void do_syscall_trace_exit(struct pt_regs *regs)
{
long errno;
/*
* We may come here right after calling schedule_user()
* in which case we can be in RCU user mode.
*/
user_exit();
/*
* The standard tile calling convention returns the value (or negative
* errno) in r0, and zero (or positive errno) in r1.
* It saves a couple of cycles on the hot path to do this work in
* registers only as we return, rather than updating the in-memory
* struct ptregs.
*/
errno = (long) regs->regs[0];
if (errno < 0 && errno > -4096)
regs->regs[1] = -errno;
else
regs->regs[1] = 0;
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, 0);
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_exit(regs, regs->regs[0]);
}
asmlinkage int syscall_trace(int dir, struct pt_regs *regs)
{
unsigned long saved_reg;
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return regs->syscallno;
if (is_compat_task()) {
/* AArch32 uses ip (r12) for scratch */
saved_reg = regs->regs[12];
regs->regs[12] = dir;
} else {
/*
* Save X7. X7 is used to denote syscall entry/exit:
* X7 = 0 -> entry, = 1 -> exit
*/
saved_reg = regs->regs[7];
regs->regs[7] = dir;
}
if (dir)
tracehook_report_syscall_exit(regs, 0);
else if (tracehook_report_syscall_entry(regs))
regs->syscallno = ~0UL;
if (is_compat_task())
regs->regs[12] = saved_reg;
else
regs->regs[7] = saved_reg;
return regs->syscallno;
}
void do_syscall_trace_exit(struct pt_regs *regs)
{
int stepping = test_thread_flag(TIF_SINGLESTEP) ||
test_thread_flag(TIF_BLOCKSTEP);
if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, stepping);
}
void syscall_trace_leave(struct pt_regs *regs)
{
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs->ctx.DX[0].U1);
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, 0);
}
asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
int step;
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}
asmlinkage void syscall_trace_exit(struct pt_regs *regs)
{
audit_syscall_exit(regs);
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, 0);
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_exit(regs, syscall_get_return_value(current, regs));
}
asmlinkage void do_syscall_trace_leave(struct pt_regs *regs)
{
int step;
if (unlikely(current->audit_context))
audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3);
step = test_thread_flag(TIF_SINGLESTEP);
if (step || test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, step);
}
asmlinkage int syscall_trace(struct pt_regs *regs, int syscall_exit_p)
{
int ret = 0;
if (test_thread_flag(TIF_SYSCALL_TRACE)) {
if (syscall_exit_p)
tracehook_report_syscall_exit(regs, 0);
else
ret = tracehook_report_syscall_entry(regs);
}
return ret;
}
/*
* Called with IRQs on and fully valid regs. Returns with IRQs off in a
* state such that we can immediately switch to user mode.
*/
__visible void syscall_return_slowpath(struct pt_regs *regs)
{
struct thread_info *ti = pt_regs_to_thread_info(regs);
u32 cached_flags = READ_ONCE(ti->flags);
bool step;
CT_WARN_ON(ct_state() != CONTEXT_KERNEL);
if (WARN(irqs_disabled(), "syscall %ld left IRQs disabled",
regs->orig_ax))
local_irq_enable();
/*
* First do one-time work. If these work items are enabled, we
* want to run them exactly once per syscall exit with IRQs on.
*/
if (cached_flags & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT |
_TIF_SINGLESTEP | _TIF_SYSCALL_TRACEPOINT)) {
audit_syscall_exit(regs);
if (cached_flags & _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(
(cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
== _TIF_SINGLESTEP);
if (step || cached_flags & _TIF_SYSCALL_TRACE)
tracehook_report_syscall_exit(regs, step);
}
#ifdef CONFIG_COMPAT
/*
* Compat syscalls set TS_COMPAT. Make sure we clear it before
* returning to user mode.
*/
ti->status &= ~TS_COMPAT;
#endif
local_irq_disable();
prepare_exit_to_usermode(regs);
}
void syscall_trace_leave(struct pt_regs *regs)
{
int ptraced = current->ptrace;
audit_syscall_exit(regs);
/* Fake a debug trap */
if (ptraced & PT_DTRACE)
send_sigtrap(current, ®s->regs, 0);
if (!test_thread_flag(TIF_SYSCALL_TRACE))
return;
tracehook_report_syscall_exit(regs, 0);
/* force do_signal() --> is_syscall() */
if (ptraced & PT_PTRACED)
set_thread_flag(TIF_SIGPENDING);
}
/*
* Notification of system call entry/exit
* - triggered by current->work.syscall_trace
*/
asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
/*
* We may come here right after calling schedule_user()
* or do_notify_resume(), in which case we can be in RCU
* user mode.
*/
user_exit();
audit_syscall_exit(regs);
if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
trace_sys_exit(regs, regs_return_value(regs));
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(regs, 0);
user_enter();
}
static void tracehook_report_syscall(struct pt_regs *regs,
enum ptrace_syscall_dir dir)
{
int regno;
unsigned long saved_reg;
/*
* A scratch register (ip(r12) on AArch32, x7 on AArch64) is
* used to denote syscall entry/exit:
*/
regno = (is_compat_task() ? 12 : 7);
saved_reg = regs->regs[regno];
regs->regs[regno] = dir;
if (dir == PTRACE_SYSCALL_EXIT)
tracehook_report_syscall_exit(regs, 0);
else if (tracehook_report_syscall_entry(regs))
regs->syscallno = ~0UL;
regs->regs[regno] = saved_reg;
}
static void syscall_slow_exit_work(struct pt_regs *regs, u32 cached_flags)
{
bool step;
audit_syscall_exit(regs);
if (cached_flags & _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(
(cached_flags & (_TIF_SINGLESTEP | _TIF_SYSCALL_EMU))
== _TIF_SINGLESTEP);
if (step || cached_flags & _TIF_SYSCALL_TRACE)
tracehook_report_syscall_exit(regs, step);
}
asmlinkage void syscall_trace_exit(struct pt_regs *regs)
{
tracehook_report_syscall_exit(regs, 0);
}
