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