Commit 42fe00e8 authored by Russell King's avatar Russell King

[ARM] ptrace cleanups.

The major points are:
- Move ptrace code from traps.c into ptrace.c so it's all in one place.
- Correct get_user_regs() to allow for the 8 byte offset.
- Fix missing ptrace_cancel_bpt() call which could miss some
  single stepping steps.
(other small pages; for details see individual file notes)
parent f0df3384
...@@ -40,12 +40,17 @@ ...@@ -40,12 +40,17 @@
* Get the address of the live pt_regs for the specified task. * Get the address of the live pt_regs for the specified task.
* These are saved onto the top kernel stack when the process * These are saved onto the top kernel stack when the process
* is not running. * is not running.
*
* Note: if a user thread is execve'd from kernel space, the
* kernel stack will not be empty on entry to the kernel, so
* ptracing these tasks will fail.
*/ */
static inline struct pt_regs * static inline struct pt_regs *
get_user_regs(struct task_struct *task) get_user_regs(struct task_struct *task)
{ {
return (struct pt_regs *) return (struct pt_regs *)
((unsigned long)task->thread_info + 8192 - sizeof(struct pt_regs)); ((unsigned long)task->thread_info + THREAD_SIZE -
8 - sizeof(struct pt_regs));
} }
/* /*
...@@ -54,7 +59,7 @@ get_user_regs(struct task_struct *task) ...@@ -54,7 +59,7 @@ get_user_regs(struct task_struct *task)
* this routine assumes that all the privileged stacks are in our * this routine assumes that all the privileged stacks are in our
* data space. * data space.
*/ */
static inline long get_stack_long(struct task_struct *task, int offset) static inline long get_user_reg(struct task_struct *task, int offset)
{ {
return get_user_regs(task)->uregs[offset]; return get_user_regs(task)->uregs[offset];
} }
...@@ -66,7 +71,7 @@ static inline long get_stack_long(struct task_struct *task, int offset) ...@@ -66,7 +71,7 @@ static inline long get_stack_long(struct task_struct *task, int offset)
* data space. * data space.
*/ */
static inline int static inline int
put_stack_long(struct task_struct *task, int offset, long data) put_user_reg(struct task_struct *task, int offset, long data)
{ {
struct pt_regs newregs, *regs = get_user_regs(task); struct pt_regs newregs, *regs = get_user_regs(task);
int ret = -EINVAL; int ret = -EINVAL;
...@@ -111,7 +116,7 @@ ptrace_getrn(struct task_struct *child, unsigned long insn) ...@@ -111,7 +116,7 @@ ptrace_getrn(struct task_struct *child, unsigned long insn)
unsigned int reg = (insn >> 16) & 15; unsigned int reg = (insn >> 16) & 15;
unsigned long val; unsigned long val;
val = get_stack_long(child, reg); val = get_user_reg(child, reg);
if (reg == 15) if (reg == 15)
val = pc_pointer(val + 8); val = pc_pointer(val + 8);
...@@ -133,10 +138,10 @@ ptrace_getaluop2(struct task_struct *child, unsigned long insn) ...@@ -133,10 +138,10 @@ ptrace_getaluop2(struct task_struct *child, unsigned long insn)
shift = (insn >> 8) & 15; shift = (insn >> 8) & 15;
type = 3; type = 3;
} else { } else {
val = get_stack_long (child, insn & 15); val = get_user_reg (child, insn & 15);
if (insn & (1 << 4)) if (insn & (1 << 4))
shift = (int)get_stack_long (child, (insn >> 8) & 15); shift = (int)get_user_reg (child, (insn >> 8) & 15);
else else
shift = (insn >> 7) & 31; shift = (insn >> 7) & 31;
...@@ -166,7 +171,7 @@ ptrace_getldrop2(struct task_struct *child, unsigned long insn) ...@@ -166,7 +171,7 @@ ptrace_getldrop2(struct task_struct *child, unsigned long insn)
int shift; int shift;
int type; int type;
val = get_stack_long(child, insn & 15); val = get_user_reg(child, insn & 15);
shift = (insn >> 7) & 31; shift = (insn >> 7) & 31;
type = (insn >> 5) & 3; type = (insn >> 5) & 3;
...@@ -215,7 +220,7 @@ get_branch_address(struct task_struct *child, unsigned long pc, unsigned long in ...@@ -215,7 +220,7 @@ get_branch_address(struct task_struct *child, unsigned long pc, unsigned long in
aluop1 = ptrace_getrn(child, insn); aluop1 = ptrace_getrn(child, insn);
aluop2 = ptrace_getaluop2(child, insn); aluop2 = ptrace_getaluop2(child, insn);
ccbit = get_stack_long(child, REG_PSR) & PSR_C_BIT ? 1 : 0; ccbit = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;
switch (insn & OP_MASK) { switch (insn & OP_MASK) {
case OP_AND: alt = aluop1 & aluop2; break; case OP_AND: alt = aluop1 & aluop2; break;
...@@ -270,13 +275,7 @@ get_branch_address(struct task_struct *child, unsigned long pc, unsigned long in ...@@ -270,13 +275,7 @@ get_branch_address(struct task_struct *child, unsigned long pc, unsigned long in
unsigned int nr_regs; unsigned int nr_regs;
if (insn & (1 << 23)) { if (insn & (1 << 23)) {
nr_regs = insn & 65535; nr_regs = hweight16(insn & 65535) << 2;
nr_regs = (nr_regs & 0x5555) + ((nr_regs & 0xaaaa) >> 1);
nr_regs = (nr_regs & 0x3333) + ((nr_regs & 0xcccc) >> 2);
nr_regs = (nr_regs & 0x0707) + ((nr_regs & 0x7070) >> 4);
nr_regs = (nr_regs & 0x000f) + ((nr_regs & 0x0f00) >> 8);
nr_regs <<= 2;
if (!(insn & (1 << 24))) if (!(insn & (1 << 24)))
nr_regs -= 4; nr_regs -= 4;
...@@ -348,6 +347,11 @@ int ptrace_set_bpt(struct task_struct *child) ...@@ -348,6 +347,11 @@ int ptrace_set_bpt(struct task_struct *child)
regs = get_user_regs(child); regs = get_user_regs(child);
pc = instruction_pointer(regs); pc = instruction_pointer(regs);
if (thumb_mode(regs)) {
printk(KERN_WARNING "ptrace: can't handle thumb mode\n");
return -EINVAL;
}
res = read_tsk_long(child, pc, &insn); res = read_tsk_long(child, pc, &insn);
if (!res) { if (!res) {
struct debug_info *dbg = &child->thread.debug; struct debug_info *dbg = &child->thread.debug;
...@@ -411,6 +415,118 @@ void ptrace_disable(struct task_struct *child) ...@@ -411,6 +415,118 @@ void ptrace_disable(struct task_struct *child)
__ptrace_cancel_bpt(child); __ptrace_cancel_bpt(child);
} }
/*
* Handle hitting a breakpoint.
*/
void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
{
siginfo_t info;
/*
* The PC is always left pointing at the next instruction. Fix this.
*/
regs->ARM_pc -= 4;
if (tsk->thread.debug.nsaved == 0)
printk(KERN_ERR "ptrace: bogus breakpoint trap\n");
__ptrace_cancel_bpt(tsk);
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void *)instruction_pointer(regs) -
(thumb_mode(regs) ? 2 : 4);
force_sig_info(SIGTRAP, &info, tsk);
}
/*
* Read the word at offset "off" into the "struct user". We
* actually access the pt_regs stored on the kernel stack.
*/
static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
unsigned long *ret)
{
unsigned long tmp;
if (off & 3 || off >= sizeof(struct user))
return -EIO;
tmp = 0;
if (off < sizeof(struct pt_regs))
tmp = get_user_reg(tsk, off >> 2);
return put_user(tmp, ret);
}
/*
* Write the word at offset "off" into "struct user". We
* actually access the pt_regs stored on the kernel stack.
*/
static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
unsigned long val)
{
if (off & 3 || off >= sizeof(struct user))
return -EIO;
if (off >= sizeof(struct pt_regs))
return 0;
return put_user_reg(tsk, off >> 2, val);
}
/*
* Get all user integer registers.
*/
static int ptrace_getregs(struct task_struct *tsk, void *uregs)
{
struct pt_regs *regs = get_user_regs(tsk);
return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
}
/*
* Set all user integer registers.
*/
static int ptrace_setregs(struct task_struct *tsk, void *uregs)
{
struct pt_regs newregs;
int ret;
ret = -EFAULT;
if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
struct pt_regs *regs = get_user_regs(tsk);
ret = -EINVAL;
if (valid_user_regs(&newregs)) {
*regs = newregs;
ret = 0;
}
}
return ret;
}
/*
* Get the child FPU state.
*/
static int ptrace_getfpregs(struct task_struct *tsk, void *ufp)
{
return copy_to_user(ufp, &tsk->thread_info->fpstate,
sizeof(struct user_fp)) ? -EFAULT : 0;
}
/*
* Set the child FPU state.
*/
static int ptrace_setfpregs(struct task_struct *tsk, void *ufp)
{
tsk->used_math = 1;
return copy_from_user(&tsk->thread_info->fpstate, ufp,
sizeof(struct user_fp)) ? -EFAULT : 0;
}
static int do_ptrace(int request, struct task_struct *child, long addr, long data) static int do_ptrace(int request, struct task_struct *child, long addr, long data)
{ {
unsigned long tmp; unsigned long tmp;
...@@ -427,18 +543,8 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat ...@@ -427,18 +543,8 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat
ret = put_user(tmp, (unsigned long *) data); ret = put_user(tmp, (unsigned long *) data);
break; break;
/*
* read the word at location "addr" in the user registers.
*/
case PTRACE_PEEKUSR: case PTRACE_PEEKUSR:
ret = -EIO; ret = ptrace_read_user(child, addr, (unsigned long *)data);
if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
break;
tmp = 0; /* Default return condition */
if (addr < sizeof(struct pt_regs))
tmp = get_stack_long(child, (int)addr >> 2);
ret = put_user(tmp, (unsigned long *)data);
break; break;
/* /*
...@@ -449,16 +555,8 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat ...@@ -449,16 +555,8 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat
ret = write_tsk_long(child, addr, data); ret = write_tsk_long(child, addr, data);
break; break;
/*
* write the word at location addr in the user registers.
*/
case PTRACE_POKEUSR: case PTRACE_POKEUSR:
ret = -EIO; ret = ptrace_write_user(child, addr, data);
if ((addr & 3) || addr < 0 || addr >= sizeof(struct user))
break;
if (addr < sizeof(struct pt_regs))
ret = put_stack_long(child, (int)addr >> 2, data);
break; break;
/* /*
...@@ -486,14 +584,12 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat ...@@ -486,14 +584,12 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat
* exit. * exit.
*/ */
case PTRACE_KILL: case PTRACE_KILL:
/* already dead */
ret = 0;
if (child->state == TASK_ZOMBIE)
break;
child->exit_code = SIGKILL;
/* make sure single-step breakpoint is gone. */ /* make sure single-step breakpoint is gone. */
__ptrace_cancel_bpt(child); __ptrace_cancel_bpt(child);
if (child->state != TASK_ZOMBIE) {
child->exit_code = SIGKILL;
wake_up_process(child); wake_up_process(child);
}
ret = 0; ret = 0;
break; break;
...@@ -512,71 +608,32 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat ...@@ -512,71 +608,32 @@ static int do_ptrace(int request, struct task_struct *child, long addr, long dat
ret = 0; ret = 0;
break; break;
/*
* detach a process that was attached.
*/
case PTRACE_DETACH: case PTRACE_DETACH:
ret = ptrace_detach(child, data); ret = ptrace_detach(child, data);
break; break;
/* case PTRACE_GETREGS:
* Get all gp regs from the child. ret = ptrace_getregs(child, (void *)data);
*/
case PTRACE_GETREGS: {
struct pt_regs *regs = get_user_regs(child);
ret = 0;
if (copy_to_user((void *)data, regs,
sizeof(struct pt_regs)))
ret = -EFAULT;
break; break;
}
/*
* Set all gp regs in the child.
*/
case PTRACE_SETREGS: {
struct pt_regs newregs;
ret = -EFAULT; case PTRACE_SETREGS:
if (copy_from_user(&newregs, (void *)data, ret = ptrace_setregs(child, (void *)data);
sizeof(struct pt_regs)) == 0) {
struct pt_regs *regs = get_user_regs(child);
ret = -EINVAL;
if (valid_user_regs(&newregs)) {
*regs = newregs;
ret = 0;
}
}
break; break;
}
/*
* Get the child FPU state.
*/
case PTRACE_GETFPREGS: case PTRACE_GETFPREGS:
ret = -EIO; ret = ptrace_getfpregs(child, (void *)data);
if (!access_ok(VERIFY_WRITE, (void *)data, sizeof(struct user_fp)))
break;
/* we should check child->used_math here */
ret = __copy_to_user((void *)data, &child->thread_info->fpstate,
sizeof(struct user_fp)) ? -EFAULT : 0;
break; break;
/*
* Set the child FPU state.
*/
case PTRACE_SETFPREGS: case PTRACE_SETFPREGS:
ret = -EIO; ret = ptrace_setfpregs(child, (void *)data);
if (!access_ok(VERIFY_READ, (void *)data, sizeof(struct user_fp)))
break; break;
child->used_math = 1; case PTRACE_SETOPTIONS:
ret = __copy_from_user(&child->thread_info->fpstate, (void *)data, if (data & PTRACE_O_TRACESYSGOOD)
sizeof(struct user_fp)) ? -EFAULT : 0; child->ptrace |= PT_TRACESYSGOOD;
else
child->ptrace &= ~PT_TRACESYSGOOD;
ret = 0;
break; break;
default: default:
......
/* /*
* linux/arch/arm/kernel/ptrace.h * linux/arch/arm/kernel/ptrace.h
* *
* Copyright (C) 2000 Russell King * Copyright (C) 2000-2002 Russell King
* *
* This program is free software; you can redistribute it and/or modify * This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as * it under the terms of the GNU General Public License version 2 as
...@@ -9,6 +9,7 @@ ...@@ -9,6 +9,7 @@
*/ */
extern void __ptrace_cancel_bpt(struct task_struct *); extern void __ptrace_cancel_bpt(struct task_struct *);
extern int ptrace_set_bpt(struct task_struct *); extern int ptrace_set_bpt(struct task_struct *);
extern void ptrace_break(struct task_struct *, struct pt_regs *);
/* /*
* Clear a breakpoint, if one exists. * Clear a breakpoint, if one exists.
......
/* /*
* linux/arch/arm/kernel/signal.c * linux/arch/arm/kernel/signal.c
* *
* Copyright (C) 1995-2001 Russell King * Copyright (C) 1995-2002 Russell King
* *
* This program is free software; you can redistribute it and/or modify * This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as * it under the terms of the GNU General Public License version 2 as
...@@ -17,15 +17,15 @@ ...@@ -17,15 +17,15 @@
#include <linux/signal.h> #include <linux/signal.h>
#include <linux/wait.h> #include <linux/wait.h>
#include <linux/ptrace.h> #include <linux/ptrace.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/personality.h> #include <linux/personality.h>
#include <linux/tty.h> #include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/elf.h> #include <linux/elf.h>
#include <asm/pgalloc.h> #include <asm/pgalloc.h>
#include <asm/ucontext.h> #include <asm/ucontext.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
#include <asm/unistd.h>
#include "ptrace.h" #include "ptrace.h"
...@@ -49,7 +49,7 @@ static const unsigned long retcodes[4] = { ...@@ -49,7 +49,7 @@ static const unsigned long retcodes[4] = {
SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
}; };
asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
/* /*
* atomically swap in the new signal mask, and wait for a signal. * atomically swap in the new signal mask, and wait for a signal.
...@@ -501,7 +501,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka, ...@@ -501,7 +501,7 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
* the kernel can handle, and then we build all the user-level signal handling * the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that. * stack-frames in one go after that.
*/ */
int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
{ {
struct k_sigaction *ka; struct k_sigaction *ka;
siginfo_t info; siginfo_t info;
...@@ -516,9 +516,6 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) ...@@ -516,9 +516,6 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
if (!user_mode(regs)) if (!user_mode(regs))
return 0; return 0;
if (!oldset)
oldset = &current->blocked;
single_stepping = ptrace_cancel_bpt(current); single_stepping = ptrace_cancel_bpt(current);
for (;;) { for (;;) {
...@@ -598,6 +595,7 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) ...@@ -598,6 +595,7 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
notify_parent(current, SIGCHLD); notify_parent(current, SIGCHLD);
schedule(); schedule();
single_stepping |= ptrace_cancel_bpt(current);
continue; continue;
} }
...@@ -655,5 +653,5 @@ asmlinkage void ...@@ -655,5 +653,5 @@ asmlinkage void
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall)
{ {
if (thread_flags & _TIF_SIGPENDING) if (thread_flags & _TIF_SIGPENDING)
do_signal(NULL, regs, syscall); do_signal(&current->blocked, regs, syscall);
} }
...@@ -372,20 +372,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) ...@@ -372,20 +372,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
return 0; return 0;
case NR(breakpoint): /* SWI BREAK_POINT */ case NR(breakpoint): /* SWI BREAK_POINT */
/* ptrace_break(current, regs);
* The PC is always left pointing at the next
* instruction. Fix this.
*/
regs->ARM_pc -= 4;
__ptrace_cancel_bpt(current);
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void *)instruction_pointer(regs) -
(thumb_mode(regs) ? 2 : 4);
force_sig_info(SIGTRAP, &info, current);
return regs->ARM_r0; return regs->ARM_r0;
#ifdef CONFIG_CPU_32 #ifdef CONFIG_CPU_32
......
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