zephyr/arch/x86/core/ia32/thread.c

145 lines
4.0 KiB
C

/*
* Copyright (c) 2010-2015 Wind River Systems, Inc.
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief Thread support primitives
*
* This module provides core thread related primitives for the IA-32
* processor architecture.
*/
#include <kernel.h>
#include <ksched.h>
#include <arch/x86/mmustructs.h>
#include <kswap.h>
/* forward declaration */
/* Initial thread stack frame, such that everything is laid out as expected
* for when z_swap() switches to it for the first time.
*/
struct _x86_initial_frame {
uint32_t swap_retval;
uint32_t ebp;
uint32_t ebx;
uint32_t esi;
uint32_t edi;
void *thread_entry;
uint32_t eflags;
k_thread_entry_t entry;
void *p1;
void *p2;
void *p3;
};
#ifdef CONFIG_X86_USERSPACE
/* Implemented in userspace.S */
extern void z_x86_syscall_entry_stub(void);
/* Syscalls invoked by 'int 0x80'. Installed in the IDT at DPL=3 so that
* userspace can invoke it.
*/
NANO_CPU_INT_REGISTER(z_x86_syscall_entry_stub, -1, -1, 0x80, 3);
#endif /* CONFIG_X86_USERSPACE */
#if defined(CONFIG_FPU) && defined(CONFIG_FPU_SHARING)
extern int z_float_disable(struct k_thread *thread);
int arch_float_disable(struct k_thread *thread)
{
#if defined(CONFIG_LAZY_FPU_SHARING)
return z_float_disable(thread);
#else
return -ENOSYS;
#endif /* CONFIG_LAZY_FPU_SHARING */
}
#endif /* CONFIG_FPU && CONFIG_FPU_SHARING */
void arch_new_thread(struct k_thread *thread, k_thread_stack_t *stack,
size_t stack_size, k_thread_entry_t entry,
void *parameter1, void *parameter2, void *parameter3,
int priority, unsigned int options)
{
char *stack_buf;
char *stack_high;
void *swap_entry;
struct _x86_initial_frame *initial_frame;
stack_buf = Z_THREAD_STACK_BUFFER(stack);
z_new_thread_init(thread, stack_buf, stack_size);
#if CONFIG_X86_STACK_PROTECTION
struct z_x86_thread_stack_header *header =
(struct z_x86_thread_stack_header *)stack;
/* Set guard area to read-only to catch stack overflows */
z_x86_mmu_set_flags(&z_x86_kernel_ptables, &header->guard_page,
MMU_PAGE_SIZE, MMU_ENTRY_READ, Z_X86_MMU_RW,
true);
#endif
#ifdef CONFIG_USERSPACE
swap_entry = z_x86_userspace_prepare_thread(thread);
#else
swap_entry = z_thread_entry;
#endif
stack_high = (char *)Z_STACK_PTR_ALIGN(stack_buf + stack_size);
/* Create an initial context on the stack expected by z_swap() */
initial_frame = (struct _x86_initial_frame *)
(stack_high - sizeof(struct _x86_initial_frame));
/* z_thread_entry() arguments */
initial_frame->entry = entry;
initial_frame->p1 = parameter1;
initial_frame->p2 = parameter2;
initial_frame->p3 = parameter3;
initial_frame->eflags = EFLAGS_INITIAL;
#ifdef _THREAD_WRAPPER_REQUIRED
initial_frame->edi = (uint32_t)swap_entry;
initial_frame->thread_entry = z_x86_thread_entry_wrapper;
#else
initial_frame->thread_entry = swap_entry;
#endif /* _THREAD_WRAPPER_REQUIRED */
/* Remaining _x86_initial_frame members can be garbage, z_thread_entry()
* doesn't care about their state when execution begins
*/
thread->callee_saved.esp = (unsigned long)initial_frame;
#if defined(CONFIG_LAZY_FPU_SHARING)
thread->arch.excNestCount = 0;
#endif /* CONFIG_LAZY_FPU_SHARING */
thread->arch.flags = 0;
}
/* The core kernel code puts the dummy thread on the stack, which unfortunately
* doesn't work for 32-bit x86 as k_thread objects must be aligned due to the
* buffer within them fed to fxsave/fxrstor.
*
* Use some sufficiently aligned bytes in the lower memory of the interrupt
* stack instead, otherwise the logic is more or less the same.
*/
void arch_switch_to_main_thread(struct k_thread *main_thread,
k_thread_stack_t *main_stack,
size_t main_stack_size,
k_thread_entry_t _main)
{
struct k_thread *dummy_thread = (struct k_thread *)
ROUND_UP(Z_THREAD_STACK_BUFFER(z_interrupt_stacks[0]),
FP_REG_SET_ALIGN);
__ASSERT(((uintptr_t)(&dummy_thread->arch.preempFloatReg) %
FP_REG_SET_ALIGN) == 0,
"unaligned dummy thread %p float member %p",
dummy_thread, &dummy_thread->arch.preempFloatReg);
z_dummy_thread_init(dummy_thread);
z_swap_unlocked();
CODE_UNREACHABLE;
}