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/*
* Signal support for Hexagon processor
*
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <linux/linkage.h>
#include <linux/syscalls.h>
#include <linux/freezer.h>
#include <linux/tracehook.h>
#include <asm/registers.h>
#include <asm/thread_info.h>
#include <asm/unistd.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
#include <asm/signal.h>
#include <asm/vdso.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
struct rt_sigframe {
unsigned long tramp[2];
struct siginfo info;
struct ucontext uc;
};
static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
size_t frame_size)
{
unsigned long sp = regs->r29;
/* Switch to signal stack if appropriate */
if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
sp = current->sas_ss_sp + current->sas_ss_size;
return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
}
static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
{
unsigned long tmp;
int err = 0;
err |= copy_to_user(&sc->sc_regs.r0, ®s->r00,
32*sizeof(unsigned long));
err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
err |= __put_user(regs->m0, &sc->sc_regs.m0);
err |= __put_user(regs->m1, &sc->sc_regs.m1);
err |= __put_user(regs->usr, &sc->sc_regs.usr);
err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
err |= __put_user(regs->gp, &sc->sc_regs.gp);
err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
return err;
}
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
unsigned long tmp;
int err = 0;
err |= copy_from_user(®s->r00, &sc->sc_regs.r0,
32 * sizeof(unsigned long));
err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
err |= __get_user(regs->m0, &sc->sc_regs.m0);
err |= __get_user(regs->m1, &sc->sc_regs.m1);
err |= __get_user(regs->usr, &sc->sc_regs.usr);
err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
err |= __get_user(regs->gp, &sc->sc_regs.gp);
err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
return err;
}
/*
* 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));
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;
}
/*
* Setup invocation of signal handler
*/
static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
struct pt_regs *regs)
{
/*
* If we're handling a signal that aborted a system call,
* set up the error return value before adding the signal
* frame to the stack.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->r00 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->r00 = -EINTR;
break;
}
/* Fall through */
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
break;
default:
break;
}
}
/*
* Set up the stack frame; not doing the SA_SIGINFO thing. We
* only set up the rt_frame flavor.
*/
/* If there was an error on setup, no signal was delivered. */
if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0)
return;
block_sigmask(ka, sig);
tracehook_signal_handler(sig, info, ka, regs,
test_thread_flag(TIF_SINGLESTEP));
}
/*
* Called from return-from-event code.
*/
static void do_signal(struct pt_regs *regs)
{
struct k_sigaction sigact;
siginfo_t info;
int signo;
if (!user_mode(regs))
return;
signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
if (signo > 0) {
handle_signal(signo, &info, &sigact, regs);
return;
}
/*
* If we came from a system call, handle the restart.
*/
if (regs->syscall_nr >= 0) {
switch (regs->r00) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->r06 = regs->syscall_nr;
break;
case -ERESTART_RESTARTBLOCK:
regs->r06 = __NR_restart_syscall;
break;
default:
goto no_restart;
}
pt_set_elr(regs, pt_elr(regs) - 4);
regs->r00 = regs->restart_r0;
}
no_restart:
/* If there's no signal to deliver, put the saved sigmask back */
restore_saved_sigmask();
}
void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
/*
* Architecture-specific wrappers for signal-related system calls
*/
asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
{
struct pt_regs *regs = current_thread_info()->regs;
return do_sigaltstack(uss, uoss, regs->r29);
}
asmlinkage int sys_rt_sigreturn(void)
{
struct pt_regs *regs = current_thread_info()->regs;
struct rt_sigframe __user *frame;
sigset_t blocked;
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;
frame = (struct rt_sigframe __user *)pt_psp(regs);
if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
goto badframe;
sigdelsetmask(&blocked, ~_BLOCKABLE);
set_current_blocked(&blocked);
if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
goto badframe;
/* Restore the user's stack as well */
pt_psp(regs) = regs->r29;
/*
* Leave a trace in the stack frame that this was a sigreturn.
* If the system call is to replay, we've already restored the
* number in the GPR slot and it will be regenerated on the
* new system call trap entry. Note that if restore_sigcontext()
* did something other than a bulk copy of the pt_regs struct,
* we could avoid this assignment by simply not overwriting
* regs->syscall_nr.
*/
regs->syscall_nr = __NR_rt_sigreturn;
/*
* If we were meticulous, we'd only call this if we knew that
* we were actually going to use an alternate stack, and we'd
* consider any error to be fatal. What we do here, in common
* with many other architectures, is call it blindly and only
* consider the -EFAULT return case to be proof of a problem.
*/
if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
goto badframe;
return 0;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
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