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/* Machine-dependent details of interruptible RPC messaging. x86_64 version.
Copyright (C) 1995-2023 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 Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Note that we must mark OPTION and TIMEOUT as outputs of this operation,
to indicate that the signal thread might mutate them as part
of sending us to a signal handler. */
#define INTR_MSG_TRAP(msg, option, send_size, rcv_size, rcv_name, timeout, notify, cancel_p, intr_port_p) \
({ \
error_t err; \
register uintptr_t rcv_size_r10 asm ("r10") = rcv_size; \
register uintptr_t rcv_name_r8 asm ("r8") = rcv_name; \
register uintptr_t timeout_r9 asm ("r9") = timeout; \
asm volatile ( \
".globl _hurd_intr_rpc_msg_about_to\n" \
".globl _hurd_intr_rpc_msg_setup_done\n" \
".globl _hurd_intr_rpc_msg_in_trap\n" \
/* Clear rax before we do the check for cancel below. This is to
detect rax being set to non-zero (actually MACH_SEND_INTERRUPTED)
from the outside (namely, _hurdsig_abort_rpcs), which signals us
to skip the trap we were about to enter. */ \
" xor %[err], %[err]\n" \
"_hurd_intr_rpc_msg_about_to:" \
/* We need to make a last check of cancel, in case we got interrupted
right before _hurd_intr_rpc_msg_about_to. */ \
" cmpl $0, %[cancel]\n" \
" jz _hurd_intr_rpc_msg_do\n" \
/* We got interrupted, note so and return EINTR. */ \
" movl $0, %[intr_port]\n" \
" movl %[eintr], %[err]\n" \
" jmp _hurd_intr_rpc_msg_sp_restored\n" \
"_hurd_intr_rpc_msg_do:" \
/* Ok, prepare the mach_msg_trap arguments. We pass the first 6 args
in registers, and push the last one and a fake return address. */ \
" pushq %[notify]\n" \
" pushq $0\n" \
"_hurd_intr_rpc_msg_setup_done:" \
/* From here on, it is safe to make us jump over the syscall. Now
check if we have been told to skip the syscall while running
the above. */ \
" test %[err], %[err]\n" \
" jnz _hurd_intr_rpc_msg_in_trap\n" \
/* Do the actual syscall. */ \
" movq $-25, %%rax\n" \
"_hurd_intr_rpc_msg_do_trap: syscall # status in %[err]\n" \
"_hurd_intr_rpc_msg_in_trap:" \
/* Clean the arguments. */ \
" addq $16, %%rsp\n" \
"_hurd_intr_rpc_msg_sp_restored:" \
: [err] "=&a" (err), "+S" (option), [intr_port] "=m" (*intr_port_p), \
"+r" (timeout_r9) \
: "D" (msg), "d" (send_size), "r" (rcv_size_r10), "r" (rcv_name_r8), \
[notify] "rm" ((uintptr_t) notify), [cancel] "m" (*cancel_p), \
[eintr] "i" (EINTR) \
: "rcx", "r11"); \
timeout = timeout_r9; \
err; \
})
#include "hurdfault.h"
/* This cannot be an inline function because it calls setjmp. */
#define SYSCALL_EXAMINE(state, callno) \
({ \
struct { unsigned char c[2]; } *p = (void *) ((state)->rip - 2); \
int result; \
if (_hurdsig_catch_memory_fault (p)) \
return 0; \
if (result = p->c[0] == 0xf && p->c[1] == 0x5) \
/* The PC appears to be just after a `syscall' instruction. \
This is a system call in progress; %rax holds the call number. */ \
*(callno) = (state)->rax; \
_hurdsig_end_catch_fault (); \
result; \
})
/* This cannot be an inline function because it calls setjmp. */
#define MSG_EXAMINE(state, msgid, rcvname, send_name, opt, tmout) \
({ \
int ret = 0; \
const struct machine_thread_state *s = (state); \
const mach_msg_header_t *msg = (const void *) s->rdi; \
*(rcvname) = s->r8; \
*(opt) = s->rsi; \
*(tmout) = s->r9; \
if (msg == 0) \
{ \
*(send_name) = MACH_PORT_NULL; \
*(msgid) = 0; \
} \
else \
{ \
ret = _hurdsig_catch_memory_fault (msg) ? -1 : 0; \
if (ret == 0) \
{ \
*(send_name) = msg->msgh_remote_port; \
*(msgid) = msg->msgh_id; \
_hurdsig_end_catch_fault (); \
} \
} \
ret; \
})
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