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/*
* Copyright 2004-2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later
*/
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/sched/task_stack.h>
#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <asm/fixed_code.h>
#include <asm/syscall.h>
/* Location of the trace bit in SYSCFG. */
#define TRACE_BITS 0x0001
struct fdpic_func_descriptor {
unsigned long text;
unsigned long GOT;
};
struct rt_sigframe {
int sig;
struct siginfo *pinfo;
void *puc;
/* This is no longer needed by the kernel, but unfortunately userspace
* code expects it to be there. */
char retcode[8];
struct siginfo info;
struct ucontext uc;
};
static inline int
rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
{
unsigned long usp = 0;
int err = 0;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
/* restore passed registers */
RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
RESTORE(p4); RESTORE(p5);
err |= __get_user(usp, &sc->sc_usp);
wrusp(usp);
RESTORE(a0w); RESTORE(a1w);
RESTORE(a0x); RESTORE(a1x);
RESTORE(astat);
RESTORE(rets);
RESTORE(pc);
RESTORE(retx);
RESTORE(fp);
RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
RESTORE(lc0); RESTORE(lc1);
RESTORE(lt0); RESTORE(lt1);
RESTORE(lb0); RESTORE(lb1);
RESTORE(seqstat);
regs->orig_p0 = -1; /* disable syscall checks */
*pr0 = regs->r0;
return err;
}
asmlinkage int sys_rt_sigreturn(void)
{
struct pt_regs *regs = current_pt_regs();
unsigned long usp = rdusp();
struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
sigset_t set;
int r0;
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return r0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
{
int err = 0;
#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
SETUP(p4); SETUP(p5);
err |= __put_user(rdusp(), &sc->sc_usp);
SETUP(a0w); SETUP(a1w);
SETUP(a0x); SETUP(a1x);
SETUP(astat);
SETUP(rets);
SETUP(pc);
SETUP(retx);
SETUP(fp);
SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
SETUP(lc0); SETUP(lc1);
SETUP(lt0); SETUP(lt1);
SETUP(lb0); SETUP(lb1);
SETUP(seqstat);
return err;
}
static inline void *get_sigframe(struct ksignal *ksig,
size_t frame_size)
{
unsigned long usp = sigsp(rdusp(), ksig);
return (void *)((usp - frame_size) & -8UL);
}
static int
setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe *frame;
int err = 0;
frame = get_sigframe(ksig, sizeof(*frame));
err |= __put_user(ksig->sig, &frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, rdusp());
err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
return -EFAULT;
/* Set up registers for signal handler */
if (current->personality & FDPIC_FUNCPTRS) {
struct fdpic_func_descriptor __user *funcptr =
(struct fdpic_func_descriptor *) ksig->ka.sa.sa_handler;
u32 pc, p3;
err |= __get_user(pc, &funcptr->text);
err |= __get_user(p3, &funcptr->GOT);
if (err)
return -EFAULT;
regs->pc = pc;
regs->p3 = p3;
} else
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
wrusp((unsigned long)frame);
regs->rets = SIGRETURN_STUB;
regs->r0 = frame->sig;
regs->r1 = (unsigned long)(&frame->info);
regs->r2 = (unsigned long)(&frame->uc);
return 0;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->r0) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->r0 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->r0 = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
do_restart:
regs->p0 = regs->orig_p0;
regs->r0 = regs->orig_r0;
regs->pc -= 2;
break;
case -ERESTART_RESTARTBLOCK:
regs->p0 = __NR_restart_syscall;
regs->pc -= 2;
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
int ret;
/* are we from a system call? to see pt_regs->orig_p0 */
if (regs->orig_p0 >= 0)
/* If so, check system call restarting.. */
handle_restart(regs, &ksig->ka, 1);
/* set up the stack frame */
ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals
* that the kernel can handle, and then we build all the user-level signal
* handling stack-frames in one go after that.
*/
asmlinkage void do_signal(struct pt_regs *regs)
{
struct ksignal ksig;
current->thread.esp0 = (unsigned long)regs;
if (get_signal(&ksig)) {
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs);
return;
}
/* Did we come from a system call? */
if (regs->orig_p0 >= 0)
/* Restart the system call - no handlers present */
handle_restart(regs, NULL, 0);
/* if there's no signal to deliver, we just put the saved sigmask
* back */
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
*/
asmlinkage void do_notify_resume(struct pt_regs *regs)
{
if (test_thread_flag(TIF_SIGPENDING))
do_signal(regs);
if (test_thread_flag(TIF_NOTIFY_RESUME)) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
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