From c5462e412deae39f681c8017722eaae0372bc6d7 Mon Sep 17 00:00:00 2001
From: Daniele Cattaneo <daniele3.cattaneo@mail.polimi.it>
Date: Thu, 30 Jan 2025 18:05:01 +0100
Subject: [PATCH] Add SMP-safe interrupt disable spinlocks
Signed-off-by: Terraneo Federico <fede.tft@miosix.org>
---
.../interfaces-impl/cpu_const_smp_impl.h | 39 +++++++++++++++
.../interfaces-impl/interrupts_smp_impl.h | 50 +++++++++++++++++++
.../common/rp2040_boot.cpp | 5 ++
.../rp2040_raspberry_pi_pico/board_settings.h | 4 ++
miosix/interfaces/cpu_const.h | 16 ++++++
miosix/interfaces/interrupts.h | 29 ++++++++++-
miosix/kernel/kernel.cpp | 31 +++++++++---
7 files changed, 167 insertions(+), 7 deletions(-)
create mode 100644 miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/cpu_const_smp_impl.h
create mode 100644 miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/interrupts_smp_impl.h
diff --git a/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/cpu_const_smp_impl.h b/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/cpu_const_smp_impl.h
new file mode 100644
index 00000000..136792db
--- /dev/null
+++ b/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/cpu_const_smp_impl.h
@@ -0,0 +1,39 @@
+/***************************************************************************
+ * Copyright (C) 2025 by Federico Terraneo, Daniele Cattaneo *
+ * *
+ * This program is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation; either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+ * GNU General Public License for more details. *
+ * *
+ * As a special exception, if other files instantiate templates or use *
+ * macros or inline functions from this file, or you compile this file *
+ * and link it with other works to produce a work based on this file, *
+ * this file does not by itself cause the resulting work to be covered *
+ * by the GNU General Public License. However the source code for this *
+ * file must still be made available in accordance with the GNU General *
+ * Public License. This exception does not invalidate any other reasons *
+ * why a work based on this file might be covered by the GNU General *
+ * Public License. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this program; if not, see <http://www.gnu.org/licenses/> *
+ ***************************************************************************/
+
+#pragma once
+
+#include "interfaces/arch_registers.h"
+
+namespace miosix {
+
+inline unsigned char getCurrentCoreId()
+{
+ return get_core_num();
+}
+
+}
diff --git a/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/interrupts_smp_impl.h b/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/interrupts_smp_impl.h
new file mode 100644
index 00000000..d5592d2a
--- /dev/null
+++ b/miosix/arch/cortexM0plus_rp2040/common/interfaces-impl/interrupts_smp_impl.h
@@ -0,0 +1,50 @@
+/***************************************************************************
+ * Copyright (C) 2025 by Federico Terraneo, Daniele Cattaneo *
+ * *
+ * This program is free software; you can redistribute it and/or modify *
+ * it under the terms of the GNU General Public License as published by *
+ * the Free Software Foundation; either version 2 of the License, or *
+ * (at your option) any later version. *
+ * *
+ * This program is distributed in the hope that it will be useful, *
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
+ * GNU General Public License for more details. *
+ * *
+ * As a special exception, if other files instantiate templates or use *
+ * macros or inline functions from this file, or you compile this file *
+ * and link it with other works to produce a work based on this file, *
+ * this file does not by itself cause the resulting work to be covered *
+ * by the GNU General Public License. However the source code for this *
+ * file must still be made available in accordance with the GNU General *
+ * Public License. This exception does not invalidate any other reasons *
+ * why a work based on this file might be covered by the GNU General *
+ * Public License. *
+ * *
+ * You should have received a copy of the GNU General Public License *
+ * along with this program; if not, see <http://www.gnu.org/licenses/> *
+ ***************************************************************************/
+
+#include "interfaces/arch_registers.h"
+
+namespace miosix {
+
+inline void globalInterruptLock() noexcept
+{
+ for(;;)
+ {
+ unsigned long lock=sio_hw->spinlock[0];
+ if(lock) break;
+ __WFE();
+ }
+ __DSB();
+}
+
+inline void globalInterruptUnlock() noexcept
+{
+ __DSB();
+ sio_hw->spinlock[0]=0;
+ __SEV();
+}
+
+} // namespace miosix
diff --git a/miosix/arch/cortexM0plus_rp2040/common/rp2040_boot.cpp b/miosix/arch/cortexM0plus_rp2040/common/rp2040_boot.cpp
index 7cc3902f..bcc4ea22 100644
--- a/miosix/arch/cortexM0plus_rp2040/common/rp2040_boot.cpp
+++ b/miosix/arch/cortexM0plus_rp2040/common/rp2040_boot.cpp
@@ -269,6 +269,11 @@ void IRQmemoryAndClockInit()
//bad hardware design.
for(unsigned int i=0; i<NUM_BANK0_GPIOS; i++)
padsbank0_hw->io[i]=toUint(Mode::DISABLED);
+
+ //QUIRK: You would expect the hardware spinlocks to be reset on a CPU
+ //reset but they are not. To release a spinlock you have to write something
+ //non-zero!
+ for(unsigned int i=0; i<32; i++) sio_hw->spinlock[i]=1;
// Setup clock generation
clockTreeSetup();
diff --git a/miosix/config/arch/cortexM0plus_rp2040/rp2040_raspberry_pi_pico/board_settings.h b/miosix/config/arch/cortexM0plus_rp2040/rp2040_raspberry_pi_pico/board_settings.h
index 95acc845..7a9a195a 100644
--- a/miosix/config/arch/cortexM0plus_rp2040/rp2040_raspberry_pi_pico/board_settings.h
+++ b/miosix/config/arch/cortexM0plus_rp2040/rp2040_raspberry_pi_pico/board_settings.h
@@ -42,6 +42,10 @@ namespace miosix {
* \{
*/
+/// \def WITH_SMP
+/// Enables multicore support
+#define WITH_SMP
+
/// Size of stack for main().
/// The C standard library is stack-heavy (iprintf requires 1KB) but the
/// RP2040 has 264KB of RAM so there is room for a big 4K stack.
diff --git a/miosix/interfaces/cpu_const.h b/miosix/interfaces/cpu_const.h
index 2b6eb2d1..84f3ef2a 100644
--- a/miosix/interfaces/cpu_const.h
+++ b/miosix/interfaces/cpu_const.h
@@ -27,6 +27,8 @@
#pragma once
+#include "config/miosix_settings.h"
+
/**
* \addtogroup Interfaces
* \{
@@ -52,8 +54,22 @@
* const unsigned int STACK_OFFSET_IN_CTXSAVE=...;
*/
+namespace miosix {
+
+inline unsigned char getCurrentCoreId();
+
+#ifndef WITH_SMP
+inline unsigned char getCurrentCoreId() { return 0; }
+#endif
+
+} // namespace miosix
+
/**
* \}
*/
#include "interfaces-impl/cpu_const_impl.h"
+
+#ifdef WITH_SMP
+#include "interfaces-impl/cpu_const_smp_impl.h"
+#endif
diff --git a/miosix/interfaces/interrupts.h b/miosix/interfaces/interrupts.h
index a33a4929..b3d3596d 100644
--- a/miosix/interfaces/interrupts.h
+++ b/miosix/interfaces/interrupts.h
@@ -1,5 +1,5 @@
/***************************************************************************
- * Copyright (C) 2023-2024 by Terraneo Federico *
+ * Copyright (C) 2023-2025 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -28,6 +28,7 @@
#pragma once
#include "e20/unmember.h"
+#include "config/miosix_settings.h"
/**
* \addtogroup Interfaces
@@ -229,6 +230,28 @@ inline void fastEnableInterrupts() noexcept;
*/
bool areInterruptsEnabled() noexcept;
+void globalInterruptLock() noexcept;
+void globalInterruptUnlock() noexcept;
+
+#ifndef WITH_SMP
+
+void globalInterruptLock() {}
+void globalInterruptUnlock() {}
+
+#endif
+
+inline void globalInterruptDisableLock() noexcept
+{
+ fastDisableInterrupts();
+ globalInterruptLock();
+}
+
+inline void globalInterruptEnableUnlock() noexcept
+{
+ globalInterruptUnlock();
+ fastEnableInterrupts();
+}
+
} //namespace miosix
/**
@@ -236,3 +259,7 @@ bool areInterruptsEnabled() noexcept;
*/
#include "interfaces-impl/interrupts_impl.h"
+
+#ifdef WITH_SMP
+#include "interfaces-impl/interrupts_smp_impl.h"
+#endif
diff --git a/miosix/kernel/kernel.cpp b/miosix/kernel/kernel.cpp
index 235b241d..32b0e2e9 100755
--- a/miosix/kernel/kernel.cpp
+++ b/miosix/kernel/kernel.cpp
@@ -1,5 +1,5 @@
/***************************************************************************
- * Copyright (C) 2008-2023 by Terraneo Federico *
+ * Copyright (C) 2008-2025 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
@@ -84,6 +84,9 @@ static bool kernelStarted=false;///<\internal becomes true after startKernel.
/// This is used by disableInterrupts() and enableInterrupts() to allow nested
/// calls to these functions.
static unsigned char interruptDisableNesting=0;
+#ifdef WITH_SMP
+static unsigned char globalIntrNestLockHoldingCore=0xFF;
+#endif
#ifdef WITH_DEEP_SLEEP
@@ -144,11 +147,23 @@ void *idleThread(void *argv)
void disableInterrupts()
{
- //Before the kernel is started interrupts are disabled,
- //so disabling them again won't hurt
- fastDisableInterrupts();
+#ifdef WITH_SMP
+ unsigned char state=globalIntrNestLockHoldingCore;
+ if(state==getCurrentCoreId())
+ {
+ if(interruptDisableNesting==0xff) errorHandler(NESTING_OVERFLOW);
+ interruptDisableNesting++;
+ } else {
+ globalInterruptDisableLock();
+ globalIntrNestLockHoldingCore=getCurrentCoreId();
+ if(interruptDisableNesting!=0) errorHandler(DISABLE_INTERRUPTS_NESTING);
+ interruptDisableNesting=1;
+ }
+#else
+ globalInterruptDisableLock();
if(interruptDisableNesting==0xff) errorHandler(NESTING_OVERFLOW);
interruptDisableNesting++;
+#endif
}
void enableInterrupts()
@@ -159,9 +174,13 @@ void enableInterrupts()
errorHandler(DISABLE_INTERRUPTS_NESTING);
}
interruptDisableNesting--;
- if(interruptDisableNesting==0 && kernelStarted==true)
+ if(interruptDisableNesting==0)
{
- fastEnableInterrupts();
+ #ifdef WITH_SMP
+ globalIntrNestLockHoldingCore=0xFF;
+ #endif
+ if(kernelStarted==true) globalInterruptEnableUnlock();
+ else globalInterruptUnlock();
}
}
--
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