zephyr/arch/xtensa/include/kernel_arch_thread.h

150 lines
4.4 KiB
C

/*
* Copyright (c) 2017 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Per-arch thread definition
*
* This file contains defintions for
*
* struct _thread_arch
* struct _callee_saved
* struct _caller_saved
*
* necessary to instantiate instances of struct k_thread.
*/
#ifndef _kernel_arch_thread__h_
#define _kernel_arch_thread__h_
#ifndef _ASMLANGUAGE
#include <zephyr/types.h>
#include <xtensa_context.h>
/*
* The following structure defines the set of 'volatile' integer registers.
* These registers need not be preserved by a called C function. Given that
* they are not preserved across function calls, they must be save/restored
* (along with the struct _caller_saved) when a preemptive context switch
* occurs.
*/
struct _caller_saved {
/*
* The volatile registers area not included in the definition of
* 'tPreempReg' since the interrupt stubs (_IntEnt/_IntExit)
* and exception stubs (_ExcEnt/_ExcEnter) use the stack to save and
* restore the values of these registers in order to support interrupt
* nesting. The stubs do _not_ copy the saved values from the stack
* into the k_thread.
*/
};
typedef struct _caller_saved _caller_saved_t;
/*
* The following structure defines the set of 'non-volatile' integer registers.
* These registers must be preserved by a called C function. These are the
* only registers that need to be saved/restored when a cooperative context
* switch occurs.
*/
struct _callee_saved {
/*
* The following registers are considered non-volatile, i.e.
* callee-saved, but their values are pushed onto the stack rather than
* stored in the k_thread structure:
*/
u32_t retval; /* a2 */
XtExcFrame *topOfStack; /* a1 = sp */
};
typedef struct _callee_saved _callee_saved_t;
/*
* The following structure defines the set of 'non-volatile' x87 FPU/MMX/SSE
* registers. These registers must be preserved by a called C function.
* These are the only registers that need to be saved/restored when a
* cooperative context switch occurs.
*/
typedef struct s_coopCoprocReg {
/*
* This structure intentionally left blank. Coprocessor's registers are
* all 'volatile' and saved using the lazy context switch mechanism.
*/
} tCoopCoprocReg;
/*
* The following structure defines the set of 'volatile' x87 FPU/MMX/SSE
* registers. These registers need not be preserved by a called C function.
* Given that they are not preserved across function calls, they must be
* save/restored (along with s_coopCoprocReg) when a preemptive context switch
* occurs.
*/
typedef struct s_preempCoprocReg {
/*
* This structure reserved coprocessor control and save area memory.
*/
#if XCHAL_CP_NUM > 0
char __aligned(4) cpStack[XT_CP_SIZE];
#endif
} tPreempCoprocReg;
/*
* The thread control stucture definition. It contains the
* various fields to manage a _single_ thread.
*/
struct _thread_arch {
/*
* See the above flag definitions above for valid bit settings. This
* field must remain near the start of struct k_thread, specifically
* before any #ifdef'ed fields since the host tools currently use a
* fixed offset to read the 'flags' field.
*/
u32_t flags;
#ifdef CONFIG_THREAD_CUSTOM_DATA
void *custom_data; /* available for custom use */
#endif
#if defined(CONFIG_THREAD_MONITOR)
/* thread entry and parameters description */
struct __thread_entry *entry;
/* next item in list of ALL threads n*/
struct k_thread *next_thread;
#endif
#ifdef CONFIG_ERRNO
int errno_var;
#endif
/*
* The location of all floating point related structures/fields MUST be
* located at the end of struct k_thread. This way only the threads
* that actually utilize non-integer capabilities need to account for
* the increased memory required for storing FP state when sizing
* stacks.
*
* Given that stacks "grow down" on Xtensa, and the k_thread is located
* at the start of a thread's "workspace" memory, the stacks of threads
* that do not utilize floating point instruction can effectively
* consume the memory occupied by the 'tCoopCoprocReg' and
* 'tPreempCoprocReg' structures without ill effect.
*/
/* non-volatile coprocessor's register storage */
tCoopCoprocReg coopCoprocReg;
/* volatile coprocessor's register storage */
tPreempCoprocReg preempCoprocReg;
};
typedef struct _thread_arch _thread_arch_t;
#endif /* _ASMLANGUAGE */
#endif /* _kernel_arch_thread__h_ */