x86: Improve the printout of the SMP bootup CPU table

As the new x86 CPU bootup printout format code maintainer, I am
taking immediate action to improve and clean (and thus indulge
my OCD) the reporting of the cores when coming up online.

Fix padding to a right-hand alignment, cleanup code and bind
reporting width to the max number of supported CPUs on the
system, like this:

 [    0.074509] smpboot: Booting Node   0, Processors:      #1  #2  #3  #4  #5  torvalds#6  torvalds#7 OK
 [    0.644008] smpboot: Booting Node   1, Processors:  torvalds#8  torvalds#9 torvalds#10 torvalds#11 torvalds#12 torvalds#13 torvalds#14 torvalds#15 OK
 [    1.245006] smpboot: Booting Node   2, Processors: torvalds#16 torvalds#17 torvalds#18 torvalds#19 torvalds#20 torvalds#21 torvalds#22 torvalds#23 OK
 [    1.864005] smpboot: Booting Node   3, Processors: torvalds#24 torvalds#25 torvalds#26 torvalds#27 torvalds#28 torvalds#29 torvalds#30 torvalds#31 OK
 [    2.489005] smpboot: Booting Node   4, Processors: torvalds#32 torvalds#33 torvalds#34 torvalds#35 torvalds#36 torvalds#37 torvalds#38 torvalds#39 OK
 [    3.093005] smpboot: Booting Node   5, Processors: torvalds#40 torvalds#41 torvalds#42 torvalds#43 torvalds#44 torvalds#45 torvalds#46 torvalds#47 OK
 [    3.698005] smpboot: Booting Node   6, Processors: torvalds#48 torvalds#49 torvalds#50 torvalds#51 #52 #53 torvalds#54 torvalds#55 OK
 [    4.304005] smpboot: Booting Node   7, Processors: torvalds#56 torvalds#57 #58 torvalds#59 torvalds#60 torvalds#61 torvalds#62 torvalds#63 OK
 [    4.961413] Brought up 64 CPUs

and this:

 [    0.072367] smpboot: Booting Node   0, Processors:    #1 #2 #3 #4 #5 torvalds#6 torvalds#7 OK
 [    0.686329] Brought up 8 CPUs

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Libin <huawei.libin@huawei.com>
Cc: wangyijing@huawei.com
Cc: fenghua.yu@intel.com
Cc: guohanjun@huawei.com
Cc: paul.gortmaker@windriver.com
Link: http://lkml.kernel.org/r/20130927143554.GF4422@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/misc.h

@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_MISC_H
+#define _ASM_X86_MISC_H
+
+int num_digits(int val);
+
+#endif /* _ASM_X86_MISC_H */

arch/x86/kernel/smpboot.c

@@ -73,11 +73,10 @@
 #include <asm/setup.h>
 #include <asm/uv/uv.h>
 #include <linux/mc146818rtc.h>
-
 #include <asm/smpboot_hooks.h>
 #include <asm/i8259.h>
-
 #include <asm/realmode.h>
+#include <asm/misc.h>
 
 /* State of each CPU */
 DEFINE_PER_CPU(int, cpu_state) = { 0 };
@@ -653,17 +652,27 @@ static void announce_cpu(int cpu, int apicid)
 {
 	static int current_node = -1;
 	int node = early_cpu_to_node(cpu);
-	int max_cpu_present = find_last_bit(cpumask_bits(cpu_present_mask), NR_CPUS);
+	static int width;
+
+	if (!width)
+		width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
 
 	if (system_state == SYSTEM_BOOTING) {
 		if (node != current_node) {
 			if (current_node > (-1))
 				pr_cont(" OK\n");
 			current_node = node;
-			pr_info("Booting Node %3d, Processors ", node);
+			pr_info("Booting Node %3d, Processors:", node);
 		}
-		pr_cont(" #%4d%s", cpu, cpu == max_cpu_present ? " OK\n" : "");
-		return;
+
+		/* Add padding for the BSP */
+		if (cpu == 1)
+			pr_cont("%*s", width + 1, " ");
+
+		pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
+
+		if (cpu == num_present_cpus() - 1)
+			pr_cont(" OK\n");
 	} else
 		pr_info("Booting Node %d Processor %d APIC 0x%x\n",
 			node, cpu, apicid);

arch/x86/lib/Makefile

@@ -16,7 +16,7 @@ clean-files := inat-tables.c
 
 obj-$(CONFIG_SMP) += msr-smp.o cache-smp.o
 
-lib-y := delay.o
+lib-y := delay.o misc.o
 lib-y += thunk_$(BITS).o
 lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o

arch/x86/lib/misc.c

@@ -0,0 +1,11 @@
+int num_digits(int val)
+{
+	int digits = 0;
+
+	while (val) {
+		val /= 10;
+		digits++;
+	}
+
+	return digits;
+}