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

and this:

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

Signed-off-by: Borislav Petkov <[email protected]>
Cc: Libin <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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;
+}