*/
#define EFL_OFFSET ((EFL-2)*4-sizeof(struct pt_regs))
+static inline struct pt_regs *get_child_regs(struct task_struct *task)
+{
+ void *stack_top = (void *)task->thread.esp0;
+ return stack_top - sizeof(struct pt_regs);
+}
+
/*
* this routine will get a word off of the processes privileged stack.
* the offset is how far from the base addr as stored in the TSS.
return retval;
}
+#define LDT_SEGMENT 4
+
+static unsigned long convert_eip_to_linear(struct task_struct *child, struct pt_regs *regs)
+{
+ unsigned long addr, seg;
+
+ addr = regs->eip;
+ seg = regs->xcs & 0xffff;
+ if (regs->eflags & VM_MASK) {
+ addr = (addr & 0xffff) + (seg << 4);
+ return addr;
+ }
+
+ /*
+ * We'll assume that the code segments in the GDT
+ * are all zero-based. That is largely true: the
+ * TLS segments are used for data, and the PNPBIOS
+ * and APM bios ones we just ignore here.
+ */
+ if (seg & LDT_SEGMENT) {
+ u32 *desc;
+ unsigned long base;
+
+ down(&child->mm->context.sem);
+ desc = child->mm->context.ldt + (seg & ~7);
+ base = (desc[0] >> 16) | ((desc[1] & 0xff) << 16) | (desc[1] & 0xff000000);
+
+ /* 16-bit code segment? */
+ if (!((desc[1] >> 22) & 1))
+ addr &= 0xffff;
+ addr += base;
+ up(&child->mm->context.sem);
+ }
+ return addr;
+}
+
+static inline int is_at_popf(struct task_struct *child, struct pt_regs *regs)
+{
+ int i, copied;
+ unsigned char opcode[16];
+ unsigned long addr = convert_eip_to_linear(child, regs);
+
+ copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
+ for (i = 0; i < copied; i++) {
+ switch (opcode[i]) {
+ /* popf */
+ case 0x9d:
+ return 1;
+ /* opcode and address size prefixes */
+ case 0x66: case 0x67:
+ continue;
+ /* irrelevant prefixes (segment overrides and repeats) */
+ case 0x26: case 0x2e:
+ case 0x36: case 0x3e:
+ case 0x64: case 0x65:
+ case 0xf0: case 0xf2: case 0xf3:
+ continue;
+
+ /*
+ * pushf: NOTE! We should probably not let
+ * the user see the TF bit being set. But
+ * it's more pain than it's worth to avoid
+ * it, and a debugger could emulate this
+ * all in user space if it _really_ cares.
+ */
+ case 0x9c:
+ default:
+ return 0;
+ }
+ }
+ return 0;
+}
+
+static void set_singlestep(struct task_struct *child)
+{
+ struct pt_regs *regs = get_child_regs(child);
+
+ /*
+ * Always set TIF_SINGLESTEP - this guarantees that
+ * we single-step system calls etc.. This will also
+ * cause us to set TF when returning to user mode.
+ */
+ set_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+ /*
+ * If TF was already set, don't do anything else
+ */
+ if (regs->eflags & TRAP_FLAG)
+ return;
+
+ /* Set TF on the kernel stack.. */
+ regs->eflags |= TRAP_FLAG;
+
+ /*
+ * ..but if TF is changed by the instruction we will trace,
+ * don't mark it as being "us" that set it, so that we
+ * won't clear it by hand later.
+ */
+ if (is_at_popf(child, regs))
+ return;
+
+ child->ptrace |= PT_DTRACE;
+}
+
+static void clear_singlestep(struct task_struct *child)
+{
+ /* Always clear TIF_SINGLESTEP... */
+ clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+ /* But touch TF only if it was set by us.. */
+ if (child->ptrace & PT_DTRACE) {
+ struct pt_regs *regs = get_child_regs(child);
+ regs->eflags &= ~TRAP_FLAG;
+ child->ptrace &= ~PT_DTRACE;
+ }
+}
+
/*
* Called by kernel/ptrace.c when detaching..
*
*/
void ptrace_disable(struct task_struct *child)
{
- long tmp;
-
- clear_tsk_thread_flag(child, TIF_SINGLESTEP);
- tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
+ clear_singlestep(child);
}
/*
if(addr < (long) &dummy->u_debugreg[4] &&
((unsigned long) data) >= TASK_SIZE-3) break;
+ /* Sanity-check data. Take one half-byte at once with
+ * check = (val >> (16 + 4*i)) & 0xf. It contains the
+ * R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
+ * 2 and 3 are LENi. Given a list of invalid values,
+ * we do mask |= 1 << invalid_value, so that
+ * (mask >> check) & 1 is a correct test for invalid
+ * values.
+ *
+ * R/Wi contains the type of the breakpoint /
+ * watchpoint, LENi contains the length of the watched
+ * data in the watchpoint case.
+ *
+ * The invalid values are:
+ * - LENi == 0x10 (undefined), so mask |= 0x0f00.
+ * - R/Wi == 0x10 (break on I/O reads or writes), so
+ * mask |= 0x4444.
+ * - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
+ * 0x1110.
+ *
+ * Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
+ *
+ * See the Intel Manual "System Programming Guide",
+ * 15.2.4
+ *
+ * Note that LENi == 0x10 is defined on x86_64 in long
+ * mode (i.e. even for 32-bit userspace software, but
+ * 64-bit kernel), so the x86_64 mask value is 0x5454.
+ * See the AMD manual no. 24593 (AMD64 System
+ * Programming)*/
+
if(addr == (long) &dummy->u_debugreg[7]) {
data &= ~DR_CONTROL_RESERVED;
for(i=0; i<4; i++)
}
break;
- case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
- case PTRACE_CONT: { /* restart after signal. */
- long tmp;
-
+ case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
+ case PTRACE_CONT: /* restart after signal. */
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
else {
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
- clear_tsk_thread_flag(child, TIF_SINGLESTEP);
child->exit_code = data;
- /* make sure the single step bit is not set. */
- tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET,tmp);
+ /* make sure the single step bit is not set. */
+ clear_singlestep(child);
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: {
- long tmp;
-
+ case PTRACE_KILL:
ret = 0;
- if (child->state == TASK_ZOMBIE) /* already dead */
+ if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
- clear_tsk_thread_flag(child, TIF_SINGLESTEP);
/* make sure the single step bit is not set. */
- tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
+ clear_singlestep(child);
wake_up_process(child);
break;
- }
-
- case PTRACE_SINGLESTEP: { /* set the trap flag. */
- long tmp;
+ case PTRACE_SINGLESTEP: /* set the trap flag. */
ret = -EIO;
if ((unsigned long) data > _NSIG)
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- if ((child->ptrace & PT_DTRACE) == 0) {
- /* Spurious delayed TF traps may occur */
- child->ptrace |= PT_DTRACE;
- }
- tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG;
- put_stack_long(child, EFL_OFFSET, tmp);
- set_tsk_thread_flag(child, TIF_SINGLESTEP);
+ set_singlestep(child);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
- }
case PTRACE_DETACH:
/* detach a process that was attached. */
break;
}
ret = 0;
- if (!child->used_math)
+ if (!tsk_used_math(child))
init_fpu(child);
get_fpregs((struct user_i387_struct __user *)data, child);
break;
ret = -EIO;
break;
}
- child->used_math = 1;
+ set_stopped_child_used_math(child);
set_fpregs(child, (struct user_i387_struct __user *)data);
ret = 0;
break;
ret = -EIO;
break;
}
- if (!child->used_math)
+ if (!tsk_used_math(child))
init_fpu(child);
ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
break;
ret = -EIO;
break;
}
- child->used_math = 1;
+ set_stopped_child_used_math(child);
ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
break;
}
return ret;
}
+void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
+{
+ struct siginfo info;
+
+ tsk->thread.trap_no = 1;
+ tsk->thread.error_code = error_code;
+
+ memset(&info, 0, sizeof(info));
+ info.si_signo = SIGTRAP;
+ info.si_code = TRAP_BRKPT;
+
+ /* User-mode eip? */
+ info.si_addr = user_mode(regs) ? (void __user *) regs->eip : NULL;
+
+ /* Send us the fakey SIGTRAP */
+ force_sig_info(SIGTRAP, &info, tsk);
+}
+
/* notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
audit_syscall_exit(current, regs->eax);
}
- if (!test_thread_flag(TIF_SYSCALL_TRACE) &&
- !test_thread_flag(TIF_SINGLESTEP))
- return;
if (!(current->ptrace & PT_PTRACED))
return;
+
+ /* Fake a debug trap */
+ if (test_thread_flag(TIF_SINGLESTEP))
+ send_sigtrap(current, regs, 0);
+
+ if (!test_thread_flag(TIF_SYSCALL_TRACE))
+ 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) &&
- !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0));
+ ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
/*
* this isn't the same as continuing with a signal, but it will do
git://git.onelab.eu / linux-2.6.git / blobdiff