static int collect_syscall(struct task_struct *target, struct syscall_info *info)
{
struct pt_regs *regs;
if (!try_get_task_stack(target)) {
/* Task has no stack, so the task isn't in a syscall. */
memset(info, 0, sizeof(*info));
info->data.nr = -1;
return 0;
}
regs = task_pt_regs(target);
if (unlikely(!regs)) {
put_task_stack(target);
return -EAGAIN;
}
info->sp = user_stack_pointer(regs);
info->data.instruction_pointer = instruction_pointer(regs);
info->data.nr = syscall_get_nr(target, regs);
if (info->data.nr != -1L)
syscall_get_arguments(target, regs,
(unsigned long *)&info->data.args[0]);
put_task_stack(target);
return 0;
}
static void notrace walk_stackframe(struct task_struct *task,
struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
{
unsigned long sp, pc;
unsigned long *ksp;
if (regs) {
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
const register unsigned long current_sp __asm__ ("sp");
sp = current_sp;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
sp = task->thread.sp;
pc = task->thread.ra;
}
if (unlikely(sp & 0x7))
return;
ksp = (unsigned long *)sp;
while (!kstack_end(ksp)) {
if (__kernel_text_address(pc) && unlikely(fn(pc, arg)))
break;
pc = (*ksp++) - 0x4;
}
}
static int collect_syscall(struct task_struct *target, long *callno,
unsigned long args[6], unsigned int maxargs,
unsigned long *sp, unsigned long *pc)
{
struct pt_regs *regs = task_pt_regs(target);
if (unlikely(!regs))
return -EAGAIN;
*sp = user_stack_pointer(regs);
*pc = instruction_pointer(regs);
*callno = syscall_get_nr(target, regs);
if (*callno != -1L && maxargs > 0)
syscall_get_arguments(target, regs, 0, maxargs, args);
return 0;
}
/*
* Setup signal stack frame with siginfo structure
*/
static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
int err = 0;
struct rt_sigframe __user *frame;
struct hexagon_vdso *vdso = current->mm->context.vdso;
frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
goto sigsegv;
if (copy_siginfo_to_user(&frame->info, info))
goto sigsegv;
/* The on-stack signal trampoline is no longer executed;
* however, the libgcc signal frame unwinding code checks for
* the presence of these two numeric magic values.
*/
err |= __put_user(0x7800d166, &frame->tramp[0]);
err |= __put_user(0x5400c004, &frame->tramp[1]);
err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs));
if (err)
goto sigsegv;
/* Load r0/r1 pair with signumber/siginfo pointer... */
regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
| (unsigned long long)signr;
regs->r02 = (unsigned long) &frame->uc;
regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
pt_psp(regs) = (unsigned long) frame;
pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
return 0;
sigsegv:
force_sigsegv(signr, current);
return -EFAULT;
}
static void notrace walk_stackframe(struct task_struct *task,
struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg)
{
unsigned long fp, sp, pc;
if (regs) {
fp = frame_pointer(regs);
sp = user_stack_pointer(regs);
pc = instruction_pointer(regs);
} else if (task == NULL || task == current) {
const register unsigned long current_sp __asm__ ("sp");
fp = (unsigned long)__builtin_frame_address(0);
sp = current_sp;
pc = (unsigned long)walk_stackframe;
} else {
/* task blocked in __switch_to */
fp = task->thread.s[0];
sp = task->thread.sp;
pc = task->thread.ra;
}
for (;;) {
unsigned long low, high;
struct stackframe *frame;
if (unlikely(!__kernel_text_address(pc) || fn(pc, arg)))
break;
/* Validate frame pointer */
low = sp + sizeof(struct stackframe);
high = ALIGN(sp, THREAD_SIZE);
if (unlikely(fp < low || fp > high || fp & 0x7))
break;
/* Unwind stack frame */
frame = (struct stackframe *)fp - 1;
sp = fp;
fp = frame->fp;
pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
(unsigned long *)(fp - 8));
}
}
/*
* Get user stack entries up to the pcstack_limit; return the number of entries
* acquired. If pcstack is NULL, return the number of entries potentially
* acquirable.
*/
unsigned long dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack,
int pcstack_limit)
{
struct task_struct *p = current;
struct mm_struct *mm = p->mm;
unsigned long tos, bos, fpc;
unsigned long *sp;
unsigned long depth = 0;
struct vm_area_struct *stack_vma;
struct page *stack_page = NULL;
struct pt_regs *regs = current_pt_regs();
if (pcstack) {
if (unlikely(pcstack_limit < 2)) {
DTRACE_CPUFLAG_SET(CPU_DTRACE_ILLOP);
return 0;
}
*pcstack++ = (uint64_t)p->pid;
*pcstack++ = (uint64_t)p->tgid;
pcstack_limit -= 2;
}
if (!user_mode(regs))
goto out;
/*
* There is always at least one address to report: the instruction
* pointer itself (frame 0).
*/
depth++;
fpc = instruction_pointer(regs);
if (pcstack) {
*pcstack++ = (uint64_t)fpc;
pcstack_limit--;
}
/*
* We cannot ustack() if this task has no mm, if this task is a kernel
* thread, or when someone else has the mmap_sem or the page_table_lock
* (because find_user_vma() ultimately does a __get_user_pages() and
* thence a follow_page(), which can take that lock).
*/
if (mm == NULL || (p->flags & PF_KTHREAD) ||
spin_is_locked(&mm->page_table_lock))
goto out;
if (!down_read_trylock(&mm->mmap_sem))
goto out;
atomic_inc(&mm->mm_users);
/*
* The following construct can be replaced with:
* tos = current_user_stack_pointer();
* once support for 4.0 is no longer necessary.
*/
#ifdef CONFIG_X86_64
tos = current_pt_regs()->sp;
#else
tos = user_stack_pointer(current_pt_regs());
#endif
stack_vma = find_user_vma(p, mm, NULL, (unsigned long) tos, 0);
if (!stack_vma ||
stack_vma->vm_start > (unsigned long) tos)
goto unlock_out;
#ifdef CONFIG_STACK_GROWSUP
#error This code does not yet work on STACK_GROWSUP platforms.
#endif
bos = stack_vma->vm_end;
if (stack_guard_page_end(stack_vma, bos))
bos -= PAGE_SIZE;
/*
* If we have a pcstack, loop as long as we are within the stack limit.
* Otherwise, loop until we run out of stack.
*/
for (sp = (unsigned long *)tos;
sp <= (unsigned long *)bos &&
((pcstack && pcstack_limit > 0) ||
!pcstack);
sp++) {
struct vm_area_struct *code_vma;
unsigned long addr;
/*
* Recheck for faultedness and pin at page boundaries.
*/
if (!stack_page || (((unsigned long)sp & PAGE_MASK) == 0)) {
if (stack_page) {
put_page(stack_page);
stack_page = NULL;
}
if (!find_user_vma(p, mm, &stack_page,
(unsigned long) sp, 1))
break;
}
DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
get_user(addr, sp);
DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT)) {
DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_BADADDR);
break;
}
if (addr == fpc)
continue;
code_vma = find_user_vma(p, mm, NULL, addr, 0);
if (!code_vma || code_vma->vm_start > addr)
continue;
if ((addr >= tos && addr <= bos) ||
(code_vma->vm_flags & VM_GROWSDOWN)) {
/* stack address - may need it for the fpstack. */
} else if (code_vma->vm_flags & VM_EXEC) {
if (pcstack) {
*pcstack++ = addr;
pcstack_limit--;
}
depth++;
}
}
if (stack_page != NULL)
put_page(stack_page);
unlock_out:
atomic_dec(&mm->mm_users);
up_read(&mm->mmap_sem);
out:
if (pcstack)
while (pcstack_limit--)
*pcstack++ = 0;
return depth;
}