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RIOT/cpu/native/include/util/ucontext.h

137 lines
3.9 KiB
C

/*
* Copyright (C) 2013 - 2016 Ludwig Knüpfer <ludwig.knuepfer@fu-berlin.de>
* Copyright (C) 2025 carl-tud
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
#ifndef UTIL_UCONTEXT_H
#define UTIL_UCONTEXT_H
#if USE_LIBUCONTEXT
# include <libucontext/libucontext.h>
#else
# include <ucontext.h>
#endif /* USE_LIBUCONTEXT */
#include <stdint.h>
#include <stdbool.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @addtogroup cpu_native
* @{
*/
/* MARK: - Context accessors */
/**
* @name Context accessors
* @{
*/
/**
* @brief Retrieves function pointer generated during calls to `makecontext`/`setcontext`/`swapcontext`
* @param context `ucontext_t`
* @returns Function pointer (does not need to be start of a function, points to instruction)
*/
static inline uintptr_t _context_get_fptr(ucontext_t *context) {
# if defined(__FreeBSD__) /* FreeBSD */
return (uintptr_t)((struct sigcontext *)context)->sc_eip;
# elif defined(__linux__) /* Linux */
# if defined(__arm__)
return (uintptr_t)((ucontext_t *)context)->uc_mcontext.arm_pc;
# elif defined(__x86_64__)
return (uintptr_t)((ucontext_t *)context)->uc_mcontext.gregs[REG_RIP];
# elif defined(__i386__)
return (uintptr_t)((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP];
# else
# error "Unsupported Linux architecture"
# endif
# else
# error "Operating system unsupported"
# endif
}
/**
* @brief Retrieves function pointer generated during calls to `makecontext`/`setcontext`/`swapcontext`
* @param context `ucontext_t`
* @param func Function pointer
*/
static inline void _context_set_fptr(ucontext_t *context, uintptr_t func) {
# if defined(__FreeBSD__) /* FreeBSD */
((struct sigcontext *)context)->sc_eip = (unsigned int)func;
# elif defined(__linux__) /* Linux */
# if defined(__arm__)
((ucontext_t *)context)->uc_mcontext.arm_lr = func;
((ucontext_t *)context)->uc_mcontext.arm_pc = func;
# elif defined(__x86_64__)
((ucontext_t *)context)->uc_mcontext.gregs[REG_RIP] = (greg_t)func;
# elif defined(__i386__)
((ucontext_t *)context)->uc_mcontext.gregs[REG_EIP] = func;
# else
# error "Unsupported Linux architecture"
# endif
# else
# error "Operating system unsupported"
# endif
}
/** @} */
/* MARK: - 64-bit support for makecontext */
/**
* @name 64-bit support for makecontext
* @{
*/
#if defined(__LP64__) || defined(DOXYGEN)
/**
* @brief Invokes thread task function
*
* This function fixes the otherwise necessary cast from `void*` to `int` of the thread
* task function pointer. We pass the task func and its argument in registers.
* See @ref makecontext64.
*/
extern void _start_task_func64(void);
#endif
/**
* @brief Like `makecontext`, allows 64-bit wide function argument on 64-bit platforms
* @param context `ucontext_t`
* @param func Function to be executed when context is applied
* @param arg Function argument, previously limited to `int` width, can now be up to 64 bits wide on 64-bit platforms
*
* Internally, we circumvent the 32-bit `int` limitation by passing the parameter in a register. This is done using
* a custom function defined in `native.S`
*/
static inline void makecontext64(ucontext_t *context, void (*func)(void), void* arg) {
# if defined(__LP64__)
/* makecontext accepts int arguments. In RIOT, we use void* for the optional argument.
* To not truncate the argument pointer, we pass it in a register to _start_task_func64. */
makecontext(context, (void (*)(void))_start_task_func64, 0);
# if defined(__x86_64__)
# if defined(__linux__)
context->uc_mcontext.gregs[REG_R14] = (greg_t)func;
context->uc_mcontext.gregs[REG_R15] = (greg_t)arg;
# endif
# endif
# else
/* On 32-bit platforms, the width of an int is enough to fit a pointer. */
makecontext(context, (void (*)(void))func, 1, arg);
# endif
}
/** @} */
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* UTIL_UCONTEXT_H */