596e77f562
Allow early boot code using thread local storage when it is enabled. Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
/*
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* Copyright (c) 2020 Intel Corporation.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <kernel_internal.h>
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#include <zephyr/arch/x86/ia32/arch.h>
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#include <zephyr/arch/x86/ia32/segmentation.h>
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#define ENTRY_NUM (GS_TLS_SEG >> 3)
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void z_x86_tls_update_gdt(struct k_thread *thread)
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{
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/*
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* GS is used for thread local storage to pointer to
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* the TLS storage area in stack. Here we update one
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* of the descriptor so GS has the new address.
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*
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* The re-loading of descriptor into GS is taken care
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* of inside the assembly swap code just before
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* swapping into the new thread.
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*/
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struct segment_descriptor *sd = &_gdt.entries[ENTRY_NUM];
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sd->base_low = thread->tls & 0xFFFFU;
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sd->base_mid = (thread->tls >> 16) & 0xFFU;
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sd->base_hi = (thread->tls >> 24) & 0xFFU;
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}
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FUNC_NO_STACK_PROTECTOR
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void z_x86_early_tls_update_gdt(char *stack_ptr)
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{
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uintptr_t *self_ptr;
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uintptr_t tls_seg = GS_TLS_SEG;
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struct segment_descriptor *sd = &_gdt.entries[ENTRY_NUM];
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/*
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* Since we are populating things backwards, store
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* the pointer to the TLS area at top of stack.
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*/
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stack_ptr -= sizeof(uintptr_t);
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self_ptr = (void *)stack_ptr;
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*self_ptr = POINTER_TO_UINT(stack_ptr);
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sd->base_low = POINTER_TO_UINT(self_ptr) & 0xFFFFU;
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sd->base_mid = (POINTER_TO_UINT(self_ptr) >> 16) & 0xFFU;
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sd->base_hi = (POINTER_TO_UINT(self_ptr) >> 24) & 0xFFU;
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__asm__ volatile(
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"movl %0, %%eax;\n\t"
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"movl %%eax, %%gs;\n\t"
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:
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: "r"(tls_seg));
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}
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