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linux/arch/arm/kernel/ptrace.c

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/*
* linux/arch/arm/kernel/ptrace.c
*
* By Ross Biro 1/23/92
* edited by Linus Torvalds
* ARM modifications Copyright (C) 2000 Russell King
*
* 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
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/init.h>
#include <linux/signal.h>
#include <linux/uaccess.h>
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/traps.h>
#define REG_PC 15
#define REG_PSR 16
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
#if 0
/*
* Breakpoint SWI instruction: SWI &9F0001
*/
#define BREAKINST_ARM 0xef9f0001
#define BREAKINST_THUMB 0xdf00 /* fill this in later */
#else
/*
* New breakpoints - use an undefined instruction. The ARM architecture
* reference manual guarantees that the following instruction space
* will produce an undefined instruction exception on all CPUs:
*
* ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
* Thumb: 1101 1110 xxxx xxxx
*/
#define BREAKINST_ARM 0xe7f001f0
#define BREAKINST_THUMB 0xde01
#endif
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) \
{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
REG_OFFSET_NAME(r0),
REG_OFFSET_NAME(r1),
REG_OFFSET_NAME(r2),
REG_OFFSET_NAME(r3),
REG_OFFSET_NAME(r4),
REG_OFFSET_NAME(r5),
REG_OFFSET_NAME(r6),
REG_OFFSET_NAME(r7),
REG_OFFSET_NAME(r8),
REG_OFFSET_NAME(r9),
REG_OFFSET_NAME(r10),
REG_OFFSET_NAME(fp),
REG_OFFSET_NAME(ip),
REG_OFFSET_NAME(sp),
REG_OFFSET_NAME(lr),
REG_OFFSET_NAME(pc),
REG_OFFSET_NAME(cpsr),
REG_OFFSET_NAME(ORIG_r0),
REG_OFFSET_END,
};
/**
* regs_query_register_offset() - query register offset from its name
* @name: the name of a register
*
* regs_query_register_offset() returns the offset of a register in struct
* pt_regs from its name. If the name is invalid, this returns -EINVAL;
*/
int regs_query_register_offset(const char *name)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (!strcmp(roff->name, name))
return roff->offset;
return -EINVAL;
}
/**
* regs_query_register_name() - query register name from its offset
* @offset: the offset of a register in struct pt_regs.
*
* regs_query_register_name() returns the name of a register from its
* offset in struct pt_regs. If the @offset is invalid, this returns NULL;
*/
const char *regs_query_register_name(unsigned int offset)
{
const struct pt_regs_offset *roff;
for (roff = regoffset_table; roff->name != NULL; roff++)
if (roff->offset == offset)
return roff->name;
return NULL;
}
/**
* regs_within_kernel_stack() - check the address in the stack
* @regs: pt_regs which contains kernel stack pointer.
* @addr: address which is checked.
*
* regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
* If @addr is within the kernel stack, it returns true. If not, returns false.
*/
bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
{
return ((addr & ~(THREAD_SIZE - 1)) ==
(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
}
/**
* regs_get_kernel_stack_nth() - get Nth entry of the stack
* @regs: pt_regs which contains kernel stack pointer.
* @n: stack entry number.
*
* regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
* is specified by @regs. If the @n th entry is NOT in the kernel stack,
* this returns 0.
*/
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
addr += n;
if (regs_within_kernel_stack(regs, (unsigned long)addr))
return *addr;
else
return 0;
}
/*
* this routine will get a word off of the processes privileged stack.
* the offset is how far from the base addr as stored in the THREAD.
* this routine assumes that all the privileged stacks are in our
* data space.
*/
static inline long get_user_reg(struct task_struct *task, int offset)
{
return task_pt_regs(task)->uregs[offset];
}
/*
* this routine will put a word on the processes privileged stack.
* the offset is how far from the base addr as stored in the THREAD.
* this routine assumes that all the privileged stacks are in our
* data space.
*/
static inline int
put_user_reg(struct task_struct *task, int offset, long data)
{
struct pt_regs newregs, *regs = task_pt_regs(task);
int ret = -EINVAL;
newregs = *regs;
newregs.uregs[offset] = data;
if (valid_user_regs(&newregs)) {
regs->uregs[offset] = data;
ret = 0;
}
return ret;
}
/*
* Called by kernel/ptrace.c when detaching..
*/
void ptrace_disable(struct task_struct *child)
{
/* Nothing to do. */
}
/*
* Handle hitting a breakpoint.
*/
void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
{
siginfo_t info;
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void __user *)instruction_pointer(regs);
force_sig_info(SIGTRAP, &info, tsk);
}
static int break_trap(struct pt_regs *regs, unsigned int instr)
{
ptrace_break(current, regs);
return 0;
}
static struct undef_hook arm_break_hook = {
.instr_mask = 0x0fffffff,
.instr_val = 0x07f001f0,
.cpsr_mask = PSR_T_BIT,
.cpsr_val = 0,
.fn = break_trap,
};
static struct undef_hook thumb_break_hook = {
.instr_mask = 0xffff,
.instr_val = 0xde01,
.cpsr_mask = PSR_T_BIT,
.cpsr_val = PSR_T_BIT,
.fn = break_trap,
};
static int thumb2_break_trap(struct pt_regs *regs, unsigned int instr)
{
unsigned int instr2;
void __user *pc;
/* Check the second half of the instruction. */
pc = (void __user *)(instruction_pointer(regs) + 2);
if (processor_mode(regs) == SVC_MODE) {
instr2 = *(u16 *) pc;
} else {
get_user(instr2, (u16 __user *)pc);
}
if (instr2 == 0xa000) {
ptrace_break(current, regs);
return 0;
} else {
return 1;
}
}
static struct undef_hook thumb2_break_hook = {
.instr_mask = 0xffff,
.instr_val = 0xf7f0,
.cpsr_mask = PSR_T_BIT,
.cpsr_val = PSR_T_BIT,
.fn = thumb2_break_trap,
};
static int __init ptrace_break_init(void)
{
register_undef_hook(&arm_break_hook);
register_undef_hook(&thumb_break_hook);
register_undef_hook(&thumb2_break_hook);
return 0;
}
core_initcall(ptrace_break_init);
/*
* 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 __user *ret)
{
unsigned long tmp;
if (off & 3 || off >= sizeof(struct user))
return -EIO;
tmp = 0;
if (off == PT_TEXT_ADDR)
tmp = tsk->mm->start_code;
else if (off == PT_DATA_ADDR)
tmp = tsk->mm->start_data;
else if (off == PT_TEXT_END_ADDR)
tmp = tsk->mm->end_code;
else 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 __user *uregs)
{
struct pt_regs *regs = task_pt_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 __user *uregs)
{
struct pt_regs newregs;
int ret;
ret = -EFAULT;
if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
struct pt_regs *regs = task_pt_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 __user *ufp)
{
return copy_to_user(ufp, &task_thread_info(tsk)->fpstate,
sizeof(struct user_fp)) ? -EFAULT : 0;
}
/*
* Set the child FPU state.
*/
static int ptrace_setfpregs(struct task_struct *tsk, void __user *ufp)
{
struct thread_info *thread = task_thread_info(tsk);
thread->used_cp[1] = thread->used_cp[2] = 1;
return copy_from_user(&thread->fpstate, ufp,
sizeof(struct user_fp)) ? -EFAULT : 0;
}
#ifdef CONFIG_IWMMXT
/*
* Get the child iWMMXt state.
*/
static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
{
struct thread_info *thread = task_thread_info(tsk);
if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
return -ENODATA;
iwmmxt_task_disable(thread); /* force it to ram */
return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
? -EFAULT : 0;
}
/*
* Set the child iWMMXt state.
*/
static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
{
struct thread_info *thread = task_thread_info(tsk);
if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
return -EACCES;
iwmmxt_task_release(thread); /* force a reload */
return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
? -EFAULT : 0;
}
#endif
#ifdef CONFIG_CRUNCH
/*
* Get the child Crunch state.
*/
static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
{
struct thread_info *thread = task_thread_info(tsk);
crunch_task_disable(thread); /* force it to ram */
return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
? -EFAULT : 0;
}
/*
* Set the child Crunch state.
*/
static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
{
struct thread_info *thread = task_thread_info(tsk);
crunch_task_release(thread); /* force a reload */
return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
? -EFAULT : 0;
}
#endif
#ifdef CONFIG_VFP
/*
* Get the child VFP state.
*/
static int ptrace_getvfpregs(struct task_struct *tsk, void __user *data)
{
struct thread_info *thread = task_thread_info(tsk);
union vfp_state *vfp = &thread->vfpstate;
struct user_vfp __user *ufp = data;
vfp_sync_hwstate(thread);
/* copy the floating point registers */
if (copy_to_user(&ufp->fpregs, &vfp->hard.fpregs,
sizeof(vfp->hard.fpregs)))
return -EFAULT;
/* copy the status and control register */
if (put_user(vfp->hard.fpscr, &ufp->fpscr))
return -EFAULT;
return 0;
}
/*
* Set the child VFP state.
*/
static int ptrace_setvfpregs(struct task_struct *tsk, void __user *data)
{
struct thread_info *thread = task_thread_info(tsk);
union vfp_state *vfp = &thread->vfpstate;
struct user_vfp __user *ufp = data;
vfp_sync_hwstate(thread);
/* copy the floating point registers */
if (copy_from_user(&vfp->hard.fpregs, &ufp->fpregs,
sizeof(vfp->hard.fpregs)))
return -EFAULT;
/* copy the status and control register */
if (get_user(vfp->hard.fpscr, &ufp->fpscr))
return -EFAULT;
vfp_flush_hwstate(thread);
return 0;
}
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/*
* Convert a virtual register number into an index for a thread_info
* breakpoint array. Breakpoints are identified using positive numbers
* whilst watchpoints are negative. The registers are laid out as pairs
* of (address, control), each pair mapping to a unique hw_breakpoint struct.
* Register 0 is reserved for describing resource information.
*/
static int ptrace_hbp_num_to_idx(long num)
{
if (num < 0)
num = (ARM_MAX_BRP << 1) - num;
return (num - 1) >> 1;
}
/*
* Returns the virtual register number for the address of the
* breakpoint at index idx.
*/
static long ptrace_hbp_idx_to_num(int idx)
{
long mid = ARM_MAX_BRP << 1;
long num = (idx << 1) + 1;
return num > mid ? mid - num : num;
}
/*
* Handle hitting a HW-breakpoint.
*/
static void ptrace_hbptriggered(struct perf_event *bp, int unused,
struct perf_sample_data *data,
struct pt_regs *regs)
{
struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
long num;
int i;
siginfo_t info;
for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
if (current->thread.debug.hbp[i] == bp)
break;
num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
info.si_signo = SIGTRAP;
info.si_errno = (int)num;
info.si_code = TRAP_HWBKPT;
info.si_addr = (void __user *)(bkpt->trigger);
force_sig_info(SIGTRAP, &info, current);
}
/*
* Set ptrace breakpoint pointers to zero for this task.
* This is required in order to prevent child processes from unregistering
* breakpoints held by their parent.
*/
void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
{
memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
}
/*
* Unregister breakpoints from this task and reset the pointers in
* the thread_struct.
*/
void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
{
int i;
struct thread_struct *t = &tsk->thread;
for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
if (t->debug.hbp[i]) {
unregister_hw_breakpoint(t->debug.hbp[i]);
t->debug.hbp[i] = NULL;
}
}
}
static u32 ptrace_get_hbp_resource_info(void)
{
u8 num_brps, num_wrps, debug_arch, wp_len;
u32 reg = 0;
num_brps = hw_breakpoint_slots(TYPE_INST);
num_wrps = hw_breakpoint_slots(TYPE_DATA);
debug_arch = arch_get_debug_arch();
wp_len = arch_get_max_wp_len();
reg |= debug_arch;
reg <<= 8;
reg |= wp_len;
reg <<= 8;
reg |= num_wrps;
reg <<= 8;
reg |= num_brps;
return reg;
}
static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
{
struct perf_event_attr attr;
ptrace_breakpoint_init(&attr);
/* Initialise fields to sane defaults. */
attr.bp_addr = 0;
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = type;
attr.disabled = 1;
return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, tsk);
}
static int ptrace_gethbpregs(struct task_struct *tsk, long num,
unsigned long __user *data)
{
u32 reg;
int idx, ret = 0;
struct perf_event *bp;
struct arch_hw_breakpoint_ctrl arch_ctrl;
if (num == 0) {
reg = ptrace_get_hbp_resource_info();
} else {
idx = ptrace_hbp_num_to_idx(num);
if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
ret = -EINVAL;
goto out;
}
bp = tsk->thread.debug.hbp[idx];
if (!bp) {
reg = 0;
goto put;
}
arch_ctrl = counter_arch_bp(bp)->ctrl;
/*
* Fix up the len because we may have adjusted it
* to compensate for an unaligned address.
*/
while (!(arch_ctrl.len & 0x1))
arch_ctrl.len >>= 1;
if (num & 0x1)
reg = bp->attr.bp_addr;
else
reg = encode_ctrl_reg(arch_ctrl);
}
put:
if (put_user(reg, data))
ret = -EFAULT;
out:
return ret;
}
static int ptrace_sethbpregs(struct task_struct *tsk, long num,
unsigned long __user *data)
{
int idx, gen_len, gen_type, implied_type, ret = 0;
u32 user_val;
struct perf_event *bp;
struct arch_hw_breakpoint_ctrl ctrl;
struct perf_event_attr attr;
if (num == 0)
goto out;
else if (num < 0)
implied_type = HW_BREAKPOINT_RW;
else
implied_type = HW_BREAKPOINT_X;
idx = ptrace_hbp_num_to_idx(num);
if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
ret = -EINVAL;
goto out;
}
if (get_user(user_val, data)) {
ret = -EFAULT;
goto out;
}
bp = tsk->thread.debug.hbp[idx];
if (!bp) {
bp = ptrace_hbp_create(tsk, implied_type);
if (IS_ERR(bp)) {
ret = PTR_ERR(bp);
goto out;
}
tsk->thread.debug.hbp[idx] = bp;
}
attr = bp->attr;
if (num & 0x1) {
/* Address */
attr.bp_addr = user_val;
} else {
/* Control */
decode_ctrl_reg(user_val, &ctrl);
ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
if (ret)
goto out;
if ((gen_type & implied_type) != gen_type) {
ret = -EINVAL;
goto out;
}
attr.bp_len = gen_len;
attr.bp_type = gen_type;
attr.disabled = !ctrl.enabled;
}
ret = modify_user_hw_breakpoint(bp, &attr);
out:
return ret;
}
#endif
long arch_ptrace(struct task_struct *child, long request,
unsigned long addr, unsigned long data)
{
int ret;
unsigned long __user *datap = (unsigned long __user *) data;
switch (request) {
case PTRACE_PEEKUSR:
ret = ptrace_read_user(child, addr, datap);
break;
case PTRACE_POKEUSR:
ret = ptrace_write_user(child, addr, data);
break;
case PTRACE_GETREGS:
ret = ptrace_getregs(child, datap);
break;
case PTRACE_SETREGS:
ret = ptrace_setregs(child, datap);
break;
case PTRACE_GETFPREGS:
ret = ptrace_getfpregs(child, datap);
break;
case PTRACE_SETFPREGS:
ret = ptrace_setfpregs(child, datap);
break;
#ifdef CONFIG_IWMMXT
case PTRACE_GETWMMXREGS:
ret = ptrace_getwmmxregs(child, datap);
break;
case PTRACE_SETWMMXREGS:
ret = ptrace_setwmmxregs(child, datap);
break;
#endif
case PTRACE_GET_THREAD_AREA:
ret = put_user(task_thread_info(child)->tp_value,
datap);
break;
case PTRACE_SET_SYSCALL:
task_thread_info(child)->syscall = data;
ret = 0;
break;
#ifdef CONFIG_CRUNCH
case PTRACE_GETCRUNCHREGS:
ret = ptrace_getcrunchregs(child, datap);
break;
case PTRACE_SETCRUNCHREGS:
ret = ptrace_setcrunchregs(child, datap);
break;
#endif
#ifdef CONFIG_VFP
case PTRACE_GETVFPREGS:
ret = ptrace_getvfpregs(child, datap);
break;
case PTRACE_SETVFPREGS:
ret = ptrace_setvfpregs(child, datap);
break;
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
case PTRACE_GETHBPREGS:
ret = ptrace_gethbpregs(child, addr,
(unsigned long __user *)data);
break;
case PTRACE_SETHBPREGS:
ret = ptrace_sethbpregs(child, addr,
(unsigned long __user *)data);
break;
#endif
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
{
unsigned long ip;
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return scno;
if (!(current->ptrace & PT_PTRACED))
return scno;
/*
* Save IP. IP is used to denote syscall entry/exit:
* IP = 0 -> entry, = 1 -> exit
*/
ip = regs->ARM_ip;
regs->ARM_ip = why;
current_thread_info()->syscall = scno;
/* 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;
}
regs->ARM_ip = ip;
return current_thread_info()->syscall;
}
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