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* Copyright (c) 2016 Cadence Design Systems, Inc.
* SPDX-License-Identifier: Apache-2.0
*/
/* XTENSA VECTORS AND LOW LEVEL HANDLERS FOR AN RTOS
*
* FIXME: A lot of this is not applicable to Zephyr, remove. In particular,
* we do not support installing interrupt or exception handlers at runtime.
*
* Xtensa low level exception and interrupt vectors and handlers for an RTOS.
*
* Interrupt handlers and user exception handlers support interaction with the
* RTOS by calling XT_RTOS_INT_ENTER and XT_RTOS_INT_EXIT before and after
* user's specific interrupt handlers. These macros are defined in
* xtensa_<rtos>.h to call suitable functions in a specific RTOS.
*
* Users can install application-specific interrupt handlers for low and medium
* level interrupts, by calling _xt_set_interrupt_handler(). These handlers can
* be written in C, and must obey C calling convention. The handler table is
* indexed by the interrupt number. Each handler may be provided with an
* argument.
*
* Note that the system timer interrupt is handled specially, and is dispatched
* to the RTOS-specific handler. This timer cannot be hooked by application
* code.
*
* Optional hooks are also provided to install a handler per level at run-time,
* made available by compiling this source file with '-DXT_INTEXC_HOOKS'
* (useful for automated testing).
*
* NOTE: This file is a template that usually needs to be modified to handle
* application specific interrupts. Search USER_EDIT for helpful comments on
* where to insert handlers and how to write them.
*
* Users can also install application-specific exception handlers in the same
* way, by calling _xt_set_exception_handler(). One handler slot is provided
* for each exception type. Note that some exceptions are handled by the
* porting layer itself, and cannot be taken over by application code in this
* manner. These are the alloca, syscall, and coprocessor exceptions.
*
* The exception handlers can be written in C, and must follow C calling
* convention. Each handler is passed a pointer to an exception frame as its
* single argument. The exception frame is created on the stack, and holds the
* saved context of the thread that took the exception. If the handler returns,
* the context will be restored and the instruction that caused the exception
* will be retried. If the handler makes any changes to the saved state in the
* exception frame, the changes will be applied when restoring the context.
*
* Because Xtensa is a configurable architecture, this port supports all user
* generated configurations (except restrictions stated in the release notes).
* This is accomplished by conditional compilation using macros and functions
* defined in the Xtensa HAL (hardware adaptation layer) for your
* configuration. Only the relevant parts of this file will be included in your
* RTOS build. For example, this file provides interrupt vector templates for
* all types and all priority levels, but only the ones in your configuration
* are built.
*
* NOTES on the use of 'call0' for long jumps instead of 'j':
*
* 1. This file should be assembled with the -mlongcalls option to xt-xcc.
*
* 2. The -mlongcalls compiler option causes 'call0 dest' to be expanded to
* a sequence 'l32r a0, dest' 'callx0 a0' which works regardless of the
* distance from the call to the destination. The linker then relaxes
* it back to 'call0 dest' if it determines that dest is within range.
* This allows more flexibility in locating code without the performance
* overhead of the 'l32r' literal data load in cases where the destination
* is in range of 'call0'. There is an additional benefit in that 'call0'
* has a longer range than 'j' due to the target being word-aligned, so
* the 'l32r' sequence is less likely needed.
*
* 3. The use of 'call0' with -mlongcalls requires that register a0 not be
* live at the time of the call, which is always the case for a function
* call but needs to be ensured if 'call0' is used as a jump in lieu of 'j'.
*
* 4. This use of 'call0' is independent of the C function call ABI.
*/
#include <offsets_short.h>
#include "xtensa_rtos.h"
#define GEN_MED_INTERRUPT(l) \
(XCHAL_NUM_INTLEVELS >= (l) && \
XCHAL_DEBUGLEVEL != (l) && \
XCHAL_EXCM_LEVEL >= (l))
#define GEN_HIGH_INTERRUPT(l) \
(XCHAL_NUM_INTLEVELS >= (l) && \
XCHAL_DEBUGLEVEL != (l) && \
(XCHAL_EXCM_LEVEL < (l) && !defined(CONFIG_XTENSA_OMIT_HIGH_INTERRUPTS)))
/*
* Defines used to access _xtos_interrupt_table.
*/
/**
* Zephyr has its own SW interrupt service routines table.
* Xtensa's table is made an alias of it.
**/
#define _xt_interrupt_table _sw_isr_table
#define XIE_ARG 0
#define XIE_HANDLER 4
#define XIE_SIZE 8
/* Macro extract_msb - return the input with only the highest bit set.
*
* Input : "ain" - Input value, clobbered.
* Output : "aout" - Output value, has only one bit set, MSB of "ain".
*
* The two arguments must be different AR registers.
*/
.macro extract_msb aout ain
1:
addi \aout, \ain, -1 /* aout = ain - 1 */
and \ain, \ain, \aout /* ain = ain & aout */
bnez \ain, 1b /* repeat until ain == 0 */
addi \aout, \aout, 1 /* return aout + 1 */
.endm
/* Macro dispatch_c_isr - dispatch interrupts to user ISRs.
* This will dispatch to user handlers (if any) that are registered in the
* XTOS dispatch table (_xtos_interrupt_table). These handlers would have
* been registered by calling _xtos_set_interrupt_handler(). There is one
* exception - the timer interrupt used by the OS will not be dispatched
* to a user handler - this must be handled by the caller of this macro.
*
* Level triggered and software interrupts are automatically deasserted by
* this code.
*
* ASSUMPTIONS:
* -- PS.INTLEVEL is set to "level" at entry
* -- PS.EXCM = 0, C calling enabled
*
* NOTE: For CALL0 ABI, a12-a15 have not yet been saved.
*
* NOTE: This macro will use registers a0 and a2-a6. The arguments are:
* level -- interrupt level
* mask -- interrupt bitmask for this level
*/
.extern _kernel
.extern _sys_power_save_idle_exit
.macro dispatch_c_isr level mask
/* Get mask of pending, enabled interrupts at this level into a2. */
.L_xt_user_int_&level&:
rsr a2, INTENABLE
rsr a3, INTERRUPT
movi a4, \mask
and a2, a2, a3
and a2, a2, a4
beqz a2, 9f /* nothing to do */
/* This bit of code provides a nice debug backtrace in the debugger.
It does take a few more instructions, so undef XT_DEBUG_BACKTRACE
if you want to save the cycles.
*/
#if XT_DEBUG_BACKTRACE
#ifndef __XTENSA_CALL0_ABI__
rsr a0, EPC_1 + \level - 1 /* return address */
movi a4, 0xC0000000 /* constant with top 2 bits set (call size) */
or a0, a0, a4 /* set top 2 bits */
addx2 a0, a4, a0 /* clear top bit -- simulating call4 size */
#endif
#endif
#ifdef CONFIG_KERNEL_EVENT_LOGGER_INTERRUPT
/*
* Register the interrupt.
* We just saved all registers.
*/
#ifdef __XTENSA_CALL0_ABI__
call0 _sys_k_event_logger_interrupt
#else
call4 _sys_k_event_logger_interrupt
#endif
#endif
#ifdef CONFIG_KERNEL_EVENT_LOGGER_SLEEP
/*
* Register the sleep enter.
* We just saved all registers.
*/
#ifdef __XTENSA_CALL0_ABI__
call0 _sys_k_event_logger_exit_sleep
#else
call4 _sys_k_event_logger_exit_sleep
#endif
#endif
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a4, _xt_intexc_hooks
l32i a4, a4, \level << 2
beqz a4, 2f
#ifdef __XTENSA_CALL0_ABI__
callx0 a4
beqz a2, 9f
#else
mov a6, a2
callx4 a4
beqz a6, 9f
mov a2, a6
#endif
2:
#endif
#ifdef CONFIG_SYS_POWER_MANAGEMENT
movi a3, _kernel
#ifdef __XTENSA_CALL0_ABI__
mov a12, a2
l32i a2, a3, _kernel_offset_to_idle
beqz a2, 10f
xor a4, a2, a2
s32i a4, a3, _kernel_offset_to_idle
call0 _sys_power_save_idle_exit
mov a2, a12
#else
l32i a6, a3, _kernel_offset_to_idle
beqz a6, 10f
xor a4, a6, a6
s32i a4, a3, _kernel_offset_to_idle
call4 _sys_power_save_idle_exit
#endif /* __XTENSA_CALL0_ABI__ */
10:
#endif /* CONFIG_SYS_POWER_MANAGEMENT */
/* Now look up in the dispatch table and call user ISR if any. */
/* If multiple bits are set then MSB has highest priority. */
extract_msb a4, a2 /* a4 = MSB of a2, a2 trashed */
#ifdef XT_USE_SWPRI
/* Enable all interrupts at this level that are numerically highe
* than the one we just selected, since they are treated as higher
* priority.
* */
movi a3, \mask /* a3 = all interrupts at this level */
add a2, a4, a4 /* a2 = a4 << 1 */
addi a2, a2, -1 /* a2 = mask of 1's <= a4 bit */
and a2, a2, a3 /* a2 = mask of all bits <= a4 at this level */
movi a3, _xt_intdata
l32i a6, a3, 4 /* a6 = _xt_vpri_mask */
neg a2, a2
addi a2, a2, -1 /* a2 = mask to apply */
and a5, a6, a2 /* mask off all bits <= a4 bit */
s32i a5, a3, 4 /* update _xt_vpri_mask */
rsr a3, INTENABLE
and a3, a3, a2 /* mask off all bits <= a4 bit */
wsr a3, INTENABLE
rsil a3, \level - 1 /* lower interrupt level by 1 */
#endif
movi a3, XT_TIMER_INTEN /* a3 = timer interrupt bit */
wsr a4, INTCLEAR /* clear sw or edge-triggered interrupt */
beq a3, a4, 7f /* if timer interrupt then skip table */
find_ms_setbit a3, a4, a3, 0 /* a3 = interrupt number */
movi a4, _xt_interrupt_table
addx8 a3, a3, a4 /* a3 = address of interrupt table entry */
l32i a4, a3, XIE_HANDLER /* a4 = handler address */
#ifdef __XTENSA_CALL0_ABI__
mov a12, a6 /* save in callee-saved reg */
l32i a2, a3, XIE_ARG /* a2 = handler arg */
callx0 a4 /* call handler */
mov a2, a12
#else
mov a2, a6 /* save in windowed reg */
l32i a6, a3, XIE_ARG /* a6 = handler arg */
callx4 a4 /* call handler */
#endif
#ifdef XT_USE_SWPRI
j 8f
#else
j .L_xt_user_int_&level& /* check for more interrupts */
#endif
7:
.ifeq XT_TIMER_INTPRI - \level
.L_xt_user_int_timer_&level&:
/*
* Interrupt handler for the RTOS tick timer if at this level.
* We'll be reading the interrupt state again after this call
* so no need to preserve any registers except a6 (vpri_mask).
*/
#ifdef __XTENSA_CALL0_ABI__
mov a12, a6
call0 XT_RTOS_TIMER_INT
mov a2, a12
#else
mov a2, a6
call4 XT_RTOS_TIMER_INT
#endif
.endif
#ifdef XT_USE_SWPRI
j 8f
#else
j .L_xt_user_int_&level& /* check for more interrupts */
#endif
#ifdef XT_USE_SWPRI
8:
/* Restore old value of _xt_vpri_mask from a2. Also update INTENABLE
* from virtual _xt_intenable which _could_ have changed during
* interrupt processing.
*/
movi a3, _xt_intdata
l32i a4, a3, 0 /* a4 = _xt_intenable */
s32i a2, a3, 4 /* update _xt_vpri_mask */
and a4, a4, a2 /* a4 = masked intenable */
wsr a4, INTENABLE /* update INTENABLE */
#endif
9:
/* done */
.endm
/* Panic handler.
*
* Should be reached by call0 (preferable) or jump only. If call0, a0 says
* where from. If on simulator, display panic message and abort, else loop
* indefinitely.
*/
.text
.global _xt_panic
.type _xt_panic,@function
.align 4
_xt_panic:
#ifdef XT_SIMULATOR
addi a4, a0, -3 /* point to call0 */
movi a3, _xt_panic_message
movi a2, SYS_log_msg
simcall
movi a2, SYS_gdb_abort
simcall
#else
rsil a2, XCHAL_EXCM_LEVEL /* disable all low & med ints */
1: j 1b /* loop infinitely */
#endif
.section .rodata, "a"
.align 4
_xt_panic_message:
.string "\n*** _xt_panic() was called from 0x%08x or jumped to. ***\n"
/* Hooks to dynamically install handlers for exceptions and interrupts. Allows
* automated regression frameworks to install handlers per test. Consists of
* an array of function pointers indexed by interrupt level, with index 0
* containing the entry for user exceptions. Initialized with all 0s, meaning
* no handler is installed at each level. See comment in xtensa_rtos.h for
* more details.
*/
#ifdef XT_INTEXC_HOOKS
.data
.global _xt_intexc_hooks
.type _xt_intexc_hooks,@object
.align 4
_xt_intexc_hooks:
.fill XT_INTEXC_HOOK_NUM, 4, 0
#endif
/* EXCEPTION AND LEVEL 1 INTERRUPT VECTORS AND LOW LEVEL HANDLERS (except
* window exception vectors).
*
* Each vector goes at a predetermined location according to the Xtensa
* hardware configuration, which is ensured by its placement in a special
* section known to the Xtensa linker support package (LSP). It performs the
* minimum necessary before jumping to the handler in the .text section.
*
* The corresponding handler goes in the normal .text section. It sets up the
* appropriate stack frame, saves a few vector-specific registers and calls
* XT_RTOS_INT_ENTER to save the rest of the interrupted context and enter the
* RTOS, then sets up a C environment. It then calls the user's interrupt
* handler code (which may be coded in C) and finally calls XT_RTOS_INT_EXIT to
* transfer control to the RTOS for scheduling.
*
* While XT_RTOS_INT_EXIT does not return directly to the interruptee,
* eventually the RTOS scheduler will want to dispatch the interrupted task or
* handler. The scheduler will return to the exit point that was saved in the
* interrupt stack frame at XT_STK_EXIT.
*/
/*
* Debug Exception.
*/
#if XCHAL_HAVE_DEBUG
.begin literal_prefix .DebugExceptionVector
.section .DebugExceptionVector.text, "ax"
.global _DebugExceptionVector
.align 4
_DebugExceptionVector:
#ifdef XT_SIMULATOR
/* In the simulator, let the debugger (if any) handle the debug
* exception, or simply stop the simulation:
*/
wsr a2, EXCSAVE+XCHAL_DEBUGLEVEL /* save a2 where sim expects it */
movi a2, SYS_gdb_enter_sktloop
simcall /* have ISS handle debug exc. */
#elif 0 /* change condition to 1 to use the HAL minimal debug handler */
wsr a3, EXCSAVE+XCHAL_DEBUGLEVEL
movi a3, xthal_debugexc_defhndlr_nw /* use default debug handler */
jx a3
#else
wsr a0, EXCSAVE+XCHAL_DEBUGLEVEL /* save original a0 somewhere */
call0 _xt_panic /* does not return */
rfi XCHAL_DEBUGLEVEL /* make a0 point here not later */
#endif
.end literal_prefix
#endif
/* Double Exception.
*
* Double exceptions are not a normal occurrence. They indicate a bug of some
* kind.
*/
#ifdef XCHAL_DOUBLEEXC_VECTOR_VADDR
.begin literal_prefix .DoubleExceptionVector
.section .DoubleExceptionVector.text, "ax"
.global _DoubleExceptionVector
.align 4
_DoubleExceptionVector:
#if XCHAL_HAVE_DEBUG
break 1, 4 /* unhandled double exception */
#endif
call0 _xt_panic /* does not return */
rfde /* make a0 point here not later */
.end literal_prefix
#endif /* XCHAL_DOUBLEEXC_VECTOR_VADDR */
/*
* Kernel Exception (including Level 1 Interrupt from kernel mode).
*/
.begin literal_prefix .KernelExceptionVector
.section .KernelExceptionVector.text, "ax"
.global _KernelExceptionVector
.align 4
_KernelExceptionVector:
wsr a0, EXCSAVE_1 /* preserve a0 */
call0 _xt_kernel_exc /* kernel exception handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.align 4
_xt_kernel_exc:
#if XCHAL_HAVE_DEBUG
break 1, 0 /* unhandled kernel exception */
#endif
call0 _xt_panic /* does not return */
rfe /* make a0 point here not there */
/* User Exception (including Level 1 Interrupt from user mode). */
.begin literal_prefix .UserExceptionVector
.section .UserExceptionVector.text, "ax"
.global _UserExceptionVector
.type _UserExceptionVector,@function
.align 4
_UserExceptionVector:
wsr a0, EXCSAVE_1 /* preserve a0 */
call0 _xt_user_exc /* user exception handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
/* Insert some waypoints for jumping beyond the signed 8-bit range of
* conditional branch instructions, so the conditional branchces to specific
* exception handlers are not taken in the mainline. Saves some cycles in the
* mainline.
*/
.text
#if XCHAL_HAVE_WINDOWED
.align 4
_xt_to_alloca_exc:
call0 _xt_alloca_exc /* in window vectors section */
/* never returns here - call0 is used as a jump (see note at top) */
#endif
.align 4
_xt_to_syscall_exc:
call0 _xt_syscall_exc
/* never returns here - call0 is used as a jump (see note at top) */
#if XCHAL_CP_NUM > 0
.align 4
_xt_to_coproc_exc:
call0 _xt_coproc_exc
/* never returns here - call0 is used as a jump (see note at top) */
#endif
/*
* User exception handler.
*/
.type _xt_user_exc,@function
.align 4
_xt_user_exc:
/* If level 1 interrupt then jump to the dispatcher */
rsr a0, EXCCAUSE
beqi a0, EXCCAUSE_LEVEL1INTERRUPT, _xt_lowint1
/* Handle any coprocessor exceptions. Rely on the fact that exception
* numbers above EXCCAUSE_CP0_DISABLED all relate to the coprocessors.
*/
#if XCHAL_CP_NUM > 0
bgeui a0, EXCCAUSE_CP0_DISABLED, _xt_to_coproc_exc
#endif
/* Handle alloca and syscall exceptions */
#if XCHAL_HAVE_WINDOWED
beqi a0, EXCCAUSE_ALLOCA, _xt_to_alloca_exc
#endif
beqi a0, EXCCAUSE_SYSCALL, _xt_to_syscall_exc
/* Handle all other exceptions. All can have user-defined handlers. */
/* NOTE: we'll stay on the user stack for exception handling. */
/* Allocate exception frame and save minimal context. */
mov a0, sp
addi sp, sp, -XT_STK_FRMSZ
s32i a0, sp, XT_STK_a1
#if XCHAL_HAVE_WINDOWED
s32e a0, sp, -12 /* for debug backtrace */
#endif
rsr a0, PS /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_1 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_1 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
#if XCHAL_HAVE_WINDOWED
s32e a0, sp, -16 /* for debug backtrace */
#endif
s32i a12, sp, XT_STK_a12 /* _xt_context_save requires A12- */
s32i a13, sp, XT_STK_a13 /* A13 to have already been saved */
call0 _xt_context_save
/* Save exc cause and vaddr into exception frame */
rsr a0, EXCCAUSE
s32i a0, sp, XT_STK_exccause
rsr a0, EXCVADDR
s32i a0, sp, XT_STK_excvaddr
/* Set up PS for C, reenable hi-pri interrupts, and clear EXCM. */
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM
#else
movi a0, PS_INTLEVEL(XCHAL_EXCM_LEVEL) | PS_UM | PS_WOE
#endif
wsr a0, PS
#ifdef XT_DEBUG_BACKTRACE
#ifndef __XTENSA_CALL0_ABI__
rsr a0, EPC_1 /* return address for debug backtrace */
/* constant with top 2 bits set (call size) */
movi a5, 0xC0000000
rsync /* wait for WSR.PS to complete */
or a0, a0, a5 /* set top 2 bits */
addx2 a0, a5, a0 /* clear top bit, simulating call4 size */
#else
rsync /* wait for WSR.PS to complete */
#endif
#endif
rsr a2, EXCCAUSE /* recover exc cause */
#ifdef XT_INTEXC_HOOKS
/* Call exception hook to pre-handle exceptions (if installed).
* Pass EXCCAUSE in a2, and check result in a2 (if -1, skip default
* handling).
*/
movi a4, _xt_intexc_hooks
l32i a4, a4, 0 /* user exception hook index 0 */
beqz a4, 1f
.Ln_xt_user_exc_call_hook:
#ifdef __XTENSA_CALL0_ABI__
callx0 a4
beqi a2, -1, .L_xt_user_done
#else
mov a6, a2
callx4 a4
beqi a6, -1, .L_xt_user_done
mov a2, a6
#endif
1:
#endif
rsr a2, EXCCAUSE /* recover exc cause */
movi a3, _xt_exception_table
addx4 a4, a2, a3 /* a4 = address of exception table entry */
l32i a4, a4, 0 /* a4 = handler address */
#ifdef __XTENSA_CALL0_ABI__
mov a2, sp /* a2 = pointer to exc frame */
callx0 a4 /* call handler */
#else
mov a6, sp /* a6 = pointer to exc frame */
callx4 a4 /* call handler */
#endif
.L_xt_user_done:
/* Restore context and return */
call0 _xt_context_restore
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, PS
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_1
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove exception frame */
rsync /* ensure PS and EPC written */
rfe /* PS.EXCM is cleared */
/*
* Exit point for dispatch. Saved in interrupt stack frame at XT_STK_EXIT
* on entry and used to return to a thread or interrupted interrupt handler.
*/
.global _xt_user_exit
.type _xt_user_exit,@function
.align 4
_xt_user_exit:
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, PS
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_1
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure PS and EPC written */
rfe /* PS.EXCM is cleared */
/* Syscall Exception Handler (jumped to from User Exception Handler).
*
* Syscall 0 is required to spill the register windows (no-op in Call 0 ABI).
* Only syscall 0 is handled here. Other syscalls return -1 to caller in a2.
*/
.text
.type _xt_syscall_exc,@function
.align 4
_xt_syscall_exc:
#ifdef __XTENSA_CALL0_ABI__
/* Save minimal regs for scratch. Syscall 0 does nothing in Call0 ABI.
* Use a minimal stack frame (16B) to save A2 & A3 for scratch.
* PS.EXCM could be cleared here, but unlikely to improve worst-case
* latency.
*/
addi sp, sp, -16
s32i a2, sp, 8
s32i a3, sp, 12
#else /* Windowed ABI */
/* Save necessary context and spill the register windows. PS.EXCM is
* still set and must remain set until after the spill. Reuse context
* save function though it saves more than necessary. For this reason,
* a full interrupt stack frame is allocated.
*/
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a12, sp, XT_STK_a12 /* _xt_context_save requires A12- */
s32i a13, sp, XT_STK_a13 /* A13 to have already been saved */
call0 _xt_context_save
#endif
/* Grab the interruptee's PC and skip over the 'syscall' instruction.
* If it's at the end of a zero-overhead loop and it's not on the last
* iteration, decrement loop counter and skip to beginning of loop.
*/
rsr a2, EPC_1 /* a2 = PC of 'syscall' */
addi a3, a2, 3 /* ++PC */
#if XCHAL_HAVE_LOOPS
rsr a0, LEND /* if (PC == LEND */
bne a3, a0, 1f
rsr a0, LCOUNT /* && LCOUNT != 0) */
beqz a0, 1f /* { */
addi a0, a0, -1 /* --LCOUNT */
rsr a3, LBEG /* PC = LBEG */
wsr a0, LCOUNT /* } */
#endif
1: wsr a3, EPC_1 /* update PC */
/* Restore interruptee's context and return from exception. */
#ifdef __XTENSA_CALL0_ABI__
l32i a2, sp, 8
l32i a3, sp, 12
addi sp, sp, 16
#else
call0 _xt_context_restore
addi sp, sp, XT_STK_FRMSZ
#endif
movi a0, -1
movnez a2, a0, a2 /* return -1 if not syscall 0 */
rsr a0, EXCSAVE_1
rfe
/*
* Co-Processor Exception Handler (jumped to from User Exception Handler).
*
* These exceptions are generated by co-processor instructions, which are only
* allowed in thread code (not in interrupts or kernel code). This restriction
* is deliberately imposed to reduce the burden of state-save/restore in
* interrupts.
*/
#if XCHAL_CP_NUM > 0
.section .rodata, "a"
/* Offset to CP n save area in thread's CP save area. */
.global _xt_coproc_sa_offset
.type _xt_coproc_sa_offset,@object
.align 16 /* minimize crossing cache boundaries */
_xt_coproc_sa_offset:
.word XT_CP0_SA, XT_CP1_SA, XT_CP2_SA, XT_CP3_SA
.word XT_CP4_SA, XT_CP5_SA, XT_CP6_SA, XT_CP7_SA
/* Bitmask for CP n's CPENABLE bit. */
.type _xt_coproc_mask,@object
.align 16,,8 /* try to keep it all in one cache line */
.set i, 0
_xt_coproc_mask:
.rept XCHAL_CP_MAX
.long (i<<16) | (1<<i) /* upper 16-bits = i, lower = bitmask */
.set i, i+1
.endr
.data
/* Owner thread of CP n, identified by thread's CP save area (0 = unowned). */
.global _xt_coproc_owner_sa
.type _xt_coproc_owner_sa,@object
.align 16,,XCHAL_CP_MAX<<2 /* minimize crossing cache boundaries */
_xt_coproc_owner_sa:
.space XCHAL_CP_MAX << 2
.text
.align 4
.L_goto_invalid:
j .L_xt_coproc_invalid /* not in a thread (invalid) */
.align 4
.L_goto_done:
j .L_xt_coproc_done
/*
* Coprocessor exception handler.
*
* At entry, only a0 has been saved (in EXCSAVE_1).
*/
.type _xt_coproc_exc,@function
.align 4
_xt_coproc_exc:
/* Allocate interrupt stack frame and save minimal context. */
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
#if XCHAL_HAVE_WINDOWED
s32e a0, sp, -12 /* for debug backtrace */
#endif
rsr a0, PS /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_1 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_1 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
#if XCHAL_HAVE_WINDOWED
s32e a0, sp, -16 /* for debug backtrace */
#endif
movi a0, _xt_user_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
rsr a0, EXCCAUSE
s32i a5, sp, XT_STK_a5 /* save a5 */
addi a5, a0, -EXCCAUSE_CP0_DISABLED /* a5 = CP index */
/* Save a few more of interruptee's registers (a5 was already saved). */
s32i a2, sp, XT_STK_a2
s32i a3, sp, XT_STK_a3
s32i a4, sp, XT_STK_a4
s32i a15, sp, XT_STK_a15
/* Get co-processor state save area of new owner thread. */
call0 XT_RTOS_CP_STATE /* a15 = new owner's save area */
beqz a15, .L_goto_invalid /* not in a thread (invalid) */
/* Enable the co-processor's bit in CPENABLE. */
movi a0, _xt_coproc_mask
rsr a4, CPENABLE /* a4 = CPENABLE */
addx4 a0, a5, a0 /* a0 = &_xt_coproc_mask[n] */
l32i a0, a0, 0 /* a0 = (n << 16) | (1 << n) */
movi a3, _xt_coproc_owner_sa /* (placed here for load slot) */
extui a2, a0, 0, 16 /* coprocessor bitmask portion */
or a4, a4, a2 /* a4 = CPENABLE | (1 << n) */
wsr a4, CPENABLE
/* Get old coprocessor owner thread (save area ptr) and assign new
* one.
*/
addx4 a3, a5, a3 /* a3 = &_xt_coproc_owner_sa[n] */
l32i a2, a3, 0 /* a2 = old owner's save area */
s32i a15, a3, 0 /* _xt_coproc_owner_sa[n] = new */
rsync /* ensure wsr.CPENABLE is complete */
/* Only need to context switch if new owner != old owner. */
beq a15, a2, .L_goto_done /* new owner == old, we're done */
/* If no old owner then nothing to save. */
beqz a2, .L_check_new
/* If old owner not actively using CP then nothing to save. */
l16ui a4, a2, XT_CPENABLE /* a4 = old owner's CPENABLE */
bnone a4, a0, .L_check_new /* old owner not using CP */
.L_save_old:
/* Save old owner's coprocessor state. */
movi a5, _xt_coproc_sa_offset
/* Mark old owner state as no longer active (CPENABLE bit n clear). */
xor a4, a4, a0 /* clear CP bit in CPENABLE */
s16i a4, a2, XT_CPENABLE /* update old owner's CPENABLE */
extui a4, a0, 16, 5 /* a4 = CP index = n */
addx4 a5, a4, a5 /* a5 = &_xt_coproc_sa_offset[n] */
/* Mark old owner state as saved (CPSTORED bit n set). */
l16ui a4, a2, XT_CPSTORED /* a4 = old owner's CPSTORED */
l32i a5, a5, 0 /* a5 = XT_CP[n]_SA offset */
or a4, a4, a0 /* set CP in old owner's CPSTORED */
s16i a4, a2, XT_CPSTORED /* update old owner's CPSTORED */
l32i a2, a2, XT_CP_ASA /* ptr to actual (aligned) save area */
extui a3, a0, 16, 5 /* a3 = CP index = n */
add a2, a2, a5 /* a2 = old owner's area for CP n */
/* The config-specific HAL macro invoked below destroys a2-5, preserves
* a0-1. It is theoretically possible for Xtensa processor designers to
* write TIE that causes more address registers to be affected, but it
* is generally unlikely. If that ever happens, more registers needs to
* be saved/restored around this macro invocation, and the value in a15
* needs to be recomputed.
*/
xchal_cpi_store_funcbody
.L_check_new:
/* Check if any state has to be restored for new owner. */
/* NOTE: a15 = new owner's save area, cannot be zero when we get
* here. */
l16ui a3, a15, XT_CPSTORED /* a3 = new owner's CPSTORED */
movi a4, _xt_coproc_sa_offset
/* full CP not saved, check callee-saved */
bnone a3, a0, .L_check_cs
xor a3, a3, a0 /* CPSTORED bit is set, clear it */
s16i a3, a15, XT_CPSTORED /* update new owner's CPSTORED */
/* Adjust new owner's save area pointers to area for CP n. */
extui a3, a0, 16, 5 /* a3 = CP index = n */
addx4 a4, a3, a4 /* a4 = &_xt_coproc_sa_offset[n] */
l32i a4, a4, 0 /* a4 = XT_CP[n]_SA */
l32i a5, a15, XT_CP_ASA /* ptr to actual (aligned) save area */
add a2, a4, a5 /* a2 = new owner's area for CP */
/* The config-specific HAL macro invoked below destroys a2-5, preserves
* a0-1. It is theoretically possible for Xtensa processor designers to
* write TIE that causes more address registers to be affected, but it
* is generally unlikely. If that ever happens, more registers needs to
* be saved/restored around this macro invocation.
*/
xchal_cpi_load_funcbody
/* Restore interruptee's saved registers. */
/* Can omit rsync for wsr.CPENABLE here because _xt_user_exit does
* it.
*/
.L_xt_coproc_done:
l32i a15, sp, XT_STK_a15
l32i a5, sp, XT_STK_a5
l32i a4, sp, XT_STK_a4
l32i a3, sp, XT_STK_a3
l32i a2, sp, XT_STK_a2
call0 _xt_user_exit /* return via exit dispatcher */
/* Never returns here - call0 is used as a jump (see note at top) */
.L_check_cs:
/* a0 = CP mask in low bits, a15 = new owner's save area */
l16ui a2, a15, XT_CP_CS_ST /* a2 = mask of CPs saved */
bnone a2, a0, .L_xt_coproc_done /* if no match then done */
and a2, a2, a0 /* a2 = which CPs to restore */
extui a2, a2, 0, 8 /* extract low 8 bits */
s32i a6, sp, XT_STK_a6 /* save extra needed regs */
s32i a7, sp, XT_STK_a7
s32i a13, sp, XT_STK_a13
s32i a14, sp, XT_STK_a14
call0 _xt_coproc_restorecs /* restore CP registers */
l32i a6, sp, XT_STK_a6 /* restore saved registers */
l32i a7, sp, XT_STK_a7
l32i a13, sp, XT_STK_a13
l32i a14, sp, XT_STK_a14
j .L_xt_coproc_done
/* Co-processor exception occurred outside a thread (not supported). */
.L_xt_coproc_invalid:
#if XCHAL_HAVE_DEBUG
break 1, 1 /* unhandled user exception */
#endif
call0 _xt_panic /* not in a thread (invalid) */
/* never returns */
#endif /* XCHAL_CP_NUM */
/*
* Level 1 interrupt dispatch. Assumes stack frame has not been allocated yet.
*/
.text
.type _xt_lowint1,@function
.align 4
_xt_lowint1:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, PS /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_1 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_1 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_user_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(1) | PS_UM
#else
movi a0, PS_INTLEVEL(1) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 1 XCHAL_INTLEVEL1_MASK
/* Done handling interrupts, transfer control to OS. */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* MEDIUM PRIORITY (LEVEL 2+) INTERRUPT VECTORS AND LOW LEVEL HANDLERS.
*
* Medium priority interrupts are by definition those with priority greater
* than 1 and not greater than XCHAL_EXCM_LEVEL. These are disabled by setting
* PS.EXCM and therefore can easily support a C environment for handlers in C,
* and interact safely with an RTOS.
*
* Each vector goes at a predetermined location according to the Xtensa
* hardware configuration, which is ensured by its placement in a special
* section known to the Xtensa linker support package (LSP). It performs the
* minimum necessary before jumping to the handler in the .text section.
*
* The corresponding handler goes in the normal .text section. It sets up the
* appropriate stack frame, saves a few vector-specific registers and calls
* XT_RTOS_INT_ENTER to save the rest of the interrupted context and enter the
* RTOS, then sets up a C environment. It then calls the user's interrupt
* handler code (which may be coded in C) and finally calls XT_RTOS_INT_EXIT to
* transfer control to the RTOS for scheduling.
*
* While XT_RTOS_INT_EXIT does not return directly to the interruptee,
* eventually the RTOS scheduler will want to dispatch the interrupted task or
* handler. The scheduler will return to the exit point that was saved in the
* interrupt stack frame at XT_STK_EXIT.
*
* FIXME: Make this a macro or something so almost-identical code isn't
* repeated 5 times!!
*/
#if GEN_MED_INTERRUPT(2)
.begin literal_prefix .Level2InterruptVector
.section .Level2InterruptVector.text, "ax"
.global _Level2Vector
.type _Level2Vector,@function
.align 4
_Level2Vector:
wsr a0, EXCSAVE_2 /* preserve a0 */
call0 _xt_medint2 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_medint2,@function
.align 4
_xt_medint2:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, EPS_2 /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_2 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_2 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_medint2_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(2) | PS_UM
#else
movi a0, PS_INTLEVEL(2) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 2 XCHAL_INTLEVEL2_MASK
/* Done handling interrupts, transfer control to OS */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* Exit point for dispatch. Saved in interrupt stack frame at
* XT_STK_EXIT on entry and used to return to a thread or interrupted
* interrupt handler.
*/
.global _xt_medint2_exit
.type _xt_medint2_exit,@function
.align 4
_xt_medint2_exit:
/* Restore only level-specific regs (the rest were already restored) */
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, EPS_2
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_2
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure EPS and EPC written */
rfi 2
#endif /* Level 2 */
#if GEN_MED_INTERRUPT(3)
.begin literal_prefix .Level3InterruptVector
.section .Level3InterruptVector.text, "ax"
.global _Level3Vector
.type _Level3Vector,@function
.align 4
_Level3Vector:
wsr a0, EXCSAVE_3 /* preserve a0 */
call0 _xt_medint3 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_medint3,@function
.align 4
_xt_medint3:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, EPS_3 /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_3 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_3 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_medint3_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(3) | PS_UM
#else
movi a0, PS_INTLEVEL(3) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 3 XCHAL_INTLEVEL3_MASK
/* Done handling interrupts, transfer control to OS */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* Exit point for dispatch. Saved in interrupt stack frame at
* XT_STK_EXITon entry and used to return to a thread or interrupted
* interrupt handler.
*/
.global _xt_medint3_exit
.type _xt_medint3_exit,@function
.align 4
_xt_medint3_exit:
/* Restore only level-specific regs (the rest were already restored) */
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, EPS_3
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_3
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure EPS and EPC written */
rfi 3
#endif /* Level 3 */
#if GEN_MED_INTERRUPT(4)
.begin literal_prefix .Level4InterruptVector
.section .Level4InterruptVector.text, "ax"
.global _Level4Vector
.type _Level4Vector,@function
.align 4
_Level4Vector:
wsr a0, EXCSAVE_4 /* preserve a0 */
call0 _xt_medint4 /* load interrupt handler */
.end literal_prefix
.text
.type _xt_medint4,@function
.align 4
_xt_medint4:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, EPS_4 /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_4 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_4 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_medint4_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(4) | PS_UM
#else
movi a0, PS_INTLEVEL(4) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 4 XCHAL_INTLEVEL4_MASK
/* Done handling interrupts, transfer control to OS */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* Exit point for dispatch. Saved in interrupt stack frame at
* XT_STK_EXIT on entry and used to return to a thread or interrupted
* interrupt handler.
*/
.global _xt_medint4_exit
.type _xt_medint4_exit,@function
.align 4
_xt_medint4_exit:
/* Restore only level-specific regs (the rest were already restored) */
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, EPS_4
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_4
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure EPS and EPC written */
rfi 4
#endif /* Level 4 */
#if GEN_MED_INTERRUPT(5)
.begin literal_prefix .Level5InterruptVector
.section .Level5InterruptVector.text, "ax"
.global _Level5Vector
.type _Level5Vector,@function
.align 4
_Level5Vector:
wsr a0, EXCSAVE_5 /* preserve a0 */
call0 _xt_medint5 /* load interrupt handler */
.end literal_prefix
.text
.type _xt_medint5,@function
.align 4
_xt_medint5:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, EPS_5 /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_5 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_5 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_medint5_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(5) | PS_UM
#else
movi a0, PS_INTLEVEL(5) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 5 XCHAL_INTLEVEL5_MASK
/* Done handling interrupts, transfer control to OS */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* Exit point for dispatch. Saved in interrupt stack frame at
* XT_STK_EXITon entry and used to return to a thread or interrupted
* interrupt handler.
*/
.global _xt_medint5_exit
.type _xt_medint5_exit,@function
.align 4
_xt_medint5_exit:
/* Restore only level-specific regs (the rest were already restored) */
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, EPS_5
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_5
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure EPS and EPC written */
rfi 5
#endif /* Level 5 */
#if GEN_MED_INTERRUPT(6)
.begin literal_prefix .Level6InterruptVector
.section .Level6InterruptVector.text, "ax"
.global _Level6Vector
.type _Level6Vector,@function
.align 4
_Level6Vector:
wsr a0, EXCSAVE_6 /* preserve a0 */
call0 _xt_medint6 /* load interrupt handler */
.end literal_prefix
.text
.type _xt_medint6,@function
.align 4
_xt_medint6:
mov a0, sp /* sp == a1 */
addi sp, sp, -XT_STK_FRMSZ /* allocate interrupt stack frame */
s32i a0, sp, XT_STK_a1 /* save pre-interrupt SP */
rsr a0, EPS_6 /* save interruptee's PS */
s32i a0, sp, XT_STK_ps
rsr a0, EPC_6 /* save interruptee's PC */
s32i a0, sp, XT_STK_pc
rsr a0, EXCSAVE_6 /* save interruptee's a0 */
s32i a0, sp, XT_STK_a0
movi a0, _xt_medint6_exit /* save exit point for dispatch */
s32i a0, sp, XT_STK_exit
/* Save rest of interrupt context and enter RTOS. */
call0 XT_RTOS_INT_ENTER /* common RTOS interrupt entry */
/* !! We are now on the RTOS system stack !! */
/* Set up PS for C, enable interrupts above this level and clear
* EXCM.
*/
#ifdef __XTENSA_CALL0_ABI__
movi a0, PS_INTLEVEL(6) | PS_UM
#else
movi a0, PS_INTLEVEL(6) | PS_UM | PS_WOE
#endif
wsr a0, PS
rsync
/* OK to call C code at this point, dispatch user ISRs */
dispatch_c_isr 6 XCHAL_INTLEVEL6_MASK
/* Done handling interrupts, transfer control to OS */
call0 XT_RTOS_INT_EXIT /* does not return directly here */
/* Exit point for dispatch. Saved in interrupt stack frame at
* XT_STK_EXIT on entry and used to return to a thread or interrupted
* interrupt handler.
*/
.global _xt_medint6_exit
.type _xt_medint6_exit,@function
.align 4
_xt_medint6_exit:
/* Restore only level-specific regs (the rest were already restored) */
l32i a0, sp, XT_STK_ps /* retrieve interruptee's PS */
wsr a0, EPS_6
l32i a0, sp, XT_STK_pc /* retrieve interruptee's PC */
wsr a0, EPC_6
l32i a0, sp, XT_STK_a0 /* retrieve interruptee's A0 */
l32i sp, sp, XT_STK_a1 /* remove interrupt stack frame */
rsync /* ensure EPS and EPC written */
rfi 6
#endif /* Level 6 */
/*
* HIGH PRIORITY (LEVEL > XCHAL_EXCM_LEVEL) INTERRUPT VECTORS AND HANDLERS
*
* High priority interrupts are by definition those with priorities greater
* than XCHAL_EXCM_LEVEL. This includes non-maskable (NMI). High priority
* interrupts cannot interact with the RTOS, that is they must save all regs
* they use and not call any RTOS function.
*
* A further restriction imposed by the Xtensa windowed architecture is that
* high priority interrupts must not modify the stack area even logically
* "above" the top of the interrupted stack (they need to provide their own
* stack or static save area).
*
* Cadence Design Systems recommends high priority interrupt handlers be coded
* in assembly and used for purposes requiring very short service times.
*
* Here are templates for high priority (level 2+) interrupt vectors. They
* assume only one interrupt per level to avoid the burden of identifying which
* interrupts at this level are pending and enabled. This allows for minimum
* latency and avoids having to save/restore a2 in addition to a0. If more than
* one interrupt per high priority level is configured, this burden is on the
* handler which in any case must provide a way to save and restore registers
* it uses without touching the interrupted stack.
*
* Each vector goes at a predetermined location according to the Xtensa
* hardware configuration, which is ensured by its placement in a special
* section known to the Xtensa linker support package (LSP). It performs the
* minimum necessary before jumping to the handler in the .text section.
*/
/* Currently only shells for high priority interrupt handlers are provided
* here. However a template and example can be found in the Cadence Design
* Systems tools documentation: "Microprocessor Programmer's Guide".
*/
#if GEN_HIGH_INTERRUPT(2)
.begin literal_prefix .Level2InterruptVector
.section .Level2InterruptVector.text, "ax"
.global _Level2Vector
.type _Level2Vector,@function
.align 4
_Level2Vector:
wsr a0, EXCSAVE_2 /* preserve a0 */
call0 _xt_highint2 /* load interrupt handler */
.end literal_prefix
.text
.type _xt_highint2,@function
.align 4
_xt_highint2:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, 2<<2
beqz a0, 1f
.Ln_xt_highint2_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT: ADD HIGH PRIORITY LEVEL 2 INTERRUPT HANDLER CODE HERE. */
.align 4
.L_xt_highint2_exit:
rsr a0, EXCSAVE_2 /* restore a0 */
rfi 2
#endif /* Level 2 */
#if GEN_HIGH_INTERRUPT(3)
.begin literal_prefix .Level3InterruptVector
.section .Level3InterruptVector.text, "ax"
.global _Level3Vector
.type _Level3Vector,@function
.align 4
_Level3Vector:
wsr a0, EXCSAVE_3 /* preserve a0 */
call0 _xt_highint3 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_highint3,@function
.align 4
_xt_highint3:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, 3<<2
beqz a0, 1f
.Ln_xt_highint3_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT: ADD HIGH PRIORITY LEVEL 3 INTERRUPT HANDLER CODE HERE. */
.align 4
.L_xt_highint3_exit:
rsr a0, EXCSAVE_3 /* restore a0 */
rfi 3
#endif /* Level 3 */
#if GEN_HIGH_INTERRUPT(4)
.begin literal_prefix .Level4InterruptVector
.section .Level4InterruptVector.text, "ax"
.global _Level4Vector
.type _Level4Vector,@function
.align 4
_Level4Vector:
wsr a0, EXCSAVE_4 /* preserve a0 */
call0 _xt_highint4 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_highint4,@function
.align 4
_xt_highint4:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, 4<<2
beqz a0, 1f
.Ln_xt_highint4_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT: ADD HIGH PRIORITY LEVEL 4 INTERRUPT HANDLER CODE HERE. */
.align 4
.L_xt_highint4_exit:
rsr a0, EXCSAVE_4 /* restore a0 */
rfi 4
#endif /* Level 4 */
#if GEN_HIGH_INTERRUPT(5)
.begin literal_prefix .Level5InterruptVector
.section .Level5InterruptVector.text, "ax"
.global _Level5Vector
.type _Level5Vector,@function
.align 4
_Level5Vector:
wsr a0, EXCSAVE_5 /* preserve a0 */
call0 _xt_highint5 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_highint5,@function
.align 4
_xt_highint5:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, 5<<2
beqz a0, 1f
.Ln_xt_highint5_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT:
* ADD HIGH PRIORITY LEVEL 5 INTERRUPT HANDLER CODE HERE.
*/
.align 4
.L_xt_highint5_exit:
rsr a0, EXCSAVE_5 /* restore a0 */
rfi 5
#endif /* Level 5 */
#if GEN_HIGH_INTERRUPT(6)
.begin literal_prefix .Level6InterruptVector
.section .Level6InterruptVector.text, "ax"
.global _Level6Vector
.type _Level6Vector,@function
.align 4
_Level6Vector:
wsr a0, EXCSAVE_6 /* preserve a0 */
call0 _xt_highint6 /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_highint6,@function
.align 4
_xt_highint6:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, 6<<2
beqz a0, 1f
.Ln_xt_highint6_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT:
* ADD HIGH PRIORITY LEVEL 6 INTERRUPT HANDLER CODE HERE.
*/
.align 4
.L_xt_highint6_exit:
rsr a0, EXCSAVE_6 /* restore a0 */
rfi 6
#endif /* Level 6 */
#if XCHAL_HAVE_NMI
.begin literal_prefix .NMIExceptionVector
.section .NMIExceptionVector.text, "ax"
.global _NMIExceptionVector
.type _NMIExceptionVector,@function
.align 4
_NMIExceptionVector:
wsr a0, EXCSAVE + XCHAL_NMILEVEL _ /* preserve a0 */
call0 _xt_nmi /* load interrupt handler */
/* never returns here - call0 is used as a jump (see note at top) */
.end literal_prefix
.text
.type _xt_nmi,@function
.align 4
_xt_nmi:
#ifdef XT_INTEXC_HOOKS
/* Call interrupt hook if present to (pre)handle interrupts. */
movi a0, _xt_intexc_hooks
l32i a0, a0, XCHAL_NMILEVEL<<2
beqz a0, 1f
.Ln_xt_nmi_call_hook:
callx0 a0 /* must NOT disturb stack! */
1:
#endif
/* USER_EDIT:
* ADD HIGH PRIORITY NON-MASKABLE INTERRUPT (NMI) HANDLER CODE HERE.
*/
.align 4
.L_xt_nmi_exit:
rsr a0, EXCSAVE + XCHAL_NMILEVEL /* restore a0 */
rfi XCHAL_NMILEVEL
#endif /* NMI */
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