tools/x86/kcpuid: Save CPUID output in an array

For each CPUID leaf/subleaf query, save the output in an output[] array
instead of spelling it out using EAX to EDX variables.

This allows the CPUID output to be accessed programmatically instead of
calling decode_bits() four times.  Loop-based access also allows "kcpuid
--detail" to print the correct output register names in next commit.

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/20250324142042.29010-5-darwi@linutronix.de

diff --git a/tools/arch/x86/kcpuid/kcpuid.c b/tools/arch/x86/kcpuid/kcpuid.c
index a90ac0b898a1671edf3d5e092f86523601087b3a..8da0e072055bfcfc8025e5f8bd8c9b39ff6c6a8a 100644 (file)
--- a/tools/arch/x86/kcpuid/kcpuid.c
+++ b/tools/arch/x86/kcpuid/kcpuid.c
@@ -51,7 +51,7 @@ static const char * const reg_names[] = {
 struct subleaf {
        u32 index;
        u32 sub;
-       u32 eax, ebx, ecx, edx;
+       u32 output[NR_REGS];
        struct reg_desc info[NR_REGS];
 };
 
@@ -119,11 +119,11 @@ static void leaf_print_raw(struct subleaf *leaf)
                if (leaf->sub == 0)
                        printf("0x%08x: subleafs:\n", leaf->index);
 
-               printf(" %2d: EAX=0x%08x, EBX=0x%08x, ECX=0x%08x, EDX=0x%08x\n",
-                       leaf->sub, leaf->eax, leaf->ebx, leaf->ecx, leaf->edx);
+               printf(" %2d: EAX=0x%08x, EBX=0x%08x, ECX=0x%08x, EDX=0x%08x\n", leaf->sub,
+                      leaf->output[0], leaf->output[1], leaf->output[2], leaf->output[3]);
        } else {
-               printf("0x%08x: EAX=0x%08x, EBX=0x%08x, ECX=0x%08x, EDX=0x%08x\n",
-                       leaf->index, leaf->eax, leaf->ebx, leaf->ecx, leaf->edx);
+               printf("0x%08x: EAX=0x%08x, EBX=0x%08x, ECX=0x%08x, EDX=0x%08x\n", leaf->index,
+                      leaf->output[0], leaf->output[1], leaf->output[2], leaf->output[3]);
        }
 }
 
@@ -163,10 +163,10 @@ static bool cpuid_store(struct cpuid_range *range, u32 f, int subleaf,
 
        leaf->index = f;
        leaf->sub = subleaf;
-       leaf->eax = a;
-       leaf->ebx = b;
-       leaf->ecx = c;
-       leaf->edx = d;
+       leaf->output[R_EAX] = a;
+       leaf->output[R_EBX] = b;
+       leaf->output[R_ECX] = c;
+       leaf->output[R_EDX] = d;
 
        return false;
 }
@@ -490,10 +490,8 @@ static void show_leaf(struct subleaf *leaf)
                                leaf->index, leaf->sub);
        }
 
-       decode_bits(leaf->eax, &leaf->info[R_EAX], R_EAX);
-       decode_bits(leaf->ebx, &leaf->info[R_EBX], R_EBX);
-       decode_bits(leaf->ecx, &leaf->info[R_ECX], R_ECX);
-       decode_bits(leaf->edx, &leaf->info[R_EDX], R_EDX);
+       for (int i = R_EAX; i < NR_REGS; i++)
+               decode_bits(leaf->output[i], &leaf->info[i], i);
 
        if (!show_raw && show_details)
                printf("\n");