blob: 46a3c6fc86658d87cec42541c692778010e1f71a [file] [log] [blame]
/*
* Copyright (c) 2020 Intel Corporation.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel_internal.h>
#include <zephyr/arch/x86/ia32/arch.h>
#include <zephyr/arch/x86/ia32/segmentation.h>
#define ENTRY_NUM (GS_TLS_SEG >> 3)
void z_x86_tls_update_gdt(struct k_thread *thread)
{
/*
* GS is used for thread local storage to pointer to
* the TLS storage area in stack. Here we update one
* of the descriptor so GS has the new address.
*
* The re-loading of descriptor into GS is taken care
* of inside the assembly swap code just before
* swapping into the new thread.
*/
struct segment_descriptor *sd = &_gdt.entries[ENTRY_NUM];
sd->base_low = thread->tls & 0xFFFFU;
sd->base_mid = (thread->tls >> 16) & 0xFFU;
sd->base_hi = (thread->tls >> 24) & 0xFFU;
}
FUNC_NO_STACK_PROTECTOR
void z_x86_early_tls_update_gdt(char *stack_ptr)
{
uintptr_t *self_ptr;
uintptr_t tls_seg = GS_TLS_SEG;
struct segment_descriptor *sd = &_gdt.entries[ENTRY_NUM];
/*
* Since we are populating things backwards, store
* the pointer to the TLS area at top of stack.
*/
stack_ptr -= sizeof(uintptr_t);
self_ptr = (void *)stack_ptr;
*self_ptr = POINTER_TO_UINT(stack_ptr);
sd->base_low = POINTER_TO_UINT(self_ptr) & 0xFFFFU;
sd->base_mid = (POINTER_TO_UINT(self_ptr) >> 16) & 0xFFU;
sd->base_hi = (POINTER_TO_UINT(self_ptr) >> 24) & 0xFFU;
__asm__ volatile(
"movl %0, %%eax;\n\t"
"movl %%eax, %%gs;\n\t"
:
: "r"(tls_seg));
}