/* * Copyright (C) 2003 PathScale, Inc. * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) * Licensed under the GPL */ #include #include #include #include #include #include #include "frame_kern.h" #include "skas.h" static int copy_sc_from_user(struct pt_regs *regs, struct sigcontext __user *from) { struct sigcontext sc; struct user_i387_struct fp; void __user *buf; int err; err = copy_from_user(&sc, from, sizeof(sc)); if (err) return err; #define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname GETREG(R8, r8); GETREG(R9, r9); GETREG(R10, r10); GETREG(R11, r11); GETREG(R12, r12); GETREG(R13, r13); GETREG(R14, r14); GETREG(R15, r15); GETREG(DI, di); GETREG(SI, si); GETREG(BP, bp); GETREG(BX, bx); GETREG(DX, dx); GETREG(AX, ax); GETREG(CX, cx); GETREG(SP, sp); GETREG(IP, ip); GETREG(EFLAGS, flags); GETREG(CS, cs); #undef GETREG buf = sc.fpstate; err = copy_from_user(&fp, buf, sizeof(struct user_i387_struct)); if (err) return 1; err = restore_fp_registers(userspace_pid[current_thread_info()->cpu], (unsigned long *) &fp); if (err < 0) { printk(KERN_ERR "copy_sc_from_user - " "restore_fp_registers failed, errno = %d\n", -err); return 1; } return 0; } static int copy_sc_to_user(struct sigcontext __user *to, struct _fpstate __user *to_fp, struct pt_regs *regs, unsigned long mask, unsigned long sp) { struct faultinfo * fi = ¤t->thread.arch.faultinfo; struct sigcontext sc; struct user_i387_struct fp; int err = 0; memset(&sc, 0, sizeof(struct sigcontext)); #define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] PUTREG(DI, di); PUTREG(SI, si); PUTREG(BP, bp); /* * Must use original RSP, which is passed in, rather than what's in * signal frame. */ sc.sp = sp; PUTREG(BX, bx); PUTREG(DX, dx); PUTREG(CX, cx); PUTREG(AX, ax); PUTREG(R8, r8); PUTREG(R9, r9); PUTREG(R10, r10); PUTREG(R11, r11); PUTREG(R12, r12); PUTREG(R13, r13); PUTREG(R14, r14); PUTREG(R15, r15); PUTREG(CS, cs); /* XXX x86_64 doesn't do this */ sc.cr2 = fi->cr2; sc.err = fi->error_code; sc.trapno = fi->trap_no; PUTREG(IP, ip); PUTREG(EFLAGS, flags); #undef PUTREG sc.oldmask = mask; err = copy_to_user(to, &sc, sizeof(struct sigcontext)); if (err) return 1; err = save_fp_registers(userspace_pid[current_thread_info()->cpu], (unsigned long *) &fp); if (err < 0) { printk(KERN_ERR "copy_sc_from_user - restore_fp_registers " "failed, errno = %d\n", -err); return 1; } if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) return 1; return err; } struct rt_sigframe { char __user *pretcode; struct ucontext uc; struct siginfo info; struct _fpstate fpstate; }; int setup_signal_stack_si(unsigned long stack_top, int sig, struct k_sigaction *ka, struct pt_regs * regs, siginfo_t *info, sigset_t *set) { struct rt_sigframe __user *frame; unsigned long save_sp = PT_REGS_RSP(regs); int err = 0; struct task_struct *me = current; frame = (struct rt_sigframe __user *) round_down(stack_top - sizeof(struct rt_sigframe), 16); /* Subtract 128 for a red zone and 8 for proper alignment */ frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto out; if (ka->sa.sa_flags & SA_SIGINFO) { err |= copy_siginfo_to_user(&frame->info, info); if (err) goto out; } /* * Update SP now because the page fault handler refuses to extend * the stack if the faulting address is too far below the current * SP, which frame now certainly is. If there's an error, the original * value is restored on the way out. * When writing the sigcontext to the stack, we have to write the * original value, so that's passed to copy_sc_to_user, which does * the right thing with it. */ PT_REGS_RSP(regs) = (unsigned long) frame; /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &frame->uc.uc_link); err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(save_sp), &frame->uc.uc_stack.ss_flags); err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, set->sig[0], save_sp); err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); if (sizeof(*set) == 16) { __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); } else err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); /* * Set up to return from userspace. If provided, use a stub * already in userspace. */ /* x86-64 should always use SA_RESTORER. */ if (ka->sa.sa_flags & SA_RESTORER) err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); else /* could use a vstub here */ goto restore_sp; if (err) goto restore_sp; /* Set up registers for signal handler */ { struct exec_domain *ed = current_thread_info()->exec_domain; if (unlikely(ed && ed->signal_invmap && sig < 32)) sig = ed->signal_invmap[sig]; } PT_REGS_RDI(regs) = sig; /* In case the signal handler was declared without prototypes */ PT_REGS_RAX(regs) = 0; /* * This also works for non SA_SIGINFO handlers because they expect the * next argument after the signal number on the stack. */ PT_REGS_RSI(regs) = (unsigned long) &frame->info; PT_REGS_RDX(regs) = (unsigned long) &frame->uc; PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler; out: return err; restore_sp: PT_REGS_RSP(regs) = save_sp; return err; } long sys_rt_sigreturn(struct pt_regs *regs) { unsigned long sp = PT_REGS_SP(¤t->thread.regs); struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(sp - 8); struct ucontext __user *uc = &frame->uc; sigset_t set; if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) goto segfault; sigdelsetmask(&set, ~_BLOCKABLE); set_current_blocked(&set); if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) goto segfault; /* Avoid ERESTART handling */ PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1; return PT_REGS_SYSCALL_RET(¤t->thread.regs); segfault: force_sig(SIGSEGV, current); return 0; }