diff options
Diffstat (limited to 'sysdeps/mach/hurd/alpha/sigreturn.c')
| -rw-r--r-- | sysdeps/mach/hurd/alpha/sigreturn.c | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/sysdeps/mach/hurd/alpha/sigreturn.c b/sysdeps/mach/hurd/alpha/sigreturn.c new file mode 100644 index 0000000000..e5dc383a3a --- /dev/null +++ b/sysdeps/mach/hurd/alpha/sigreturn.c @@ -0,0 +1,212 @@ +/* Return from signal handler in GNU C library for Hurd. Alpha version. +Copyright (C) 1994, 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <hurd.h> +#include <hurd/signal.h> +#include <hurd/threadvar.h> +#include <hurd/msg.h> +#include <stdlib.h> +#include <string.h> +#include <mach/machine/alpha_instruction.h> + +int +__sigreturn (struct sigcontext *scp) +{ + struct hurd_sigstate *ss; + mach_port_t *reply_port; + + if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK)) + { + errno = EINVAL; + return -1; + } + + ss = _hurd_self_sigstate (); + __spin_lock (&ss->lock); + + /* Restore the set of blocked signals, and the intr_port slot. */ + ss->blocked = scp->sc_mask; + ss->intr_port = scp->sc_intr_port; + + /* Check for pending signals that were blocked by the old set. */ + if (ss->pending & ~ss->blocked) + { + /* There are pending signals that just became unblocked. Wake up the + signal thread to deliver them. But first, squirrel away SCP where + the signal thread will notice it if it runs another handler, and + arrange to have us called over again in the new reality. */ + ss->context = scp; + /* Clear the intr_port slot, since we are not in fact doing + an interruptible RPC right now. If SS->intr_port is not null, + the SCP context is doing an interruptible RPC, but the signal + thread will examine us while we are blocked in the sig_post RPC. */ + ss->intr_port = MACH_PORT_NULL; + __spin_unlock (&ss->lock); + __msg_sig_post (_hurd_msgport, 0, __mach_task_self ()); + /* If a pending signal was handled, sig_post never returned. */ + __spin_lock (&ss->lock); + } + + if (scp->sc_onstack) + { + ss->sigaltstack.ss_flags &= ~SA_ONSTACK; /* XXX threadvars */ + /* XXX cannot unlock until off sigstack */ + abort (); + } + else + __spin_unlock (&ss->lock); + + /* Destroy the MiG reply port used by the signal handler, and restore the + reply port in use by the thread when interrupted. */ + reply_port = + (mach_port_t *) __hurd_threadvar_location (_HURD_THREADVAR_MIG_REPLY); + if (*reply_port) + __mach_port_destroy (__mach_task_self (), *reply_port); + *reply_port = scp->sc_reply_port; + + if (scp->sc_used_fpa) + { + /* Restore FPU state. */ + + /* Restore the floating-point control/status register. + We must do this first because the compiler will need + a temporary FP register for the load. */ + asm volatile ("mt_fpcr %0" : : "f" (scp->sc_fpcsr)); + + /* Restore floating-point registers. */ +#define restore_fpr(n) \ + asm volatile ("ldt $f" #n ",%0" : : "m" (scp->sc_fpregs[n])) + restore_fpr (0); + restore_fpr (1); + restore_fpr (2); + restore_fpr (3); + restore_fpr (4); + restore_fpr (5); + restore_fpr (6); + restore_fpr (7); + restore_fpr (8); + restore_fpr (9); + restore_fpr (10); + restore_fpr (11); + restore_fpr (12); + restore_fpr (13); + restore_fpr (14); + restore_fpr (15); + restore_fpr (16); + restore_fpr (17); + restore_fpr (18); + restore_fpr (19); + restore_fpr (20); + restore_fpr (21); + restore_fpr (22); + restore_fpr (23); + restore_fpr (24); + restore_fpr (25); + restore_fpr (26); + restore_fpr (27); + restore_fpr (28); + restore_fpr (29); + restore_fpr (30); + } + + /* Load all the registers from the sigcontext. */ +#define restore_gpr(n) \ + asm volatile ("ldq $" #n ",%0" : : "m" (scpreg->sc_regs[n])) + + { + /* The `rei' PAL pseudo-instruction restores registers $2..$7, the PC + and processor status. So we can use these few registers for our + working variables. Unfortunately, it finds its data on the stack + and merely pops the SP ($30) over the words of state restored, + allowing no other option for the new SP value. So we must push the + registers and PSW it will to restore, onto the user's stack and let + it pop them from there. */ + register const struct sigcontext *const scpreg asm ("$2") = scp; + register integer_t *usp asm ("$3") = (integer_t *) scpreg->sc_regs[30]; + register integer_t usp_align asm ("$4"); + + /* Push an 8-word "trap frame" onto the user stack for `rei': + registers $2..$7, the PC, and the PSW. */ + + register struct rei_frame + { + integer_t regs[5], pc, ps; + } *rei_frame asm ("$5"); + + usp -= 8; + /* `rei' demands that the stack be aligned to a 64 byte (8 word) + boundary; bits 61..56 of the PSW are OR'd back into the SP value + after popping the 8-word trap frame, so we store (sp % 64) + there and this restores the original user SP. */ + usp_align = (integer_t) usp & 63L; + rei_frame = (void *) ((integer_t) usp & ~63L); + + /* Copy the registers and PC from the sigcontext. */ + memcpy (rei_frame->regs, &scpreg->sc_regs[2], sizeof rei_frame->regs); + rei_frame->pc = scpreg->sc_pc; + + /* Compute the new PS value to be restored. `rei' adds the value at + bits 61..56 to the SP to compensate for the alignment above that + cleared the low 6 bits; bits 5..3 are the new mode/privilege level + (must be >= current mode; 3 == user mode); bits 2..0 are "software", + unused by the processor or kernel (XXX should trampoline save these? + How?); in user mode, `rei' demands that all other bits be zero. */ + rei_frame->ps = (usp_align << 56) | (3 << 3); /* XXX low 3 bits??? */ + + /* Restore the other general registers: everything except $2..$7, which + are in the `rei' trap frame we set up above, and $30, which is the + SP which is popped by `rei'. */ + restore_gpr (1); + restore_gpr (8); + restore_gpr (9); + restore_gpr (10); + restore_gpr (11); + restore_gpr (12); + restore_gpr (13); + restore_gpr (14); + restore_gpr (15); + restore_gpr (16); + restore_gpr (17); + restore_gpr (18); + restore_gpr (19); + restore_gpr (20); + restore_gpr (21); + restore_gpr (22); + restore_gpr (23); + restore_gpr (24); + restore_gpr (25); + restore_gpr (26); + restore_gpr (27); + restore_gpr (28); + restore_gpr (29); + + /* Switch the stack pointer to the trap frame set up on + the user stack and do the magical `rei' PAL call. */ + asm volatile ("mov %0, $30\n" + "call_pal %1" + : : "r" (rei_frame), "i" (op_rei)); + /* Firewall. */ + asm volatile ("call_pal %0" : : "i" (op_halt)); + } + + /* NOTREACHED */ + return -1; +} + +weak_alias (__sigreturn, sigreturn) |