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authorRoland McGrath <roland@redhat.com>2008-01-30 13:31:01 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-30 13:31:01 +0100
commitd52e9d690fff1fd9d0ccffe375fd01b700f82a64 (patch)
tree5738041b8623af86b35d033ffc6285b202d28c4f /arch/x86/kernel/ptrace.c
parent0f5340933f9bacb403f49baaf8073320e3984841 (diff)
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>
Diffstat (limited to 'arch/x86/kernel/ptrace.c')
-rw-r--r--arch/x86/kernel/ptrace.c484
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;
+}