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authorRoland McGrath <roland@gnu.org>1995-08-17 22:55:22 +0000
committerRoland McGrath <roland@gnu.org>1995-08-17 22:55:22 +0000
commit3fe9de0da5e8ad28a8ba86cc26ae6057984bde10 (patch)
tree248915736b58d19467d401ad3295c7113aee56cf /sysdeps/mach/hurd/i386/trampoline.c
parent191abc516c6f0ecd02f84ec98994b223252b48d7 (diff)
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Thu Aug 17 16:18:38 1995 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
* hurd/intr-msg.c: Use INTR_MSG_TRAP macro from machine-dependent "intr-msg.h" for special syscall code, instead of i386-specific asm. * hurd/hurdsig.c: Use INTR_MSG_BACK_OUT macro from machine-dependent "intr-msg.h" before mutating thread state to skip RPC. * sysdeps/mach/hurd/i386/trampoline.c: If PC is inside _hurd_intr_rpc_mach_msg special syscall code, use real SP saved in %ecx. * Makeconfig (link-libc): New variable; use shared library if available. (+link): Use it. * sysdeps/mach/hurd/fork.c (_hurd_fork_locks): Variable removed. Instead, declare with `symbol_set_declare'. (fork): Use symbol_set_* macros for _hurd_fork_locks. Use SS->thread instead of __mach_thread_self (). Suspend all other threads during task_create and port copying.
Diffstat (limited to 'sysdeps/mach/hurd/i386/trampoline.c')
-rw-r--r--sysdeps/mach/hurd/i386/trampoline.c29
1 files changed, 28 insertions, 1 deletions
diff --git a/sysdeps/mach/hurd/i386/trampoline.c b/sysdeps/mach/hurd/i386/trampoline.c
index 7adffc40be..9e947a46e7 100644
--- a/sysdeps/mach/hurd/i386/trampoline.c
+++ b/sysdeps/mach/hurd/i386/trampoline.c
@@ -45,6 +45,9 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
struct machine_thread_all_state *state)
{
__label__ trampoline, rpc_wait_trampoline, firewall;
+ extern const void _hurd_intr_rpc_msg_in_trap;
+ extern const void _hurd_intr_rpc_msg_cx_sp;
+ extern const void _hurd_intr_rpc_msg_sp_restored;
void *volatile sigsp;
struct sigcontext *scp;
struct
@@ -80,6 +83,11 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
if (! machine_get_basic_state (ss->thread, state))
return NULL;
+ /* Save the original SP in the gratuitous `esp' slot.
+ We may need to reset the SP (the `uesp' slot) to avoid clobbering an
+ interrupted RPC frame. */
+ state->basic.esp = state->basic.uesp;
+
if ((ss->actions[signo].sa_flags & SA_ONSTACK) &&
!(ss->sigaltstack.ss_flags & (SA_DISABLE|SA_ONSTACK)))
{
@@ -88,6 +96,24 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
/* XXX need to set up base of new stack for
per-thread variables, cthreads. */
}
+ /* This code has intimate knowledge of the special mach_msg system call
+ done in intr-msg.c; that code does:
+ movl %esp, %ecx
+ leal ARGS, %esp
+ _hurd_intr_rpc_msg_cx_sp: movl $-25, %eax
+ _hurd_intr_rpc_msg_do_trap: lcall $7, $0
+ _hurd_intr_rpc_msg_in_trap: movl %ecx, %esp
+ _hurd_intr_rpc_msg_sp_restored:
+ We must check for the window during which %esp points at the
+ mach_msg arguments. The space below until %ecx is used by
+ the _hurd_intr_rpc_mach_msg frame, and must not be clobbered. */
+ else if (state->basic.eip >= (int) &_hurd_intr_rpc_msg_cx_sp &&
+ state->basic.eip < (int) &_hurd_intr_rpc_msg_sp_restored)
+ /* The SP now points at the mach_msg args, but there is more stack
+ space used below it. The real SP is saved in %ecx; we must push the
+ new frame below there, and restore that value as the SP on
+ sigreturn. */
+ sigsp = (char *) (state->basic.uesp = state->basic.ecx);
else
sigsp = (char *) state->basic.uesp;
@@ -166,7 +192,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
message reception, since the request message has already been
sent. */
- struct mach_msg_trap_args *args = (void *) state->basic.uesp;
+ struct mach_msg_trap_args *args = (void *) state->basic.esp;
if (_hurdsig_catch_fault (SIGSEGV))
{
@@ -192,6 +218,7 @@ _hurd_setup_sighandler (struct hurd_sigstate *ss, __sighandler_t handler,
state->basic.eip = (int) &&rpc_wait_trampoline;
/* The reply-receiving trampoline code runs initially on the original
user stack. We pass it the signal stack pointer in %ebx. */
+ state->basic.uesp = state->basic.esp; /* Restore mach_msg syscall SP. */
state->basic.ebx = (int) sigsp;
/* After doing the message receive, the trampoline code will need to
update the %eax value to be restored by sigreturn. To simplify