kernel: cleanup and formally define CPU start fn

The "key" parameter is legacy, remove it.

Add a typedef for the expected function pointer type.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>

arch/arc/core/arc_smp.c

@@ -24,7 +24,7 @@
 #define ARCV2_ICI_IRQ_PRIORITY 1
 
 volatile struct {
-	void (*fn)(int, void*);
+	arch_cpustart_t fn;
 	void *arg;
 } arc_cpu_init[CONFIG_MP_NUM_CPUS];
 
@@ -46,7 +46,7 @@ volatile _cpu_t *_curr_cpu[CONFIG_MP_NUM_CPUS];
 
 /* Called from Zephyr initialization */
 void arch_start_cpu(int cpu_num, k_thread_stack_t *stack, int sz,
-		    void (*fn)(int, void *), void *arg)
+		    arch_cpustart_t fn, void *arg)
 {
 	_curr_cpu[cpu_num] = &(_kernel.cpus[cpu_num]);
 	arc_cpu_init[cpu_num].fn = fn;
@@ -69,7 +69,7 @@ void arch_start_cpu(int cpu_num, k_thread_stack_t *stack, int sz,
 /* the C entry of slave cores */
 void z_arc_slave_start(int cpu_num)
 {
-	void (*fn)(int, void*);
+	arch_cpustart_t fn;
 
 #ifdef CONFIG_SMP
 	z_icache_setup();
@@ -82,7 +82,7 @@ void z_arc_slave_start(int cpu_num)
 	/* call the function set by arch_start_cpu */
 	fn = arc_cpu_init[cpu_num].fn;
 
-	fn(cpu_num, arc_cpu_init[cpu_num].arg);
+	fn(arc_cpu_init[cpu_num].arg);
 }
 
 #ifdef CONFIG_SMP

arch/x86/core/ia32/crt0.S

@@ -240,7 +240,6 @@ __csSet:
 #endif
 
 	pushl	%ebx		/* pointer to multiboot info, or NULL */
-	pushl	%eax		/* junk, unused argument */
 	call	z_x86_prep_c	/* enter kernel; never returns */
 
 _x86_bss_zero:

arch/x86/core/intel64/cpu.c

@@ -94,11 +94,11 @@ struct x86_cpuboot x86_cpuboot[] = {
 
 /*
  * Send the INIT/STARTUP IPI sequence required to start up CPU 'cpu_num', which
- * will enter the kernel at fn(---, arg), running on the specified stack.
+ * will enter the kernel at fn(arg), running on the specified stack.
  */
 
 void arch_start_cpu(int cpu_num, k_thread_stack_t *stack, int sz,
-			void (*fn)(int key, void *data), void *arg)
+		    arch_cpustart_t fn, void *arg)
 {
 	u8_t vector = ((unsigned long) x86_ap_start) >> 12;
 	u8_t apic_id = x86_cpu_loapics[cpu_num];

arch/x86/core/intel64/locore.S

@@ -196,7 +196,7 @@ go64:	movl %cr4, %eax			/* enable PAE and SSE */
 	/* don't replace CALL with JMP; honor the ABI stack alignment! */
 
 	incl __x86_cpuboot_t_ready_OFFSET(%rbp)
-	movq __x86_cpuboot_t_arg_OFFSET(%rbp), %rsi
+	movq __x86_cpuboot_t_arg_OFFSET(%rbp), %rdi
 	call *__x86_cpuboot_t_fn_OFFSET(%rbp) /* enter kernel; never return */
 
 /*

arch/x86/core/prep_c.c

@@ -11,9 +11,12 @@
 
 extern FUNC_NORETURN void z_cstart(void);
 
-FUNC_NORETURN void z_x86_prep_c(int unused, struct multiboot_info *info)
+/* Early global initialization functions, C domain. This runs only on the first
+ * CPU for SMP systems.
+ */
+FUNC_NORETURN void z_x86_prep_c(void *arg)
 {
-	ARG_UNUSED(unused);
+	struct multiboot_info *info = arg;
 
 	_kernel.cpus[0].nested = 0;
 	_kernel.cpus[0].irq_stack = Z_THREAD_STACK_BUFFER(_interrupt_stack) +

arch/x86/include/intel64/kernel_arch_data.h

@@ -23,7 +23,7 @@ struct x86_cpuboot {
 	u16_t tr;		/* selector for task register */
 	struct x86_tss64 *gs_base; /* Base address for GS segment */
 	u64_t sp;		/* initial stack pointer */
-	void *fn;		/* kernel entry function */
+	arch_cpustart_t fn;	/* kernel entry function */
 	void *arg;		/* argument for above function */
 #ifdef CONFIG_X86_MMU
 	struct x86_page_tables *ptables; /* Runtime page tables to install */

arch/x86/include/kernel_arch_func.h

@@ -36,7 +36,7 @@ extern K_THREAD_STACK_DEFINE(_interrupt_stack3, CONFIG_ISR_STACK_SIZE);
 
 struct multiboot_info;
 
-extern FUNC_NORETURN void z_x86_prep_c(int dummy, struct multiboot_info *info);
+extern FUNC_NORETURN void z_x86_prep_c(void *arg);
 
 #ifdef CONFIG_X86_VERY_EARLY_CONSOLE
 /* Setup ultra-minimal serial driver for printk() */

include/sys/arch_interface.h

@@ -159,6 +159,13 @@ void arch_cpu_atomic_idle(unsigned int key);
  * @{
  */
 
+/**
+ * Per-cpu entry function
+ *
+ * @param context parameter, implementation specific
+ */
+typedef FUNC_NORETURN void (*arch_cpustart_t)(void *data);
+
 /**
  * @brief Start a numbered CPU on a MP-capable system
  *
@@ -176,12 +183,11 @@ void arch_cpu_atomic_idle(unsigned int key);
  * @param cpu_num Integer number of the CPU
  * @param stack Stack memory for the CPU
  * @param sz Stack buffer size, in bytes
- * @param fn Function to begin running on the CPU.  First argument is
+ * @param fn Function to begin running on the CPU.
- *        an irq_unlock() key.
  * @param arg Untyped argument to be passed to "fn"
  */
 void arch_start_cpu(int cpu_num, k_thread_stack_t *stack, int sz,
-		    void (*fn)(int key, void *data), void *arg);
+		    arch_cpustart_t fn, void *arg);
 /** @} */
 
 

kernel/smp.c

@@ -65,7 +65,7 @@ extern k_thread_stack_t _interrupt_stack2[];
 extern k_thread_stack_t _interrupt_stack3[];
 
 #if CONFIG_MP_NUM_CPUS > 1
-static void smp_init_top(int key, void *arg)
+static FUNC_NORETURN void smp_init_top(void *arg)
 {
 	atomic_t *start_flag = arg;
 

soc/xtensa/esp32/esp32-mp.c

@@ -24,7 +24,7 @@
 
 struct cpustart_rec {
 	int cpu;
-	void (*fn)(int, void *);
+	arch_cpustart_t fn;
 	char *stack_top;
 	void *arg;
 	int vecbase;
@@ -93,7 +93,7 @@ static void appcpu_entry2(void)
 	__asm__ volatile("wsr.MISC0 %0" : : "r"(cpu));
 
 	*start_rec->alive = 1;
-	start_rec->fn(ps, start_rec->arg);
+	start_rec->fn(start_rec->arg);
 }
 
 /* Defines a locally callable "function" named _stack-switch().  The
@@ -191,7 +191,7 @@ static void appcpu_start(void)
 }
 
 void arch_start_cpu(int cpu_num, k_thread_stack_t *stack, int sz,
-		    void (*fn)(int, void *), void *arg)
+		    arch_cpustart_t fn, void *arg)
 {
 	volatile struct cpustart_rec sr;
 	int vb;

tests/kernel/mp/src/main.c

@@ -33,10 +33,8 @@ volatile int cpu_running;
  * @{
  * @}
  */
-void cpu1_fn(int key, void *arg)
+FUNC_NORETURN void cpu1_fn(void *arg)
 {
-	ARG_UNUSED(key);
-
 	zassert_true(arg == &cpu_arg && *(int *)arg == 12345, "wrong arg");
 
 	cpu_running = 1;