x86/{boot,cpu}: rework AP boot stack management

8 files changed, 60 insertions, 38 deletions

diff --git a/arch/x86/machine/boot.c b/arch/x86/machine/boot.c
index c1970f5d..f62ad09b 100644
--- a/arch/x86/machine/boot.c
+++ b/arch/x86/machine/boot.c
@@ -75,7 +75,6 @@
 
 alignas(CPU_DATA_ALIGN) char boot_stack[BOOT_STACK_SIZE] __bootdata;
 alignas(CPU_DATA_ALIGN) char boot_ap_stack[BOOT_STACK_SIZE] __bootdata;
-unsigned int boot_ap_id __bootdata;
 
 #ifdef __LP64__
 alignas(PAGE_SIZE) pmap_pte_t boot_pml4[PMAP_L3_PTES_PER_PT] __bootdata;
@@ -122,6 +121,12 @@ static char boot_panic_meminfo_msg[] __bootdata
 static char boot_panic_cmdline_msg[] __bootdata
     = "boot: command line too long";
 
+static volatile unsigned int boot_ap_id __bootdata;
+static char *boot_ap_stacks[CONFIG_MAX_CPUS - 1] __initdata;
+
+pmap_pte_t * boot_ap_setup(void);
+char * boot_get_ap_stack(void);
+
 void * __boot
 boot_memcpy(void *dest, const void *src, size_t n)
 {
@@ -500,9 +505,47 @@ boot_main(void)
 }
 
 void __init
+boot_alloc_ap_stacks(void)
+{
+    char *stack;
+
+    for (unsigned int i = 1; i < cpu_count(); i++) {
+        stack = kmem_alloc(BOOT_STACK_SIZE);
+
+        if (!stack) {
+            panic("boot: unable to allocate stack for cpu%u", i);
+        }
+
+        boot_ap_stacks[i - 1] = stack;
+    }
+}
+
+void __init
+boot_set_ap_id(unsigned int ap_id)
+{
+    boot_ap_id = ap_id;
+}
+
+pmap_pte_t * __boot
+boot_ap_setup(void)
+{
+    return pmap_ap_setup_paging(boot_ap_id);
+}
+
+char * __init
+boot_get_ap_stack(void)
+{
+    unsigned int index;
+
+    index = boot_ap_id - 1;
+    assert(boot_ap_id < ARRAY_SIZE(boot_ap_stacks));
+    return boot_ap_stacks[index];
+}
+
+void __init
 boot_ap_main(void)
 {
-    cpu_ap_setup();
+    cpu_ap_setup(boot_ap_id);
     thread_ap_setup();
     pmap_ap_setup();
     percpu_ap_setup();
diff --git a/arch/x86/machine/boot.h b/arch/x86/machine/boot.h
index 087f0c2a..a3f4ecb8 100644
--- a/arch/x86/machine/boot.h
+++ b/arch/x86/machine/boot.h
@@ -79,11 +79,6 @@ extern char _boot;
 extern char _boot_end;
 
 /*
- * This variable contains the CPU ID of an AP during early initialization.
- */
-extern unsigned int boot_ap_id;
-
-/*
  * Size of the trampoline code used for APs.
  */
 extern uint32_t boot_mp_trampoline_size;
@@ -123,6 +118,10 @@ void boot_main(void);
  */
 void boot_ap_main(void);
 
+void boot_alloc_ap_stacks(void);
+
+void boot_set_ap_id(unsigned int ap_id);
+
 /*
  * Log kernel version and other architecture-specific information.
  */
diff --git a/arch/x86/machine/boot_asm.S b/arch/x86/machine/boot_asm.S
index d9bdc3df..bfec4483 100644
--- a/arch/x86/machine/boot_asm.S
+++ b/arch/x86/machine/boot_asm.S
@@ -313,7 +313,7 @@ ASM_ENTRY(boot_ap_start32)
  .code64
 #endif /* __LP64__ */
 
- call pmap_ap_setup_paging
+ call boot_ap_setup
 
 #ifdef __LP64__
  movq %rax, %cr3
@@ -327,7 +327,7 @@ ASM_ENTRY(boot_ap_start32)
 1:
 #endif /* __LP64__ */
 
- call cpu_get_boot_stack
+ call boot_get_ap_stack
 
 #ifdef __LP64__
  movq %rax, %rsp
diff --git a/arch/x86/machine/cpu.c b/arch/x86/machine/cpu.c
index 5eb9ce2d..f2acd77d 100644
--- a/arch/x86/machine/cpu.c
+++ b/arch/x86/machine/cpu.c
@@ -420,12 +420,6 @@ cpu_delay(unsigned long usecs)
     } while (total > 0);
 }
 
-void * __init
-cpu_get_boot_stack(void)
-{
-    return percpu_var(cpu_desc.boot_stack, boot_ap_id); // TODO Pass as argument
-}
-
 void *
 cpu_get_intr_stack(void)
 {
@@ -1254,7 +1248,6 @@ cpu_mp_setup(void)
 {
     uint16_t reset_vector[2];
     struct cpu *cpu;
-    unsigned int i;
     void *ptr;
 
     if (cpu_count() == 1) {
@@ -1279,14 +1272,7 @@ cpu_mp_setup(void)
     io_write_byte(CPU_MP_CMOS_PORT_REG, CPU_MP_CMOS_REG_RESET);
     io_write_byte(CPU_MP_CMOS_PORT_DATA, CPU_MP_CMOS_DATA_RESET_WARM);
 
-    for (i = 1; i < cpu_count(); i++) {
-        cpu = percpu_ptr(cpu_desc, i);
-        cpu->boot_stack = kmem_alloc(BOOT_STACK_SIZE);
-
-        if (!cpu->boot_stack) {
-            panic("cpu: unable to allocate boot stack for cpu%u", i);
-        }
-    }
+    boot_alloc_ap_stacks();
 
     /*
      * This function creates per-CPU copies of the page tables. Just in case,
@@ -1294,9 +1280,9 @@ cpu_mp_setup(void)
      */
     pmap_mp_setup();
 
-    for (i = 1; i < cpu_count(); i++) {
+    for (unsigned int i = 1; i < cpu_count(); i++) {
         cpu = percpu_ptr(cpu_desc, i);
-        boot_ap_id = i;
+        boot_set_ap_id(i);
 
         /* Perform the "Universal Start-up Algorithm" */
         lapic_ipi_init_assert(cpu->apic_id);
@@ -1315,11 +1301,11 @@ cpu_mp_setup(void)
 }
 
 void __init
-cpu_ap_setup(void)
+cpu_ap_setup(unsigned int ap_id)
 {
     struct cpu *cpu;
 
-    cpu = percpu_ptr(cpu_desc, boot_ap_id);
+    cpu = percpu_ptr(cpu_desc, ap_id);
     cpu_build(cpu);
     cpu_check(cpu_current());
     lapic_ap_setup();
diff --git a/arch/x86/machine/cpu.h b/arch/x86/machine/cpu.h
index b94c149d..94291acc 100644
--- a/arch/x86/machine/cpu.h
+++ b/arch/x86/machine/cpu.h
@@ -600,11 +600,6 @@ uint64_t cpu_get_freq(void);
 void cpu_delay(unsigned long usecs);
 
 /*
- * Return the address of the boot stack allocated for the current processor.
- */
-void * cpu_get_boot_stack(void);
-
-/*
  * Log processor information.
  */
 void cpu_log_info(const struct cpu *cpu);
@@ -629,7 +624,7 @@ void cpu_mp_setup(void);
 /*
  * CPU initialization on APs.
  */
-void cpu_ap_setup(void);
+void cpu_ap_setup(unsigned int ap_id);
 
 static inline unsigned int
 cpu_apic_id(unsigned int cpu)
diff --git a/arch/x86/machine/cpu_i.h b/arch/x86/machine/cpu_i.h
index 2c28573e..f877fce3 100644
--- a/arch/x86/machine/cpu_i.h
+++ b/arch/x86/machine/cpu_i.h
@@ -158,7 +158,6 @@ struct cpu {
 #endif /* __LP64__ */
 
     volatile int state; // TODO Atomic accessors
-    void *boot_stack;
 
     alignas(CPU_DATA_ALIGN) char intr_stack[CPU_INTR_STACK_SIZE];
     alignas(CPU_DATA_ALIGN) char df_stack[CPU_INTR_STACK_SIZE];
diff --git a/arch/x86/machine/pmap.c b/arch/x86/machine/pmap.c
index c8f0437d..73c31ca4 100644
--- a/arch/x86/machine/pmap.c
+++ b/arch/x86/machine/pmap.c
@@ -484,7 +484,7 @@ pmap_setup_paging(void)
 }
 
 pmap_pte_t * __boot
-pmap_ap_setup_paging(void)
+pmap_ap_setup_paging(unsigned int ap_id)
 {
     struct pmap_cpu_table *cpu_table;
     struct pmap *pmap;
@@ -494,7 +494,7 @@ pmap_ap_setup_paging(void)
     pmap_boot_enable_pgext(pgsize);
 
     pmap = (void *)BOOT_VTOP((uintptr_t)&pmap_kernel_pmap);
-    cpu_table = (void *)BOOT_VTOP((uintptr_t)pmap->cpu_tables[boot_ap_id]);
+    cpu_table = (void *)BOOT_VTOP((uintptr_t)pmap->cpu_tables[ap_id]);
 
 #ifdef CONFIG_X86_PAE
     return (void *)(uint32_t)cpu_table->root_ptp_pa;
diff --git a/arch/x86/machine/pmap.h b/arch/x86/machine/pmap.h
index 3a6a1209..d3a0d251 100644
--- a/arch/x86/machine/pmap.h
+++ b/arch/x86/machine/pmap.h
@@ -203,7 +203,7 @@ pmap_pte_t * pmap_setup_paging(void);
 /*
  * This function is called by the AP bootstrap code before paging is enabled.
  */
-pmap_pte_t * pmap_ap_setup_paging(void);
+pmap_pte_t * pmap_ap_setup_paging(unsigned int ap_id);
 
 /*
  * Initialize the pmap module on APs.