diff options
Diffstat (limited to 'sysdeps/l4/hurd/ia32/signal-dispatch-lowlevel.c')
| -rw-r--r-- | sysdeps/l4/hurd/ia32/signal-dispatch-lowlevel.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/sysdeps/l4/hurd/ia32/signal-dispatch-lowlevel.c b/sysdeps/l4/hurd/ia32/signal-dispatch-lowlevel.c new file mode 100644 index 00000000..bb6ac2a5 --- /dev/null +++ b/sysdeps/l4/hurd/ia32/signal-dispatch-lowlevel.c @@ -0,0 +1,213 @@ +/* signal-dispatch-lowlevel.c - ia32 specific signal handling functions. + Copyright (C) 2008 Free Software Foundation, Inc. + Written by Neal H. Walfield <neal@gnu.org>. + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License + as published by the Free Software Foundation; either version 3 of + the License, or (at your option) any later version. + + The GNU Hurd 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this program. If not, see + <http://www.gnu.org/licenses/>. */ + +#include <pt-internal.h> +#include <sig-internal.h> + +#include <hurd/thread.h> +#include <pthread.h> +#include <stdint.h> +#include <atomic.h> + +extern char _signal_dispatch_entry; +/* - 0(%esp) a pointer to the thread's struct signal_state. + - 4(%esp) a pointer to a siginfo_t. + - 8(%esp) is a pointer to the ss_flags field (or NULL). + - 12(%esp)+4 is the value of the sp when the thread was interrupted (intr_sp) + - 0(intr_sp) is the value of the ip when the thread was interrupted. + - 16(%esp) - 16 byte register save area +*/ +__asm__ ("\n\ + .globl _signal_dispatch_entry\n\ +_signal_dispatch_entry:\n\ + /* Save caller saved registers (16 bytes). */\n\ + mov %eax, 16(%esp)\n\ + mov %ecx, 16+4(%esp)\n\ + mov %edx, 16+8(%esp)\n\ + pushf\n\ + popl %eax\n\ + mov %eax, 16+12(%esp)\n\ +\n\ + /* Reset EFLAGS. */\n\ + cld\n\ + call signal_dispatch\n\ +\n\ + /* Get the original stack and begin restoration. */\n\ + mov 12(%esp), %edx\n\ +\n\ + /* Move the saved registers to the user stack. */\n\ + sub $16, %edx\n\ + /* eax. */\n\ + mov 16+0(%esp), %ecx\n\ + mov %ecx, 0(%edx)\n\ + /* ecx. */\n\ + mov 16+4(%esp), %ecx\n\ + mov %ecx, 4(%edx)\n\ + /* edx. */\n\ + mov 16+8(%esp), %ecx\n\ + mov %ecx, 8(%edx)\n\ + /* eflags. */\n\ + mov 16+12(%esp), %ecx\n\ + mov %ecx, 12(%edx)\n\ +\n\ + /* Get the pointer to the sigaltstack flags. */\n\ + mov 8(%esp), %ecx\n\ +\n\ + /* Restore the user stack. */\n\ + mov %edx, %esp\n\ +\n\ + /* Clear the SA_ONSTACK flag. */\n\ + and %ecx, %ecx\n\ + jz after_clear\n\ + lock; and $~1, 0(%ecx)\n\ +after_clear:\n\ +\n\ + /* Restore eflags, the scratch regs and the original sp and ip. */\n\ + popl %eax\n\ + popl %ecx\n\ + popl %edx\n\ + popf\n\ + ret\n"); + +extern char _signal_dispatch_entry_self; +/* - 0(%esp) is the return address (we ignore it) + - 4(%esp) is the sp to load + + Since we are returning to signal_dispatch_lowlevel's caller, we + also need to restore its frame pointer. */ +__asm__ ("\n\ + .globl _signal_dispatch_entry_self\n\ +_signal_dispatch_entry_self:\n\ + mov 0(%ebp), %ebp\n\ + mov 4(%esp), %esp\n\ + jmp _signal_dispatch_entry\n"); + +void +signal_dispatch_lowlevel (struct signal_state *ss, pthread_t tid, + siginfo_t si) +{ + assert (pthread_mutex_trylock (&ss->lock) == EBUSY); + + struct __pthread *thread = __pthread_getid (tid); + + bool self = tid == pthread_self (); + + uintptr_t intr_sp; + + if (self) + { + /* The return address is just before the first argument. */ + intr_sp = (uintptr_t) &ss - 4; + assert (* (void **) intr_sp == __builtin_return_address (0)); + } + else + { + struct hurd_thread_exregs_in in; + memset (&in, 0, sizeof (in)); + struct hurd_thread_exregs_out out; + + error_t err; + err = rm_thread_exregs (ADDR_VOID, thread->object.addr, + HURD_EXREGS_STOP | HURD_EXREGS_ABORT_IPC + | HURD_EXREGS_GET_REGS, + in, &out); + if (err) + panic ("Failed to modify thread " ADDR_FMT, + ADDR_PRINTF (thread->object.addr)); + + intr_sp = out.sp; + + /* Push the ip on the user stack. */ + intr_sp -= 4; + * (uintptr_t *) intr_sp = out.ip; + } + + bool altstack = false; + uintptr_t sp; + if (! (ss->actions[si.si_signo - 1].sa_flags & SA_ONSTACK) + || (ss->stack.ss_flags & SS_DISABLE) + || (ss->stack.ss_flags & SS_ONSTACK)) + { + assert (! self); + sp = intr_sp; + } + else + { + /* The stack grows down. */ + sp = (uintptr_t) ss->stack.ss_sp + ss->stack.ss_size; + + /* We know intimately that SS_ONSTACK is the least significant + bit. */ + assert (SS_ONSTACK == 1); + atomic_bit_set (&ss->stack.ss_flags, 0); + + altstack = true; + } + + /* Set up the call frame for a call to signal_dispatch_entry. */ + + /* Allocate a siginfo structure on the stack. */ + sp = sp - sizeof (siginfo_t); + siginfo_t *sip = (void *) sp; + /* Copy the user supplied values. */ + *sip = si; + + /* Add space for the 4 caller saved registers. */ + sp -= 4 * sizeof (uintptr_t); + + /* Save the interrupted sp. */ + sp -= 4; + * (uintptr_t *) sp = intr_sp; + + /* Address of the ss_flags. */ + sp -= 4; + if (altstack) + * (uintptr_t *) sp = (uintptr_t) &ss->stack.ss_flags; + else + * (uintptr_t *) sp = 0; + + /* Push the parameters to signal_dispatch. */ + + /* signal info structure. */ + sp -= 4; + * (uintptr_t *) sp = (uintptr_t) sip; + + /* The ss. */ + sp -= 4; + * (uintptr_t *) sp = (uintptr_t) ss; + + pthread_mutex_transfer_np (&ss->lock, tid); + + if (self) + ((void (*) (uintptr_t)) &_signal_dispatch_entry_self) ((uintptr_t) sp); + else + { + struct hurd_thread_exregs_in in; + struct hurd_thread_exregs_out out; + + in.sp = sp; + in.ip = (uintptr_t) &_signal_dispatch_entry; + + rm_thread_exregs (ADDR_VOID, thread->object.addr, + HURD_EXREGS_SET_SP_IP + | HURD_EXREGS_START | HURD_EXREGS_ABORT_IPC, + in, &out); + } +} |