Linux-2.6.33.2/arch/x86/kernel/ptrace.c
/* By Ross Biro 1/23/92 */
/*
* Pentium III FXSR, SSE support
* Gareth Hughes <gareth@valinux.com>, May 2000
*
* BTS tracing
* Markus Metzger <markus.t.metzger@intel.com>, Dec 2007
*/
#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/regset.h>
#include <linux/tracehook.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/signal.h>
#include <linux/workqueue.h>
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/debugreg.h>
#include <asm/ldt.h>
#include <asm/desc.h>
#include <asm/prctl.h>
#include <asm/proto.h>
#include <asm/ds.h>
#include <asm/hw_breakpoint.h>
#include "tls.h"
#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>
enum x86_regset {
REGSET_GENERAL,
REGSET_FP,
REGSET_XFP,
REGSET_IOPERM64 = REGSET_XFP,
REGSET_TLS,
REGSET_IOPERM32,
};
struct pt_regs_offset {
const char *name;
int offset;
};
#define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}
static const struct pt_regs_offset regoffset_table[] = {
#ifdef CONFIG_X86_64
REG_OFFSET_NAME(r15),
REG_OFFSET_NAME(r14),
REG_OFFSET_NAME(r13),
REG_OFFSET_NAME(r12),
REG_OFFSET_NAME(r11),
REG_OFFSET_NAME(r10),
REG_OFFSET_NAME(r9),
REG_OFFSET_NAME(r8),
#endif
REG_OFFSET_NAME(bx),
REG_OFFSET_NAME(cx),
REG_OFFSET_NAME(dx),
REG_OFFSET_NAME(si),
REG_OFFSET_NAME(di),
REG_OFFSET_NAME(bp),
REG_OFFSET_NAME(ax),
#ifdef CONFIG_X86_32
REG_OFFSET_NAME(ds),
REG_OFFSET_NAME(es),
REG_OFFSET_NAME(fs),
REG_OFFSET_NAME(gs),
#endif
REG_OFFSET_NAME(orig_ax),
REG_OFFSET_NAME(ip),
REG_OFFSET_NAME(cs),
REG_OFFSET_NAME(flags),
REG_OFFSET_NAME(sp),
REG_OFFSET_NAME(ss),
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;
}
static const int arg_offs_table[] = {
#ifdef CONFIG_X86_32
[0] = offsetof(struct pt_regs, ax),
[1] = offsetof(struct pt_regs, dx),
[2] = offsetof(struct pt_regs, cx)
#else /* CONFIG_X86_64 */
[0] = offsetof(struct pt_regs, di),
[1] = offsetof(struct pt_regs, si),
[2] = offsetof(struct pt_regs, dx),
[3] = offsetof(struct pt_regs, cx),
[4] = offsetof(struct pt_regs, r8),
[5] = offsetof(struct pt_regs, r9)
#endif
};
/**
* regs_get_argument_nth() - get Nth argument at function call
* @regs: pt_regs which contains registers at function entry.
* @n: argument number.
*
* regs_get_argument_nth() returns @n th argument of a function call.
* Since usually the kernel stack will be changed right after function entry,
* you must use this at function entry. If the @n th entry is NOT in the
* kernel stack or pt_regs, this returns 0.
*/
unsigned long regs_get_argument_nth(struct pt_regs *regs, unsigned int n)
{
if (n < ARRAY_SIZE(arg_offs_table))
return *(unsigned long *)((char *)regs + arg_offs_table[n]);
else {
/*
* The typical case: arg n is on the stack.
* (Note: stack[0] = return address, so skip it)
*/
n -= ARRAY_SIZE(arg_offs_table);
return regs_get_kernel_stack_nth(regs, 1 + n);
}
}
/*
* does not yet catch signals sent when the child dies.
* in exit.c or in signal.c.
*/
/*
* Determines which flags the user has access to [1 = access, 0 = no access].
*/
#define FLAG_MASK_32 ((unsigned long) \
(X86_EFLAGS_CF | X86_EFLAGS_PF | \
X86_EFLAGS_AF | X86_EFLAGS_ZF | \
X86_EFLAGS_SF | X86_EFLAGS_TF | \
X86_EFLAGS_DF | X86_EFLAGS_OF | \
X86_EFLAGS_RF | X86_EFLAGS_AC))
/*
* Determines whether a value may be installed in a segment register.
*/
static inline bool invalid_selector(u16 value)
{
return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
}
#ifdef CONFIG_X86_32
#define FLAG_MASK FLAG_MASK_32
static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
{
BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
return ®s->bx + (regno >> 2);
}
static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
{
/*
* Returning the value truncates it to 16 bits.
*/
unsigned int retval;
if (offset != offsetof(struct user_regs_struct, gs))
retval = *pt_regs_access(task_pt_regs(task), offset);
else {
if (task == current)
retval = get_user_gs(task_pt_regs(task));
else
retval = task_user_gs(task);
}
return retval;
}
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
/*
* The value argument was already truncated to 16 bits.
*/
if (invalid_selector(value))
return -EIO;
/*
* For %cs and %ss we cannot permit a null selector.
* We can permit a bogus selector as long as it has USER_RPL.
* Null selectors are fine for other segment registers, but
* we will never get back to user mode with invalid %cs or %ss
* and will take the trap in iret instead. Much code relies
* on user_mode() to distinguish a user trap frame (which can
* safely use invalid selectors) from a kernel trap frame.
*/
switch (offset) {
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ss):
if (unlikely(value == 0))
return -EIO;
default:
*pt_regs_access(task_pt_regs(task), offset) = value;
break;
case offsetof(struct user_regs_struct, gs):
if (task == current)
set_user_gs(task_pt_regs(task), value);
else
task_user_gs(task) = value;
}
return 0;
}
#else /* CONFIG_X86_64 */
#define FLAG_MASK (FLAG_MASK_32 | X86_EFLAGS_NT)
static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
{
BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
return ®s->r15 + (offset / sizeof(regs->r15));
}
static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
{
/*
* Returning the value truncates it to 16 bits.
*/
unsigned int seg;
switch (offset) {
case offsetof(struct user_regs_struct, fs):
if (task == current) {
/* Older gas can't assemble movq %?s,%r?? */
asm("movl %%fs,%0" : "=r" (seg));
return seg;
}
return task->thread.fsindex;
case offsetof(struct user_regs_struct, gs):
if (task == current) {
asm("movl %%gs,%0" : "=r" (seg));
return seg;
}
return task->thread.gsindex;
case offsetof(struct user_regs_struct, ds):
if (task == current) {
asm("movl %%ds,%0" : "=r" (seg));
return seg;
}
return task->thread.ds;
case offsetof(struct user_regs_struct, es):
if (task == current) {
asm("movl %%es,%0" : "=r" (seg));
return seg;
}
return task->thread.es;
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ss):
break;
}
return *pt_regs_access(task_pt_regs(task), offset);
}
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
/*
* The value argument was already truncated to 16 bits.
*/
if (invalid_selector(value))
return -EIO;
switch (offset) {
case offsetof(struct user_regs_struct,fs):
/*
* If this is setting fs as for normal 64-bit use but
* setting fs_base has implicitly changed it, leave it.
*/
if ((value == FS_TLS_SEL && task->thread.fsindex == 0 &&
task->thread.fs != 0) ||
(value == 0 && task->thread.fsindex == FS_TLS_SEL &&
task->thread.fs == 0))
break;
task->thread.fsindex = value;
if (task == current)
loadsegment(fs, task->thread.fsindex);
break;
case offsetof(struct user_regs_struct,gs):
/*
* If this is setting gs as for normal 64-bit use but
* setting gs_base has implicitly changed it, leave it.
*/
if ((value == GS_TLS_SEL && task->thread.gsindex == 0 &&
task->thread.gs != 0) ||
(value == 0 && task->thread.gsindex == GS_TLS_SEL &&
task->thread.gs == 0))
break;
task->thread.gsindex = value;
if (task == current)
load_gs_index(task->thread.gsindex);
break;
case offsetof(struct user_regs_struct,ds):
task->thread.ds = value;
if (task == current)
loadsegment(ds, task->thread.ds);
break;
case offsetof(struct user_regs_struct,es):
task->thread.es = value;
if (task == current)
loadsegment(es, task->thread.es);
break;
/*
* Can't actually change these in 64-bit mode.
*/
case offsetof(struct user_regs_struct,cs):
if (unlikely(value == 0))
return -EIO;
#ifdef CONFIG_IA32_EMULATION
if (test_tsk_thread_flag(task, TIF_IA32))
task_pt_regs(task)->cs = value;
#endif
break;
case offsetof(struct user_regs_struct,ss):
if (unlikely(value == 0))
return -EIO;
#ifdef CONFIG_IA32_EMULATION
if (test_tsk_thread_flag(task, TIF_IA32))
task_pt_regs(task)->ss = value;
#endif
break;
}
return 0;
}
#endif /* CONFIG_X86_32 */
static unsigned long get_flags(struct task_struct *task)
{
unsigned long retval = task_pt_regs(task)->flags;
/*
* If the debugger set TF, hide it from the readout.
*/
if (test_tsk_thread_flag(task, TIF_FORCED_TF))
retval &= ~X86_EFLAGS_TF;
return retval;
}
static int set_flags(struct task_struct *task, unsigned long value)
{
struct pt_regs *regs = task_pt_regs(task);
/*
* If the user value contains TF, mark that
* it was not "us" (the debugger) that set it.
* If not, make sure it stays set if we had.
*/
if (value & X86_EFLAGS_TF)
clear_tsk_thread_flag(task, TIF_FORCED_TF);
else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
value |= X86_EFLAGS_TF;
regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
return 0;
}
static int putreg(struct task_struct *child,
unsigned long offset, unsigned long value)
{
switch (offset) {
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ds):
case offsetof(struct user_regs_struct, es):
case offsetof(struct user_regs_struct, fs):
case offsetof(struct user_regs_struct, gs):
case offsetof(struct user_regs_struct, ss):
return set_segment_reg(child, offset, value);
case offsetof(struct user_regs_struct, flags):
return set_flags(child, value);
#ifdef CONFIG_X86_64
case offsetof(struct user_regs_struct,fs_base):
if (value >= TASK_SIZE_OF(child))
return -EIO;
/*
* When changing the segment base, use do_arch_prctl
* to set either thread.fs or thread.fsindex and the
* corresponding GDT slot.
*/
if (child->thread.fs != value)
return do_arch_prctl(child, ARCH_SET_FS, value);
return 0;
case offsetof(struct user_regs_struct,gs_base):
/*
* Exactly the same here as the %fs handling above.
*/
if (value >= TASK_SIZE_OF(child))
return -EIO;
if (child->thread.gs != value)
return do_arch_prctl(child, ARCH_SET_GS, value);
return 0;
#endif
}
*pt_regs_access(task_pt_regs(child), offset) = value;
return 0;
}
static unsigned long getreg(struct task_struct *task, unsigned long offset)
{
switch (offset) {
case offsetof(struct user_regs_struct, cs):
case offsetof(struct user_regs_struct, ds):
case offsetof(struct user_regs_struct, es):
case offsetof(struct user_regs_struct, fs):
case offsetof(struct user_regs_struct, gs):
case offsetof(struct user_regs_struct, ss):
return get_segment_reg(task, offset);
case offsetof(struct user_regs_struct, flags):
return get_flags(task);
#ifdef CONFIG_X86_64
case offsetof(struct user_regs_struct, fs_base): {
/*
* do_arch_prctl may have used a GDT slot instead of
* the MSR. To userland, it appears the same either
* way, except the %fs segment selector might not be 0.
*/
unsigned int seg = task->thread.fsindex;
if (task->thread.fs != 0)
return task->thread.fs;
if (task == current)
asm("movl %%fs,%0" : "=r" (seg));
if (seg != FS_TLS_SEL)
return 0;
return get_desc_base(&task->thread.tls_array[FS_TLS]);
}
case offsetof(struct user_regs_struct, gs_base): {
/*
* Exactly the same here as the %fs handling above.
*/
unsigned int seg = task->thread.gsindex;
if (task->thread.gs != 0)
return task->thread.gs;
if (task == current)
asm("movl %%gs,%0" : "=r" (seg));
if (seg != GS_TLS_SEL)
return 0;
return get_desc_base(&task->thread.tls_array[GS_TLS]);
}
#endif
}
return *pt_regs_access(task_pt_regs(task), offset);
}
static int genregs_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (kbuf) {
unsigned long *k = kbuf;
while (count >= sizeof(*k)) {
*k++ = getreg(target, pos);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
unsigned long __user *u = ubuf;
while (count >= sizeof(*u)) {
if (__put_user(getreg(target, pos), u++))
return -EFAULT;
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return 0;
}
static int genregs_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret = 0;
if (kbuf) {
const unsigned long *k = kbuf;
while (count >= sizeof(*k) && !ret) {
ret = putreg(target, pos, *k++);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
const unsigned long __user *u = ubuf;
while (count >= sizeof(*u) && !ret) {
unsigned long word;
ret = __get_user(word, u++);
if (ret)
break;
ret = putreg(target, pos, word);
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return ret;
}
static void ptrace_triggered(struct perf_event *bp, int nmi,
struct perf_sample_data *data,
struct pt_regs *regs)
{
int i;
struct thread_struct *thread = &(current->thread);
/*
* Store in the virtual DR6 register the fact that the breakpoint
* was hit so the thread's debugger will see it.
*/
for (i = 0; i < HBP_NUM; i++) {
if (thread->ptrace_bps[i] == bp)
break;
}
thread->debugreg6 |= (DR_TRAP0 << i);
}
/*
* Walk through every ptrace breakpoints for this thread and
* build the dr7 value on top of their attributes.
*
*/
static unsigned long ptrace_get_dr7(struct perf_event *bp[])
{
int i;
int dr7 = 0;
struct arch_hw_breakpoint *info;
for (i = 0; i < HBP_NUM; i++) {
if (bp[i] && !bp[i]->attr.disabled) {
info = counter_arch_bp(bp[i]);
dr7 |= encode_dr7(i, info->len, info->type);
}
}
return dr7;
}
static int
ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
struct task_struct *tsk, int disabled)
{
int err;
int gen_len, gen_type;
struct perf_event_attr attr;
/*
* We shoud have at least an inactive breakpoint at this
* slot. It means the user is writing dr7 without having
* written the address register first
*/
if (!bp)
return -EINVAL;
err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
if (err)
return err;
attr = bp->attr;
attr.bp_len = gen_len;
attr.bp_type = gen_type;
attr.disabled = disabled;
return modify_user_hw_breakpoint(bp, &attr);
}
/*
* Handle ptrace writes to debug register 7.
*/
static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
{
struct thread_struct *thread = &(tsk->thread);
unsigned long old_dr7;
int i, orig_ret = 0, rc = 0;
int enabled, second_pass = 0;
unsigned len, type;
struct perf_event *bp;
data &= ~DR_CONTROL_RESERVED;
old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
restore:
/*
* Loop through all the hardware breakpoints, making the
* appropriate changes to each.
*/
for (i = 0; i < HBP_NUM; i++) {
enabled = decode_dr7(data, i, &len, &type);
bp = thread->ptrace_bps[i];
if (!enabled) {
if (bp) {
/*
* Don't unregister the breakpoints right-away,
* unless all register_user_hw_breakpoint()
* requests have succeeded. This prevents
* any window of opportunity for debug
* register grabbing by other users.
*/
if (!second_pass)
continue;
rc = ptrace_modify_breakpoint(bp, len, type,
tsk, 1);
if (rc)
break;
}
continue;
}
rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
if (rc)
break;
}
/*
* Make a second pass to free the remaining unused breakpoints
* or to restore the original breakpoints if an error occurred.
*/
if (!second_pass) {
second_pass = 1;
if (rc < 0) {
orig_ret = rc;
data = old_dr7;
}
goto restore;
}
return ((orig_ret < 0) ? orig_ret : rc);
}
/*
* Handle PTRACE_PEEKUSR calls for the debug register area.
*/
static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
{
struct thread_struct *thread = &(tsk->thread);
unsigned long val = 0;
if (n < HBP_NUM) {
struct perf_event *bp;
bp = thread->ptrace_bps[n];
if (!bp)
return 0;
val = bp->hw.info.address;
} else if (n == 6) {
val = thread->debugreg6;
} else if (n == 7) {
val = thread->ptrace_dr7;
}
return val;
}
static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
unsigned long addr)
{
struct perf_event *bp;
struct thread_struct *t = &tsk->thread;
struct perf_event_attr attr;
if (!t->ptrace_bps[nr]) {
hw_breakpoint_init(&attr);
/*
* Put stub len and type to register (reserve) an inactive but
* correct bp
*/
attr.bp_addr = addr;
attr.bp_len = HW_BREAKPOINT_LEN_1;
attr.bp_type = HW_BREAKPOINT_W;
attr.disabled = 1;
bp = register_user_hw_breakpoint(&attr, ptrace_triggered, tsk);
/*
* CHECKME: the previous code returned -EIO if the addr wasn't
* a valid task virtual addr. The new one will return -EINVAL in
* this case.
* -EINVAL may be what we want for in-kernel breakpoints users,
* but -EIO looks better for ptrace, since we refuse a register
* writing for the user. And anyway this is the previous
* behaviour.
*/
if (IS_ERR(bp))
return PTR_ERR(bp);
t->ptrace_bps[nr] = bp;
} else {
int err;
bp = t->ptrace_bps[nr];
attr = bp->attr;
attr.bp_addr = addr;
err = modify_user_hw_breakpoint(bp, &attr);
if (err)
return err;
}
return 0;
}
/*
* Handle PTRACE_POKEUSR calls for the debug register area.
*/
int ptrace_set_debugreg(struct task_struct *tsk, int n, unsigned long val)
{
struct thread_struct *thread = &(tsk->thread);
int rc = 0;
/* There are no DR4 or DR5 registers */
if (n == 4 || n == 5)
return -EIO;
if (n == 6) {
thread->debugreg6 = val;
goto ret_path;
}
if (n < HBP_NUM) {
rc = ptrace_set_breakpoint_addr(tsk, n, val);
if (rc)
return rc;
}
/* All that's left is DR7 */
if (n == 7) {
rc = ptrace_write_dr7(tsk, val);
if (!rc)
thread->ptrace_dr7 = val;
}
ret_path:
return rc;
}
/*
* These access the current or another (stopped) task's io permission
* bitmap for debugging or core dump.
*/
static int ioperm_active(struct task_struct *target,
const struct user_regset *regset)
{
return target->thread.io_bitmap_max / regset->size;
}
static int ioperm_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (!target->thread.io_bitmap_ptr)
return -ENXIO;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
target->thread.io_bitmap_ptr,
0, IO_BITMAP_BYTES);
}
#ifdef CONFIG_X86_PTRACE_BTS
/*
* A branch trace store context.
*
* Contexts may only be installed by ptrace_bts_config() and only for
* ptraced tasks.
*
* Contexts are destroyed when the tracee is detached from the tracer.
* The actual destruction work requires interrupts enabled, so the
* work is deferred and will be scheduled during __ptrace_unlink().
*
* Contexts hold an additional task_struct reference on the traced
* task, as well as a reference on the tracer's mm.
*
* Ptrace already holds a task_struct for the duration of ptrace operations,
* but since destruction is deferred, it may be executed after both
* tracer and tracee exited.
*/
struct bts_context {
/* The branch trace handle. */
struct bts_tracer *tracer;
/* The buffer used to store the branch trace and its size. */
void *buffer;
unsigned int size;
/* The mm that paid for the above buffer. */
struct mm_struct *mm;
/* The task this context belongs to. */
struct task_struct *task;
/* The signal to send on a bts buffer overflow. */
unsigned int bts_ovfl_signal;
/* The work struct to destroy a context. */
struct work_struct work;
};
static int alloc_bts_buffer(struct bts_context *context, unsigned int size)
{
void *buffer = NULL;
int err = -ENOMEM;
err = account_locked_memory(current->mm, current->signal->rlim, size);
if (err < 0)
return err;
buffer = kzalloc(size, GFP_KERNEL);
if (!buffer)
goto out_refund;
context->buffer = buffer;
context->size = size;
context->mm = get_task_mm(current);
return 0;
out_refund:
refund_locked_memory(current->mm, size);
return err;
}
static inline void free_bts_buffer(struct bts_context *context)
{
if (!context->buffer)
return;
kfree(context->buffer);
context->buffer = NULL;
refund_locked_memory(context->mm, context->size);
context->size = 0;
mmput(context->mm);
context->mm = NULL;
}
static void free_bts_context_work(struct work_struct *w)
{
struct bts_context *context;
context = container_of(w, struct bts_context, work);
ds_release_bts(context->tracer);
put_task_struct(context->task);
free_bts_buffer(context);
kfree(context);
}
static inline void free_bts_context(struct bts_context *context)
{
INIT_WORK(&context->work, free_bts_context_work);
schedule_work(&context->work);
}
static inline struct bts_context *alloc_bts_context(struct task_struct *task)
{
struct bts_context *context = kzalloc(sizeof(*context), GFP_KERNEL);
if (context) {
context->task = task;
task->bts = context;
get_task_struct(task);
}
return context;
}
static int ptrace_bts_read_record(struct task_struct *child, size_t index,
struct bts_struct __user *out)
{
struct bts_context *context;
const struct bts_trace *trace;
struct bts_struct bts;
const unsigned char *at;
int error;
context = child->bts;
if (!context)
return -ESRCH;
trace = ds_read_bts(context->tracer);
if (!trace)
return -ESRCH;
at = trace->ds.top - ((index + 1) * trace->ds.size);
if ((void *)at < trace->ds.begin)
at += (trace->ds.n * trace->ds.size);
if (!trace->read)
return -EOPNOTSUPP;
error = trace->read(context->tracer, at, &bts);
if (error < 0)
return error;
if (copy_to_user(out, &bts, sizeof(bts)))
return -EFAULT;
return sizeof(bts);
}
static int ptrace_bts_drain(struct task_struct *child,
long size,
struct bts_struct __user *out)
{
struct bts_context *context;
const struct bts_trace *trace;
const unsigned char *at;
int error, drained = 0;
context = child->bts;
if (!context)
return -ESRCH;
trace = ds_read_bts(context->tracer);
if (!trace)
return -ESRCH;
if (!trace->read)
return -EOPNOTSUPP;
if (size < (trace->ds.top - trace->ds.begin))
return -EIO;
for (at = trace->ds.begin; (void *)at < trace->ds.top;
out++, drained++, at += trace->ds.size) {
struct bts_struct bts;
error = trace->read(context->tracer, at, &bts);
if (error < 0)
return error;
if (copy_to_user(out, &bts, sizeof(bts)))
return -EFAULT;
}
memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);
error = ds_reset_bts(context->tracer);
if (error < 0)
return error;
return drained;
}
static int ptrace_bts_config(struct task_struct *child,
long cfg_size,
const struct ptrace_bts_config __user *ucfg)
{
struct bts_context *context;
struct ptrace_bts_config cfg;
unsigned int flags = 0;
if (cfg_size < sizeof(cfg))
return -EIO;
if (copy_from_user(&cfg, ucfg, sizeof(cfg)))
return -EFAULT;
context = child->bts;
if (!context)
context = alloc_bts_context(child);
if (!context)
return -ENOMEM;
if (cfg.flags & PTRACE_BTS_O_SIGNAL) {
if (!cfg.signal)
return -EINVAL;
return -EOPNOTSUPP;
context->bts_ovfl_signal = cfg.signal;
}
ds_release_bts(context->tracer);
context->tracer = NULL;
if ((cfg.flags & PTRACE_BTS_O_ALLOC) && (cfg.size != context->size)) {
int err;
free_bts_buffer(context);
if (!cfg.size)
return 0;
err = alloc_bts_buffer(context, cfg.size);
if (err < 0)
return err;
}
if (cfg.flags & PTRACE_BTS_O_TRACE)
flags |= BTS_USER;
if (cfg.flags & PTRACE_BTS_O_SCHED)
flags |= BTS_TIMESTAMPS;
context->tracer =
ds_request_bts_task(child, context->buffer, context->size,
NULL, (size_t)-1, flags);
if (unlikely(IS_ERR(context->tracer))) {
int error = PTR_ERR(context->tracer);
free_bts_buffer(context);
context->tracer = NULL;
return error;
}
return sizeof(cfg);
}
static int ptrace_bts_status(struct task_struct *child,
long cfg_size,
struct ptrace_bts_config __user *ucfg)
{
struct bts_context *context;
const struct bts_trace *trace;
struct ptrace_bts_config cfg;
context = child->bts;
if (!context)
return -ESRCH;
if (cfg_size < sizeof(cfg))
return -EIO;
trace = ds_read_bts(context->tracer);
if (!trace)
return -ESRCH;
memset(&cfg, 0, sizeof(cfg));
cfg.size = trace->ds.end - trace->ds.begin;
cfg.signal = context->bts_ovfl_signal;
cfg.bts_size = sizeof(struct bts_struct);
if (cfg.signal)
cfg.flags |= PTRACE_BTS_O_SIGNAL;
if (trace->ds.flags & BTS_USER)
cfg.flags |= PTRACE_BTS_O_TRACE;
if (trace->ds.flags & BTS_TIMESTAMPS)
cfg.flags |= PTRACE_BTS_O_SCHED;
if (copy_to_user(ucfg, &cfg, sizeof(cfg)))
return -EFAULT;
return sizeof(cfg);
}
static int ptrace_bts_clear(struct task_struct *child)
{
struct bts_context *context;
const struct bts_trace *trace;
context = child->bts;
if (!context)
return -ESRCH;
trace = ds_read_bts(context->tracer);
if (!trace)
return -ESRCH;
memset(trace->ds.begin, 0, trace->ds.n * trace->ds.size);
return ds_reset_bts(context->tracer);
}
static int ptrace_bts_size(struct task_struct *child)
{
struct bts_context *context;
const struct bts_trace *trace;
context = child->bts;
if (!context)
return -ESRCH;
trace = ds_read_bts(context->tracer);
if (!trace)
return -ESRCH;
return (trace->ds.top - trace->ds.begin) / trace->ds.size;
}
/*
* Called from __ptrace_unlink() after the child has been moved back
* to its original parent.
*/
void ptrace_bts_untrace(struct task_struct *child)
{
if (unlikely(child->bts)) {
free_bts_context(child->bts);
child->bts = NULL;
}
}
#endif /* CONFIG_X86_PTRACE_BTS */
/*
* Called by kernel/ptrace.c when detaching..
*
* Make sure the single step bit is not set.
*/
void ptrace_disable(struct task_struct *child)
{
user_disable_single_step(child);
#ifdef TIF_SYSCALL_EMU
clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
#endif
}
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
static const struct user_regset_view user_x86_32_view; /* Initialized below. */
#endif
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
int ret;
unsigned long __user *datap = (unsigned long __user *)data;
switch (request) {
/* read the word at location addr in the USER area. */
case PTRACE_PEEKUSR: {
unsigned long tmp;
ret = -EIO;
if ((addr & (sizeof(data) - 1)) || addr < 0 ||
addr >= sizeof(struct user))
break;
tmp = 0; /* Default return condition */
if (addr < sizeof(struct user_regs_struct))
tmp = getreg(child, addr);
else if (addr >= offsetof(struct user, u_debugreg[0]) &&
addr <= offsetof(struct user, u_debugreg[7])) {
addr -= offsetof(struct user, u_debugreg[0]);
tmp = ptrace_get_debugreg(child, addr / sizeof(data));
}
ret = put_user(tmp, datap);
break;
}
case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
ret = -EIO;
if ((addr & (sizeof(data) - 1)) || addr < 0 ||
addr >= sizeof(struct user))
break;
if (addr < sizeof(struct user_regs_struct))
ret = putreg(child, addr, data);
else if (addr >= offsetof(struct user, u_debugreg[0]) &&
addr <= offsetof(struct user, u_debugreg[7])) {
addr -= offsetof(struct user, u_debugreg[0]);
ret = ptrace_set_debugreg(child,
addr / sizeof(data), data);
}
break;
case PTRACE_GETREGS: /* Get all gp regs from the child. */
return copy_regset_to_user(child,
task_user_regset_view(current),
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child,
task_user_regset_view(current),
REGSET_GENERAL,
0, sizeof(struct user_regs_struct),
datap);
case PTRACE_GETFPREGS: /* Get the child FPU state. */
return copy_regset_to_user(child,
task_user_regset_view(current),
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
case PTRACE_SETFPREGS: /* Set the child FPU state. */
return copy_regset_from_user(child,
task_user_regset_view(current),
REGSET_FP,
0, sizeof(struct user_i387_struct),
datap);
#ifdef CONFIG_X86_32
case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
return copy_regset_to_user(child, &user_x86_32_view,
REGSET_XFP,
0, sizeof(struct user_fxsr_struct),
datap) ? -EIO : 0;
case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
return copy_regset_from_user(child, &user_x86_32_view,
REGSET_XFP,
0, sizeof(struct user_fxsr_struct),
datap) ? -EIO : 0;
#endif
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
case PTRACE_GET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_get_thread_area(child, addr,
(struct user_desc __user *) data);
break;
case PTRACE_SET_THREAD_AREA:
if (addr < 0)
return -EIO;
ret = do_set_thread_area(child, addr,
(struct user_desc __user *) data, 0);
break;
#endif
#ifdef CONFIG_X86_64
/* normal 64bit interface to access TLS data.
Works just like arch_prctl, except that the arguments
are reversed. */
case PTRACE_ARCH_PRCTL:
ret = do_arch_prctl(child, data, addr);
break;
#endif
/*
* These bits need more cooking - not enabled yet:
*/
#ifdef CONFIG_X86_PTRACE_BTS
case PTRACE_BTS_CONFIG:
ret = ptrace_bts_config
(child, data, (struct ptrace_bts_config __user *)addr);
break;
case PTRACE_BTS_STATUS:
ret = ptrace_bts_status
(child, data, (struct ptrace_bts_config __user *)addr);
break;
case PTRACE_BTS_SIZE:
ret = ptrace_bts_size(child);
break;
case PTRACE_BTS_GET:
ret = ptrace_bts_read_record
(child, data, (struct bts_struct __user *) addr);
break;
case PTRACE_BTS_CLEAR:
ret = ptrace_bts_clear(child);
break;
case PTRACE_BTS_DRAIN:
ret = ptrace_bts_drain
(child, data, (struct bts_struct __user *) addr);
break;
#endif /* CONFIG_X86_PTRACE_BTS */
default:
ret = ptrace_request(child, request, addr, data);
break;
}
return ret;
}
#ifdef CONFIG_IA32_EMULATION
#include <linux/compat.h>
#include <linux/syscalls.h>
#include <asm/ia32.h>
#include <asm/user32.h>
#define R32(l,q) \
case offsetof(struct user32, regs.l): \
regs->q = value; break
#define SEG32(rs) \
case offsetof(struct user32, regs.rs): \
return set_segment_reg(child, \
offsetof(struct user_regs_struct, rs), \
value); \
break
static int putreg32(struct task_struct *child, unsigned regno, u32 value)
{
struct pt_regs *regs = task_pt_regs(child);
switch (regno) {
SEG32(cs);
SEG32(ds);
SEG32(es);
SEG32(fs);
SEG32(gs);
SEG32(ss);
R32(ebx, bx);
R32(ecx, cx);
R32(edx, dx);
R32(edi, di);
R32(esi, si);
R32(ebp, bp);
R32(eax, ax);
R32(eip, ip);
R32(esp, sp);
case offsetof(struct user32, regs.orig_eax):
/*
* A 32-bit debugger setting orig_eax means to restore
* the state of the task restarting a 32-bit syscall.
* Make sure we interpret the -ERESTART* codes correctly
* in case the task is not actually still sitting at the
* exit from a 32-bit syscall with TS_COMPAT still set.
*/
regs->orig_ax = value;
if (syscall_get_nr(child, regs) >= 0)
task_thread_info(child)->status |= TS_COMPAT;
break;
case offsetof(struct user32, regs.eflags):
return set_flags(child, value);
case offsetof(struct user32, u_debugreg[0]) ...
offsetof(struct user32, u_debugreg[7]):
regno -= offsetof(struct user32, u_debugreg[0]);
return ptrace_set_debugreg(child, regno / 4, value);
default:
if (regno > sizeof(struct user32) || (regno & 3))
return -EIO;
/*
* Other dummy fields in the virtual user structure
* are ignored
*/
break;
}
return 0;
}
#undef R32
#undef SEG32
#define R32(l,q) \
case offsetof(struct user32, regs.l): \
*val = regs->q; break
#define SEG32(rs) \
case offsetof(struct user32, regs.rs): \
*val = get_segment_reg(child, \
offsetof(struct user_regs_struct, rs)); \
break
static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
{
struct pt_regs *regs = task_pt_regs(child);
switch (regno) {
SEG32(ds);
SEG32(es);
SEG32(fs);
SEG32(gs);
R32(cs, cs);
R32(ss, ss);
R32(ebx, bx);
R32(ecx, cx);
R32(edx, dx);
R32(edi, di);
R32(esi, si);
R32(ebp, bp);
R32(eax, ax);
R32(orig_eax, orig_ax);
R32(eip, ip);
R32(esp, sp);
case offsetof(struct user32, regs.eflags):
*val = get_flags(child);
break;
case offsetof(struct user32, u_debugreg[0]) ...
offsetof(struct user32, u_debugreg[7]):
regno -= offsetof(struct user32, u_debugreg[0]);
*val = ptrace_get_debugreg(child, regno / 4);
break;
default:
if (regno > sizeof(struct user32) || (regno & 3))
return -EIO;
/*
* Other dummy fields in the virtual user structure
* are ignored
*/
*val = 0;
break;
}
return 0;
}
#undef R32
#undef SEG32
static int genregs32_get(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (kbuf) {
compat_ulong_t *k = kbuf;
while (count >= sizeof(*k)) {
getreg32(target, pos, k++);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
compat_ulong_t __user *u = ubuf;
while (count >= sizeof(*u)) {
compat_ulong_t word;
getreg32(target, pos, &word);
if (__put_user(word, u++))
return -EFAULT;
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return 0;
}
static int genregs32_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret = 0;
if (kbuf) {
const compat_ulong_t *k = kbuf;
while (count >= sizeof(*k) && !ret) {
ret = putreg32(target, pos, *k++);
count -= sizeof(*k);
pos += sizeof(*k);
}
} else {
const compat_ulong_t __user *u = ubuf;
while (count >= sizeof(*u) && !ret) {
compat_ulong_t word;
ret = __get_user(word, u++);
if (ret)
break;
ret = putreg32(target, pos, word);
count -= sizeof(*u);
pos += sizeof(*u);
}
}
return ret;
}
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
compat_ulong_t caddr, compat_ulong_t cdata)
{
unsigned long addr = caddr;
unsigned long data = cdata;
void __user *datap = compat_ptr(data);
int ret;
__u32 val;
switch (request) {
case PTRACE_PEEKUSR:
ret = getreg32(child, addr, &val);
if (ret == 0)
ret = put_user(val, (__u32 __user *)datap);
break;
case PTRACE_POKEUSR:
ret = putreg32(child, addr, data);
break;
case PTRACE_GETREGS: /* Get all gp regs from the child. */
return copy_regset_to_user(child, &user_x86_32_view,
REGSET_GENERAL,
0, sizeof(struct user_regs_struct32),
datap);
case PTRACE_SETREGS: /* Set all gp regs in the child. */
return copy_regset_from_user(child, &user_x86_32_view,
REGSET_GENERAL, 0,
sizeof(struct user_regs_struct32),
datap);
case PTRACE_GETFPREGS: /* Get the child FPU state. */
return copy_regset_to_user(child, &user_x86_32_view,
REGSET_FP, 0,
sizeof(struct user_i387_ia32_struct),
datap);
case PTRACE_SETFPREGS: /* Set the child FPU state. */
return copy_regset_from_user(
child, &user_x86_32_view, REGSET_FP,
0, sizeof(struct user_i387_ia32_struct), datap);
case PTRACE_GETFPXREGS: /* Get the child extended FPU state. */
return copy_regset_to_user(child, &user_x86_32_view,
REGSET_XFP, 0,
sizeof(struct user32_fxsr_struct),
datap);
case PTRACE_SETFPXREGS: /* Set the child extended FPU state. */
return copy_regset_from_user(child, &user_x86_32_view,
REGSET_XFP, 0,
sizeof(struct user32_fxsr_struct),
datap);
case PTRACE_GET_THREAD_AREA:
case PTRACE_SET_THREAD_AREA:
#ifdef CONFIG_X86_PTRACE_BTS
case PTRACE_BTS_CONFIG:
case PTRACE_BTS_STATUS:
case PTRACE_BTS_SIZE:
case PTRACE_BTS_GET:
case PTRACE_BTS_CLEAR:
case PTRACE_BTS_DRAIN:
#endif /* CONFIG_X86_PTRACE_BTS */
return arch_ptrace(child, request, addr, data);
default:
return compat_ptrace_request(child, request, addr, data);
}
return ret;
}
#endif /* CONFIG_IA32_EMULATION */
#ifdef CONFIG_X86_64
static const struct user_regset x86_64_regsets[] = {
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS,
.n = sizeof(struct user_regs_struct) / sizeof(long),
.size = sizeof(long), .align = sizeof(long),
.get = genregs_get, .set = genregs_set
},
[REGSET_FP] = {
.core_note_type = NT_PRFPREG,
.n = sizeof(struct user_i387_struct) / sizeof(long),
.size = sizeof(long), .align = sizeof(long),
.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
},
[REGSET_IOPERM64] = {
.core_note_type = NT_386_IOPERM,
.n = IO_BITMAP_LONGS,
.size = sizeof(long), .align = sizeof(long),
.active = ioperm_active, .get = ioperm_get
},
};
static const struct user_regset_view user_x86_64_view = {
.name = "x86_64", .e_machine = EM_X86_64,
.regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
};
#else /* CONFIG_X86_32 */
#define user_regs_struct32 user_regs_struct
#define genregs32_get genregs_get
#define genregs32_set genregs_set
#define user_i387_ia32_struct user_i387_struct
#define user32_fxsr_struct user_fxsr_struct
#endif /* CONFIG_X86_64 */
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
static const struct user_regset x86_32_regsets[] = {
[REGSET_GENERAL] = {
.core_note_type = NT_PRSTATUS,
.n = sizeof(struct user_regs_struct32) / sizeof(u32),
.size = sizeof(u32), .align = sizeof(u32),
.get = genregs32_get, .set = genregs32_set
},
[REGSET_FP] = {
.core_note_type = NT_PRFPREG,
.n = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
.size = sizeof(u32), .align = sizeof(u32),
.active = fpregs_active, .get = fpregs_get, .set = fpregs_set
},
[REGSET_XFP] = {
.core_note_type = NT_PRXFPREG,
.n = sizeof(struct user32_fxsr_struct) / sizeof(u32),
.size = sizeof(u32), .align = sizeof(u32),
.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
},
[REGSET_TLS] = {
.core_note_type = NT_386_TLS,
.n = GDT_ENTRY_TLS_ENTRIES, .bias = GDT_ENTRY_TLS_MIN,
.size = sizeof(struct user_desc),
.align = sizeof(struct user_desc),
.active = regset_tls_active,
.get = regset_tls_get, .set = regset_tls_set
},
[REGSET_IOPERM32] = {
.core_note_type = NT_386_IOPERM,
.n = IO_BITMAP_BYTES / sizeof(u32),
.size = sizeof(u32), .align = sizeof(u32),
.active = ioperm_active, .get = ioperm_get
},
};
static const struct user_regset_view user_x86_32_view = {
.name = "i386", .e_machine = EM_386,
.regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
};
#endif
const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_IA32_EMULATION
if (test_tsk_thread_flag(task, TIF_IA32))
#endif
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
return &user_x86_32_view;
#endif
#ifdef CONFIG_X86_64
return &user_x86_64_view;
#endif
}
static void fill_sigtrap_info(struct task_struct *tsk,
struct pt_regs *regs,
int error_code, int si_code,
struct siginfo *info)
{
tsk->thread.trap_no = 1;
tsk->thread.error_code = error_code;
memset(info, 0, sizeof(*info));
info->si_signo = SIGTRAP;
info->si_code = si_code;
info->si_addr = user_mode_vm(regs) ? (void __user *)regs->ip : NULL;
}
void user_single_step_siginfo(struct task_struct *tsk,
struct pt_regs *regs,
struct siginfo *info)
{
fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info);
}
void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
int error_code, int si_code)
{
struct siginfo info;
fill_sigtrap_info(tsk, regs, error_code, si_code, &info);
/* Send us the fake SIGTRAP */
force_sig_info(SIGTRAP, &info, tsk);
}
#ifdef CONFIG_X86_32
# define IS_IA32 1
#elif defined CONFIG_IA32_EMULATION
# define IS_IA32 is_compat_task()
#else
# define IS_IA32 0
#endif
/*
* We must return the syscall number to actually look up in the table.
* This can be -1L to skip running any syscall at all.
*/
asmregparm long syscall_trace_enter(struct pt_regs *regs)
{
long ret = 0;
/*
* If we stepped into a sysenter/syscall insn, it trapped in
* kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
* If user-mode had set TF itself, then it's still clear from
* do_debug() and we need to set it again to restore the user
* state. If we entered on the slow path, TF was already set.
*/
if (test_thread_flag(TIF_SINGLESTEP))
regs->flags |= X86_EFLAGS_TF;
/* do the secure computing check first */
secure_computing(regs->orig_ax);
if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
ret = -1L;
if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
tracehook_report_syscall_entry(regs))
ret = -1L;
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_enter(regs, regs->orig_ax);
if (unlikely(current->audit_context)) {
if (IS_IA32)
audit_syscall_entry(AUDIT_ARCH_I386,
regs->orig_ax,
regs->bx, regs->cx,
regs->dx, regs->si);
#ifdef CONFIG_X86_64
else
audit_syscall_entry(AUDIT_ARCH_X86_64,
regs->orig_ax,
regs->di, regs->si,
regs->dx, regs->r10);
#endif
}
return ret ?: regs->orig_ax;
}
asmregparm void syscall_trace_leave(struct pt_regs *regs)
{
bool step;
if (unlikely(current->audit_context))
audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->ax);
/*
* If TIF_SYSCALL_EMU is set, we only get here because of
* TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
* We already reported this syscall instruction in
* syscall_trace_enter().
*/
step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
!test_thread_flag(TIF_SYSCALL_EMU);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}