| 1 | /*
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| 2 | * Copyright (c) 2018 CZ.NIC, z.s.p.o.
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #include <context.h>
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| 30 | #include <setjmp.h>
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| 31 | #include <tls.h>
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| 32 | #include <libarch/fibril.h>
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| 33 | #include <libarch/faddr.h>
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| 34 |
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| 35 | /**
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| 36 | * Saves current context to the variable pointed to by `self`,
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| 37 | * and restores the context denoted by `other`.
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| 38 | *
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| 39 | * When the `self` context is later restored by another call to
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| 40 | * `context_swap()`, the control flow behaves as if the earlier call to
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| 41 | * `context_swap()` just returned.
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| 42 | */
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| 43 | void context_swap(context_t *self, context_t *other)
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| 44 | {
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| 45 | if (!__setjmp(self))
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| 46 | __longjmp(other, 1);
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| 47 | }
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| 48 |
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| 49 | void context_create(context_t *context, const context_create_t *arg)
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| 50 | {
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| 51 | __setjmp(context);
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| 52 | context_set(context, FADDR(arg->fn), arg->stack_base,
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| 53 | arg->stack_size, arg->tls);
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| 54 | }
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| 55 |
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| 56 | uintptr_t context_get_pc(context_t *ctx)
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| 57 | {
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| 58 | // This is a simple wrapper for now, and exists to allow
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| 59 | // potential future implementation of context_swap to omit
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| 60 | // program counter from the context structure (e.g. if it's
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| 61 | // stored on the stack).
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| 62 | return ctx->pc;
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| 63 | }
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| 64 |
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| 65 | uintptr_t context_get_fp(context_t *ctx)
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| 66 | {
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| 67 | return _context_get_fp(ctx);
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| 68 | }
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