x86: Add ap_online() to consolidate final "AP is alive!" code
Add ap_online() to consolidate the last stage of onlining an AP CPU.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20220615232943.1465490-14-seanjc@google.com
diff --git a/lib/x86/setup.c b/lib/x86/setup.c
index 00d6e9c..7df0256 100644
--- a/lib/x86/setup.c
+++ b/lib/x86/setup.c
@@ -392,12 +392,5 @@
save_id();
enable_apic();
enable_x2apic();
- sti();
- asm volatile ("nop");
- printf("setup: AP %d online\n", apic_id());
- atomic_inc(&cpu_online_count);
-
- /* Only the BSP runs the test's main(), APs are given work via IPIs. */
- for (;;)
- asm volatile("hlt");
+ ap_online();
}
diff --git a/lib/x86/smp.c b/lib/x86/smp.c
index dd4eb8c..feaab7a 100644
--- a/lib/x86/smp.c
+++ b/lib/x86/smp.c
@@ -82,6 +82,18 @@
this_cpu_write_smp_id(apic_id());
}
+void ap_online(void)
+{
+ irq_enable();
+
+ printf("setup: CPU %d online\n", apic_id());
+ atomic_inc(&cpu_online_count);
+
+ /* Only the BSP runs the test's main(), APs are given work via IPIs. */
+ for (;;)
+ asm volatile("hlt");
+}
+
static void __on_cpu(int cpu, void (*function)(void *data), void *data, int wait)
{
const u32 ipi_icr = APIC_INT_ASSERT | APIC_DEST_PHYSICAL | APIC_DM_FIXED | IPI_VECTOR;
diff --git a/lib/x86/smp.h b/lib/x86/smp.h
index 3ddc39e..08a440b 100644
--- a/lib/x86/smp.h
+++ b/lib/x86/smp.h
@@ -85,6 +85,7 @@
void on_cpus(void (*function)(void *data), void *data);
void smp_reset_apic(void);
void bringup_aps(void);
+void ap_online(void);
extern atomic_t cpu_online_count;
extern unsigned char online_cpus[(MAX_TEST_CPUS + 7) / 8];
diff --git a/x86/cstart.S b/x86/cstart.S
index fdbe343..e82bed7 100644
--- a/x86/cstart.S
+++ b/x86/cstart.S
@@ -101,12 +101,10 @@
call save_id
call enable_apic
call enable_x2apic
- sti
- nop
- lock incw cpu_online_count
+ call ap_online
-1: hlt
- jmp 1b
+ /* ap_online() should never return */
+ ud2
start32:
setup_tr_and_percpu
