- make non overridable symbols .global to cause link error if you have e.g. isr_irq11 and there aren't 11 vector table entries

- omit guts of __unhandler_user_irq if not needed, but keep label and separate breakpoint (since there is an alignment hole of 2 bytes anyway)

Author: kilograham

src/rp2_common/hardware_exception/exception.c

@@ -31,12 +31,14 @@ static inline exception_handler_t *get_exception_table(void) {
 #endif
 }
 
+#if !PICO_NO_RAM_VECTOR_TABLE
 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_exception_table()[num] = handler;
     __dmb();
     restore_interrupts_from_disabled(save);
 }
+#endif
 
 static inline void check_exception_param(__unused enum exception_number num) {
     invalid_params_if(HARDWARE_EXCEPTION, num < MIN_EXCEPTION_NUM || num > MAX_EXCEPTION_NUM);
@@ -54,10 +56,12 @@ exception_handler_t exception_set_exclusive_handler(enum exception_number num, e
     exception_handler_t current = exception_get_vtable_handler(num);
     hard_assert(handler == current || exception_is_compile_time_default(current));
     set_raw_exception_handler_and_restore_interrupts(num, handler, save);
+    return current;
 #else
+    ((void)num);
+    ((void)handler);
     panic_unsupported();
 #endif
-    return current;
 }
 
 void exception_restore_handler(enum exception_number num, exception_handler_t original_handler) {
@@ -66,6 +70,8 @@ void exception_restore_handler(enum exception_number num, exception_handler_t or
     uint32_t save = save_and_disable_interrupts();
     set_raw_exception_handler_and_restore_interrupts(num, original_handler, save);
 #else
+    ((void)num);
+    ((void)original_handler);
     panic_unsupported();
 #endif
 }

src/rp2_common/hardware_irq/irq.c

@@ -51,13 +51,6 @@ static inline void *remove_thumb_bit(void *addr) {
 #endif
 }
 
-static void set_raw_irq_handler_and_unlock(uint num, irq_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()[VTABLE_FIRST_IRQ + num] = handler;
-    __dmb();
-    spin_unlock(spin_lock_instance(PICO_SPINLOCK_ID_IRQ), save);
-}
-
 void irq_set_enabled(uint num, bool enabled) {
     check_irq_param(num);
     // really should update irq_set_mask_enabled?
@@ -129,7 +122,7 @@ void irq_set_pending(uint num) {
 #endif
 }
 
-#if !PICO_DISABLE_SHARED_IRQ_HANDLERS
+#if !PICO_DISABLE_SHARED_IRQ_HANDLERS && !PICO_NO_RAM_VECTOR_TABLE
 // limited by 8 bit relative links (and reality)
 static_assert(PICO_MAX_SHARED_IRQ_HANDLERS >= 1 && PICO_MAX_SHARED_IRQ_HANDLERS < 0x7f, "");
 
@@ -203,9 +196,17 @@ bool irq_has_shared_handler(uint irq_num) {
     return handler && is_shared_irq_raw_handler(handler);
 }
 
-#else // PICO_DISABLE_SHARED_IRQ_HANDLERS
+static void set_raw_irq_handler_and_unlock(uint num, irq_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()[VTABLE_FIRST_IRQ + num] = handler;
+    __dmb();
+    spin_unlock(spin_lock_instance(PICO_SPINLOCK_ID_IRQ), save);
+}
+
+#else // PICO_DISABLE_SHARED_IRQ_HANDLERS && PICO_NO_RAM_VECTOR_TABLE
 #define is_shared_irq_raw_handler(h) false
 bool irq_has_shared_handler(uint irq_num) {
+    ((void)irq_num);
     return false;
 }
 #endif
@@ -225,6 +226,7 @@ void irq_set_exclusive_handler(uint num, irq_handler_t handler) {
     hard_assert(current == __unhandled_user_irq || current == handler);
     set_raw_irq_handler_and_unlock(num, handler, save);
 #else
+    ((void)handler);
     panic_unsupported();
 #endif
 }
@@ -246,7 +248,7 @@ irq_handler_t irq_get_exclusive_handler(uint num) {
 }
 
 
-#if !PICO_DISABLE_SHARED_IRQ_HANDLERS
+#if !PICO_DISABLE_SHARED_IRQ_HANDLERS && !PICO_NO_RAM_VECTOR_TABLE
 
 #ifndef __riscv
 
@@ -356,6 +358,8 @@ static inline int8_t get_slot_index(struct irq_handler_chain_slot *slot) {
 void irq_add_shared_handler(uint num, irq_handler_t handler, uint8_t order_priority) {
     check_irq_param(num);
 #if PICO_NO_RAM_VECTOR_TABLE
+    ((void)handler);
+    ((void)order_priority);
     panic_unsupported();
 #elif PICO_DISABLE_SHARED_IRQ_HANDLERS
     irq_set_exclusive_handler(num, handler);
@@ -449,7 +453,7 @@ void irq_add_shared_handler(uint num, irq_handler_t handler, uint8_t order_prior
 #endif // !PICO_NO_RAM_VECTOR_TABLE && !PICO_DISABLE_SHARED_IRQ_HANDLERS
 }
 
-#if !PICO_DISABLE_SHARED_IRQ_HANDLERS
+#if !PICO_DISABLE_SHARED_IRQ_HANDLERS && !PICO_NO_RAM_VECTOR_TABLE
 static inline irq_handler_t handler_from_slot(struct irq_handler_chain_slot *slot) {
 #ifndef __riscv
     return slot->handler;
@@ -574,6 +578,8 @@ void irq_remove_handler(uint num, irq_handler_t handler) {
     }
     set_raw_irq_handler_and_unlock(num, vtable_handler, save);
 #else
+    ((void)num);
+    ((void)handler);
     panic_unsupported();
 #endif
 }
@@ -614,7 +620,7 @@ uint irq_get_priority(uint num) {
 #endif
 }
 
-#if !PICO_DISABLE_SHARED_IRQ_HANDLERS
+#if !PICO_DISABLE_SHARED_IRQ_HANDLERS && !PICO_NO_RAM_VECTOR_TABLE
 // used by irq_handler_chain.S to remove the last link in a handler chain after it executes
 // note this must be called only with the last slot in a chain (and during the exception)
 void irq_add_tail_to_free_list(struct irq_handler_chain_slot *slot) {

src/rp2_common/pico_crt0/crt0.S

@@ -168,25 +168,14 @@ __default_isrs_start:
     bkpt #0
 .endm
 
-// these are separated out for clarity
-decl_isr_bkpt isr_invalid
-#if !PICO_MINIMAL_STORED_VECTOR_TABLE
-decl_isr_bkpt isr_nmi
-decl_isr_bkpt isr_hardfault
-decl_isr_bkpt isr_svcall
-decl_isr_bkpt isr_pendsv
-decl_isr_bkpt isr_systick
-
-.global __default_isrs_end
-__default_isrs_end:
-
 .altmacro
 .macro decl_isr name
 #if !PICO_MINIMAL_STORED_VECTOR_TABLE | PICO_NO_FLASH
 // We declare a weak label, so user can override
 .weak \name
 #else
-// We declare a strong label, so user can't override (their version would not automatically be used)
+// We declare a strong global label, so user can't override (their version would not automatically be used)
+.global \name
 #endif
 .type \name,%function
 .thumb_func
@@ -197,7 +186,8 @@ __default_isrs_end:
 .if \num < PICO_NUM_VTABLE_IRQS
 decl_isr \func
 .elseif \num < NUM_IRQS
-// We declare a strong label, so user can't override, since there is no vtable entry
+// We declare a strong global label, so user can't override (their version would not automatically be used)
+.global \func
 .type \func,%function
 .thumb_func
 \func:
@@ -288,17 +278,34 @@ if_irq_decl 79 isr_irq79
 #error more IRQ entries required
 #endif
 
-#endif  // #if !PICO_MINIMAL_STORED_VECTOR_TABLE
 // All unhandled USER IRQs fall through to here
 .global __unhandled_user_irq
 .thumb_func
 __unhandled_user_irq:
+// if we include the implementation if there could be a valid IRQ hanler in the vtable that uses it
+#if !(PICO_NO_RAM_VECTOR_TABLE && PICO_MINIMAL_STORED_VECTOR_TABLE)
     mrs  r0, ipsr
     subs r0, #16
 .global unhandled_user_irq_num_in_r0
 unhandled_user_irq_num_in_r0:
+#endif
+    // note the next instruction is a breakpoint too, however we have a 2 byte alignment hole
+    // and it is preferrable to have distinct labels, to inform the user what has happened in the debugger.
     bkpt #0
 
+decl_isr_bkpt isr_invalid
+#if !PICO_MINIMAL_STORED_VECTOR_TABLE
+// these are separated out for clarity
+decl_isr_bkpt isr_nmi
+decl_isr_bkpt isr_hardfault
+decl_isr_bkpt isr_svcall
+decl_isr_bkpt isr_pendsv
+decl_isr_bkpt isr_systick
+#endif
+
+.global __default_isrs_end
+__default_isrs_end:
+
 // ----------------------------------------------------------------------------
 
 .section .binary_info_header, "a"