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