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Diffstat (limited to 'core/nds32/switch.S')
| -rw-r--r-- | core/nds32/switch.S | 109 |
1 files changed, 0 insertions, 109 deletions
diff --git a/core/nds32/switch.S b/core/nds32/switch.S deleted file mode 100644 index 631b0e0fe2..0000000000 --- a/core/nds32/switch.S +++ /dev/null @@ -1,109 +0,0 @@ -/* Copyright 2013 The Chromium OS Authors. All rights reserved. - * Use of this source code is governed by a BSD-style license that can be - * found in the LICENSE file. - * - * Context switching - */ - -#include "config.h" -#include "cpu.h" - -.section .ram_code - -/** - * Task context switching - * - * Change the task scheduled after returning from an interruption. - * - * This function must be called in interrupt context. - * - * Save the registers of the current task below the interrupt context on - * its task, then restore the live registers of the next task and set the - * process stack pointer to the new stack. - * - * $r0: pointer to the task to switch from - * $r1: pointer to the task to switch to - * $r2: pointer to the stack where the interrupt entry context is saved - * - * the structure of the saved context on the stack is : - * (top to bottom) - * sp, lp, fp, r15, r5, r4, r3, r2, r1, r0, r10, r9, r8, r7, r6, ipc, ipsw - * interrupt entry frame <|> - */ -.global __switch_task -__switch_task: - /* get the (new) highest priority task pointer in r0 */ - jal next_sched_task - movi55 $r3, 0 - /* pointer to the current task (which are switching from) */ - lwi.gp $r1, [ + current_task] - /* reset the re-scheduling request */ - swi.gp $r3, [ + need_resched] - /* Nothing to do: let's return to keep the same task scheduled */ - beq $r1, $r0, 1f - /* save our new scheduled task */ - swi.gp $r0, [ + current_task] - /* get the program status word saved at exception entry */ - mfsr $r4, $IPSW /* to save SP_ADJ bit */ - /* get the task program counter saved at exception entry */ - mfsr $r5, $IPC - /* get the new scheduled task stack pointer */ - lw $r3, [$r0] - /* save ipsw, ipc, r6, r7, r8, r9, r10 on the current process stack */ - smw.adm $r4, [$fp], $r10, 0 - /* restore ipsw, ipc, r6, r7, r8, r9, r10 from the next stack context */ - lmw.bim $r4, [$r3], $r10, 0 - /* set the program status word to restore SP_ADJ bit */ - mtsr $r4, $IPSW - /* set the task program counter to restore at exception exit */ - mtsr $r5, $IPC - /* save the task stack pointer in its context */ - sw $fp, [$r1] - /* barrier: ensure IPC is taken into account before IRET */ - dsb - /* exception frame pointer for the new task */ - mov55 $fp, $r3 -1: /* un-pile the interruption entry context */ - /* isr exit */ - jal end_irq_handler - /* restore r0-r5 */ - lmw.bim $r0, [$fp], $r5, 0 - /* restore r15, fp, lp and sp */ - lmw.bi $r15, [$fp], $r15, 0xb - /* restore PC and PSW */ - iret - -.text -/** - * Start the task scheduling. - * - * $r0 is a pointer to task_stack_ready, which is set to 1 after - * the task stack is set up. - */ -.global __task_start -__task_start: - /* - * Disable global interrupt here to ensure below sequence won't be - * broken. The "iret" instruction of ISR will enable GIE again. - */ - setgie.d - /* area used as thread stack for the first switch */ - la $r3, scratchpad - - movi55 $r4, 1 - movi55 $r2, 0 /* syscall 3rd parameter : not an IRQ emulation */ - movi55 $r1, 0 /* syscall 2nd parameter : re-schedule nothing */ - movi55 $r0, 0 /* syscall 1st parameter : de-schedule nothing */ - - /* put the stack pointer at the top of the stack in scratchpad */ - addi $sp, $r3, 4 * TASK_SCRATCHPAD_SIZE - /* we are ready to re-schedule */ - swi.gp $r4, [ + need_resched] - swi.gp $r4, [ + start_called] - - /* trigger scheduling to execute the task with the highest priority */ - syscall 0 - /* we should never return here: set code to EC_ERROR_UNKNOWN */ - movi55 $r0, 0x1 - ret5 $lp - |