370 lines
10 KiB
C
370 lines
10 KiB
C
/*
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* Kernel support for the ptrace() and syscall tracing interfaces.
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*
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* Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
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* Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
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* Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/errno.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/personality.h>
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#include <linux/security.h>
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#include <linux/compat.h>
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#include <linux/signal.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <asm/asm-offsets.h>
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/* PSW bits we allow the debugger to modify */
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#define USER_PSW_BITS (PSW_N | PSW_V | PSW_CB)
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#undef DEBUG_PTRACE
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#ifdef DEBUG_PTRACE
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#define DBG(x...) printk(x)
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#else
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#define DBG(x...)
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#endif
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#ifdef CONFIG_64BIT
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/* This function is needed to translate 32 bit pt_regs offsets in to
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* 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
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* will request offset 12 if it wants gr3, but the lower 32 bits of
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* the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
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* This code relies on a 32 bit pt_regs being comprised of 32 bit values
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* except for the fp registers which (a) are 64 bits, and (b) follow
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* the gr registers at the start of pt_regs. The 32 bit pt_regs should
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* be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
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* being 64 bit in both cases.
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*/
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static long translate_usr_offset(long offset)
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{
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if (offset < 0)
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return -1;
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else if (offset <= 32*4) /* gr[0..31] */
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return offset * 2 + 4;
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else if (offset <= 32*4+32*8) /* gr[0..31] + fr[0..31] */
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return offset + 32*4;
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else if (offset < sizeof(struct pt_regs)/2 + 32*4)
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return offset * 2 + 4 - 32*8;
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else
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return -1;
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}
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#endif
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/*
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* Called by kernel/ptrace.c when detaching..
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*
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* Make sure single step bits etc are not set.
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*/
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void ptrace_disable(struct task_struct *child)
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{
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/* make sure the trap bits are not set */
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pa_psw(child)->r = 0;
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pa_psw(child)->t = 0;
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pa_psw(child)->h = 0;
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pa_psw(child)->l = 0;
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}
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long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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{
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long ret;
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#ifdef DEBUG_PTRACE
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long oaddr=addr, odata=data;
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#endif
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switch (request) {
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case PTRACE_PEEKTEXT: /* read word at location addr. */
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case PTRACE_PEEKDATA: {
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#ifdef CONFIG_64BIT
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if (__is_compat_task(child)) {
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int copied;
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unsigned int tmp;
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addr &= 0xffffffffL;
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copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
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ret = -EIO;
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if (copied != sizeof(tmp))
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goto out_tsk;
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ret = put_user(tmp,(unsigned int *) data);
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DBG("sys_ptrace(PEEK%s, %d, %lx, %lx) returning %ld, data %x\n",
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request == PTRACE_PEEKTEXT ? "TEXT" : "DATA",
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pid, oaddr, odata, ret, tmp);
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}
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else
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#endif
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ret = generic_ptrace_peekdata(child, addr, data);
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goto out_tsk;
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}
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/* when I and D space are separate, this will have to be fixed. */
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case PTRACE_POKETEXT: /* write the word at location addr. */
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case PTRACE_POKEDATA:
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ret = 0;
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#ifdef CONFIG_64BIT
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if (__is_compat_task(child)) {
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unsigned int tmp = (unsigned int)data;
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DBG("sys_ptrace(POKE%s, %d, %lx, %lx)\n",
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request == PTRACE_POKETEXT ? "TEXT" : "DATA",
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pid, oaddr, odata);
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addr &= 0xffffffffL;
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if (access_process_vm(child, addr, &tmp, sizeof(tmp), 1) == sizeof(tmp))
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goto out_tsk;
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}
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else
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#endif
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{
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if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data))
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goto out_tsk;
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}
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ret = -EIO;
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goto out_tsk;
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/* Read the word at location addr in the USER area. For ptraced
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processes, the kernel saves all regs on a syscall. */
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case PTRACE_PEEKUSR: {
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ret = -EIO;
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#ifdef CONFIG_64BIT
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if (__is_compat_task(child)) {
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unsigned int tmp;
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if (addr & (sizeof(int)-1))
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goto out_tsk;
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if ((addr = translate_usr_offset(addr)) < 0)
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goto out_tsk;
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tmp = *(unsigned int *) ((char *) task_regs(child) + addr);
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ret = put_user(tmp, (unsigned int *) data);
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DBG("sys_ptrace(PEEKUSR, %d, %lx, %lx) returning %ld, addr %lx, data %x\n",
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pid, oaddr, odata, ret, addr, tmp);
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}
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else
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#endif
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{
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unsigned long tmp;
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if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs))
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goto out_tsk;
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tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
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ret = put_user(tmp, (unsigned long *) data);
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}
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goto out_tsk;
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}
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/* Write the word at location addr in the USER area. This will need
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to change when the kernel no longer saves all regs on a syscall.
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FIXME. There is a problem at the moment in that r3-r18 are only
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saved if the process is ptraced on syscall entry, and even then
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those values are overwritten by actual register values on syscall
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exit. */
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case PTRACE_POKEUSR:
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ret = -EIO;
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/* Some register values written here may be ignored in
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* entry.S:syscall_restore_rfi; e.g. iaoq is written with
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* r31/r31+4, and not with the values in pt_regs.
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*/
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/* PT_PSW=0, so this is valid for 32 bit processes under 64
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* bit kernels.
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*/
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if (addr == PT_PSW) {
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/* PT_PSW=0, so this is valid for 32 bit processes
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* under 64 bit kernels.
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*
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* Allow writing to Nullify, Divide-step-correction,
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* and carry/borrow bits.
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* BEWARE, if you set N, and then single step, it won't
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* stop on the nullified instruction.
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*/
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DBG("sys_ptrace(POKEUSR, %d, %lx, %lx)\n",
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pid, oaddr, odata);
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data &= USER_PSW_BITS;
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task_regs(child)->gr[0] &= ~USER_PSW_BITS;
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task_regs(child)->gr[0] |= data;
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ret = 0;
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goto out_tsk;
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}
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#ifdef CONFIG_64BIT
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if (__is_compat_task(child)) {
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if (addr & (sizeof(int)-1))
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goto out_tsk;
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if ((addr = translate_usr_offset(addr)) < 0)
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goto out_tsk;
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DBG("sys_ptrace(POKEUSR, %d, %lx, %lx) addr %lx\n",
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pid, oaddr, odata, addr);
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if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
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/* Special case, fp regs are 64 bits anyway */
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*(unsigned int *) ((char *) task_regs(child) + addr) = data;
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ret = 0;
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}
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else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
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addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
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addr == PT_SAR+4) {
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/* Zero the top 32 bits */
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*(unsigned int *) ((char *) task_regs(child) + addr - 4) = 0;
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*(unsigned int *) ((char *) task_regs(child) + addr) = data;
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ret = 0;
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}
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goto out_tsk;
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}
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else
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#endif
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{
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if ((addr & (sizeof(long)-1)) || (unsigned long) addr >= sizeof(struct pt_regs))
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goto out_tsk;
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if ((addr >= PT_GR1 && addr <= PT_GR31) ||
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addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
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(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
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addr == PT_SAR) {
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*(unsigned long *) ((char *) task_regs(child) + addr) = data;
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ret = 0;
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}
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goto out_tsk;
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}
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case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
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case PTRACE_CONT:
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ret = -EIO;
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DBG("sys_ptrace(%s)\n",
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request == PTRACE_SYSCALL ? "SYSCALL" : "CONT");
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if (!valid_signal(data))
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goto out_tsk;
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child->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP);
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if (request == PTRACE_SYSCALL) {
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set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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} else {
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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}
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child->exit_code = data;
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goto out_wake_notrap;
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case PTRACE_KILL:
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/*
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* make the child exit. Best I can do is send it a
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* sigkill. perhaps it should be put in the status
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* that it wants to exit.
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*/
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ret = 0;
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DBG("sys_ptrace(KILL)\n");
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if (child->exit_state == EXIT_ZOMBIE) /* already dead */
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goto out_tsk;
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child->exit_code = SIGKILL;
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goto out_wake_notrap;
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case PTRACE_SINGLEBLOCK:
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DBG("sys_ptrace(SINGLEBLOCK)\n");
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ret = -EIO;
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if (!valid_signal(data))
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goto out_tsk;
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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child->ptrace &= ~PT_SINGLESTEP;
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child->ptrace |= PT_BLOCKSTEP;
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child->exit_code = data;
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/* Enable taken branch trap. */
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pa_psw(child)->r = 0;
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pa_psw(child)->t = 1;
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pa_psw(child)->h = 0;
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pa_psw(child)->l = 0;
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goto out_wake;
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case PTRACE_SINGLESTEP:
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DBG("sys_ptrace(SINGLESTEP)\n");
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ret = -EIO;
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if (!valid_signal(data))
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goto out_tsk;
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clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
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child->ptrace &= ~PT_BLOCKSTEP;
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child->ptrace |= PT_SINGLESTEP;
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child->exit_code = data;
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if (pa_psw(child)->n) {
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struct siginfo si;
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/* Nullified, just crank over the queue. */
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task_regs(child)->iaoq[0] = task_regs(child)->iaoq[1];
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task_regs(child)->iasq[0] = task_regs(child)->iasq[1];
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task_regs(child)->iaoq[1] = task_regs(child)->iaoq[0] + 4;
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pa_psw(child)->n = 0;
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pa_psw(child)->x = 0;
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pa_psw(child)->y = 0;
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pa_psw(child)->z = 0;
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pa_psw(child)->b = 0;
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ptrace_disable(child);
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/* Don't wake up the child, but let the
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parent know something happened. */
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si.si_code = TRAP_TRACE;
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si.si_addr = (void __user *) (task_regs(child)->iaoq[0] & ~3);
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si.si_signo = SIGTRAP;
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si.si_errno = 0;
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force_sig_info(SIGTRAP, &si, child);
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//notify_parent(child, SIGCHLD);
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//ret = 0;
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goto out_wake;
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}
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/* Enable recovery counter traps. The recovery counter
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* itself will be set to zero on a task switch. If the
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* task is suspended on a syscall then the syscall return
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* path will overwrite the recovery counter with a suitable
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* value such that it traps once back in user space. We
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* disable interrupts in the childs PSW here also, to avoid
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* interrupts while the recovery counter is decrementing.
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*/
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pa_psw(child)->r = 1;
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pa_psw(child)->t = 0;
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pa_psw(child)->h = 0;
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pa_psw(child)->l = 0;
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/* give it a chance to run. */
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goto out_wake;
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case PTRACE_GETEVENTMSG:
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ret = put_user(child->ptrace_message, (unsigned int __user *) data);
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goto out_tsk;
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default:
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ret = ptrace_request(child, request, addr, data);
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goto out_tsk;
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}
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out_wake_notrap:
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ptrace_disable(child);
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out_wake:
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wake_up_process(child);
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ret = 0;
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out_tsk:
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DBG("arch_ptrace(%ld, %d, %lx, %lx) returning %ld\n",
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request, pid, oaddr, odata, ret);
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return ret;
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}
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void syscall_trace(void)
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{
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if (!test_thread_flag(TIF_SYSCALL_TRACE))
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return;
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if (!(current->ptrace & PT_PTRACED))
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return;
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ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
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? 0x80 : 0));
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/*
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* this isn't the same as continuing with a signal, but it will do
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* for normal use. strace only continues with a signal if the
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* stopping signal is not SIGTRAP. -brl
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*/
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if (current->exit_code) {
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send_sig(current->exit_code, current, 1);
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current->exit_code = 0;
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}
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}
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