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linux/arch/powerpc/kernel/ptrace.c
Benjamin Herrenschmidt e17666ba48 [POWERPC] ptrace updates & new, better requests 
The powerpc ptrace interface is dodgy at best. We have defined our
"own" versions of GETREGS/SETREGS/GETFPREGS/SETFPREGS that strangely
take arguments in reverse order from other archs (in addition to having
different request numbers) and have subtle issue, like not accessing
all of the registers in their respective categories.

This patch moves the implementation of those to a separate function
in order to facilitate their deprecation in the future, and provides
new ptrace requests that mirror the x86 and sparc ones and use the
same numbers:

   PTRACE_GETREGS    : returns an entire pt_regs (the whole thing,
                       not only the 32 GPRs, though that doesn't
                       include the FPRs etc... There's a compat version
                       for 32 bits that returns a 32 bits compatible
                       pt_regs (44 uints)

   PTRACE_SETREGS    : sets an entire pt_regs (the whole thing,
                       not only the 32 GPRs, though that doesn't
                       include the FPRs etc... Some registers cannot be
                       written to and will just be dropped, this is the
                       same as with POKEUSR, that is anything above MQ
                       on 32 bits and CCR on 64 bits. There is a compat
                       version as well.

   PTRACE_GETFPREGS  : returns all the FP registers -including- the FPSCR
                       that is 33 doubles (regardless of 32/64 bits)

   PTRACE_SETFPREGS  : sets all the FP registers -including- the FPSCR
                       that is 33 doubles (regardless of 32/64 bits)

And two that only exist on 64 bits kernels:

   PTRACE_GETREGS64  : Same as PTRACE_GETREGS, except there is no compat
                       function, a 32 bits process will obtain the full 64
                       bits registers

   PTRACE_SETREGS64  : Same as PTRACE_SETREGS, except there is no compat
                       function, a 32 bits process will set the full 64
                       bits registers

The two later ones makes things easier to have a 32 bits debugger on a
64 bits program (or on a 32 bits program that uses the full 64 bits of
the GPRs, which is possible though has issues that will be fixed in a
later patch).

Finally, while at it, the patch removes a whole bunch of code duplication
between ptrace32.c and ptrace.c, in large part by having the former call
into the later for all requests that don't need any special "compat"
treatment.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-14 22:29:56 +10:00

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/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "arch/m68k/kernel/ptrace.c"
* Copyright (C) 1994 by Hamish Macdonald
* Taken from linux/kernel/ptrace.c and modified for M680x0.
* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
*
* Modified by Cort Dougan (cort@hq.fsmlabs.com)
* and Paul Mackerras (paulus@samba.org).
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file README.legal in the main directory of
* this archive for more details.
*/
#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/signal.h>
#include <linux/seccomp.h>
#include <linux/audit.h>
#ifdef CONFIG_PPC32
#include <linux/module.h>
#endif
#include <asm/uaccess.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#ifdef CONFIG_PPC64
#include "ptrace-ppc64.h"
#else
#include "ptrace-ppc32.h"
#endif
#include "ptrace-common.h"
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure single step bits etc are not set.
*/
void ptrace_disable(struct task_struct *child)
{
/* make sure the single step bit is not set. */
clear_single_step(child);
}
/*
* Here are the old "legacy" powerpc specific getregs/setregs ptrace calls,
* we mark them as obsolete now, they will be removed in a future version
*/
static long arch_ptrace_old(struct task_struct *child, long request, long addr,
long data)
{
int ret = -EPERM;
switch(request) {
case PPC_PTRACE_GETREGS: { /* Get GPRs 0 - 31. */
int i;
unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
unsigned long __user *tmp = (unsigned long __user *)addr;
for (i = 0; i < 32; i++) {
ret = put_user(*reg, tmp);
if (ret)
break;
reg++;
tmp++;
}
break;
}
case PPC_PTRACE_SETREGS: { /* Set GPRs 0 - 31. */
int i;
unsigned long *reg = &((unsigned long *)child->thread.regs)[0];
unsigned long __user *tmp = (unsigned long __user *)addr;
for (i = 0; i < 32; i++) {
ret = get_user(*reg, tmp);
if (ret)
break;
reg++;
tmp++;
}
break;
}
case PPC_PTRACE_GETFPREGS: { /* Get FPRs 0 - 31. */
flush_fp_to_thread(child);
ret = get_fpregs((void __user *)addr, child, 0);
break;
}
case PPC_PTRACE_SETFPREGS: { /* Get FPRs 0 - 31. */
flush_fp_to_thread(child);
ret = set_fpregs((void __user *)addr, child, 0);
break;
}
}
return ret;
}
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret = -EPERM;
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: {
unsigned long tmp;
int copied;
copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
ret = -EIO;
if (copied != sizeof(tmp))
break;
ret = put_user(tmp,(unsigned long __user *) data);
break;
}
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long index, tmp;
ret = -EIO;
/* convert to index and check */
#ifdef CONFIG_PPC32
index = (unsigned long) addr >> 2;
if ((addr & 3) || (index > PT_FPSCR)
|| (child->thread.regs == NULL))
#else
index = (unsigned long) addr >> 3;
if ((addr & 7) || (index > PT_FPSCR))
#endif
break;
#ifdef CONFIG_PPC32
CHECK_FULL_REGS(child->thread.regs);
#endif
if (index < PT_FPR0) {
tmp = get_reg(child, (int) index);
} else {
flush_fp_to_thread(child);
tmp = ((unsigned long *)child->thread.fpr)[index - PT_FPR0];
}
ret = put_user(tmp,(unsigned long __user *) data);
break;
}
/* If 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 = 0;
if (access_process_vm(child, addr, &data, sizeof(data), 1)
== sizeof(data))
break;
ret = -EIO;
break;
/* write the word at location addr in the USER area */
case PTRACE_POKEUSR: {
unsigned long index;
ret = -EIO;
/* convert to index and check */
#ifdef CONFIG_PPC32
index = (unsigned long) addr >> 2;
if ((addr & 3) || (index > PT_FPSCR)
|| (child->thread.regs == NULL))
#else
index = (unsigned long) addr >> 3;
if ((addr & 7) || (index > PT_FPSCR))
#endif
break;
#ifdef CONFIG_PPC32
CHECK_FULL_REGS(child->thread.regs);
#endif
if (index == PT_ORIG_R3)
break;
if (index < PT_FPR0) {
ret = put_reg(child, index, data);
} else {
flush_fp_to_thread(child);
((unsigned long *)child->thread.fpr)[index - PT_FPR0] = data;
ret = 0;
}
break;
}
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: { /* restart after signal. */
ret = -EIO;
if (!valid_signal(data))
break;
if (request == PTRACE_SYSCALL)
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
else
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
child->exit_code = data;
/* make sure the single step bit is not set. */
clear_single_step(child);
wake_up_process(child);
ret = 0;
break;
}
/*
* make the child exit. Best I can do is send it a sigkill.
* perhaps it should be put in the status that it wants to
* exit.
*/
case PTRACE_KILL: {
ret = 0;
if (child->exit_state == EXIT_ZOMBIE) /* already dead */
break;
child->exit_code = SIGKILL;
/* make sure the single step bit is not set. */
clear_single_step(child);
wake_up_process(child);
break;
}
case PTRACE_SINGLESTEP: { /* set the trap flag. */
ret = -EIO;
if (!valid_signal(data))
break;
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
set_single_step(child);
child->exit_code = data;
/* give it a chance to run. */
wake_up_process(child);
ret = 0;
break;
}
#ifdef CONFIG_PPC64
case PTRACE_GET_DEBUGREG: {
ret = -EINVAL;
/* We only support one DABR and no IABRS at the moment */
if (addr > 0)
break;
ret = put_user(child->thread.dabr,
(unsigned long __user *)data);
break;
}
case PTRACE_SET_DEBUGREG:
ret = ptrace_set_debugreg(child, addr, data);
break;
#endif
case PTRACE_DETACH:
ret = ptrace_detach(child, data);
break;
#ifdef CONFIG_PPC64
case PTRACE_GETREGS64:
#endif
case PTRACE_GETREGS: { /* Get all pt_regs from the child. */
int ui;
if (!access_ok(VERIFY_WRITE, (void __user *)data,
sizeof(struct pt_regs))) {
ret = -EIO;
break;
}
ret = 0;
for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
ret |= __put_user(get_reg(child, ui),
(unsigned long __user *) data);
data += sizeof(long);
}
break;
}
#ifdef CONFIG_PPC64
case PTRACE_SETREGS64:
#endif
case PTRACE_SETREGS: { /* Set all gp regs in the child. */
unsigned long tmp;
int ui;
if (!access_ok(VERIFY_READ, (void __user *)data,
sizeof(struct pt_regs))) {
ret = -EIO;
break;
}
ret = 0;
for (ui = 0; ui < PT_REGS_COUNT; ui ++) {
ret = __get_user(tmp, (unsigned long __user *) data);
if (ret)
break;
put_reg(child, ui, tmp);
data += sizeof(long);
}
break;
}
case PTRACE_GETFPREGS: { /* Get the child FPU state (FPR0...31 + FPSCR) */
flush_fp_to_thread(child);
ret = get_fpregs((void __user *)data, child, 1);
break;
}
case PTRACE_SETFPREGS: { /* Set the child FPU state (FPR0...31 + FPSCR) */
flush_fp_to_thread(child);
ret = set_fpregs((void __user *)data, child, 1);
break;
}
#ifdef CONFIG_ALTIVEC
case PTRACE_GETVRREGS:
/* Get the child altivec register state. */
flush_altivec_to_thread(child);
ret = get_vrregs((unsigned long __user *)data, child);
break;
case PTRACE_SETVRREGS:
/* Set the child altivec register state. */
flush_altivec_to_thread(child);
ret = set_vrregs(child, (unsigned long __user *)data);
break;
#endif
#ifdef CONFIG_SPE
case PTRACE_GETEVRREGS:
/* Get the child spe register state. */
if (child->thread.regs->msr & MSR_SPE)
giveup_spe(child);
ret = get_evrregs((unsigned long __user *)data, child);
break;
case PTRACE_SETEVRREGS:
/* Set the child spe register state. */
/* this is to clear the MSR_SPE bit to force a reload
* of register state from memory */
if (child->thread.regs->msr & MSR_SPE)
giveup_spe(child);
ret = set_evrregs(child, (unsigned long __user *)data);
break;
#endif
/* Old reverse args ptrace callss */
case PPC_PTRACE_GETREGS: /* Get GPRs 0 - 31. */
case PPC_PTRACE_SETREGS: /* Set GPRs 0 - 31. */
case PPC_PTRACE_GETFPREGS: /* Get FPRs 0 - 31. */
case PPC_PTRACE_SETFPREGS: /* Get FPRs 0 - 31. */
ret = arch_ptrace_old(child, request, addr, data);
break;
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
static void do_syscall_trace(void)
{
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
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;
}
}
void do_syscall_trace_enter(struct pt_regs *regs)
{
secure_computing(regs->gpr[0]);
if (test_thread_flag(TIF_SYSCALL_TRACE)
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
if (unlikely(current->audit_context)) {
#ifdef CONFIG_PPC64
if (!test_thread_flag(TIF_32BIT))
audit_syscall_entry(AUDIT_ARCH_PPC64,
regs->gpr[0],
regs->gpr[3], regs->gpr[4],
regs->gpr[5], regs->gpr[6]);
else
#endif
audit_syscall_entry(AUDIT_ARCH_PPC,
regs->gpr[0],
regs->gpr[3] & 0xffffffff,
regs->gpr[4] & 0xffffffff,
regs->gpr[5] & 0xffffffff,
regs->gpr[6] & 0xffffffff);
}
}
void do_syscall_trace_leave(struct pt_regs *regs)
{
if (unlikely(current->audit_context))
audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS,
regs->result);
if ((test_thread_flag(TIF_SYSCALL_TRACE)
|| test_thread_flag(TIF_SINGLESTEP))
&& (current->ptrace & PT_PTRACED))
do_syscall_trace();
}
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