arm64: add support for thread local storage

Adds the necessary bits to initialize TLS in the stack
area and sets up CPU registers during context switch.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2020-09-29 10:10:00 -07:00 committed by Andrew Boie
commit df77e2af8b
5 changed files with 58 additions and 0 deletions

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@ -32,6 +32,7 @@ config ARM
# FIXME: current state of the code for all ARM requires this, but
# is really only necessary for Cortex-M with ARM MPU!
select GEN_PRIV_STACKS
select ARCH_HAS_THREAD_LOCAL_STORAGE if ARM64
help
ARM architecture

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@ -30,3 +30,4 @@ endif ()
zephyr_library_sources_ifdef(CONFIG_GEN_SW_ISR_TABLE isr_wrapper.S)
zephyr_library_sources_ifdef(CONFIG_IRQ_OFFLOAD irq_offload.c)
zephyr_library_sources_ifdef(CONFIG_ARM_MMU arm_mmu.c)
zephyr_library_sources_ifdef(CONFIG_THREAD_LOCAL_STORAGE ../common/tls.c)

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@ -48,6 +48,19 @@ SECTION_FUNC(TEXT, z_arm64_context_switch)
mov x1, sp
str x1, [x2]
#ifdef CONFIG_THREAD_LOCAL_STORAGE
/* Grab the TLS pointer */
ldr x2, =_thread_offset_to_tls
add x2, x2, x0
ldr x2, [x2]
/* Store in the "Thread ID" register.
* This register is used as a base pointer to all
* thread variables with offsets added by toolchain.
*/
msr tpidr_el0, x2
#endif
/* addr of callee-saved regs in thread in x2 */
ldr x2, =_thread_offset_to_callee_saved
add x2, x2, x0

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@ -0,0 +1,42 @@
/*
* Copyright (c) 2020 Intel Corporation
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <kernel.h>
#include <kernel_structs.h>
#include <kernel_internal.h>
#include <kernel_tls.h>
#include <sys/util.h>
size_t arch_tls_stack_setup(struct k_thread *new_thread, char *stack_ptr)
{
/*
* TLS area for ARM has some data fields following by
* thread data and bss. These fields are supposed to be
* used by toolchain and OS TLS code to aid in locating
* the TLS data/bss. Zephyr currently has no use for
* this so we can simply skip these. However, since GCC
* is generating code assuming these fields are there,
* we simply skip them when setting the TLS pointer.
*/
/*
* Since we are populating things backwards,
* setup the TLS data/bss area first.
*/
stack_ptr -= z_tls_data_size();
z_tls_copy(stack_ptr);
/* Skip two pointers due to toolchain */
stack_ptr -= sizeof(uintptr_t) * 2;
/*
* Set thread TLS pointer which is used in
* context switch to point to TLS area.
*/
new_thread->tls = POINTER_TO_UINT(stack_ptr);
return (z_tls_data_size() + (sizeof(uintptr_t) * 2));
}

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@ -165,6 +165,7 @@ SECTIONS
_image_rodata_start = .;
#include <linker/common-rom.ld>
#include <linker/thread-local-storage.ld>
SECTION_PROLOGUE(_RODATA_SECTION_NAME,,)
{