),
current_thread_info()->flags, current->ptrace);
#endif
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;
}
}
asmlinkage void syscall_trace_enter(struct pt_regs *regs)
{
/* do the secure computing check first */
secure_computing(regs->orig_rax);
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
syscall_trace(regs);
if (unlikely(current->audit_context)) {
if (test_thread_flag(TIF_IA32)) {
audit_syscall_entry(AUDIT_ARCH_I386,
regs->orig_rax,
regs->rbx, regs->rcx,
regs->rdx, regs->rsi);
} else {
audit_syscall_entry(AUDIT_ARCH_X86_64,
regs->orig_rax,
regs->rdi, regs->rsi,
regs->rdx, regs->r10);
}
}
}
asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
if (unlikely(current->audit_context))
audit_syscall_exit(AUDITSC_RESULT(regs->rax), regs->rax);
if ((test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SINGLESTEP))
&& (current->ptrace & PT_PTRACED))
syscall_trace(regs);
}
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