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EPD-nRF52-hema213/SDK/12.3.0_d7731ad/components/libraries/svc/nrf_svc_handler.c
2025-03-04 21:47:57 +08:00

183 lines
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C

/**
* Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form, except as embedded into a Nordic
* Semiconductor ASA integrated circuit in a product or a software update for
* such product, must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. Neither the name of Nordic Semiconductor ASA nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* 4. This software, with or without modification, must only be used with a
* Nordic Semiconductor ASA integrated circuit.
*
* 5. Any software provided in binary form under this license must not be reverse
* engineered, decompiled, modified and/or disassembled.
*
* THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <stdbool.h>
#include <stdint.h>
#include "nrf_svc_function.h"
#include "nrf_error.h"
#include "nrf_log.h"
//lint -save -e19 -e526
NRF_SECTION_VARS_CREATE_SECTION(svc_data, const nrf_svc_func_t);
//lint -restore
#define SVC_DATA_SECTION_VARS_GET(i) NRF_SECTION_VARS_GET((i), nrf_svc_func_reg_t, svc_data)
#define SVC_DATA_SECTION_VARS_COUNT NRF_SECTION_VARS_COUNT(nrf_svc_func_reg_t, svc_data)
/**@brief Function for handling second stage of SuperVisor Calls (SVC).
*
* @details The function will use loop through the registered svc functions stored
* in the named section "svc_data" and will call the registered function
* if the svn_num corresponds with the registration.
*
* @param[in] svc_num SVC number for function to be executed
* @param[in] p_svc_args Argument list for the SVC.
*
* @return This function returns by updating p_svc_arsg[0]. This will be reported back to the caller of SVC
* @ref NRF_ERROR_SVC_HANDLER_MISSING is returned if no SVC handler is implemented for the
* provided svc_num.
*/
void nrf_svc_handler_c(uint8_t svc_num, uint32_t * p_svc_args)
{
uint32_t const num_funcs = SVC_DATA_SECTION_VARS_COUNT;
bool handled = false;
uint32_t svci_num = NRF_SVCI_SVC_NUM_INVALID;
if(svc_num == NRF_SVCI_SVC_NUM)
{
/* load the stacked R12 as the svci_num */
svci_num = p_svc_args[4];
}
for (int i = 0; i < num_funcs; i++)
{
nrf_svc_func_reg_t const * func_reg = SVC_DATA_SECTION_VARS_GET(i);
if (func_reg->svc_num != svc_num)
{
continue;
}
if(svci_num != NRF_SVCI_SVC_NUM_INVALID && func_reg->svci_num != svci_num)
{
continue;
}
p_svc_args[0] = func_reg->func_ptr(p_svc_args[0], p_svc_args[1], p_svc_args[2], p_svc_args[3]);
handled = true;
}
if (handled == false)
{
p_svc_args[0] = NRF_ERROR_SVC_HANDLER_MISSING;
}
}
/**@brief Function for handling the first stage of SuperVisor Calls (SVC) in assembly.
*
* @details The function will use the link register (LR) to determine the stack (PSP or MSP) to be
* used and then decode the SVC number afterwards. After decoding the SVC number then
* @ref C_SVC_Handler is called for further processing of the SVC.
*/
#if defined ( __CC_ARM )
__ASM void SVC_Handler(void)
{
EXC_RETURN_CMD_PSP EQU 0xFFFFFFFD ; EXC_RETURN using PSP for ARM Cortex.If Link register contains this value it indicates the PSP was used before the SVC, otherwise the MSP was used.
IMPORT nrf_svc_handler_c
LDR R0, =EXC_RETURN_CMD_PSP ; Load the EXC_RETURN into R0 to be able to compare against LR to determine stack pointer used.
CMP R0, LR ; Compare the link register with R0.If equal then PSP was used, otherwise MSP was used before SVC.
BNE UseMSP ; Branch to code fetching SVC arguments using MSP.
MRS R1, PSP ; Move PSP into R1.
B Call_nrf_svc_handler_c ; Branch to call_nrf_svc_handler_c below.
UseMSP ;
MRS R1, MSP ; MSP was used, therefore Move MSP into R1.
Call_nrf_svc_handler_c ;
LDR R0, [R1, #24] ; The arguments for the SVC was stacked.R1 contains Stack Pointer, the values stacked before SVC are R0, R1, R2, R3, R12, LR, PC(Return address), xPSR.
; R1 contains current SP so the PC of the stacked frame is at SP + 6 words(24 bytes).We load the PC into R0.
SUBS R0, #2 ; The PC before the SVC is in R0.We subtract 2 to get the address prior to the instruction executed where the SVC number is located.
LDRB R0, [R0] ; SVC instruction low octet : Load the byte at the address before the PC to fetch the SVC number.
LDR R2, =nrf_svc_handler_c ; Load address of C implementation of SVC handler.
BX R2 ; Branch to C implementation of SVC handler.R0 is now the SVC number, R1 is the StackPointer where the arguments(R0 - R3) of the original SVC are located.
ALIGN
}
#elif defined ( __GNUC__ )
void __attribute__((naked)) SVC_Handler(void)
{
const uint32_t exc_return = 0xFFFFFFFD; // EXC_RETURN using PSP for ARM Cortex. If Link register contains this value it indicates the PSP was used before the SVC, otherwise the MSP was used.
__ASM volatile(
"cmp lr, %0\t\n" // Compare the link register with argument 0 (%0), which is exc_return. If equal then PSP was used, otherwise MSP was used before SVC.
"bne UseMSP\t\n" // Branch to code fetching SVC arguments using MSP.
"mrs r1, psp\t\n" // Move PSP into R1.
"b Call_nrf_svc_handler_c\t\n" // Branch to Call_nrf_svc_handler_c below.
"UseMSP:\t\n" //
"mrs r1, msp\t\n" // MSP was used, therefore Move MSP into R1.
"Call_nrf_svc_handler_c:\t\n" //
"ldr r0, [r1, #24]\t\n" // The arguments for the SVC was stacked. R1 contains Stack Pointer, the values stacked before SVC are R0, R1, R2, R3, R12, LR, PC (Return address), xPSR.
// R1 contains current SP so the PC of the stacked frame is at SP + 6 words (24 bytes). We load the PC into R0.
"sub r0, r0, #2\t\n" // The PC before the SVC is in R0. We subtract 2 to get the address prior to the instruction executed where the SVC number is located.
"ldrb r0, [r0]\t\n" // SVC instruction low octet: Load the byte at the address before the PC to fetch the SVC number.
"bx %1\t\n" // Branch to C implementation of SVC handler, argument 1 (%1). R0 is now the SVC number, R1 is the StackPointer where the arguments (R0-R3) of the original SVC are located.
".align\t\n" //
:: "r" (exc_return), "r" (nrf_svc_handler_c) // Argument list for the gcc assembly. exc_return is %0, nrf_svc_handler_c is %1.
: "r0", "r1" // List of register maintained manually.
);
}
#elif defined ( __ICCARM__ )
void SVC_Handler(void)
{
__ASM("movs r0, #0x02\n" // Load 0x02 into R6 to prepare for exec return test.
"mvns r0, r0\n" // Invert R0 to obtain exec return code using PSP for ARM Cortex.
"cmp lr, r0\n" // Compare the link register with argument 0 (%0), which is exc_return. If equal then PSP was used, otherwise MSP was used before SVC.
"bne.n UseMSP\n" // Branch to code fetching SVC arguments using MSP.
"mrs r1, psp\n" // Move PSP into R1.
"b.n Call_nrf_svc_handler_c\t\n" // Branch to Call_nrf_svc_handler_c below.
"UseMSP: \n" //
"mrs r1, msp\n" // MSP was used, therefore Move MSP into R1.
"Call_nrf_svc_handler_c: \n" //
"ldr r0, [r1, #24]\n" // The arguments for the SVC was stacked. R1 contains Stack Pointer, the values stacked before SVC are R0, R1, R2, R3, R12, LR, PC (Return address), xPSR.
// R1 contains current SP so the PC of the stacked frame is at SP + 6 words (24 bytes). We load the PC into R0.
"subs r0, #0x02\n" // The PC before the SVC is in R0. We subtract 2 to get the address prior to the instruction executed where the SVC number is located.
"ldrb r0, [r0]\n" // SVC instruction low octet: Load the byte at the address before the PC to fetch the SVC number.
"bx %0\n" // Branch to C implementation of SVC handler, argument 1 (%1). R0 is now the SVC number, R1 is the StackPointer where the arguments (R0-R3) of the original SVC are located.
:: "r" (nrf_svc_handler_c) // Argument list for the gcc assembly. nrf_svc_handler_c is %0.
: "r0", "r1" // List of register maintained manually.
);
}
#else
#error Compiler not supported.
#endif