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 void syscall_trace_exit(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
trace_sys_exit(regs, regs_return_value(regs));
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
}
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_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));
}
/*
* 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);
}
/*
* 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 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);
}