147 lines
3.9 KiB
ArmAsm
147 lines
3.9 KiB
ArmAsm
/*
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* Copyright (c) 2016 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 <arch/nios2/asm.h>
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#include <kernel_structs.h>
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#include <offsets_short.h>
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/* exports */
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GTEXT(_Swap)
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GTEXT(_thread_entry_wrapper)
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/* imports */
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GTEXT(_sys_k_event_logger_context_switch)
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GTEXT(_k_neg_eagain)
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/* unsigned int _Swap(unsigned int key)
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*
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* Always called with interrupts locked
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*/
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SECTION_FUNC(exception.other, _Swap)
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/* Get a reference to _kernel in r10 */
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movhi r10, %hi(_kernel)
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ori r10, r10, %lo(_kernel)
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/* Get the pointer to kernel->current */
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ldw r11, _kernel_offset_to_current(r10)
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/* Store all the callee saved registers. We either got here via
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* an exception or from a cooperative invocation of _Swap() from C
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* domain, so all the caller-saved registers have already been
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* saved by the exception asm or the calling C code already.
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*/
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stw r16, _thread_offset_to_r16(r11)
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stw r17, _thread_offset_to_r17(r11)
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stw r18, _thread_offset_to_r18(r11)
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stw r19, _thread_offset_to_r19(r11)
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stw r20, _thread_offset_to_r20(r11)
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stw r21, _thread_offset_to_r21(r11)
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stw r22, _thread_offset_to_r22(r11)
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stw r23, _thread_offset_to_r23(r11)
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stw r28, _thread_offset_to_r28(r11)
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stw ra, _thread_offset_to_ra(r11)
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stw sp, _thread_offset_to_sp(r11)
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/* r4 has the 'key' argument which is the result of irq_lock()
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* before this was called
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*/
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stw r4, _thread_offset_to_key(r11)
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/* Populate default return value */
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movhi r5, %hi(_k_neg_eagain)
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ori r5, r5, %lo(_k_neg_eagain)
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ldw r4, (r5)
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stw r4, _thread_offset_to_retval(r11)
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#if CONFIG_KERNEL_EVENT_LOGGER_CONTEXT_SWITCH
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call _sys_k_event_logger_context_switch
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/* Restore caller-saved r10. We could have stuck its value
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* onto the stack, but less instructions to just use immediates
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*/
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movhi r10, %hi(_kernel)
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ori r10, r10, %lo(_kernel)
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#endif /* CONFIG_KERNEL_EVENT_LOGGER_CONTEXT_SWITCH */
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movhi r10, %hi(_kernel)
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ori r10, r10, %lo(_kernel)
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/* get cached thread to run */
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ldw r2, _kernel_offset_to_ready_q_cache(r10)
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/* At this point r2 points to the next thread to be swapped in */
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/* the thread to be swapped in is now the current thread */
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stw r2, _kernel_offset_to_current(r10)
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/* Restore callee-saved registers and switch to the incoming
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* thread's stack
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*/
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ldw r16, _thread_offset_to_r16(r2)
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ldw r17, _thread_offset_to_r17(r2)
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ldw r18, _thread_offset_to_r18(r2)
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ldw r19, _thread_offset_to_r19(r2)
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ldw r20, _thread_offset_to_r20(r2)
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ldw r21, _thread_offset_to_r21(r2)
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ldw r22, _thread_offset_to_r22(r2)
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ldw r23, _thread_offset_to_r23(r2)
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ldw r28, _thread_offset_to_r28(r2)
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ldw ra, _thread_offset_to_ra(r2)
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ldw sp, _thread_offset_to_sp(r2)
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/* We need to irq_unlock(current->coopReg.key);
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* key was supplied as argument to _Swap(). Fetch it.
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*/
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ldw r3, _thread_offset_to_key(r2)
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/*
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* Load return value into r2 (return value register). -EAGAIN unless
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* someone previously called _set_thread_return_value(). Do this before
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* we potentially unlock interrupts.
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*/
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ldw r2, _thread_offset_to_retval(r2)
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/* Now do irq_unlock(current->coopReg.key) */
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#if (ALT_CPU_NUM_OF_SHADOW_REG_SETS > 0) || \
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(defined ALT_CPU_EIC_PRESENT) || \
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(defined ALT_CPU_MMU_PRESENT) || \
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(defined ALT_CPU_MPU_PRESENT)
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andi r3, r3, NIOS2_STATUS_PIE_MSK
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beq r3, zero, no_unlock
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rdctl r3, status
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ori r3, r3, NIOS2_STATUS_PIE_MSK
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wrctl status, r3
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no_unlock:
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#else
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wrctl status, r3
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#endif
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ret
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/* void _thread_entry_wrapper(void)
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*/
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SECTION_FUNC(TEXT, _thread_entry_wrapper)
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/* This all corresponds to struct init_stack_frame defined in
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* thread.c. We need to take this stuff off the stack and put
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* it in the apporpriate registers
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*/
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/* Can't return from here, just put NULL in ra */
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movi ra, 0
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/* Calling convention has first 4 arguments in registers r4-r7. */
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ldw r4, 0(sp)
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ldw r5, 4(sp)
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ldw r6, 8(sp)
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ldw r7, 12(sp)
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/* pop all the stuff that we just loaded into registers */
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addi sp, sp, 16
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call _thread_entry
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