--- /dev/null
+/*
+ * Kernel support for the ptrace() and syscall tracing interfaces.
+ *
+ * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
+ * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
+ * Copyright (C) 2008 Helge Deller <deller@gmx.de>
+ */
+
+#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/tracehook.h>
+#include <linux/user.h>
+#include <linux/personality.h>
+#include <linux/security.h>
+#include <linux/seccomp.h>
+#include <linux/compat.h>
+#include <linux/signal.h>
+#include <linux/audit.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/asm-offsets.h>
+
+/* PSW bits we allow the debugger to modify */
+#define USER_PSW_BITS (PSW_N | PSW_B | PSW_V | PSW_CB)
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure single step bits etc are not set.
+ */
+void ptrace_disable(struct task_struct *task)
+{
+ clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+ clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
+
+ /* make sure the trap bits are not set */
+ pa_psw(task)->r = 0;
+ pa_psw(task)->t = 0;
+ pa_psw(task)->h = 0;
+ pa_psw(task)->l = 0;
+}
+
+/*
+ * The following functions are called by ptrace_resume() when
+ * enabling or disabling single/block tracing.
+ */
+void user_disable_single_step(struct task_struct *task)
+{
+ ptrace_disable(task);
+}
+
+void user_enable_single_step(struct task_struct *task)
+{
+ clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
+ set_tsk_thread_flag(task, TIF_SINGLESTEP);
+
+ if (pa_psw(task)->n) {
+ struct siginfo si;
+
+ /* Nullified, just crank over the queue. */
+ task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
+ task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
+ task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
+ pa_psw(task)->n = 0;
+ pa_psw(task)->x = 0;
+ pa_psw(task)->y = 0;
+ pa_psw(task)->z = 0;
+ pa_psw(task)->b = 0;
+ ptrace_disable(task);
+ /* Don't wake up the task, but let the
+ parent know something happened. */
+ si.si_code = TRAP_TRACE;
+ si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
+ si.si_signo = SIGTRAP;
+ si.si_errno = 0;
+ force_sig_info(SIGTRAP, &si, task);
+ /* notify_parent(task, SIGCHLD); */
+ return;
+ }
+
+ /* Enable recovery counter traps. The recovery counter
+ * itself will be set to zero on a task switch. If the
+ * task is suspended on a syscall then the syscall return
+ * path will overwrite the recovery counter with a suitable
+ * value such that it traps once back in user space. We
+ * disable interrupts in the tasks PSW here also, to avoid
+ * interrupts while the recovery counter is decrementing.
+ */
+ pa_psw(task)->r = 1;
+ pa_psw(task)->t = 0;
+ pa_psw(task)->h = 0;
+ pa_psw(task)->l = 0;
+}
+
+void user_enable_block_step(struct task_struct *task)
+{
+ clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+ set_tsk_thread_flag(task, TIF_BLOCKSTEP);
+
+ /* Enable taken branch trap. */
+ pa_psw(task)->r = 0;
+ pa_psw(task)->t = 1;
+ pa_psw(task)->h = 0;
+ pa_psw(task)->l = 0;
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+ unsigned long addr, unsigned long data)
+{
+ unsigned long tmp;
+ long ret = -EIO;
+
+ switch (request) {
+
+ /* Read the word at location addr in the USER area. For ptraced
+ processes, the kernel saves all regs on a syscall. */
+ case PTRACE_PEEKUSR:
+ if ((addr & (sizeof(unsigned long)-1)) ||
+ addr >= sizeof(struct pt_regs))
+ break;
+ tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
+ ret = put_user(tmp, (unsigned long __user *) data);
+ break;
+
+ /* Write the word at location addr in the USER area. This will need
+ to change when the kernel no longer saves all regs on a syscall.
+ FIXME. There is a problem at the moment in that r3-r18 are only
+ saved if the process is ptraced on syscall entry, and even then
+ those values are overwritten by actual register values on syscall
+ exit. */
+ case PTRACE_POKEUSR:
+ /* Some register values written here may be ignored in
+ * entry.S:syscall_restore_rfi; e.g. iaoq is written with
+ * r31/r31+4, and not with the values in pt_regs.
+ */
+ if (addr == PT_PSW) {
+ /* Allow writing to Nullify, Divide-step-correction,
+ * and carry/borrow bits.
+ * BEWARE, if you set N, and then single step, it won't
+ * stop on the nullified instruction.
+ */
+ data &= USER_PSW_BITS;
+ task_regs(child)->gr[0] &= ~USER_PSW_BITS;
+ task_regs(child)->gr[0] |= data;
+ ret = 0;
+ break;
+ }
+
+ if ((addr & (sizeof(unsigned long)-1)) ||
+ addr >= sizeof(struct pt_regs))
+ break;
+ if ((addr >= PT_GR1 && addr <= PT_GR31) ||
+ addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
+ (addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
+ addr == PT_SAR) {
+ *(unsigned long *) ((char *) task_regs(child) + addr) = data;
+ ret = 0;
+ }
+ break;
+
+ default:
+ ret = ptrace_request(child, request, addr, data);
+ break;
+ }
+
+ return ret;
+}
+
+
+#ifdef CONFIG_COMPAT
+
+/* This function is needed to translate 32 bit pt_regs offsets in to
+ * 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
+ * will request offset 12 if it wants gr3, but the lower 32 bits of
+ * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
+ * This code relies on a 32 bit pt_regs being comprised of 32 bit values
+ * except for the fp registers which (a) are 64 bits, and (b) follow
+ * the gr registers at the start of pt_regs. The 32 bit pt_regs should
+ * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
+ * being 64 bit in both cases.
+ */
+
+static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
+{
+ if (offset < 0)
+ return sizeof(struct pt_regs);
+ else if (offset <= 32*4) /* gr[0..31] */
+ return offset * 2 + 4;
+ else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */
+ return offset + 32*4;
+ else if (offset < sizeof(struct pt_regs)/2 + 32*4)
+ return offset * 2 + 4 - 32*8;
+ else
+ return sizeof(struct pt_regs);
+}
+
+long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
+ compat_ulong_t addr, compat_ulong_t data)
+{
+ compat_uint_t tmp;
+ long ret = -EIO;
+
+ switch (request) {
+
+ case PTRACE_PEEKUSR:
+ if (addr & (sizeof(compat_uint_t)-1))
+ break;
+ addr = translate_usr_offset(addr);
+ if (addr >= sizeof(struct pt_regs))
+ break;
+
+ tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
+ ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
+ break;
+
+ /* Write the word at location addr in the USER area. This will need
+ to change when the kernel no longer saves all regs on a syscall.
+ FIXME. There is a problem at the moment in that r3-r18 are only
+ saved if the process is ptraced on syscall entry, and even then
+ those values are overwritten by actual register values on syscall
+ exit. */
+ case PTRACE_POKEUSR:
+ /* Some register values written here may be ignored in
+ * entry.S:syscall_restore_rfi; e.g. iaoq is written with
+ * r31/r31+4, and not with the values in pt_regs.
+ */
+ if (addr == PT_PSW) {
+ /* Since PT_PSW==0, it is valid for 32 bit processes
+ * under 64 bit kernels as well.
+ */
+ ret = arch_ptrace(child, request, addr, data);
+ } else {
+ if (addr & (sizeof(compat_uint_t)-1))
+ break;
+ addr = translate_usr_offset(addr);
+ if (addr >= sizeof(struct pt_regs))
+ break;
+ if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
+ /* Special case, fp regs are 64 bits anyway */
+ *(__u64 *) ((char *) task_regs(child) + addr) = data;
+ ret = 0;
+ }
+ else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
+ addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
+ addr == PT_SAR+4) {
+ /* Zero the top 32 bits */
+ *(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
+ *(__u32 *) ((char *) task_regs(child) + addr) = data;
+ ret = 0;
+ }
+ }
+ break;
+
+ default:
+ ret = compat_ptrace_request(child, request, addr, data);
+ break;
+ }
+
+ return ret;
+}
+#endif
+
+long do_syscall_trace_enter(struct pt_regs *regs)
+{
+ long ret = 0;
+
+ /* Do the secure computing check first. */
+ secure_computing_strict(regs->gr[20]);
+
+ if (test_thread_flag(TIF_SYSCALL_TRACE) &&
+ tracehook_report_syscall_entry(regs))
+ ret = -1L;
+
+#ifdef CONFIG_64BIT
+ if (!is_compat_task())
+ audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
+ regs->gr[24], regs->gr[23]);
+ else
+#endif
+ audit_syscall_entry(regs->gr[20] & 0xffffffff,
+ regs->gr[26] & 0xffffffff,
+ regs->gr[25] & 0xffffffff,
+ regs->gr[24] & 0xffffffff,
+ regs->gr[23] & 0xffffffff);
+
+ return ret ? : regs->gr[20];
+}
+
+void do_syscall_trace_exit(struct pt_regs *regs)
+{
+ int stepping = test_thread_flag(TIF_SINGLESTEP) ||
+ test_thread_flag(TIF_BLOCKSTEP);
+
+ audit_syscall_exit(regs);
+
+ if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
+ tracehook_report_syscall_exit(regs, stepping);
+}
Code Review / kvmfornfv.git / blobdiff