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/*
* Copyright (C) 2013-2014 Altera Corporation
* Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2004 Microtronix Datacom Ltd
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 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.
*/
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/resume_user_mode.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
/*
* Do a signal return; undo the signal stack.
*
* Keep the return code on the stack quadword aligned!
* That makes the cache flush below easier.
*/
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
};
static inline int rt_restore_ucontext(struct pt_regs *regs,
struct switch_stack *sw,
struct ucontext __user *uc, int *pr2)
{
int temp;
unsigned long __user *gregs = uc->uc_mcontext.gregs;
int err;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
err = __get_user(temp, &uc->uc_mcontext.version);
if (temp != MCONTEXT_VERSION)
goto badframe;
/* restore passed registers */
err |= __get_user(regs->r1, &gregs[0]);
err |= __get_user(regs->r2, &gregs[1]);
err |= __get_user(regs->r3, &gregs[2]);
err |= __get_user(regs->r4, &gregs[3]);
err |= __get_user(regs->r5, &gregs[4]);
err |= __get_user(regs->r6, &gregs[5]);
err |= __get_user(regs->r7, &gregs[6]);
err |= __get_user(regs->r8, &gregs[7]);
err |= __get_user(regs->r9, &gregs[8]);
err |= __get_user(regs->r10, &gregs[9]);
err |= __get_user(regs->r11, &gregs[10]);
err |= __get_user(regs->r12, &gregs[11]);
err |= __get_user(regs->r13, &gregs[12]);
err |= __get_user(regs->r14, &gregs[13]);
err |= __get_user(regs->r15, &gregs[14]);
err |= __get_user(sw->r16, &gregs[15]);
err |= __get_user(sw->r17, &gregs[16]);
err |= __get_user(sw->r18, &gregs[17]);
err |= __get_user(sw->r19, &gregs[18]);
err |= __get_user(sw->r20, &gregs[19]);
err |= __get_user(sw->r21, &gregs[20]);
err |= __get_user(sw->r22, &gregs[21]);
err |= __get_user(sw->r23, &gregs[22]);
/* gregs[23] is handled below */
err |= __get_user(sw->fp, &gregs[24]); /* Verify, should this be
settable */
err |= __get_user(sw->gp, &gregs[25]); /* Verify, should this be
settable */
err |= __get_user(temp, &gregs[26]); /* Not really necessary no user
settable bits */
err |= __get_user(regs->ea, &gregs[27]);
err |= __get_user(regs->ra, &gregs[23]);
err |= __get_user(regs->sp, &gregs[28]);
regs->orig_r2 = -1; /* disable syscall checks */
err |= restore_altstack(&uc->uc_stack);
if (err)
goto badframe;
*pr2 = regs->r2;
return err;
badframe:
return 1;
}
asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
{
struct pt_regs *regs = (struct pt_regs *)(sw + 1);
/* Verify, can we follow the stack back */
struct rt_sigframe __user *frame;
sigset_t set;
int rval;
frame = (struct rt_sigframe __user *) regs->sp;
if (!access_ok(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_ucontext(regs, sw, &frame->uc, &rval))
goto badframe;
return rval;
badframe:
force_sig(SIGSEGV);
return 0;
}
static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
unsigned long __user *gregs = uc->uc_mcontext.gregs;
int err = 0;
err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
err |= __put_user(regs->r1, &gregs[0]);
err |= __put_user(regs->r2, &gregs[1]);
err |= __put_user(regs->r3, &gregs[2]);
err |= __put_user(regs->r4, &gregs[3]);
err |= __put_user(regs->r5, &gregs[4]);
err |= __put_user(regs->r6, &gregs[5]);
err |= __put_user(regs->r7, &gregs[6]);
err |= __put_user(regs->r8, &gregs[7]);
err |= __put_user(regs->r9, &gregs[8]);
err |= __put_user(regs->r10, &gregs[9]);
err |= __put_user(regs->r11, &gregs[10]);
err |= __put_user(regs->r12, &gregs[11]);
err |= __put_user(regs->r13, &gregs[12]);
err |= __put_user(regs->r14, &gregs[13]);
err |= __put_user(regs->r15, &gregs[14]);
err |= __put_user(sw->r16, &gregs[15]);
err |= __put_user(sw->r17, &gregs[16]);
err |= __put_user(sw->r18, &gregs[17]);
err |= __put_user(sw->r19, &gregs[18]);
err |= __put_user(sw->r20, &gregs[19]);
err |= __put_user(sw->r21, &gregs[20]);
err |= __put_user(sw->r22, &gregs[21]);
err |= __put_user(sw->r23, &gregs[22]);
err |= __put_user(regs->ra, &gregs[23]);
err |= __put_user(sw->fp, &gregs[24]);
err |= __put_user(sw->gp, &gregs[25]);
err |= __put_user(regs->ea, &gregs[27]);
err |= __put_user(regs->sp, &gregs[28]);
return err;
}
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
size_t frame_size)
{
unsigned long usp;
/* Default to using normal stack. */
usp = regs->sp;
/* This is the X/Open sanctioned signal stack switching. */
usp = sigsp(usp, ksig);
/* Verify, is it 32 or 64 bit aligned */
return (void __user *)((usp - frame_size) & -8UL);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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, regs->sp);
err |= rt_setup_ucontext(&frame->uc, regs);
err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up to return from userspace; jump to fixed address sigreturn
trampoline on kuser page. */
regs->ra = (unsigned long) (0x1044);
/* Set up registers for signal handler */
regs->sp = (unsigned long) frame;
regs->r4 = (unsigned long) ksig->sig;
regs->r5 = (unsigned long) &frame->info;
regs->r6 = (unsigned long) &frame->uc;
regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
return 0;
give_sigsegv:
force_sigsegv(ksig->sig);
return -EFAULT;
}
/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
int ret;
sigset_t *oldset = sigmask_to_save();
/* set up the stack frame */
ret = setup_rt_frame(ksig, oldset, regs);
signal_setup_done(ret, ksig, 0);
}
static int do_signal(struct pt_regs *regs)
{
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
int restart = 0;
struct ksignal ksig;
current->thread.kregs = regs;
/*
* If we were from a system call, check for system call restarting...
*/
if (regs->orig_r2 >= 0 && regs->r1) {
continue_addr = regs->ea;
restart_addr = continue_addr - 4;
retval = regs->r2;
/*
* Prepare for system call restart. We do this here so that a
* debugger will see the already changed PC.
*/
switch (retval) {
case ERESTART_RESTARTBLOCK:
restart = -2;
fallthrough;
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
restart++;
regs->r2 = regs->orig_r2;
regs->r7 = regs->orig_r7;
regs->ea = restart_addr;
break;
}
regs->orig_r2 = -1;
}
if (get_signal(&ksig)) {
/* handler */
if (unlikely(restart && regs->ea == restart_addr)) {
if (retval == ERESTARTNOHAND ||
retval == ERESTART_RESTARTBLOCK ||
(retval == ERESTARTSYS
&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
regs->r2 = EINTR;
regs->r7 = 1;
regs->ea = continue_addr;
}
}
handle_signal(&ksig, regs);
return 0;
}
/*
* No handler present
*/
if (unlikely(restart) && regs->ea == restart_addr) {
regs->ea = continue_addr;
regs->r2 = __NR_restart_syscall;
}
/*
* If there's no signal to deliver, we just put the saved sigmask back.
*/
restore_saved_sigmask();
return restart;
}
asmlinkage int do_notify_resume(struct pt_regs *regs)
{
/*
* We want the common case to go fast, which is why we may in certain
* cases get here from kernel mode. Just return without doing anything
* if so.
*/
if (!user_mode(regs))
return 0;
if (test_thread_flag(TIF_SIGPENDING) ||
test_thread_flag(TIF_NOTIFY_SIGNAL)) {
int restart = do_signal(regs);
if (unlikely(restart)) {
/*
* Restart without handlers.
* Deal with it without leaving
* the kernel space.
*/
return restart;
}
} else if (test_thread_flag(TIF_NOTIFY_RESUME))
resume_user_mode_work(regs);
return 0;
}
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