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arch: arm: cortex_m: use C rather than asm in isr_wrapper & exc_exit

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Asm is notoriously harder to maintain than C and requires core specific
adaptation which impairs even more the readability of the code.

This is a first step in reducing the amount of ASM in arch/arm/cortex_m

Signed-off-by: Wilfried Chauveau <wilfried.chauveau@arm.com>
This commit is contained in:
Wilfried Chauveau 2023-10-06 06:13:17 +01:00 • committed by Carles Cufí
commit 8e55468af2
4 changed files with 102 additions and 198 deletions
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4
arch/arm/core/cortex_m/CMakeLists.txt
View file

@ -3,7 +3,7 @@
zephyr_library()
zephyr_library_sources(
exc_exit.S
exc_exit.c
fault.c
fault_s.S
fpu.c
@ -20,7 +20,7 @@ zephyr_library_sources(
)
zephyr_library_sources_ifndef(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER irq_init.c)
zephyr_library_sources_ifdef(CONFIG_GEN_SW_ISR_TABLE isr_wrapper.S)
zephyr_library_sources_ifdef(CONFIG_GEN_SW_ISR_TABLE isr_wrapper.c)
zephyr_library_sources_ifdef(CONFIG_DEBUG_COREDUMP coredump.c)
zephyr_library_sources_ifdef(CONFIG_THREAD_LOCAL_STORAGE __aeabi_read_tp.S)
zephyr_library_sources_ifdef(CONFIG_SEMIHOST semihost.c)

56
arch/arm/core/cortex_m/exc_exit.S → arch/arm/core/cortex_m/exc_exit.c
View file

@ -1,5 +1,6 @@
/*
* Copyright (c) 2013-2014 Wind River Systems, Inc.
* Copyright (c) 2023 Arm Limited
*
* SPDX-License-Identifier: Apache-2.0
*/
@ -13,16 +14,9 @@
* wrapped around by _isr_wrapper()).
*/
#include <zephyr/toolchain.h>
#include <zephyr/linker/sections.h>
#include <offsets_short.h>
#include <zephyr/arch/cpu.h>
_ASM_FILE_PROLOGUE
GTEXT(z_arm_exc_exit)
GTEXT(z_arm_int_exit)
GDATA(_kernel)
#include <zephyr/kernel.h>
#include <kswap.h>
#include <cmsis_core.h>
/**
*
@ -48,12 +42,7 @@ GDATA(_kernel)
* }
*
*/
SECTION_SUBSEC_FUNC(TEXT, _HandlerModeExit, z_arm_int_exit)
/* z_arm_int_exit falls through to z_arm_exc_exit (they are aliases of each
* other)
*/
FUNC_ALIAS(z_arm_exc_exit, z_arm_int_exit, void);
/**
*
@ -63,36 +52,15 @@ SECTION_SUBSEC_FUNC(TEXT, _HandlerModeExit, z_arm_int_exit)
* See z_arm_int_exit().
*
*/
SECTION_SUBSEC_FUNC(TEXT, _HandlerModeExit, z_arm_exc_exit)
Z_GENERIC_SECTION(.text._HandlerModeExit) void z_arm_exc_exit(void)
{
#ifdef CONFIG_PREEMPT_ENABLED
ldr r3, =_kernel
ldr r1, [r3, #_kernel_offset_to_current]
ldr r0, [r3, #_kernel_offset_to_ready_q_cache]
cmp r0, r1
beq _EXIT_EXC
/* context switch required, pend the PendSV exception */
ldr r1, =_SCS_ICSR
ldr r2, =_SCS_ICSR_PENDSV
str r2, [r1]
_ExcExitWithGdbStub:
_EXIT_EXC:
if (_kernel.ready_q.cache != _kernel.cpus->current) {
SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
}
#endif /* CONFIG_PREEMPT_ENABLED */
#ifdef CONFIG_STACK_SENTINEL
push {r0, lr}
bl z_check_stack_sentinel
#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
pop {r0, r1}
mov lr, r1
#else
pop {r0, lr}
#endif /* CONFIG_ARMV6_M_ARMV8_M_BASELINE */
z_check_stack_sentinel();
#endif /* CONFIG_STACK_SENTINEL */
bx lr
}

152
arch/arm/core/cortex_m/isr_wrapper.S
View file

@ -1,152 +0,0 @@
/*
* Copyright (c) 2013-2014 Wind River Systems, Inc.
* Copyright (c) 2020 Stephanos Ioannidis <root@stephanos.io>
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief ARM Cortex-M wrapper for ISRs with parameter
*
* Wrapper installed in vector table for handling dynamic interrupts that accept
* a parameter.
*/
/*
* Tell armclang that stack alignment are ensured.
*/
.eabi_attribute Tag_ABI_align_preserved, 1
#include <zephyr/toolchain.h>
#include <zephyr/linker/sections.h>
#include <offsets_short.h>
#include <zephyr/arch/cpu.h>
#include <zephyr/sw_isr_table.h>
_ASM_FILE_PROLOGUE
GDATA(_sw_isr_table)
GTEXT(_isr_wrapper)
GTEXT(z_arm_int_exit)
/**
*
* @brief Wrapper around ISRs when inserted in software ISR table
*
* When inserted in the vector table, _isr_wrapper() demuxes the ISR table
* using the running interrupt number as the index, and invokes the registered
* ISR with its corresponding argument. When returning from the ISR, it
* determines if a context switch needs to happen (see documentation for
* z_arm_pendsv()) and pends the PendSV exception if so: the latter will
* perform the context switch itself.
*
*/
SECTION_FUNC(TEXT, _isr_wrapper)
push {r0,lr} /* r0, lr are now the first items on the stack */
#ifdef CONFIG_TRACING_ISR
bl sys_trace_isr_enter
#endif
#ifdef CONFIG_PM
/*
* All interrupts are disabled when handling idle wakeup. For tickless
* idle, this ensures that the calculation and programming of the
* device for the next timer deadline is not interrupted. For
* non-tickless idle, this ensures that the clearing of the kernel idle
* state is not interrupted. In each case, z_pm_save_idle_exit
* is called with interrupts disabled.
*/
/*
* Disable interrupts to prevent nesting while exiting idle state. This
* is only necessary for the Cortex-M because it is the only ARM
* architecture variant that automatically enables interrupts when
* entering an ISR.
*/
cpsid i /* PRIMASK = 1 */
/* is this a wakeup from idle ? */
ldr r2, =_kernel
/* requested idle duration, in ticks */
ldr r0, [r2, #_kernel_offset_to_idle]
cmp r0, #0
#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
beq _idle_state_cleared
movs.n r1, #0
/* clear kernel idle state */
str r1, [r2, #_kernel_offset_to_idle]
bl z_pm_save_idle_exit
_idle_state_cleared:
#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
ittt ne
movne r1, #0
/* clear kernel idle state */
strne r1, [r2, #_kernel_offset_to_idle]
blne z_pm_save_idle_exit
#else
#error Unknown ARM architecture
#endif /* CONFIG_ARMV6_M_ARMV8_M_BASELINE */
cpsie i /* re-enable interrupts (PRIMASK = 0) */
#endif /* CONFIG_PM */
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
bl z_soc_irq_get_active
#else
mrs r0, IPSR /* get exception number */
#endif /* CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER */
#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
ldr r1, =16
subs r0, r1 /* get IRQ number */
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
push {r0}
#endif /* CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER */
lsls r0, #3 /* table is 8-byte wide */
#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
sub r0, r0, #16 /* get IRQ number */
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
push {r0}
#endif /* CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER */
lsl r0, r0, #3 /* table is 8-byte wide */
#else
#error Unknown ARM architecture
#endif /* CONFIG_ARMV6_M_ARMV8_M_BASELINE */
ldr r1, =_sw_isr_table
add r1, r1, r0 /* table entry: ISRs must have their MSB set to stay
* in thumb mode */
ldm r1!,{r0,r3} /* arg in r0, ISR in r3 */
blx r3 /* call ISR */
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
pop {r0}
bl z_soc_irq_eoi
#endif /* CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER */
#ifdef CONFIG_TRACING_ISR
bl sys_trace_isr_exit
#endif
#if defined(CONFIG_ARMV6_M_ARMV8_M_BASELINE)
pop {r0, r3}
mov lr, r3
#elif defined(CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
pop {r0, lr}
#else
#error Unknown ARM architecture
#endif /* CONFIG_ARMV6_M_ARMV8_M_BASELINE */
/* Use 'bx' instead of 'b' because 'bx' can jump further, and use
* 'bx' instead of 'blx' because exception return is done in
* z_arm_int_exit() */
ldr r1, =z_arm_int_exit
bx r1

88
arch/arm/core/cortex_m/isr_wrapper.c Normal file
View file

@ -0,0 +1,88 @@
/*
* Copyright (c) 2013-2014 Wind River Systems, Inc.
* Copyright (c) 2020 Stephanos Ioannidis <root@stephanos.io>
* Copyright (c) 2023 Arm Limited
*
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @file
* @brief ARM Cortex-M wrapper for ISRs with parameter
*
* Wrapper installed in vector table for handling dynamic interrupts that accept
* a parameter.
*/
#include <zephyr/kernel.h>
#include <zephyr/irq.h>
#include <zephyr/pm/pm.h>
#include <cmsis_core.h>
/**
*
* @brief Wrapper around ISRs when inserted in software ISR table
*
* When inserted in the vector table, _isr_wrapper() demuxes the ISR table
* using the running interrupt number as the index, and invokes the registered
* ISR with its corresponding argument. When returning from the ISR, it
* determines if a context switch needs to happen (see documentation for
* z_arm_pendsv()) and pends the PendSV exception if so: the latter will
* perform the context switch itself.
*
*/
void _isr_wrapper(void)
{
#ifdef CONFIG_TRACING_ISR
sys_trace_isr_enter();
#endif /* CONFIG_TRACING_ISR */
#ifdef CONFIG_PM
/*
* All interrupts are disabled when handling idle wakeup. For tickless
* idle, this ensures that the calculation and programming of the
* device for the next timer deadline is not interrupted. For
* non-tickless idle, this ensures that the clearing of the kernel idle
* state is not interrupted. In each case, z_pm_save_idle_exit
* is called with interrupts disabled.
*/
/*
* Disable interrupts to prevent nesting while exiting idle state. This
* is only necessary for the Cortex-M because it is the only ARM
* architecture variant that automatically enables interrupts when
* entering an ISR.
*/
__disable_irq();
/* is this a wakeup from idle ? */
/* requested idle duration, in ticks */
if (_kernel.idle != 0) {
/* clear kernel idle state */
_kernel.idle = 0;
z_pm_save_idle_exit();
}
/* re-enable interrupts */
__enable_irq();
#endif /* CONFIG_PM */
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
int32_t irq_number = z_soc_irq_get_active();
#else
/* _sw_isr_table does not map the expections, only the interrupts. */
int32_t irq_number = __get_IPSR();
#endif
irq_number -= 16;
struct _isr_table_entry *entry = &_sw_isr_table[irq_number];
(entry->isr)(entry->arg);
#if defined(CONFIG_ARM_CUSTOM_INTERRUPT_CONTROLLER)
z_soc_irq_eoi(irq_number);
#endif
#ifdef CONFIG_TRACING_ISR
sys_trace_isr_exit();
#endif /* CONFIG_TRACING_ISR */
z_arm_exc_exit();
}