6310546dba
When the underlying debugport transport is reliable, GDB's additional checksums and acknowledgements are redundant. NoAckMode eliminates the the acks and allows us to skip checking RX checksums. The GDB packet framing does not change, so unfortunately (valid) checksums are still included as message trailers. The gdb(4) stub in FreeBSD advertises support for the feature in response to the client's 'qSupported' request IFF the current debugport has the gdb_dbfeatures flag GDB_DBGP_FEAT_RELIABLE set. Currently, only netgdb(4) supports this feature. If the remote GDB client supports the feature and does not have it disabled via a GDB configuration knob, it may instruct our gdb(4) stub to enter NoAckMode. Unless and until it issues that command, we must continue to transmit acks as usual (and for now, we continue to wait until we receive them as well, even if we know the debugport is on a reliable transport). In the kernel sources, the sense of the flag representing the state of the feature is reversed from that of the GDB command. (I.e., it is 'gdb_ackmode', not 'gdb_noackmode.') This is to avoid confusing double- negative conditions. For reference, see: * https://sourceware.org/gdb/onlinedocs/gdb/Packet-Acknowledgment.html * https://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#QStartNoAckMode Reviewed by: jhb, markj (both earlier version) Differential Revision: https://reviews.freebsd.org/D21761
74 lines
2.6 KiB
C
74 lines
2.6 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2004 Marcel Moolenaar
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _GDB_GDB_H_
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#define _GDB_GDB_H_
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typedef int gdb_checkc_f(void);
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typedef int gdb_getc_f(void);
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typedef void gdb_init_f(void);
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typedef int gdb_probe_f(void);
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typedef void gdb_putc_f(int);
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typedef void gdb_term_f(void);
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struct gdb_dbgport {
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const char *gdb_name;
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gdb_getc_f *gdb_getc;
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gdb_init_f *gdb_init;
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gdb_probe_f *gdb_probe;
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gdb_putc_f *gdb_putc;
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gdb_term_f *gdb_term;
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int gdb_active;
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void (*gdb_sendpacket)(const void *, size_t);
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int gdb_dbfeatures;
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};
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#define GDB_DBGP_FEAT_WANTTERM 0x1 /* Want gdb_term() invocation when
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leaving GDB. gdb_term has been
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deadcode and never invoked for so
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long I don't want to just blindly
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start invoking it without opt-in. */
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#define GDB_DBGP_FEAT_RELIABLE 0x2 /* The debugport promises it is a
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reliable transport, which allows GDB
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acks to be turned off. */
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#define GDB_DBGPORT(name, probe, init, term, getc, putc) \
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static struct gdb_dbgport name##_gdb_dbgport = { \
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.gdb_name = #name, \
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.gdb_probe = probe, \
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.gdb_init = init, \
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.gdb_term = term, \
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.gdb_getc = getc, \
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.gdb_putc = putc, \
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}; \
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DATA_SET(gdb_dbgport_set, name##_gdb_dbgport)
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#endif /* !_GDB_GDB_H_ */
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