mirror of
https://github.com/zephyrproject-rtos/zephyr
synced 2025-09-01 16:23:34 +00:00
9175d20ceb
- There's no clear need to disable frame pointers if this feature is used, remove this directive. - The 'top' and 'base' terms are reversed. The 'base' is the high address of the stack. The top is the lowest address, where we cannot push further down. Fixup member and offset names to correspond to how these terms are used in hardware documentation. - Use correct pointers for stack top location - Fatal exceptions now go through _NanoFatalErrorHandler to report the faulting ip and thread. Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
173 lines
4.6 KiB
ArmAsm
173 lines
4.6 KiB
ArmAsm
/*
|
|
* Copyright (c) 2014-2015 Wind River Systems, Inc.
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* @brief Thread context switching
|
|
*
|
|
* This module implements the routines necessary for thread context switching
|
|
* on ARCv2 CPUs.
|
|
*
|
|
* See isr_wrapper.S for details.
|
|
*/
|
|
|
|
#include <kernel_structs.h>
|
|
#include <offsets_short.h>
|
|
#include <toolchain.h>
|
|
#include <arch/cpu.h>
|
|
#include <v2/irq.h>
|
|
#include <swap_macros.h>
|
|
|
|
GTEXT(__swap)
|
|
GDATA(_k_neg_eagain)
|
|
GDATA(_kernel)
|
|
|
|
/**
|
|
*
|
|
* @brief Initiate a cooperative context switch
|
|
*
|
|
* The __swap() routine is invoked by various kernel services to effect
|
|
* a cooperative context switch. Prior to invoking __swap(), the caller
|
|
* disables interrupts via irq_lock() and the return 'key' is passed as a
|
|
* parameter to __swap(). The key is in fact the value stored in the register
|
|
* operand of a CLRI instruction.
|
|
*
|
|
* It stores the intlock key parameter into current->intlock_key.
|
|
|
|
* Given that __swap() is called to effect a cooperative context switch,
|
|
* the caller-saved integer registers are saved on the stack by the function
|
|
* call preamble to __swap(). This creates a custom stack frame that will be
|
|
* popped when returning from __swap(), but is not suitable for handling a
|
|
* return from an exception. Thus, the fact that the thread is pending because
|
|
* of a cooperative call to __swap() has to be recorded via the _CAUSE_COOP code
|
|
* in the relinquish_cause of the thread's k_thread structure. The
|
|
* _IrqExit()/_FirqExit() code will take care of doing the right thing to
|
|
* restore the thread status.
|
|
*
|
|
* When __swap() is invoked, we know the decision to perform a context switch or
|
|
* not has already been taken and a context switch must happen.
|
|
*
|
|
* @return may contain a return value setup by a call to
|
|
* _set_thread_return_value()
|
|
*
|
|
* C function prototype:
|
|
*
|
|
* unsigned int __swap (unsigned int key);
|
|
*
|
|
*/
|
|
|
|
SECTION_FUNC(TEXT, __swap)
|
|
|
|
/* interrupts are locked, interrupt key is in r0 */
|
|
|
|
mov r1, _kernel
|
|
ld_s r2, [r1, _kernel_offset_to_current]
|
|
|
|
/* save intlock key */
|
|
st_s r0, [r2, _thread_offset_to_intlock_key]
|
|
st _CAUSE_COOP, [r2, _thread_offset_to_relinquish_cause]
|
|
|
|
/*
|
|
* Carve space for the return value. Setting it to a defafult of
|
|
* -EAGAIN eliminates the need for the timeout code to set it.
|
|
* If another value is ever needed, it can be modified with
|
|
* _set_thread_return_value().
|
|
*/
|
|
ld r3, [_k_neg_eagain]
|
|
st_s r3, [r2, _thread_offset_to_return_value]
|
|
|
|
/*
|
|
* Save status32 and blink on the stack before the callee-saved registers.
|
|
* This is the same layout as the start of an IRQ stack frame.
|
|
*/
|
|
lr r3, [_ARC_V2_STATUS32]
|
|
push_s r3
|
|
#ifdef CONFIG_ARC_STACK_CHECKING
|
|
/* disable stack checking during swap */
|
|
bclr r3, r3, _ARC_V2_STATUS32_SC_BIT
|
|
kflag r3
|
|
#endif
|
|
push_s blink
|
|
|
|
_save_callee_saved_regs
|
|
|
|
/* get the cached thread to run */
|
|
ld_s r2, [r1, _kernel_offset_to_ready_q_cache]
|
|
|
|
/* entering here, r2 contains the new current thread */
|
|
#ifdef CONFIG_ARC_STACK_CHECKING
|
|
/* Use stack top and base registers from restored context */
|
|
ld r3, [r2, _thread_offset_to_stack_base]
|
|
sr r3, [_ARC_V2_KSTACK_BASE]
|
|
ld r3, [r2, _thread_offset_to_stack_top]
|
|
sr r3, [_ARC_V2_KSTACK_TOP]
|
|
#endif
|
|
/* XXX - can be moved to delay slot of _CAUSE_RIRQ ? */
|
|
st_s r2, [r1, _kernel_offset_to_current]
|
|
|
|
_load_callee_saved_regs
|
|
|
|
ld_s r3, [r2, _thread_offset_to_relinquish_cause]
|
|
|
|
breq r3, _CAUSE_RIRQ, _swap_return_from_rirq
|
|
nop
|
|
breq r3, _CAUSE_FIRQ, _swap_return_from_firq
|
|
nop
|
|
|
|
/* fall through to _swap_return_from_coop */
|
|
|
|
.balign 4
|
|
_swap_return_from_coop:
|
|
|
|
ld_s r1, [r2, _thread_offset_to_intlock_key]
|
|
st 0, [r2, _thread_offset_to_intlock_key]
|
|
ld_s r0, [r2, _thread_offset_to_return_value]
|
|
|
|
lr ilink, [_ARC_V2_STATUS32]
|
|
bbit1 ilink, _ARC_V2_STATUS32_AE_BIT, _return_from_exc
|
|
|
|
pop_s blink /* pc into blink */
|
|
pop_s r3 /* status32 into r3 */
|
|
kflag r3 /* write status32 */
|
|
|
|
j_s.d [blink] /* always execute delay slot */
|
|
seti r1 /* delay slot */
|
|
|
|
|
|
.balign 4
|
|
_swap_return_from_rirq:
|
|
_swap_return_from_firq:
|
|
|
|
lr r3, [_ARC_V2_STATUS32]
|
|
bbit1 r3, _ARC_V2_STATUS32_AE_BIT, _return_from_exc_irq
|
|
|
|
/* pretend interrupt happened to use rtie instruction */
|
|
lr r3, [_ARC_V2_AUX_IRQ_ACT]
|
|
brne r3,0,_swap_already_in_irq
|
|
|
|
or r3,r3,(1<<(CONFIG_NUM_IRQ_PRIO_LEVELS-1)) /* use lowest */
|
|
sr r3, [_ARC_V2_AUX_IRQ_ACT]
|
|
|
|
_swap_already_in_irq:
|
|
rtie
|
|
|
|
.balign 4
|
|
_return_from_exc_irq:
|
|
_pop_irq_stack_frame
|
|
sub_s sp, sp, 8
|
|
|
|
_return_from_exc:
|
|
|
|
/* put the return address to eret */
|
|
ld ilink, [sp] /* pc into ilink */
|
|
sr ilink, [_ARC_V2_ERET]
|
|
|
|
/* put status32 into estatus */
|
|
ld ilink, [sp, 4] /* status32 into ilink */
|
|
sr ilink, [_ARC_V2_ERSTATUS]
|
|
add_s sp, sp, 8
|
|
rtie
|