/* * SPDX-FileCopyrightText: 2015-2024 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #include "sdkconfig.h" #include "portmacro.h" #include "freertos/FreeRTOSConfig.h" #include "soc/soc_caps.h" #include "riscv/rvruntime-frames.h" .extern pxCurrentTCBs #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD #include "esp_private/hw_stack_guard.h" #endif .global port_uxInterruptNesting .global port_xSchedulerRunning .global xIsrStackTop .global pxCurrentTCBs .global vTaskSwitchContext .global xPortSwitchFlag #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD .global xIsrStackBottom .global esp_hw_stack_guard_monitor_stop .global esp_hw_stack_guard_monitor_start .global esp_hw_stack_guard_set_bounds #endif /* CONFIG_ESP_SYSTEM_HW_STACK_GUARD */ .section .text #if SOC_CPU_COPROC_NUM > 0 #if SOC_CPU_HAS_FPU /* Bit to set in mstatus to enable the FPU */ #define CSR_MSTATUS_FPU_ENABLE (1 << 13) /* Bit to clear in mstatus to disable the FPU */ #define CSR_MSTATUS_FPU_DISABLE (3 << 13) .macro save_fpu_regs frame=sp fsw ft0, RV_FPU_FT0(\frame) fsw ft1, RV_FPU_FT1(\frame) fsw ft2, RV_FPU_FT2(\frame) fsw ft3, RV_FPU_FT3(\frame) fsw ft4, RV_FPU_FT4(\frame) fsw ft5, RV_FPU_FT5(\frame) fsw ft6, RV_FPU_FT6(\frame) fsw ft7, RV_FPU_FT7(\frame) fsw fs0, RV_FPU_FS0(\frame) fsw fs1, RV_FPU_FS1(\frame) fsw fa0, RV_FPU_FA0(\frame) fsw fa1, RV_FPU_FA1(\frame) fsw fa2, RV_FPU_FA2(\frame) fsw fa3, RV_FPU_FA3(\frame) fsw fa4, RV_FPU_FA4(\frame) fsw fa5, RV_FPU_FA5(\frame) fsw fa6, RV_FPU_FA6(\frame) fsw fa7, RV_FPU_FA7(\frame) fsw fs2, RV_FPU_FS2(\frame) fsw fs3, RV_FPU_FS3(\frame) fsw fs4, RV_FPU_FS4(\frame) fsw fs5, RV_FPU_FS5(\frame) fsw fs6, RV_FPU_FS6(\frame) fsw fs7, RV_FPU_FS7(\frame) fsw fs8, RV_FPU_FS8(\frame) fsw fs9, RV_FPU_FS9(\frame) fsw fs10, RV_FPU_FS10(\frame) fsw fs11, RV_FPU_FS11(\frame) fsw ft8, RV_FPU_FT8 (\frame) fsw ft9, RV_FPU_FT9 (\frame) fsw ft10, RV_FPU_FT10(\frame) fsw ft11, RV_FPU_FT11(\frame) .endm .macro restore_fpu_regs frame=sp flw ft0, RV_FPU_FT0(\frame) flw ft1, RV_FPU_FT1(\frame) flw ft2, RV_FPU_FT2(\frame) flw ft3, RV_FPU_FT3(\frame) flw ft4, RV_FPU_FT4(\frame) flw ft5, RV_FPU_FT5(\frame) flw ft6, RV_FPU_FT6(\frame) flw ft7, RV_FPU_FT7(\frame) flw fs0, RV_FPU_FS0(\frame) flw fs1, RV_FPU_FS1(\frame) flw fa0, RV_FPU_FA0(\frame) flw fa1, RV_FPU_FA1(\frame) flw fa2, RV_FPU_FA2(\frame) flw fa3, RV_FPU_FA3(\frame) flw fa4, RV_FPU_FA4(\frame) flw fa5, RV_FPU_FA5(\frame) flw fa6, RV_FPU_FA6(\frame) flw fa7, RV_FPU_FA7(\frame) flw fs2, RV_FPU_FS2(\frame) flw fs3, RV_FPU_FS3(\frame) flw fs4, RV_FPU_FS4(\frame) flw fs5, RV_FPU_FS5(\frame) flw fs6, RV_FPU_FS6(\frame) flw fs7, RV_FPU_FS7(\frame) flw fs8, RV_FPU_FS8(\frame) flw fs9, RV_FPU_FS9(\frame) flw fs10, RV_FPU_FS10(\frame) flw fs11, RV_FPU_FS11(\frame) flw ft8, RV_FPU_FT8(\frame) flw ft9, RV_FPU_FT9(\frame) flw ft10, RV_FPU_FT10(\frame) flw ft11, RV_FPU_FT11(\frame) .endm .macro fpu_read_dirty_bit reg csrr \reg, mstatus srli \reg, \reg, 13 andi \reg, \reg, 1 .endm .macro fpu_clear_dirty_bit reg li \reg, 1 << 13 csrc mstatus, \reg .endm .macro fpu_enable reg li \reg, CSR_MSTATUS_FPU_ENABLE csrs mstatus, \reg .endm .macro fpu_disable reg li \reg, CSR_MSTATUS_FPU_DISABLE csrc mstatus, \reg .endm .global vPortTaskPinToCore .global vPortCoprocUsedInISR .global pxPortUpdateCoprocOwner /** * @brief Save the current FPU context in the FPU owner's save area * * @param sp Interuptee's RvExcFrame address * * Note: Since this routine is ONLY meant to be called from _panic_handler routine, * it is possible to alter `s0-s11` registers */ .global rtos_save_fpu_coproc .type rtos_save_fpu_coproc, @function rtos_save_fpu_coproc: /* If we are in an interrupt context, we have to abort. We don't allow using the FPU from ISR */ #if ( configNUM_CORES > 1 ) csrr a2, mhartid /* a2 = coreID */ slli a2, a2, 2 /* a2 = coreID * 4 */ la a1, port_uxInterruptNesting /* a1 = &port_uxInterruptNesting */ add a1, a1, a2 /* a1 = &port_uxInterruptNesting[coreID] */ lw a1, 0(a1) /* a1 = port_uxInterruptNesting[coreID] */ #else /* ( configNUM_CORES <= 1 ) */ lw a1, (port_uxInterruptNesting) /* a1 = port_uxInterruptNesting */ #endif /* ( configNUM_CORES > 1 ) */ /* SP still contains the RvExcFrame address */ mv a0, sp bnez a1, vPortCoprocUsedInISR /* Enable the FPU needed by the current task */ fpu_enable a1 mv s0, ra call rtos_current_tcb /* If the current TCB is NULL, the FPU is used during initialization, even before * the scheduler started. Consider this a valid usage, the FPU will be disabled * as soon as the scheduler is started anyway*/ beqz a0, rtos_save_fpu_coproc_norestore mv s1, a0 /* s1 = pxCurrentTCBs */ /* Prepare parameters of pxPortUpdateCoprocOwner */ mv a2, a0 li a1, FPU_COPROC_IDX csrr a0, mhartid call pxPortUpdateCoprocOwner /* If the save area is NULL, no need to save context */ beqz a0, rtos_save_fpu_coproc_nosave /* Save the FPU context in the structure */ lw a0, RV_COPROC_SA+FPU_COPROC_IDX*4(a0) /* a0 = RvCoprocSaveArea->sa_coprocs[FPU_COPROC_IDX] */ save_fpu_regs a0 csrr a1, fcsr sw a1, RV_FPU_FCSR(a0) rtos_save_fpu_coproc_nosave: #if ( configNUM_CORES > 1 ) /* Pin current task to current core */ mv a0, s1 csrr a1, mhartid call vPortTaskPinToCore #endif /* configNUM_CORES > 1 */ /* Check if we have to restore a previous FPU context from the current TCB */ mv a0, s1 /* Do not allocate memory for the FPU yet, delay this until another task wants to use it. * This guarantees that if a stack overflow occurs when allocating FPU context on the stack, * the current task context is flushed and updated in the TCB, generating a correct backtrace * from the panic handler. */ li a1, 0 li a2, FPU_COPROC_IDX call pxPortGetCoprocArea /* Get the enable flags from the coprocessor save area */ lw a1, RV_COPROC_ENABLE(a0) /* To avoid having branches below, set the FPU enable flag now */ ori a2, a1, 1 << FPU_COPROC_IDX sw a2, RV_COPROC_ENABLE(a0) /* Check if the former FPU enable bit was set */ andi a2, a1, 1 << FPU_COPROC_IDX beqz a2, rtos_save_fpu_coproc_norestore /* FPU enable bit was set, restore the FPU context */ lw a0, RV_COPROC_SA+FPU_COPROC_IDX*4(a0) /* a0 = RvCoprocSaveArea->sa_coprocs[FPU_COPROC_IDX] */ restore_fpu_regs a0 lw a1, RV_FPU_FCSR(a0) csrw fcsr, a1 rtos_save_fpu_coproc_norestore: /* Return from routine via s0, instead of ra */ jr s0 .size rtos_save_fpu_coproc, .-rtos_save_fpu_coproc #endif /* SOC_CPU_HAS_FPU */ #endif /* SOC_CPU_COPROC_NUM > 0 */ /** * @brief Get current TCB on current core */ .type rtos_current_tcb, @function rtos_current_tcb: #if ( configNUM_CORES > 1 ) csrr a1, mhartid slli a1, a1, 2 la a0, pxCurrentTCBs /* a0 = &pxCurrentTCBs */ add a0, a0, a1 /* a0 = &pxCurrentTCBs[coreID] */ lw a0, 0(a0) /* a0 = pxCurrentTCBs[coreID] */ #else /* Recover the stack of next task */ lw a0, pxCurrentTCBs #endif /* ( configNUM_CORES > 1 ) */ ret .size, .-rtos_current_tcb /** * This function makes the RTOS aware about an ISR entering. It takes the * current task stack pointer and places it into the pxCurrentTCBs. * It then loads the ISR stack into sp. * TODO: ISR nesting code improvements ? * In the routines below, let's use a0-a5 registers to let the compiler generate * 16-bit instructions. */ .global rtos_int_enter .type rtos_int_enter, @function rtos_int_enter: #if ( configNUM_CORES > 1 ) csrr a5, mhartid /* a5 = coreID */ slli a5, a5, 2 /* a5 = coreID * 4 */ la a0, port_xSchedulerRunning /* a0 = &port_xSchedulerRunning */ add a0, a0, a5 /* a0 = &port_xSchedulerRunning[coreID] */ lw a0, (a0) /* a0 = port_xSchedulerRunning[coreID] */ #else lw a0, port_xSchedulerRunning /* a0 = port_xSchedulerRunning */ #endif /* ( configNUM_CORES > 1 ) */ beqz a0, rtos_int_enter_end /* if (port_xSchedulerRunning[coreID] == 0) jump to rtos_int_enter_end */ /* Increment the ISR nesting count */ la a0, port_uxInterruptNesting /* a0 = &port_uxInterruptNesting */ #if ( configNUM_CORES > 1 ) add a0, a0, a5 /* a0 = &port_uxInterruptNesting[coreID] // a5 already contains coreID * 4 */ #endif /* ( configNUM_CORES > 1 ) */ lw a1, 0(a0) /* a1 = port_uxInterruptNesting[coreID] */ addi a2, a1, 1 /* a2 = a1 + 1 */ sw a2, 0(a0) /* port_uxInterruptNesting[coreID] = a2 */ /* If we reached here from another low-priority ISR, i.e, port_uxInterruptNesting[coreID] > 0, then skip stack pushing to TCB */ bnez a1, rtos_int_enter_end /* if (port_uxInterruptNesting[coreID] > 0) jump to rtos_int_enter_end */ #if SOC_CPU_COPROC_NUM > 0 /* Disable the FPU to forbid the ISR from using it. We don't need to re-enable it manually since the caller * will restore `mstatus` before returning from interrupt. */ fpu_disable a0 #endif /* SOC_CPU_COPROC_NUM > 0 */ #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD /* esp_hw_stack_guard_monitor_stop(); pass the scratch registers */ ESP_HW_STACK_GUARD_MONITOR_STOP_CUR_CORE a0 a1 #endif /* CONFIG_ESP_SYSTEM_HW_STACK_GUARD */ /* Save the current sp in pxCurrentTCBs[coreID] and load the ISR stack on to sp */ #if ( configNUM_CORES > 1 ) la a0, pxCurrentTCBs /* a0 = &pxCurrentTCBs */ add a0, a0, a5 /* a0 = &pxCurrentTCBs[coreID] // a5 already contains coreID * 4 */ lw a0, (a0) /* a0 = pxCurrentTCBs[coreID] */ sw sp, 0(a0) /* pxCurrentTCBs[coreID] = sp */ la a0, xIsrStackTop /* a0 = &xIsrStackTop */ add a0, a0, a5 /* a0 = &xIsrStackTop[coreID] // a5 already contains coreID * 4 */ lw sp, (a0) /* sp = xIsrStackTop[coreID] */ #else lw a0, pxCurrentTCBs /* a0 = pxCurrentTCBs */ sw sp, 0(a0) /* pxCurrentTCBs[0] = sp */ lw sp, xIsrStackTop /* sp = xIsrStackTop */ #endif /* ( configNUM_CORES > 1 ) */ #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD /* Prepare the parameters for esp_hw_stack_guard_set_bounds(xIsrStackBottom, xIsrStackTop); */ #if ( configNUM_CORES > 1 ) /* Load the xIsrStack for the current core and set the new bounds */ la a0, xIsrStackBottom add a0, a0, a5 /* a0 = &xIsrStackBottom[coreID] */ lw a0, (a0) /* a0 = xIsrStackBottom[coreID] */ #else lw a0, xIsrStackBottom #endif /* ( configNUM_CORES > 1 ) */ mv a1, sp /* esp_hw_stack_guard_set_bounds(xIsrStackBottom[coreID], xIsrStackTop[coreID]); */ ESP_HW_STACK_GUARD_SET_BOUNDS_CUR_CORE a2 ESP_HW_STACK_GUARD_MONITOR_START_CUR_CORE a0 a1 #endif /* CONFIG_ESP_SYSTEM_HW_STACK_GUARD */ rtos_int_enter_end: ret /** * @brief Restore the stack pointer of the next task to run. * * @param a0 Former mstatus * * @returns New mstatus (potentially with coprocessors disabled) */ .global rtos_int_exit .type rtos_int_exit, @function rtos_int_exit: /* To speed up this routine and because this current routine is only meant to be called from the interrupt * handler, let's use callee-saved registers instead of stack space. Registers `s3-s11` are not used by * the caller */ mv s11, a0 #if ( configNUM_CORES > 1 ) csrr a1, mhartid /* a1 = coreID */ slli a1, a1, 2 /* a1 = a1 * 4 */ la a0, port_xSchedulerRunning /* a0 = &port_xSchedulerRunning */ add a0, a0, a1 /* a0 = &port_xSchedulerRunning[coreID] */ lw a0, (a0) /* a0 = port_xSchedulerRunning[coreID] */ #else lw a0, port_xSchedulerRunning /* a0 = port_xSchedulerRunning */ #endif /* ( configNUM_CORES > 1 ) */ beqz a0, rtos_int_exit_end /* if (port_uxSchedulerRunning == 0) jump to rtos_int_exit_end */ /* Update nesting interrupts counter */ la a2, port_uxInterruptNesting /* a2 = &port_uxInterruptNesting */ #if ( configNUM_CORES > 1 ) add a2, a2, a1 /* a2 = &port_uxInterruptNesting[coreID] // a1 already contains coreID * 4 */ #endif /* ( configNUM_CORES > 1 ) */ lw a0, 0(a2) /* a0 = port_uxInterruptNesting[coreID] */ /* Already zero, protect against underflow */ beqz a0, isr_skip_decrement /* if (port_uxInterruptNesting[coreID] == 0) jump to isr_skip_decrement */ addi a0, a0, -1 /* a0 = a0 - 1 */ sw a0, 0(a2) /* port_uxInterruptNesting[coreID] = a0 */ /* May still have interrupts pending, skip section below and exit */ bnez a0, rtos_int_exit_end isr_skip_decrement: /* If the CPU reached this label, a2 (uxInterruptNesting) is 0 for sure */ /* Schedule the next task if a yield is pending */ la a0, xPortSwitchFlag /* a0 = &xPortSwitchFlag */ #if ( configNUM_CORES > 1 ) add a0, a0, a1 /* a0 = &xPortSwitchFlag[coreID] // a1 already contains coreID * 4 */ #endif /* ( configNUM_CORES > 1 ) */ lw a2, 0(a0) /* a2 = xPortSwitchFlag[coreID] */ beqz a2, no_switch /* if (xPortSwitchFlag[coreID] == 0) jump to no_switch */ /* Preserve return address and schedule next task. To speed up the process, and because this current routine * is only meant to be called from the interrupt handle, let's save some speed and space by using callee-saved * registers instead of stack space. Registers `s3-s11` are not used by the caller */ mv s10, ra #if ( SOC_CPU_COPROC_NUM > 0 ) /* In the cases where the newly scheduled task is different from the previously running one, * we have to disable the coprocessor(s) to let them trigger an exception on first use. * Else, if the same task is scheduled, do not change the coprocessor(s) state. */ call rtos_current_tcb mv s9, a0 call vTaskSwitchContext call rtos_current_tcb beq a0, s9, rtos_int_exit_no_change /* Disable the coprocessors in s11 register (former mstatus) */ li a0, ~CSR_MSTATUS_FPU_DISABLE and s11, s11, a0 rtos_int_exit_no_change: #else /* ( SOC_CPU_COPROC_NUM == 0 ) */ call vTaskSwitchContext #endif /* ( SOC_CPU_COPROC_NUM > 0 ) */ mv ra, s10 /* Clears the switch pending flag */ la a0, xPortSwitchFlag /* a0 = &xPortSwitchFlag */ #if ( configNUM_CORES > 1 ) /* C routine vTaskSwitchContext may change the temp registers, so we read again */ csrr a1, mhartid /* a1 = coreID */ slli a1, a1, 2 /* a1 = a1 * 4 */ add a0, a0, a1 /* a0 = &xPortSwitchFlag[coreID]; */ #endif /* ( configNUM_CORES > 1 ) */ sw zero, 0(a0) /* xPortSwitchFlag[coreID] = 0; */ no_switch: #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD /* esp_hw_stack_guard_monitor_stop(); pass the scratch registers */ ESP_HW_STACK_GUARD_MONITOR_STOP_CUR_CORE a0 a1 #endif /* CONFIG_ESP_SYSTEM_HW_STACK_GUARD */ #if ( configNUM_CORES > 1 ) /* Recover the stack of next task and prepare to exit */ csrr a1, mhartid slli a1, a1, 2 la a0, pxCurrentTCBs /* a0 = &pxCurrentTCBs */ add a0, a0, a1 /* a0 = &pxCurrentTCBs[coreID] */ lw a0, 0(a0) /* a0 = pxCurrentTCBs[coreID] */ lw sp, 0(a0) /* sp = previous sp */ #else /* Recover the stack of next task */ lw a0, pxCurrentTCBs lw sp, 0(a0) #endif /* ( configNUM_CORES > 1 ) */ #if CONFIG_ESP_SYSTEM_HW_STACK_GUARD /* esp_hw_stack_guard_set_bounds(pxCurrentTCBs[0]->pxStack, * pxCurrentTCBs[0]->pxEndOfStack); */ lw a1, PORT_OFFSET_PX_END_OF_STACK(a0) lw a0, PORT_OFFSET_PX_STACK(a0) ESP_HW_STACK_GUARD_SET_BOUNDS_CUR_CORE a2 /* esp_hw_stack_guard_monitor_start(); */ ESP_HW_STACK_GUARD_MONITOR_START_CUR_CORE a0 a1 #endif /* CONFIG_ESP_SYSTEM_HW_STACK_GUARD */ rtos_int_exit_end: mv a0, s11 /* a0 = new mstatus */ ret