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https://github.com/zephyrproject-rtos/zephyr
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6564974bae
System call arguments, at the arch layer, are single words. So passing wider values requires splitting them into two registers at call time. This gets even more complicated for values (e.g k_timeout_t) that may have different sizes depending on configuration. This patch adds a feature to gen_syscalls.py to detect functions with wide arguments and automatically generates code to split/unsplit them. Unfortunately the current scheme of Z_SYSCALL_DECLARE_* macros won't work with functions like this, because for N arguments (our current maximum N is 10) there are 2^N possible configurations of argument widths. So this generates the complete functions for each handler and wrapper, effectively doing in python what was originally done in the preprocessor. Another complexity is that traditional the z_hdlr_*() function for a system call has taken the raw list of word arguments, which does not work when some of those arguments must be 64 bit types. So instead of using a single Z_SYSCALL_HANDLER macro, this splits the job of z_hdlr_*() into two steps: An automatically-generated unmarshalling function, z_mrsh_*(), which then calls a user-supplied verification function z_vrfy_*(). The verification function is typesafe, and is a simple C function with exactly the same argument and return signature as the syscall impl function. It is also not responsible for validating the pointers to the extra parameter array or a wide return value, that code gets automatically generated. This commit includes new vrfy/msrh handling for all syscalls invoked during CI runs. Future commits will port the less testable code. Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
48 lines
936 B
C
48 lines
936 B
C
/*
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* Copyright (c) 2015 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/** @file
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*
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* @brief Per-thread errno accessor function
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*
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* Allow accessing the errno for the current thread without involving the
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* context switching.
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*/
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#include <kernel_structs.h>
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#include <syscall_handler.h>
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/*
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* Define _k_neg_eagain for use in assembly files as errno.h is
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* not assembly language safe.
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* FIXME: wastes 4 bytes
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*/
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const int _k_neg_eagain = -EAGAIN;
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#ifdef CONFIG_ERRNO
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#ifdef CONFIG_USERSPACE
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int *z_impl_z_errno(void)
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{
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/* Initialized to the lowest address in the stack so the thread can
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* directly read/write it
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*/
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return &_current->userspace_local_data->errno_var;
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}
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static inline int *z_vrfy_z_errno(void)
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{
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return z_impl_z_errno();
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}
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#include <syscalls/z_errno_mrsh.c>
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#else
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int *z_impl_z_errno(void)
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{
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return &_current->errno_var;
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}
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#endif /* CONFIG_USERSPACE */
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#endif /* CONFIG_ERRNO */
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