tools/x86/kcpuid: Simplify usage() handling

Refactor usage() to accept an exit code parameter and exit the program
after usage output.  This streamlines its callers' code paths.

Remove the "Invalid option" error message since getopt_long(3) already
emits a similar message by default.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250324142042.29010-4-darwi@linutronix.de

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index 25b10feeb7209373c1e2edf435b2a645b5f3c46b..a90ac0b898a1671edf3d5e092f86523601087b3a 100644 (file)
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -10,6 +10,7 @@
 
 #define ARRAY_SIZE(x)  (sizeof(x) / sizeof((x)[0]))
 #define min(a, b)      (((a) < (b)) ? (a) : (b))
+#define __noreturn     __attribute__((__noreturn__))
 
 typedef unsigned int u32;
 typedef unsigned long long u64;
@@ -584,17 +585,17 @@ static void setup_platform_cpuid(void)
        leafs_ext = setup_cpuid_range(0x80000000);
 }
 
-static void usage(void)
+static void __noreturn usage(int exit_code)
 {
-       warnx("kcpuid [-abdfhr] [-l leaf] [-s subleaf]\n"
-             "\t-a|--all             Show both bit flags and complex bit fields info\n"
-             "\t-b|--bitflags        Show boolean flags only\n"
-             "\t-d|--detail          Show details of the flag/fields (default)\n"
-             "\t-f|--flags           Specify the CPUID CSV file\n"
-             "\t-h|--help            Show usage info\n"
-             "\t-l|--leaf=index      Specify the leaf you want to check\n"
-             "\t-r|--raw             Show raw CPUID data\n"
-             "\t-s|--subleaf=sub     Specify the subleaf you want to check"
+       errx(exit_code, "kcpuid [-abdfhr] [-l leaf] [-s subleaf]\n"
+            "\t-a|--all             Show both bit flags and complex bit fields info\n"
+            "\t-b|--bitflags        Show boolean flags only\n"
+            "\t-d|--detail          Show details of the flag/fields (default)\n"
+            "\t-f|--flags           Specify the CPUID CSV file\n"
+            "\t-h|--help            Show usage info\n"
+            "\t-l|--leaf=index      Specify the leaf you want to check\n"
+            "\t-r|--raw             Show raw CPUID data\n"
+            "\t-s|--subleaf=sub     Specify the subleaf you want to check"
        );
 }
 
@@ -610,7 +611,7 @@ static struct option opts[] = {
        { NULL, 0, NULL, 0 }
 };
 
-static int parse_options(int argc, char *argv[])
+static void parse_options(int argc, char *argv[])
 {
        int c;
 
@@ -630,9 +631,7 @@ static int parse_options(int argc, char *argv[])
                        user_csv = optarg;
                        break;
                case 'h':
-                       usage();
-                       exit(1);
-                       break;
+                       usage(EXIT_SUCCESS);
                case 'l':
                        /* main leaf */
                        user_index = strtoul(optarg, NULL, 0);
@@ -645,11 +644,8 @@ static int parse_options(int argc, char *argv[])
                        user_sub = strtoul(optarg, NULL, 0);
                        break;
                default:
-                       warnx("Invalid option '%c'", optopt);
-                       return -1;
-       }
-
-       return 0;
+                       usage(EXIT_FAILURE);
+               }
 }
 
 /*
@@ -662,8 +658,7 @@ static int parse_options(int argc, char *argv[])
  */
 int main(int argc, char *argv[])
 {
-       if (parse_options(argc, argv))
-               return -1;
+       parse_options(argc, argv);
 
        /* Setup the cpuid leafs of current platform */
        setup_platform_cpuid();