/* * linux/arch/parisc/kernel/signal.c: Architecture-specific signal * handling support. * * Copyright (C) 2000 David Huggins-Daines * Copyright (C) 2000 Linuxcare, Inc. * * Based on the ia64, i386, and alpha versions. * * Like the IA-64, we are a recent enough port (we are *starting* * with glibc2.2) that we do not need to support the old non-realtime * Linux signals. Therefore we don't. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_COMPAT #include "signal32.h" #endif #define DEBUG_SIG 0 #define DEBUG_SIG_LEVEL 2 #if DEBUG_SIG #define DBG(LEVEL, ...) \ ((DEBUG_SIG_LEVEL >= LEVEL) \ ? printk(__VA_ARGS__) : (void) 0) #else #define DBG(LEVEL, ...) #endif /* gcc will complain if a pointer is cast to an integer of different * size. If you really need to do this (and we do for an ELF32 user * application in an ELF64 kernel) then you have to do a cast to an * integer of the same size first. The A() macro accomplishes * this. */ #define A(__x) ((unsigned long)(__x)) /* * Do a signal return - restore sigcontext. */ /* Trampoline for calling rt_sigreturn() */ #define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */ #define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */ #define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */ #define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */ #define INSN_NOP 0x08000240 /* nop */ /* For debugging */ #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */ static long restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) { long err = 0; err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr)); err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr)); err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq)); err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq)); err |= __get_user(regs->sar, &sc->sc_sar); DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n", regs->iaoq[0],regs->iaoq[1]); DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]); return err; } void sys_rt_sigreturn(struct pt_regs *regs, int in_syscall) { struct rt_sigframe __user *frame; sigset_t set; unsigned long usp = (regs->gr[30] & ~(0x01UL)); unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE; #ifdef CONFIG_64BIT compat_sigset_t compat_set; struct compat_rt_sigframe __user * compat_frame; if (is_compat_task()) sigframe_size = PARISC_RT_SIGFRAME_SIZE32; #endif current->restart_block.fn = do_no_restart_syscall; /* Unwind the user stack to get the rt_sigframe structure. */ frame = (struct rt_sigframe __user *) (usp - sigframe_size); DBG(2,"sys_rt_sigreturn: frame is %p\n", frame); regs->orig_r28 = 1; /* no restarts for sigreturn */ #ifdef CONFIG_64BIT compat_frame = (struct compat_rt_sigframe __user *)frame; if (is_compat_task()) { DBG(2,"sys_rt_sigreturn: ELF32 process.\n"); if (__copy_from_user(&compat_set, &compat_frame->uc.uc_sigmask, sizeof(compat_set))) goto give_sigsegv; sigset_32to64(&set,&compat_set); } else #endif { if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto give_sigsegv; } set_current_blocked(&set); /* Good thing we saved the old gr[30], eh? */ #ifdef CONFIG_64BIT if (is_compat_task()) { DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n", &compat_frame->uc.uc_mcontext); // FIXME: Load upper half from register file if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, &compat_frame->regs, regs)) goto give_sigsegv; DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", usp, &compat_frame->uc.uc_stack); if (compat_restore_altstack(&compat_frame->uc.uc_stack)) goto give_sigsegv; } else #endif { DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n", &frame->uc.uc_mcontext); if (restore_sigcontext(&frame->uc.uc_mcontext, regs)) goto give_sigsegv; DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", usp, &frame->uc.uc_stack); if (restore_altstack(&frame->uc.uc_stack)) goto give_sigsegv; } /* If we are on the syscall path IAOQ will not be restored, and * if we are on the interrupt path we must not corrupt gr31. */ if (in_syscall) regs->gr[31] = regs->iaoq[0]; #if DEBUG_SIG DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]); show_regs(regs); #endif return; give_sigsegv: DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n"); force_sig(SIGSEGV, current); return; } /* * Set up a signal frame. */ static inline void __user * get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) { /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we don't use the parameter it doesn't matter */ DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n", (unsigned long)ka, sp, frame_size); /* Align alternate stack and reserve 64 bytes for the signal handler's frame marker. */ if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp)) sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */ DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp); return (void __user *) sp; /* Stacks grow up. Fun. */ } static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall) { unsigned long flags = 0; long err = 0; if (on_sig_stack((unsigned long) sc)) flags |= PARISC_SC_FLAG_ONSTACK; if (in_syscall) { flags |= PARISC_SC_FLAG_IN_SYSCALL; /* regs->iaoq is undefined in the syscall return path */ err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]); err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]); err |= __put_user(regs->sr[3], &sc->sc_iasq[0]); err |= __put_user(regs->sr[3], &sc->sc_iasq[1]); DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n", regs->gr[31], regs->gr[31]+4); } else { err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq)); err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq)); DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", regs->iaoq[0], regs->iaoq[1]); } err |= __put_user(flags, &sc->sc_flags); err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr)); err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr)); err |= __put_user(regs->sar, &sc->sc_sar); DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]); return err; } static long setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs, int in_syscall) { struct rt_sigframe __user *frame; unsigned long rp, usp; unsigned long haddr, sigframe_size; unsigned long start, end; int err = 0; #ifdef CONFIG_64BIT struct compat_rt_sigframe __user * compat_frame; compat_sigset_t compat_set; #endif usp = (regs->gr[30] & ~(0x01UL)); /*FIXME: frame_size parameter is unused, remove it. */ frame = get_sigframe(&ksig->ka, usp, sizeof(*frame)); DBG(1,"SETUP_RT_FRAME: START\n"); DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info); #ifdef CONFIG_64BIT compat_frame = (struct compat_rt_sigframe __user *)frame; if (is_compat_task()) { DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info); err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info); err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]); DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc); DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext); err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, &compat_frame->regs, regs, in_syscall); sigset_64to32(&compat_set,set); err |= __copy_to_user(&compat_frame->uc.uc_sigmask, &compat_set, sizeof(compat_set)); } else #endif { DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info); err |= copy_siginfo_to_user(&frame->info, &ksig->info); err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]); DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc); DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext); err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall); /* FIXME: Should probably be converted as well for the compat case */ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); } if (err) return -EFAULT; /* Set up to return from userspace. If provided, use a stub already in userspace. The first words of tramp are used to save the previous sigrestartblock trampoline that might be on the stack. We start the sigreturn trampoline at SIGRESTARTBLOCK_TRAMP+X. */ err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0, &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]); err |= __put_user(INSN_LDI_R20, &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]); err |= __put_user(INSN_BLE_SR2_R0, &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]); err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]); #if DEBUG_SIG /* Assert that we're flushing in the correct space... */ { unsigned long sid; asm ("mfsp %%sr3,%0" : "=r" (sid)); DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n", sid, frame->tramp); } #endif start = (unsigned long) &frame->tramp[0]; end = (unsigned long) &frame->tramp[TRAMP_SIZE]; flush_user_dcache_range_asm(start, end); flush_user_icache_range_asm(start, end); /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP */ rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP]; if (err) return -EFAULT; haddr = A(ksig->ka.sa.sa_handler); /* The sa_handler may be a pointer to a function descriptor */ #ifdef CONFIG_64BIT if (is_compat_task()) { #endif if (haddr & PA_PLABEL_FDESC) { Elf32_Fdesc fdesc; Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3); err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); if (err) return -EFAULT; haddr = fdesc.addr; regs->gr[19] = fdesc.gp; } #ifdef CONFIG_64BIT } else { Elf64_Fdesc fdesc; Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3); err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); if (err) return -EFAULT; haddr = fdesc.addr; regs->gr[19] = fdesc.gp; DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n", haddr, regs->gr[19], in_syscall); } #endif /* The syscall return path will create IAOQ values from r31. */ sigframe_size = PARISC_RT_SIGFRAME_SIZE; #ifdef CONFIG_64BIT if (is_compat_task()) sigframe_size = PARISC_RT_SIGFRAME_SIZE32; #endif if (in_syscall) { regs->gr[31] = haddr; #ifdef CONFIG_64BIT if (!test_thread_flag(TIF_32BIT)) sigframe_size |= 1; #endif } else { unsigned long psw = USER_PSW; #ifdef CONFIG_64BIT if (!test_thread_flag(TIF_32BIT)) psw |= PSW_W; #endif /* If we are singlestepping, arrange a trap to be delivered when we return to userspace. Note the semantics -- we should trap before the first insn in the handler is executed. Ref: http://sources.redhat.com/ml/gdb/2004-11/msg00245.html */ if (pa_psw(current)->r) { pa_psw(current)->r = 0; psw |= PSW_R; mtctl(-1, 0); } regs->gr[0] = psw; regs->iaoq[0] = haddr | 3; regs->iaoq[1] = regs->iaoq[0] + 4; } regs->gr[2] = rp; /* userland return pointer */ regs->gr[26] = ksig->sig; /* signal number */ #ifdef CONFIG_64BIT if (is_compat_task()) { regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */ regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */ } else #endif { regs->gr[25] = A(&frame->info); /* siginfo pointer */ regs->gr[24] = A(&frame->uc); /* ucontext pointer */ } DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n", regs->gr[30], sigframe_size, regs->gr[30] + sigframe_size); /* Raise the user stack pointer to make a proper call frame. */ regs->gr[30] = (A(frame) + sigframe_size); DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n", current->comm, current->pid, frame, regs->gr[30], regs->iaoq[0], regs->iaoq[1], rp); return 0; } /* * OK, we're invoking a handler. */ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall) { int ret; sigset_t *oldset = sigmask_to_save(); DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n", ksig->sig, ksig->ka, ksig->info, oldset, regs); /* Set up the stack frame */ ret = setup_rt_frame(ksig, oldset, regs, in_syscall); signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) || test_thread_flag(TIF_BLOCKSTEP)); DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n", regs->gr[28]); } /* * Check how the syscall number gets loaded into %r20 within * the delay branch in userspace and adjust as needed. */ static void check_syscallno_in_delay_branch(struct pt_regs *regs) { u32 opcode, source_reg; u32 __user *uaddr; int err; /* Usually we don't have to restore %r20 (the system call number) * because it gets loaded in the delay slot of the branch external * instruction via the ldi instruction. * In some cases a register-to-register copy instruction might have * been used instead, in which case we need to copy the syscall * number into the source register before returning to userspace. */ /* A syscall is just a branch, so all we have to do is fiddle the * return pointer so that the ble instruction gets executed again. */ regs->gr[31] -= 8; /* delayed branching */ /* Get assembler opcode of code in delay branch */ uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4); err = get_user(opcode, uaddr); if (err) return; /* Check if delay branch uses "ldi int,%r20" */ if ((opcode & 0xffff0000) == 0x34140000) return; /* everything ok, just return */ /* Check if delay branch uses "nop" */ if (opcode == INSN_NOP) return; /* Check if delay branch uses "copy %rX,%r20" */ if ((opcode & 0xffe0ffff) == 0x08000254) { source_reg = (opcode >> 16) & 31; regs->gr[source_reg] = regs->gr[20]; return; } pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n", current->comm, task_pid_nr(current), opcode); } static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka) { if (regs->orig_r28) return; regs->orig_r28 = 1; /* no more restarts */ /* Check the return code */ switch (regs->gr[28]) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: DBG(1,"ERESTARTNOHAND: returning -EINTR\n"); regs->gr[28] = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { DBG(1,"ERESTARTSYS: putting -EINTR\n"); regs->gr[28] = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: check_syscallno_in_delay_branch(regs); break; } } static inline void insert_restart_trampoline(struct pt_regs *regs) { if (regs->orig_r28) return; regs->orig_r28 = 1; /* no more restarts */ switch(regs->gr[28]) { case -ERESTART_RESTARTBLOCK: { /* Restart the system call - no handlers present */ unsigned int *usp = (unsigned int *)regs->gr[30]; unsigned long start = (unsigned long) &usp[2]; unsigned long end = (unsigned long) &usp[5]; long err = 0; /* Setup a trampoline to restart the syscall * with __NR_restart_syscall * * 0: * 4: <2nd half for 64-bit> * 8: ldw 0(%sp), %r31 * 12: be 0x100(%sr2, %r0) * 16: ldi __NR_restart_syscall, %r20 */ #ifdef CONFIG_64BIT err |= put_user(regs->gr[31] >> 32, &usp[0]); err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]); err |= put_user(0x0fc010df, &usp[2]); #else err |= put_user(regs->gr[31], &usp[0]); err |= put_user(0x0fc0109f, &usp[2]); #endif err |= put_user(0xe0008200, &usp[3]); err |= put_user(0x34140000, &usp[4]); WARN_ON(err); /* flush data/instruction cache for new insns */ flush_user_dcache_range_asm(start, end); flush_user_icache_range_asm(start, end); regs->gr[31] = regs->gr[30] + 8; return; } case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: check_syscallno_in_delay_branch(regs); return; default: break; } } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. * * We need to be able to restore the syscall arguments (r21-r26) to * restart syscalls. Thus, the syscall path should save them in the * pt_regs structure (it's okay to do so since they are caller-save * registers). As noted below, the syscall number gets restored for * us due to the magic of delayed branching. */ asmlinkage void do_signal(struct pt_regs *regs, long in_syscall) { struct ksignal ksig; DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n", regs, regs->sr[7], in_syscall); if (get_signal(&ksig)) { DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]); /* Restart a system call if necessary. */ if (in_syscall) syscall_restart(regs, &ksig.ka); handle_signal(&ksig, regs, in_syscall); return; } /* Did we come from a system call? */ if (in_syscall) insert_restart_trampoline(regs); DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", regs->gr[28]); restore_saved_sigmask(); } void do_notify_resume(struct pt_regs *regs, long in_syscall) { if (test_thread_flag(TIF_SIGPENDING)) do_signal(regs, in_syscall); if (test_thread_flag(TIF_NOTIFY_RESUME)) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); } }