x86: ptrace_32 renamed

This renames ptrace_32.c back to ptrace.c, in preparation
for merging the 32/64 versions of these files.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 484 insertions, 0 deletions

diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
new file mode 100644
index 00000000000..fed83d06613
--- /dev/null
+++ b/arch/x86/kernel/ptrace.c
@@ -0,0 +1,484 @@
+/* By Ross Biro 1/23/92 */
+/*
+ * Pentium III FXSR, SSE support
+ *	Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+
+#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/i387.h>
+#include <asm/debugreg.h>
+#include <asm/ldt.h>
+#include <asm/desc.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), NT(14), IOPL(12-13), IF(9).
+ * Also masks reserved bits (31-22, 15, 5, 3, 1).
+ */
+#define FLAG_MASK 0x00050dd5
+
+static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
+{
+	BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
+	if (regno > FS)
+		--regno;
+	return &regs->bx + regno;
+}
+
+static int putreg(struct task_struct *child,
+	unsigned long regno, unsigned long value)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	regno >>= 2;
+	switch (regno) {
+	case GS:
+		if (value && (value & 3) != 3)
+			return -EIO;
+		child->thread.gs = value;
+		if (child == current)
+			/*
+			 * The user-mode %gs is not affected by
+			 * kernel entry, so we must update the CPU.
+			 */
+			loadsegment(gs, value);
+		return 0;
+	case DS:
+	case ES:
+	case FS:
+		if (value && (value & 3) != 3)
+			return -EIO;
+		value &= 0xffff;
+		break;
+	case SS:
+	case CS:
+		if ((value & 3) != 3)
+			return -EIO;
+		value &= 0xffff;
+		break;
+	case EFL:
+		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->flags & ~FLAG_MASK;
+		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 retval = ~0UL;
+
+	regno >>= 2;
+	switch (regno) {
+	case EFL:
+		/*
+		 * If the debugger set TF, hide it from the readout.
+		 */
+		retval = regs->flags;
+		if (test_tsk_thread_flag(child, TIF_FORCED_TF))
+			retval &= ~X86_EFLAGS_TF;
+		break;
+	case GS:
+		retval = child->thread.gs;
+		if (child == current)
+			savesegment(gs, retval);
+		break;
+	case DS:
+	case ES:
+	case FS:
+	case SS:
+	case CS:
+		retval = 0xffff;
+		/* fall through */
+	default:
+		retval &= *pt_regs_access(regs, regno);
+	}
+	return retval;
+}
+
+/*
+ * This function is trivial and will be inlined by the compiler.
+ * Having it separates the implementation details of debug
+ * registers from the interface details of ptrace.
+ */
+static 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;
+}
+
+static int ptrace_set_debugreg(struct task_struct *child,
+			       int n, unsigned long data)
+{
+	int i;
+
+	if (unlikely(n == 4 || n == 5))
+		return -EIO;
+
+	if (n < 4 && unlikely(data >= TASK_SIZE - 3))
+		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:
+		child->thread.debugreg6 = data;
+		break;
+
+	case 7:
+		/*
+		 * 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)
+		 */
+		data &= ~DR_CONTROL_RESERVED;
+		for (i = 0; i < 4; i++)
+			if ((0x5f54 >> ((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;
+}
+
+/*
+ * 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);
+	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+}
+
+long arch_ptrace(struct task_struct *child, long request, long addr, long data)
+{
+	struct user * dummy = NULL;
+	int i, ret;
+	unsigned long __user *datap = (unsigned long __user *)data;
+
+	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 & 3) || addr < 0 ||
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		tmp = 0;  /* Default return condition */
+		if(addr < FRAME_SIZE*sizeof(long))
+			tmp = getreg(child, addr);
+		if(addr >= (long) &dummy->u_debugreg[0] &&
+		   addr <= (long) &dummy->u_debugreg[7]){
+			addr -= (long) &dummy->u_debugreg[0];
+			addr = addr >> 2;
+			tmp = ptrace_get_debugreg(child, addr);
+		}
+		ret = put_user(tmp, datap);
+		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 & 3) || addr < 0 ||
+		    addr > sizeof(struct user) - 3)
+			break;
+
+		if (addr < FRAME_SIZE*sizeof(long)) {
+			ret = putreg(child, addr, data);
+			break;
+		}
+		/* We need to be very careful here.  We implicitly
+		   want to modify a portion of the task_struct, and we
+		   have to be selective about what portions we allow someone
+		   to modify. */
+
+		  ret = -EIO;
+		  if(addr >= (long) &dummy->u_debugreg[0] &&
+		     addr <= (long) &dummy->u_debugreg[7]){
+			  addr -= (long) &dummy->u_debugreg;
+			  addr = addr >> 2;
+			  ret = ptrace_set_debugreg(child, addr, data);
+		  }
+		  break;
+
+	case PTRACE_GETREGS: { /* Get all gp regs from the child. */
+	  	if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
+			__put_user(getreg(child, i), datap);
+			datap++;
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_SETREGS: { /* Set all gp regs in the child. */
+		unsigned long tmp;
+	  	if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
+			ret = -EIO;
+			break;
+		}
+		for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
+			__get_user(tmp, datap);
+			putreg(child, i, tmp);
+			datap++;
+		}
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_GETFPREGS: { /* Get the child FPU state. */
+		if (!access_ok(VERIFY_WRITE, datap,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		ret = 0;
+		if (!tsk_used_math(child))
+			init_fpu(child);
+		get_fpregs((struct user_i387_struct __user *)data, child);
+		break;
+	}
+
+	case PTRACE_SETFPREGS: { /* Set the child FPU state. */
+		if (!access_ok(VERIFY_READ, datap,
+			       sizeof(struct user_i387_struct))) {
+			ret = -EIO;
+			break;
+		}
+		set_stopped_child_used_math(child);
+		set_fpregs(child, (struct user_i387_struct __user *)data);
+		ret = 0;
+		break;
+	}
+
+	case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
+		if (!access_ok(VERIFY_WRITE, datap,
+			       sizeof(struct user_fxsr_struct))) {
+			ret = -EIO;
+			break;
+		}
+		if (!tsk_used_math(child))
+			init_fpu(child);
+		ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
+		break;
+	}
+
+	case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
+		if (!access_ok(VERIFY_READ, datap,
+			       sizeof(struct user_fxsr_struct))) {
+			ret = -EIO;
+			break;
+		}
+		set_stopped_child_used_math(child);
+		ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
+		break;
+	}
+
+	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;
+
+	default:
+		ret = ptrace_request(child, request, addr, 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 ip? */
+	info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
+
+	/* Send us the fake SIGTRAP */
+	force_sig_info(SIGTRAP, &info, tsk);
+}
+
+/* notification of system call entry/exit
+ * - triggered by current->work.syscall_trace
+ */
+__attribute__((regparm(3)))
+int do_syscall_trace(struct pt_regs *regs, int entryexit)
+{
+	int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
+	/*
+	 * With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
+	 * interception
+	 */
+	int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
+	int ret = 0;
+
+	/* do the secure computing check first */
+	if (!entryexit)
+		secure_computing(regs->orig_ax);
+
+	if (unlikely(current->audit_context)) {
+		if (entryexit)
+			audit_syscall_exit(AUDITSC_RESULT(regs->ax),
+						regs->ax);
+		/* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
+		 * on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
+		 * not used, entry.S will call us only on syscall exit, not
+		 * entry; so when TIF_SYSCALL_AUDIT is used we must avoid
+		 * calling send_sigtrap() on syscall entry.
+		 *
+		 * Note that when PTRACE_SYSEMU_SINGLESTEP is used,
+		 * is_singlestep is false, despite his name, so we will still do
+		 * the correct thing.
+		 */
+		else if (is_singlestep)
+			goto out;
+	}
+
+	if (!(current->ptrace & PT_PTRACED))
+		goto out;
+
+	/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
+	 * and then is resumed with SYSEMU_SINGLESTEP, it will come in
+	 * here. We have to check this and return */
+	if (is_sysemu && entryexit)
+		return 0;
+
+	/* Fake a debug trap */
+	if (is_singlestep)
+		send_sigtrap(current, regs, 0);
+
+ 	if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
+		goto out;
+
+	/* the 0x80 provides a way for the tracing parent to distinguish
+	   between a syscall stop and SIGTRAP delivery */
+	/* Note that the debugger could change the result of test_thread_flag!*/
+	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;
+	}
+	ret = is_sysemu;
+out:
+	if (unlikely(current->audit_context) && !entryexit)
+		audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_ax,
+				    regs->bx, regs->cx, regs->dx, regs->si);
+	if (ret == 0)
+		return 0;
+
+	regs->orig_ax = -1; /* force skip of syscall restarting */
+	if (unlikely(current->audit_context))
+		audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
+	return 1;
+}