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1311e997d4
This excludes all headers in /usr/include/dev because that directory is bonkers huge (18M). We can add these on an as-needed basis.
84 lines
No EOL
2.8 KiB
C
Vendored
84 lines
No EOL
2.8 KiB
C
Vendored
/* $OpenBSD: xcall.h,v 1.1 2025/07/13 05:45:21 dlg Exp $ */
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/*
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* Copyright (c) 2025 David Gwynne <dlg@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* CPU crosscall API
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*
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* Work to execute on a CPU is wrapped in a struct xcall, which is
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* like a task or timeout. Each CPU (in an MP kernel) has an array
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* of pointers to xcall structs. The local CPU uses CAS ops to try
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* and swap their xcall onto one of the slots on the remote CPU,
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* and will spin until space becomes available. Once the xcall has
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* been added, an IPI is sent to the remote CPU to kick of processing
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* of the array. The xcall IPI handler defers processing of the
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* xcall array to a low IPL level using a softintr handler.
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*
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* To implement this API on an architecture requires the following:
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*
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* 1. A device has to depend on the xcall attribute to have the
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* xcall code included in the kernel build. e.g., on amd64 the cpu
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* device depends on the xcall attribute, as defined in
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* src/sys/arch/amd64/conf/files.amd64:
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*
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* device cpu: xcall
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*
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* The rest of the changes are only necessary for MULTIPROCESSOR builds:
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*
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* 2. struct cpu_info has to have a `struct xcall_cpu ci_xcall` member.
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*
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* 3. cpu_xcall_establish has to be called against each cpu_info struct.
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*
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* 4. cpu_xcall_ipi has to be provided by machine/intr.h.
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*
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* 5. The MD xcall IPI handler has to call cpu_xcall_dispatch.
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*/
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#ifndef _SYS_XCALL_H
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#define _SYS_XCALL_H
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struct xcall {
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void (*xc_func)(void *);
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void *xc_arg;
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};
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/* MD code adds this to struct cpu_info as ci_xcall */
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struct xcall_cpu {
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struct xcall *xci_xcalls[4];
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void *xci_softintr;
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};
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#ifdef _KERNEL
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#define XCALL_INITIALIZER(_f, _a) { \
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.xc_func = _f, \
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.xc_arg = _a, \
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}
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void cpu_xcall_set(struct xcall *, void (*)(void *), void *);
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void cpu_xcall(struct cpu_info *, struct xcall *);
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void cpu_xcall_sync(struct cpu_info *, void (*)(void *), void *,
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const char *);
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/* MD cpu setup calls this */
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void cpu_xcall_establish(struct cpu_info *);
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/* MD ipi handler calls this */
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void cpu_xcall_dispatch(struct cpu_info *);
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#endif /* _KERNEL */
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#endif /* _SYS_XCALL_H */ |