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x86: Early TLS initialization

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Allow early boot code using thread local storage when
it is enabled.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
This commit is contained in:
Flavio Ceolin 2023-08-01 15:06:01 -07:00 • committed by Chris Friedt
commit 596e77f562
2 changed files with 35 additions and 0 deletions
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9
arch/x86/core/ia32/crt0.S
View file

@ -44,6 +44,10 @@
GDATA(_sse_mxcsr_default_value)
#endif
#if defined(CONFIG_THREAD_LOCAL_STORAGE)
GTEXT(z_x86_early_tls_update_gdt)
#endif
GDATA(x86_cpu_boot_arg)
.macro install_page_tables
@ -252,6 +256,11 @@ __csSet:
#endif
#endif /* Z_VM_KERNEL */
#ifdef CONFIG_THREAD_LOCAL_STORAGE
pushl %esp
call z_x86_early_tls_update_gdt
popl %esp
#endif
/* Clear BSS */
#ifdef CONFIG_LINKER_USE_BOOT_SECTION
call z_bss_zero_boot

26
arch/x86/core/ia32/tls.c
View file

@ -28,3 +28,29 @@ void z_x86_tls_update_gdt(struct k_thread *thread)
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));
}