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257 lines
8.9 KiB
C
257 lines
8.9 KiB
C
/* Set thread_state for sighandler, and sigcontext to recover. For PowerPC.
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Copyright (C) 1994,1995,1996,1997,1998,1999,2001,2005
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <hurd/signal.h>
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#include <hurd/userlink.h>
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#include <thread_state.h>
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#include <assert.h>
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#include <errno.h>
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#include "hurdfault.h"
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#include <intr-msg.h>
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struct sigcontext *
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_hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
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int signo, struct hurd_signal_detail *detail,
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volatile int rpc_wait,
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struct machine_thread_all_state *state)
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{
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void trampoline (void);
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void rpc_wait_trampoline (void);
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void *volatile sigsp;
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struct sigcontext *scp;
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if (ss->context)
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{
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/* We have a previous sigcontext that sigreturn was about
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to restore when another signal arrived. We will just base
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our setup on that. */
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if (! _hurdsig_catch_memory_fault (ss->context))
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{
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memcpy (&state->basic, &ss->context->sc_ppc_thread_state,
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sizeof (state->basic));
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memcpy (&state->exc, &ss->context->sc_ppc_exc_state,
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sizeof (state->exc));
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memcpy (&state->fpu, &ss->context->sc_ppc_float_state,
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sizeof (state->fpu));
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state->set = (1 << PPC_THREAD_STATE) | (1 << PPC_EXCEPTION_STATE)
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| (1 << PPC_FLOAT_STATE);
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}
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}
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if (! machine_get_basic_state (ss->thread, state))
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return NULL;
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if ((ss->actions[signo].sa_flags & SA_ONSTACK) &&
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!(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
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{
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sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
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ss->sigaltstack.ss_flags |= SS_ONSTACK;
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/* XXX need to set up base of new stack for
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per-thread variables, cthreads. */
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}
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else
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sigsp = (char *) state->basic.SP;
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/* Set up the sigcontext structure on the stack. This is all the stack
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needs, since the args are passed in registers (below). */
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sigsp -= sizeof (*scp);
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scp = sigsp;
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sigsp -= 16; /* Reserve some space for a stack frame. */
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if (_hurdsig_catch_memory_fault (scp))
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{
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/* We got a fault trying to write the stack frame.
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We cannot set up the signal handler.
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Returning NULL tells our caller, who will nuke us with a SIGILL. */
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return NULL;
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}
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else
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{
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int ok;
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/* Set up the sigcontext from the current state of the thread. */
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scp->sc_onstack = ss->sigaltstack.ss_flags & SS_ONSTACK ? 1 : 0;
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/* struct sigcontext is laid out so that starting at sc_srr0
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mimics a struct ppc_thread_state. */
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memcpy (&scp->sc_ppc_thread_state,
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&state->basic, sizeof (state->basic));
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/* struct sigcontext is laid out so that starting at sc_dar
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mimics a struct ppc_exc_state. */
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ok = machine_get_state (ss->thread, state, PPC_EXCEPTION_STATE,
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&state->exc, &scp->sc_ppc_exc_state,
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sizeof (state->exc));
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/* struct sigcontext is laid out so that starting at sc_fprs[0]
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mimics a struct ppc_float_state. */
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if (ok)
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ok = machine_get_state (ss->thread, state, PPC_FLOAT_STATE,
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&state->fpu, &scp->sc_ppc_float_state,
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sizeof (state->fpu));
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_hurdsig_end_catch_fault ();
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if (!ok)
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return NULL;
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}
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/* Modify the thread state to call the trampoline code on the new stack. */
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if (rpc_wait)
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{
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/* The signalee thread was blocked in a mach_msg_trap system call,
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still waiting for a reply. We will have it run the special
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trampoline code which retries the message receive before running
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the signal handler.
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To do this we change the OPTION argument in its registers to
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enable only message reception, since the request message has
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already been sent. */
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/* The system call arguments are stored in consecutive registers
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starting with r3. */
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struct mach_msg_trap_args *args = (void *) &state->basic.r3;
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if (_hurdsig_catch_memory_fault (args))
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{
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/* Faulted accessing ARGS. Bomb. */
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return NULL;
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}
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assert (args->option & MACH_RCV_MSG);
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/* Disable the message-send, since it has already completed. The
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calls we retry need only wait to receive the reply message. */
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args->option &= ~MACH_SEND_MSG;
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/* Limit the time to receive the reply message, in case the server
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claimed that `interrupt_operation' succeeded but in fact the RPC
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is hung. */
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args->option |= MACH_RCV_TIMEOUT;
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args->timeout = _hurd_interrupted_rpc_timeout;
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_hurdsig_end_catch_fault ();
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state->basic.PC = (int) rpc_wait_trampoline;
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/* After doing the message receive, the trampoline code will need to
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update the r3 value to be restored by sigreturn. To simplify
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the assembly code, we pass the address of its slot in SCP to the
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trampoline code in r10. */
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state->basic.r10 = (long int) &scp->sc_gprs[3];
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/* We must preserve the mach_msg_trap args in r3..r9.
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Pass the handler args to the trampoline code in r11..r13. */
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state->basic.r11 = signo;
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state->basic.r12 = detail->code;
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state->basic.r13 = (int) scp;
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}
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else
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{
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state->basic.PC = (int) trampoline;
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state->basic.r3 = signo;
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state->basic.r4 = detail->code;
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state->basic.r5 = (int) scp;
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}
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state->basic.r1 = (int) sigsp; /* r1 is the stack pointer. */
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/* We pass the handler function to the trampoline code in ctr. */
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state->basic.ctr = (int) handler;
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/* In r15, we store the address of __sigreturn itself,
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for the trampoline code to use. */
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state->basic.r15 = (int) &__sigreturn;
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/* In r16, we save the SCP value to pass to __sigreturn
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after the handler returns. */
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state->basic.r16 = (int) scp;
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/* In r3, we store a pointer to the registers in STATE so that the
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trampoline code can load the registers from that. For some reason,
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thread_set_state doesn't set all registers. */
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state->basic.r17 = state->basic.r3; /* Store the real r3 in r17. */
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state->basic.r3 = (int) &state->basic.r0;
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return scp;
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}
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/* The trampoline code follows. This used to be located inside
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_hurd_setup_sighandler, but was optimized away by gcc 2.95. */
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/* This function sets some registers which the trampoline code uses
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and which are not automatically set by thread_set_state.
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In r3 we have a pointer to the registers in STATE. */
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asm ("trampoline_load_registers:\n"
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"lwz 17,68(3)\n" /* The real r3. */
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"lwz 4,16(3)\n"
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"lwz 5,20(3)\n"
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"lwz 6,24(3)\n"
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"lwz 7,28(3)\n"
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"lwz 8,32(3)\n"
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"lwz 9,36(3)\n"
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"lwz 10,40(3)\n"
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"lwz 11,44(3)\n"
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"lwz 12,48(3)\n"
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"lwz 13,52(3)\n"
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"lwz 14,56(3)\n"
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"lwz 15,60(3)\n"
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"lwz 16,64(3)\n"
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"mr 3,17\n"
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"blr\n");
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asm ("rpc_wait_trampoline:\n");
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/* This is the entry point when we have an RPC reply message to receive
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before running the handler. The MACH_MSG_SEND bit has already been
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cleared in the OPTION argument in our registers. For our convenience,
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r10 points to the sc_regs[3] member of the sigcontext (saved r3). */
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asm (/* Retry the interrupted mach_msg system call. */
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"bl trampoline_load_registers\n"
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"li 0, -25\n" /* mach_msg_trap */
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"sc\n"
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/* When the sigcontext was saved, r3 was MACH_RCV_INTERRUPTED. But
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now the message receive has completed and the original caller of
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the RPC (i.e. the code running when the signal arrived) needs to
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see the final return value of the message receive in r3. So
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store the new r3 value into the sc_regs[3] member of the sigcontext
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(whose address is in r10 to make this code simpler). */
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"stw 3, 0(10)\n"
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/* Since the argument registers needed to have the mach_msg_trap
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arguments, we've stored the arguments to the handler function
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in registers r11..r13 of the state structure. */
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"mr 3,11\n"
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"mr 4,12\n"
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"mr 5,13\n");
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asm ("trampoline:\n");
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/* Entry point for running the handler normally. The arguments to the
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handler function are already in the standard registers:
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r3 SIGNO
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r4 SIGCODE
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r5 SCP
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r16 also contains SCP; this value is callee-saved (and so should not get
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clobbered by running the handler). We use this saved value to pass to
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__sigreturn, so the handler can clobber the argument registers if it
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likes. */
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asm ("bl trampoline_load_registers\n"
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"bctrl\n" /* Call the handler function. */
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"mtctr 15\n" /* Copy &__sigreturn to CTR. */
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"mr 3,16\n" /* Copy the saved SCP to r3. */
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"bctr\n" /* Call __sigreturn (SCP). */
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);
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