fef
7e6dbad05f
The old strategy was to only do context switching from within the PendSV handler. This worked fine until now because all syscalls were handled either atomically or just returned -EAGAIN if the resource was locked or busy. However, with the introduction of I/O wait, we need to be able to sleep directly from within the kernel by moving the context switching completely into the kernel.
45 lines
1 KiB
C
45 lines
1 KiB
C
/* See the end of this file for copyright, license, and warranty information. */
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#include <ardix/file.h>
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#include <ardix/malloc.h>
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#include <ardix/syscall.h>
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#include <ardix/userspace.h>
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#include <errno.h>
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#include <stddef.h>
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#include <toolchain.h>
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long sys_read(int fd, __user void *buf, size_t len)
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{
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long ret;
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void *copy;
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struct file *f = file_get(fd);
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if (f == NULL)
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return -EBADF;
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copy = malloc(len);
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if (copy == NULL)
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return -ENOMEM;
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ret = file_read(copy, f, len);
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if (ret >= 0)
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ret = copy_to_user(buf, copy, ret);
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free(copy);
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file_put(f);
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return ret;
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}
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/*
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* This file is part of Ardix.
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* Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.
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*
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* Ardix is non-violent software: you may only use, redistribute,
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* and/or modify it under the terms of the CNPLv6+ as found in
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* the LICENSE file in the source code root directory or at
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* <https://git.pixie.town/thufie/CNPL>.
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*
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* Ardix comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPLv6+ for details.
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*/
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