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/*
* arch/xtensa/kernel/signal.c
*
* Default platform functions.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2005, 2006 Tensilica Inc.
* Copyright (C) 1991, 1992 Linus Torvalds
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*
* Chris Zankel <chris@zankel.net>
* Joe Taylor <joe@tensilica.com>
*/
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/personality.h>
#include <linux/tracehook.h>
#include <linux/sched/task_stack.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <asm/coprocessor.h>
#include <asm/unistd.h>
extern struct task_struct *coproc_owners[];
struct rt_sigframe
{
struct siginfo info;
struct ucontext uc;
struct {
xtregs_opt_t opt;
xtregs_user_t user;
#if XTENSA_HAVE_COPROCESSORS
xtregs_coprocessor_t cp;
#endif
} xtregs;
unsigned char retcode[6];
unsigned int window[4];
};
/*
* Flush register windows stored in pt_regs to stack.
* Returns 1 for errors.
*/
int
flush_window_regs_user(struct pt_regs *regs)
{
const unsigned long ws = regs->windowstart;
const unsigned long wb = regs->windowbase;
unsigned long sp = 0;
unsigned long wm;
int err = 1;
int base;
/* Return if no other frames. */
if (regs->wmask == 1)
return 0;
/* Rotate windowmask and skip empty frames. */
wm = (ws >> wb) | (ws << (XCHAL_NUM_AREGS / 4 - wb));
base = (XCHAL_NUM_AREGS / 4) - (regs->wmask >> 4);
/* For call8 or call12 frames, we need the previous stack pointer. */
if ((regs->wmask & 2) == 0)
if (__get_user(sp, (int*)(regs->areg[base * 4 + 1] - 12)))
goto errout;
/* Spill frames to stack. */
while (base < XCHAL_NUM_AREGS / 4) {
int m = (wm >> base);
int inc = 0;
/* Save registers a4..a7 (call8) or a4...a11 (call12) */
if (m & 2) { /* call4 */
inc = 1;
} else if (m & 4) { /* call8 */
if (copy_to_user(&SPILL_SLOT_CALL8(sp, 4),
®s->areg[(base + 1) * 4], 16))
goto errout;
inc = 2;
} else if (m & 8) { /* call12 */
if (copy_to_user(&SPILL_SLOT_CALL12(sp, 4),
®s->areg[(base + 1) * 4], 32))
goto errout;
inc = 3;
}
/* Save current frame a0..a3 under next SP */
sp = regs->areg[((base + inc) * 4 + 1) % XCHAL_NUM_AREGS];
if (copy_to_user(&SPILL_SLOT(sp, 0), ®s->areg[base * 4], 16))
goto errout;
/* Get current stack pointer for next loop iteration. */
sp = regs->areg[base * 4 + 1];
base += inc;
}
regs->wmask = 1;
regs->windowstart = 1 << wb;
return 0;
errout:
return err;
}
/*
* Note: We don't copy double exception 'regs', we have to finish double exc.
* first before we return to signal handler! This dbl.exc.handler might cause
* another double exception, but I think we are fine as the situation is the
* same as if we had returned to the signal handerl and got an interrupt
* immediately...
*/
static int
setup_sigcontext(struct rt_sigframe __user *frame, struct pt_regs *regs)
{
struct sigcontext __user *sc = &frame->uc.uc_mcontext;
struct thread_info *ti = current_thread_info();
int err = 0;
#define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
COPY(pc);
COPY(ps);
COPY(lbeg);
COPY(lend);
COPY(lcount);
COPY(sar);
#undef COPY
err |= flush_window_regs_user(regs);
err |= __copy_to_user (sc->sc_a, regs->areg, 16 * 4);
err |= __put_user(0, &sc->sc_xtregs);
if (err)
return err;
#if XTENSA_HAVE_COPROCESSORS
coprocessor_flush_all(ti);
coprocessor_release_all(ti);
err |= __copy_to_user(&frame->xtregs.cp, &ti->xtregs_cp,
sizeof (frame->xtregs.cp));
#endif
err |= __copy_to_user(&frame->xtregs.opt, ®s->xtregs_opt,
sizeof (xtregs_opt_t));
err |= __copy_to_user(&frame->xtregs.user, &ti->xtregs_user,
sizeof (xtregs_user_t));
err |= __put_user(err ? NULL : &frame->xtregs, &sc->sc_xtregs);
return err;
}
static int
restore_sigcontext(struct pt_regs *regs, struct rt_sigframe __user *frame)
{
struct sigcontext __user *sc = &frame->uc.uc_mcontext;
struct thread_info *ti = current_thread_info();
unsigned int err = 0;
unsigned long ps;
#define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
COPY(pc);
COPY(lbeg);
COPY(lend);
COPY(lcount);
COPY(sar);
#undef COPY
/* All registers were flushed to stack. Start with a pristine frame. */
regs->wmask = 1;
regs->windowbase = 0;
regs->windowstart = 1;
regs->syscall = NO_SYSCALL; /* disable syscall checks */
/* For PS, restore only PS.CALLINC.
* Assume that all other bits are either the same as for the signal
* handler, or the user mode value doesn't matter (e.g. PS.OWB).
*/
err |= __get_user(ps, &sc->sc_ps);
regs->ps = (regs->ps & ~PS_CALLINC_MASK) | (ps & PS_CALLINC_MASK);
/* Additional corruption checks */
if ((regs->lcount > 0)
&& ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )
err = 1;
err |= __copy_from_user(regs->areg, sc->sc_a, 16 * 4);
if (err)
return err;
/* The signal handler may have used coprocessors in which
* case they are still enabled. We disable them to force a
* reloading of the original task's CP state by the lazy
* context-switching mechanisms of CP exception handling.
* Also, we essentially discard any coprocessor state that the
* signal handler created. */
#if XTENSA_HAVE_COPROCESSORS
coprocessor_release_all(ti);
err |= __copy_from_user(&ti->xtregs_cp, &frame->xtregs.cp,
sizeof (frame->xtregs.cp));
#endif
err |= __copy_from_user(&ti->xtregs_user, &frame->xtregs.user,
sizeof (xtregs_user_t));
err |= __copy_from_user(®s->xtregs_opt, &frame->xtregs.opt,
sizeof (xtregs_opt_t));
return err;
}
/*
* Do a signal return; undo the signal stack.
*/
asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3,
long a4, long a5, struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
sigset_t set;
int ret;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
if (regs->depc > 64)
panic("rt_sigreturn in double exception!\n");
frame = (struct rt_sigframe __user *) regs->
|