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Revert "arch/riscv: Use arch_switch() for context swap"

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This reverts commit be28de692c.

The purpose of this commit will be reintroduced later on top of
a cleaner codebase.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2022-03-09 17:46:30 -05:00 • committed by Anas Nashif
commit 442ab22bdc
6 changed files with 204 additions and 248 deletions
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50
arch/riscv/core/switch.S
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@ -1,50 +0,0 @@
/*
* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <toolchain.h>
#include <linker/sections.h>
#include <offsets_short.h>
#include <arch/cpu.h>
/* exports */
GTEXT(arch_switch)
GTEXT(z_thread_entry_wrapper)
/* Use ABI name of registers for the sake of simplicity */
/*
* void arch_switch(void *switch_to, void **switched_from);
*
* Always called with interrupts locked
*
* a0 = (struct k_thread *) switch_to
* a1 = (struct k_thread **) address of output thread switch_handle field
*/
SECTION_FUNC(exception.other, arch_switch)
/* Make a system call to perform context switch */
ecall
/* Return */
ret
/*
* void z_thread_entry_wrapper(k_thread_entry_t, void *, void *, void *)
*/
SECTION_FUNC(TEXT, z_thread_entry_wrapper)
/*
* z_thread_entry_wrapper is called for every new thread upon the return
* of arch_switch or ISR. Its address, as well as its input function
* arguments thread_entry_t, void *, void *, void * are restored from
* the thread stack (initialized via function _thread).
* In this case, thread_entry_t, * void *, void * and void * are stored
* in registers a0, a1, a2 and a3. These registers are used as arguments
* to function z_thread_entry. Hence, just call z_thread_entry with
* return address set to 0 to indicate a non-returning function call.
*/
jal x0, z_thread_entry