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Include "thread_state.h" instead of <mach/thread_status.h>.
(struct mach_msg_trap_args): New type.
(trampoline): Function removed.
(_hurd_setup_sighandler): Take struct hurd_sigstate * arg instead of FLAGS
and SIGALTSTACK args; take new flag arg RPC_WAIT; use struct
machine_thread_all_state * for STATE arg.
New declared labels `trampoline', `rpc_wait_trampoline' mark asm code at
end of function (after return).
Add another struct sigcontext * to STACKFRAME after the first one, for the
arg to __sigreturn.
If SS->context is set, fill registers in SCP from that instead of STATE,
and reset SS->INTR_PORT from it.
If RPC_WAIT is set, set up to use rpc_wait_trampoline and frob args to
mach_msg_trap syscall in progress so that it will retry the receive
operation (but not resend!).
{rpc_wait_trampoline, trampoline}: New trampoline code.
(_hurd_rcv_interrupted_p): New function.
This commit is contained in:
Roland McGrath
parent
817a880cc1
commit
62833ce689
@ -18,67 +18,240 @@ not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <hurd/signal.h>
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#include <mach/thread_status.h>
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#include "thread_state.h"
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struct mach_msg_trap_args
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{
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/* This is the order of arguments to mach_msg_trap. */
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mach_msg_header_t *msg;
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mach_msg_option_t option;
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mach_msg_size_t send_size;
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mach_msg_size_t rcv_size;
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mach_port_t rcv_name;
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mach_msg_timeout_t timeout;
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mach_port_t notify;
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};
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static void
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trampoline (void (*handler) (int signo, int sigcode, struct sigcontext *scp),
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int signo, int sigcode, struct sigcontext *scp)
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{
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(*handler) (signo, sigcode, scp);
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(void) __sigreturn (scp); /* Does not return. */
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while (1)
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LOSE; /* Firewall. */
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}
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struct sigcontext *
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_hurd_setup_sighandler (int flags,
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__sighandler_t handler,
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struct sigaltstack *sigaltstack,
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_hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
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int signo, int sigcode,
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void *state)
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int rpc_wait,
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struct machine_thread_all_state *state)
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{
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struct mips_thread_state *ts;
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__label__ trampoline, rpc_wait_trampoline;
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void *sigsp;
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struct sigcontext *scp;
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ts = state;
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if ((flags & SA_ONSTACK) &&
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!(sigaltstack->ss_flags & (SA_DISABLE|SA_ONSTACK)))
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if (ss->context)
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{
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sigsp = sigaltstack->ss_sp + sigaltstack->ss_size;
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sigaltstack->ss_flags |= SA_ONSTACK;
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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 (! setjmp (_hurd_sigthread_fault_env))
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{
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memcpy (&state->basic, &ss->context->sc_mips_thread_state,
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sizeof (state->basic));
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memcpy (&state->exc, &ss->context->sc_mips_exc_state,
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sizeof (state->exc));
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state->set = (1 << MIPS_THREAD_STATE) | (1 << MIPS_EXC_STATE);
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if (state->exc.coproc_state & SC_COPROC_USE_FPU)
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{
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memcpy (&state->fpu, &ss->context->sc_mips_loat_state,
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sizeof (state->fpu));
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state->set |= (1 << MIPS_FLOAT_STATE);
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}
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assert (! rpc_wait);
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/* The intr_port slot was cleared before sigreturn sent us the
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sig_post that made us notice this pending signal, so
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_hurd_internal_post_signal wouldn't do interrupt_operation.
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After we return, our caller will set SCP->sc_intr_port (in the
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new context) from SS->intr_port and clear SS->intr_port. Now
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that we are restoring this old context recorded by sigreturn,
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we want to restore its intr_port too; so store it in
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SS->intr_port now, so it will end up in SCP->sc_intr_port
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later. */
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ss->intr_port = ss->context->sc_intr_port;
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}
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/* If the sigreturn context was bogus, just ignore it. */
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ss->context = NULL;
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}
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else 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 & (SA_DISABLE|SA_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 |= SA_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 *) ts->r29;
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sigsp = (char *) state->basic.r29;
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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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/* Set up the sigcontext from the current state of the thread. */
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if (! setjmp (_hurd_sigthread_fault_env))
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{
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/* Set up the sigcontext from the current state of the thread. */
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scp->sc_onstack = sigaltstack->ss_flags & SA_ONSTACK ? 1 : 0;
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scp->sc_onstack = ss->sigaltstack.ss_flags & SA_ONSTACK ? 1 : 0;
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/* struct sigcontext is laid out so that starting at sc_gpr
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mimics a struct mips_thread_state. */
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memcpy (scp->sc_gpr, &ts, sizeof ts);
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/* struct sigcontext is laid out so that starting at sc_gpr
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mimics a struct mips_thread_state. */
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memcpy (&scp->sc_mips_thread_state,
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&state->basic, sizeof (state->basic));
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/* Modify the thread state to call `trampoline' on the new stack. */
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/* struct sigcontext is laid out so that starting at sc_cause
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mimics a struct mips_exc_state. */
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if (! machine_get_state (ss->thread, state, MIPS_EXC_STATE,
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&state->exc, &scp->sc_cause,
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sizeof (state->exc)))
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return NULL;
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if ((scp->sc_coproc_used & SC_COPROC_USE_FPU) &&
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/* struct sigcontext is laid out so that starting at sc_fpr
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mimics a struct mips_float_state. This state
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is only meaningful if the coprocessor was used. */
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! machine_get_state (ss->thread, state, MIPS_FLOAT_STATE,
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&state->fpu,
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&scp->sc_mips_float_state, sizeof (state->fpu)))
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return NULL;
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}
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else
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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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/* These registers are used for passing the first four arguments to a
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function (the rest go on the stack). Fortunately `trampoline' takes
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just four arguments, so they all fit in registers. */
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ts->r4 = (int) handler;
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ts->r5 = signo;
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ts->r6 = sigcode;
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ts->r7 = (int) scp;
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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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ts->r29 = (int) sigsp; /* r29 is the stack pointer register. */
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ts->pc = (int) &trampoline;
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/* The system call arguments are stored in consecutive registers
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starting with a0 ($4). */
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struct mach_msg_trap_args *args = (void *) &state->basic.r4;
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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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state->basic.pc = (int) &&rpc_wait_trampoline;
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state->basic.r29 = (int) sigsp; /* $29 is the stack pointer register. */
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/* After doing the message receive, the trampoline code will need to
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update the v0 ($2) 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 v1 ($3). */
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state->basic.r3 = (int) &scp->sc_gpr[1];
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/* We must preserve the mach_msg_trap args in a0..t2 ($4..$10).
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Pass the handler args to the trampoline code in s1..s3 ($17..$19). */
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state->basic.r17 = signo;
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state->basic.r18 = sigcode;
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state->basic.r19 = (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.r29 = (int) sigsp;
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state->basic.r4 = signo;
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state->basic.r5 = sigcode;
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state->basic.r6 = (int) scp;
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}
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/* We pass the handler function to the trampoline code in at ($1). */
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state->basic.r1 = (int) handler;
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/* In the callee-saved register s0 ($16), we save the SCP value to pass
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to __sigreturn after the handler returns. */
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state->basic.r16 = (int) scp;
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return scp;
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/* The trampoline code follows. This is not actually executed as part of
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this function, it is just convenient to write it that way. */
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rpc_wait_trampoline:
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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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$3 points to the sc_gpr[1] member of the sigcontext (saved v0 ($2)). */
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asm volatile
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(".set noat; .set noreorder; .set nomacro\n"
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/* Retry the interrupted mach_msg system call. */
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"li v0, -25\n" /* mach_msg_trap */
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"syscall\n"
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/* When the sigcontext was saved, v0 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 v0. So
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store the new v0 value into the sc_gpr[1] member of the sigcontext
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(whose address is in v1 to make this code simpler). */
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"sw v0, (v1)\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 s1..s3 ($17..$19). */
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"move a0, s1\n"
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"move a1, s2\n"
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"move a2, s3\n");
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trampoline:
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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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a0 SIGNO
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a1 SIGCODE
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a2 SCP
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*/
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asm volatile
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("jal $1; nop\n" /* Call the handler function. */
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/* Call __sigreturn (SCP); this cannot return. */
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"j %0\n"
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"move a0, s0" /* Set up arg from saved SCP in delay slot. */
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: : "i" (&__sigreturn));
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/* NOTREACHED */
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asm volatile (".set reorder; .set at; .set macro");
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return NULL;
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}
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/* STATE describes a thread that had intr_port set (meaning it was inside
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HURD_EINTR_RPC), after it has been thread_abort'd. It it looks to have
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just completed a mach_msg_trap system call that returned
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MACH_RCV_INTERRUPTED, return nonzero and set *PORT to the receive right
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being waited on. */
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int
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_hurdsig_rcv_interrupted_p (struct machine_thread_all_state *state,
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mach_port_t *port)
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{
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if (! setjmp (_hurd_sigthread_fault_env))
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{
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const unsigned int *pc = (void *) state->basic.pc;
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if (state->basic.r2 == MACH_RCV_INTERRUPTED &&
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pc[-1] == 0xc) /* syscall */
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{
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/* We did just return from a mach_msg_trap system call
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doing a message receive that was interrupted.
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Examine the parameters to find the receive right. */
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struct mach_msg_trap_args *args = (void *) &state->basic.r4;
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*port = args->rcv_name;
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return 1;
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}
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}
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return 0;
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}
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