x86: minor adjustments for do_boot_cpu

This patch provides minor adjustments for do_boot_cpus
in both architectures to allow for integration
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/smpboot_32.c

@@ -556,7 +556,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
  * Returns zero if CPU booted OK, else error code from wakeup_secondary_cpu.
  */
 {
-	unsigned long boot_error;
+	unsigned long boot_error = 0;
 	int timeout;
 	unsigned long start_eip;
 	unsigned short nmi_high = 0, nmi_low = 0;
@@ -566,11 +566,7 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 	};
 	INIT_WORK(&c_idle.work, do_fork_idle);
 
-	/*
-	 * Save current MTRR state in case it was changed since early boot
-	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
-	 */
-	mtrr_save_state();
+	alternatives_smp_switch(1);
 
 	c_idle.idle = get_idle_for_cpu(cpu);
 
@@ -607,8 +603,6 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 	/* start_eip had better be page-aligned! */
 	start_eip = setup_trampoline();
 
-	alternatives_smp_switch(1);
-
 	/* So we see what's up   */
 	printk("Booting processor %d/%d ip %lx\n", cpu, apicid, start_eip);
 	/* Stack for startup_32 can be just as for start_secondary onwards */
@@ -628,6 +622,12 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 	store_NMI_vector(&nmi_high, &nmi_low);
 
 	smpboot_setup_warm_reset_vector(start_eip);
+	/*
+	 * Be paranoid about clearing APIC errors.
+	 */
+	apic_write(APIC_ESR, 0);
+	apic_read(APIC_ESR);
+
 
 	/*
 	 * Starting actual IPI sequence...
@@ -864,6 +864,12 @@ int __cpuinit native_cpu_up(unsigned int cpu)
 		return -EINVAL;
 	}
 
+	/*
+	 * Save current MTRR state in case it was changed since early boot
+	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
+	 */
+	mtrr_save_state();
+
 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 
 	__smp_prepare_cpu(cpu);

arch/x86/kernel/smpboot_64.c

@@ -432,7 +432,7 @@ static void __cpuinit do_fork_idle(struct work_struct *work)
  */
 static int __cpuinit do_boot_cpu(int cpu, int apicid)
 {
-	unsigned long boot_error;
+	unsigned long boot_error = 0;
 	int timeout;
 	unsigned long start_rip;
 	struct create_idle c_idle = {
@@ -530,11 +530,6 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid)
 	apic_write(APIC_ESR, 0);
 	apic_read(APIC_ESR);
 
-	/*
-	 * Status is now clean
-	 */
-	boot_error = 0;
-
 	/*
 	 * Starting actual IPI sequence...
 	 */
@@ -564,7 +559,7 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid)
 			print_cpu_info(&cpu_data(cpu));
 		} else {
 			boot_error = 1;
-			if (*((volatile unsigned char *)phys_to_virt(SMP_TRAMPOLINE_BASE))
+			if (*((volatile unsigned char *)trampoline_base)
 					== 0xA5)
 				/* trampoline started but...? */
 				printk("Stuck ??\n");
@@ -583,10 +578,12 @@ static int __cpuinit do_boot_cpu(int cpu, int apicid)
 		cpu_clear(cpu, cpu_present_map);
 		cpu_clear(cpu, cpu_possible_map);
 		per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
-		return -EIO;
 	}
 
-	return 0;
+	/* mark "stuck" area as not stuck */
+	*((volatile unsigned long *)trampoline_base) = 0;
+
+	return boot_error;
 }
 
 cycles_t cacheflush_time;