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 000000000000..fed83d066135
--- /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;
+}