Add hardware_exception for setting exception handlers at runtime (#380)

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Graham Sanderson 2021-05-05 11:45:39 -05:00 committed by GitHub
parent 7fc75d8c90
commit 53f1915a6b
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9 changed files with 185 additions and 1 deletions

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@ -17,6 +17,7 @@
* \defgroup hardware_clocks hardware_clocks * \defgroup hardware_clocks hardware_clocks
* \defgroup hardware_divider hardware_divider * \defgroup hardware_divider hardware_divider
* \defgroup hardware_dma hardware_dma * \defgroup hardware_dma hardware_dma
* \defgroup hardware_exception hardware_exception
* \defgroup hardware_flash hardware_flash * \defgroup hardware_flash hardware_flash
* \defgroup hardware_gpio hardware_gpio * \defgroup hardware_gpio hardware_gpio
* \defgroup hardware_i2c hardware_i2c * \defgroup hardware_i2c hardware_i2c

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@ -10,6 +10,7 @@ pico_add_subdirectory(hardware_adc)
pico_add_subdirectory(hardware_clocks) pico_add_subdirectory(hardware_clocks)
pico_add_subdirectory(hardware_dma) pico_add_subdirectory(hardware_dma)
pico_add_subdirectory(hardware_divider) pico_add_subdirectory(hardware_divider)
pico_add_subdirectory(hardware_exception)
pico_add_subdirectory(hardware_flash) pico_add_subdirectory(hardware_flash)
pico_add_subdirectory(hardware_gpio) pico_add_subdirectory(hardware_gpio)
pico_add_subdirectory(hardware_i2c) pico_add_subdirectory(hardware_i2c)

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@ -0,0 +1 @@
pico_simple_hardware_target(exception)

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@ -0,0 +1,65 @@
/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include "hardware/exception.h"
#include "hardware/regs/m0plus.h"
#include "hardware/platform_defs.h"
#include "hardware/structs/scb.h"
#include "pico/mutex.h"
#include "pico/assert.h"
#ifndef exception_is_compile_time_default
static bool exception_is_compile_time_default(exception_handler_t handler) {
extern char __default_isrs_start;
extern char __default_isrs_end;
return ((uintptr_t)handler) >= (uintptr_t)&__default_isrs_start &&
((uintptr_t)handler) < (uintptr_t)&__default_isrs_end;
}
#endif
static inline exception_handler_t *get_vtable(void) {
return (exception_handler_t *) scb_hw->vtor;
}
static void set_raw_exception_handler_and_restore_interrupts(enum exception_number num, exception_handler_t handler, uint32_t save) {
// update vtable (vtable_handler may be same or updated depending on cases, but we do it anyway for compactness)
get_vtable()[16 + num] = handler;
__dmb();
restore_interrupts(save);
}
static inline void check_exception_param(__unused enum exception_number num) {
invalid_params_if(EXCEPTION, num < NMI_EXCEPTION || num >=0);
}
exception_handler_t exception_get_vtable_handler(enum exception_number num) {
check_exception_param(num);
return get_vtable()[16 + num];
}
exception_handler_t exception_set_exclusive_handler(enum exception_number num, exception_handler_t handler) {
check_exception_param(num);
#if !PICO_NO_RAM_VECTOR_TABLE
uint32_t save = save_and_disable_interrupts();
exception_handler_t current = exception_get_vtable_handler(num);
hard_assert(exception_is_compile_time_default(current));
set_raw_exception_handler_and_restore_interrupts(num, handler, save);
#else
panic_unsupported();
#endif
return current;
}
void exception_restore_handler(enum exception_number num, exception_handler_t original_handler) {
hard_assert(exception_is_compile_time_default(original_handler));
#if !PICO_NO_RAM_VECTOR_TABLE
uint32_t save = save_and_disable_interrupts();
set_raw_exception_handler_and_restore_interrupts(num, original_handler, save);
#else
panic_unsupported();
#endif
}

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@ -0,0 +1,106 @@
/*
* Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef _HARDWARE_EXCEPTION_H_
#define _HARDWARE_EXCEPTION_H_
#include "pico.h"
#include "hardware/address_mapped.h"
#include "hardware/regs/m0plus.h"
/** \file exception.h
* \defgroup hardware_exception hardware_exception
*
* Methods for setting processor exception handlers
*
* Exceptions are identified by a \ref exception_num which is a number from -15 to -1; these are the numbers relative to
* the index of the first IRQ vector in the vector table. (i.e. vector table index is exception_num plus 16)
*
* There is one set of exception handlers per core, so the exception handlers for each core as set by these methods are independent.
*
* \note That all exception APIs affect the executing core only (i.e. the core calling the function).
*/
// PICO_CONFIG: PARAM_ASSERTIONS_ENABLED_EXCEPTION, Enable/disable assertions in the exception module, type=bool, default=0, group=hardware_exception
#ifndef PARAM_ASSERTIONS_ENABLED_EXCEPTION
#define PARAM_ASSERTIONS_ENABLED_EXCEPTION 0
#endif
#ifdef __cplusplus
extern "C" {
#endif
/*! \brief Exception number definitions
*
* Note for consistency with irq numbers, these numbers are defined to be negative. The VTABLE index is
* the number here plus 16.
*
* Name | Value | Exception
* ---------------------|-------|----------
* NMI_EXCEPTION | -14 | Non Maskable Interrupt
* HARDFAULT_EXCEPTION | -13 | HardFault
* SVCALL_EXCEPTION | -5 | SV Call
* PENDSV_EXCEPTION | -2 | Pend SV
* SYSTICK_EXCEPTION | -1 | System Tick
*
* \ingroup hardware_exception
*/
enum exception_number {
NMI_EXCEPTION = -14, /* Non Maskable Interrupt */
HARDFAULT_EXCEPTION = -13, /* HardFault Interrupt */
SVCALL_EXCEPTION = -5, /* SV Call Interrupt */
PENDSV_EXCEPTION = -2, /* Pend SV Interrupt */
SYSTICK_EXCEPTION = -1, /* System Tick Interrupt */
};
/*! \brief Exception handler function type
* \ingroup hardware_exception
*
* All exceptions handlers should be of this type, and follow normal ARM EABI register saving conventions
*/
typedef void (*exception_handler_t)(void);
/*! \brief Set the exception handler for an exception on the executing core.
* \ingroup hardware_exception
*
* This method will assert if an exception handler has been set for this exception number on this core via
* this method, without an intervening restore via exception_restore_handler.
*
* \note this method may not be used to override an exception handler that was specified at link time by
* providing a strong replacement for the weakly defined stub exception handlers. It will assert in this case too.
*
* \param num Exception number
* \param handler The handler to set
* \see exception_number
*/
exception_handler_t exception_set_exclusive_handler(enum exception_number num, exception_handler_t handler);
/*! \brief Restore the original exception handler for an exception on this core
* \ingroup hardware_exception
*
* This method may be used to restore the exception handler for an exception on this core to the state
* prior to the call to exception_set_exclusive_handler(), so that exception_set_exclusive_handler()
* may be called again in the future.
*
* \param num Exception number \ref exception_nums
* \param original_handler The original handler returned from \ref exception_set_exclusive_handler
* \see exception_set_exclusive_handler()
*/
void exception_restore_handler(enum exception_number, exception_handler_t original_handler);
/*! \brief Get the current exception handler for the specified exception from the currently installed vector table
* of the execution core
* \ingroup hardware_exception
*
* \param num Exception number
* \return the address stored in the VTABLE for the given exception number
*/
exception_handler_t exception_get_vtable_handler(enum exception_number num);
#ifdef __cplusplus
}
#endif
#endif

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@ -255,7 +255,7 @@ static inline void irq_clear(uint int_num) {
void irq_set_pending(uint num); void irq_set_pending(uint num);
/*! \brief Perform IRQ priority intiialization for the current core /*! \brief Perform IRQ priority initialization for the current core
* *
* \note This is an internal method and user should generally not call it. * \note This is an internal method and user should generally not call it.
*/ */

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@ -74,6 +74,11 @@ __vectors:
.word isr_irq30 .word isr_irq30
.word isr_irq31 .word isr_irq31
// all default exception handlers do nothing, and we can check for them being set to our
// default values by them pointing to between __defaults_isrs_start and __default_isrs_end
.global __default_isrs_start
__default_isrs_start:
// Declare a weak symbol for each ISR. // Declare a weak symbol for each ISR.
// By default, they will fall through to the undefined IRQ handler below (breakpoint), // By default, they will fall through to the undefined IRQ handler below (breakpoint),
// but can be overridden by C functions with correct name. // but can be overridden by C functions with correct name.
@ -94,6 +99,9 @@ decl_isr_bkpt isr_svcall
decl_isr_bkpt isr_pendsv decl_isr_bkpt isr_pendsv
decl_isr_bkpt isr_systick decl_isr_bkpt isr_systick
.global __default_isrs_end
__default_isrs_end:
.macro decl_isr name .macro decl_isr name
.weak \name .weak \name
.type \name,%function .type \name,%function

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@ -6,6 +6,7 @@ target_link_libraries(kitchen_sink_libs INTERFACE
hardware_adc hardware_adc
hardware_clocks hardware_clocks
hardware_divider hardware_divider
hardware_exception
hardware_dma hardware_dma
hardware_flash hardware_flash
hardware_gpio hardware_gpio

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@ -11,6 +11,7 @@
#include "hardware/clocks.h" #include "hardware/clocks.h"
#include "hardware/divider.h" #include "hardware/divider.h"
#include "hardware/dma.h" #include "hardware/dma.h"
#include "hardware/exception.h"
#include "hardware/flash.h" #include "hardware/flash.h"
#include "hardware/gpio.h" #include "hardware/gpio.h"
#include "hardware/i2c.h" #include "hardware/i2c.h"