x86/cpu: improve CPU flags handling

5 files changed, 154 insertions, 46 deletions

diff --git a/arch/x86/machine/boot_asm.S b/arch/x86/machine/boot_asm.S
index bfec4483..2b350f25 100644
--- a/arch/x86/machine/boot_asm.S
+++ b/arch/x86/machine/boot_asm.S
@@ -132,13 +132,13 @@ ASM_END(boot_gdtr)
 ASM_ENTRY(boot_check_long_mode)
  pushl %eax
  pushl %ebx
- movl $0x80000000, %eax
+ movl $CPU_CPUID_EXT_BIT, %eax
  cpuid
- cmpl $0x80000000, %eax
+ cmpl $CPU_CPUID_EXT_BIT, %eax
  jbe boot_no_long_mode
- movl $0x80000001, %eax
+ movl $(CPU_CPUID_EXT_BIT | 1), %eax
  cpuid
- testl $CPU_FEATURE4_LM, %edx
+ testl $CPU_CPUID_EXT1_EDX_LM, %edx
  jz boot_no_long_mode
  popl %ebx
  popl %eax
diff --git a/arch/x86/machine/cpu.c b/arch/x86/machine/cpu.c
index e8cdb19d..7edcc805 100644
--- a/arch/x86/machine/cpu.c
+++ b/arch/x86/machine/cpu.c
@@ -253,6 +253,18 @@ static const struct cpu_vendor cpu_vendors[] = {
     { CPU_VENDOR_AMD,   "AuthenticAMD" },
 };
 
+static const char *cpu_feature_names[] = {
+    [CPU_FEATURE_FPU]   = "fpu",
+    [CPU_FEATURE_PSE]   = "pse",
+    [CPU_FEATURE_PAE]   = "pae",
+    [CPU_FEATURE_MSR]   = "msr",
+    [CPU_FEATURE_CX8]   = "cx8",
+    [CPU_FEATURE_APIC]  = "apic",
+    [CPU_FEATURE_PGE]   = "pge",
+    [CPU_FEATURE_1GP]   = "1gp",
+    [CPU_FEATURE_LM]    = "lm",
+};
+
 static void __init
 cpu_exc_handler_init(struct cpu_exc_handler *handler, cpu_exc_handler_fn_t fn)
 {
@@ -851,6 +863,40 @@ cpu_tss_init_i386_double_fault(struct cpu_tss *tss, const void *df_stack_top)
 }
 #endif /* __LP64__ */
 
+static void __init
+cpu_feature_map_init(struct cpu_feature_map *map)
+{
+    bitmap_zero(map->flags, CPU_NR_FEATURES);
+}
+
+static void __init
+cpu_feature_map_cset(struct cpu_feature_map *map, unsigned int word,
+                     unsigned int mask, enum cpu_feature feature)
+{
+    if (word & mask) {
+        bitmap_set(map->flags, feature);
+    }
+}
+
+static void __init
+cpu_feature_map_basic1_edx(struct cpu_feature_map *map, unsigned int edx)
+{
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_FPU, CPU_FEATURE_FPU);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_PSE, CPU_FEATURE_PSE);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_PAE, CPU_FEATURE_PAE);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_MSR, CPU_FEATURE_MSR);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_CX8, CPU_FEATURE_CX8);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_APIC, CPU_FEATURE_APIC);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_BASIC1_EDX_PGE, CPU_FEATURE_PGE);
+}
+
+static void __init
+cpu_feature_map_ext1_edx(struct cpu_feature_map *map, unsigned int edx)
+{
+    cpu_feature_map_cset(map, edx, CPU_CPUID_EXT1_EDX_1GP, CPU_FEATURE_1GP);
+    cpu_feature_map_cset(map, edx, CPU_CPUID_EXT1_EDX_LM, CPU_FEATURE_LM);
+}
+
 static struct cpu_tss * __init
 cpu_get_tss(struct cpu *cpu)
 {
@@ -1021,13 +1067,13 @@ cpu_build(struct cpu *cpu)
                          >> CPU_CPUID_CLFLUSH_SHIFT) * 8;
     cpu->initial_apic_id = (ebx & CPU_CPUID_APIC_ID_MASK)
                            >> CPU_CPUID_APIC_ID_SHIFT;
-    cpu->features1 = ecx;
-    cpu->features2 = edx;
+    cpu_feature_map_init(&cpu->feature_map);
+    cpu_feature_map_basic1_edx(&cpu->feature_map, edx);
 
-    eax = 0x80000000;
+    eax = CPU_CPUID_EXT_BIT;
     cpu_cpuid(&eax, &ebx, &ecx, &edx);
 
-    if (eax <= 0x80000000) {
+    if (eax <= CPU_CPUID_EXT_BIT) {
         max_extended = 0;
     } else {
         max_extended = eax;
@@ -1035,32 +1081,28 @@ cpu_build(struct cpu *cpu)
 
     cpu->cpuid_max_extended = max_extended;
 
-    if (max_extended < 0x80000001) {
-        cpu->features3 = 0;
-        cpu->features4 = 0;
-    } else {
-        eax = 0x80000001;
+    if (max_extended >= (CPU_CPUID_EXT_BIT | 1)) {
+        eax = CPU_CPUID_EXT_BIT | 1;
         cpu_cpuid(&eax, &ebx, &ecx, &edx);
-        cpu->features3 = ecx;
-        cpu->features4 = edx;
+        cpu_feature_map_ext1_edx(&cpu->feature_map, edx);
     }
 
-    if (max_extended >= 0x80000004) {
-        eax = 0x80000002;
+    if (max_extended >= (CPU_CPUID_EXT_BIT | 4)) {
+        eax = CPU_CPUID_EXT_BIT | 2;
         cpu_cpuid(&eax, &ebx, &ecx, &edx);
         memcpy(cpu->model_name, &eax, sizeof(eax));
         memcpy(cpu->model_name + 4, &ebx, sizeof(ebx));
         memcpy(cpu->model_name + 8, &ecx, sizeof(ecx));
         memcpy(cpu->model_name + 12, &edx, sizeof(edx));
 
-        eax = 0x80000003;
+        eax = CPU_CPUID_EXT_BIT | 3;
         cpu_cpuid(&eax, &ebx, &ecx, &edx);
         memcpy(cpu->model_name + 16, &eax, sizeof(eax));
         memcpy(cpu->model_name + 20, &ebx, sizeof(ebx));
         memcpy(cpu->model_name + 24, &ecx, sizeof(ecx));
         memcpy(cpu->model_name + 28, &edx, sizeof(edx));
 
-        eax = 0x80000004;
+        eax = CPU_CPUID_EXT_BIT | 4;
         cpu_cpuid(&eax, &ebx, &ecx, &edx);
         memcpy(cpu->model_name + 32, &eax, sizeof(eax));
         memcpy(cpu->model_name + 36, &ebx, sizeof(ebx));
@@ -1070,8 +1112,8 @@ cpu_build(struct cpu *cpu)
         cpu->model_name[sizeof(cpu->model_name) - 1] = '\0';
     }
 
-    if (max_extended >= 0x80000008) {
-        eax = 0x80000008;
+    if (max_extended >= (CPU_CPUID_EXT_BIT | 8)) {
+        eax = CPU_CPUID_EXT_BIT | 8;
         cpu_cpuid(&eax, &ebx, &ecx, &edx);
         cpu->phys_addr_width = (unsigned short)eax & 0xff;
         cpu->virt_addr_width = ((unsigned short)eax >> 8) & 0xff;
@@ -1122,7 +1164,7 @@ cpu_panic_on_missing_feature(const char *feature)
 static void __init
 cpu_check(const struct cpu *cpu)
 {
-    if (!(cpu->features2 & CPU_FEATURE2_FPU)) {
+    if (!cpu_has_feature(cpu, CPU_FEATURE_FPU)) {
         cpu_panic_on_missing_feature("fpu");
     }
 
@@ -1133,7 +1175,7 @@ cpu_check(const struct cpu *cpu)
      * just disabled when building with it.
      */
 #if !defined(__LP64__) && !defined(__clang__)
-    if (!(cpu->features2 & CPU_FEATURE2_CX8)) {
+    if (!cpu_has_feature(cpu, CPU_FEATURE_CX8)) {
         cpu_panic_on_missing_feature("cx8");
     }
 #endif
@@ -1154,6 +1196,9 @@ INIT_OP_DEFINE(cpu_check_bsp,
 void __init
 cpu_log_info(const struct cpu *cpu)
 {
+    char features[60], *ptr;
+    size_t size, bytes;
+
     log_info("cpu%u: %s, type %u, family %u, model %u, stepping %u",
              cpu->id, cpu->vendor_str, cpu->type, cpu->family, cpu->model,
              cpu->stepping);
@@ -1170,6 +1215,32 @@ cpu_log_info(const struct cpu *cpu)
     log_info("cpu%u: frequency: %llu.%02llu MHz", cpu->id,
              (unsigned long long)cpu_freq / 1000000,
              (unsigned long long)cpu_freq % 1000000);
+
+    ptr = features;
+    size = sizeof(features);
+
+    for (size_t i = 0; i < ARRAY_SIZE(cpu_feature_names); i++) {
+        if (!cpu_has_feature(cpu, i)) {
+            continue;
+        }
+
+        assert(strlen(cpu_feature_names[i]) < sizeof(features));
+        bytes = snprintf(ptr, size, " %s", cpu_feature_names[i]);
+
+        if (bytes >= size) {
+            *ptr = '\0';
+            log_info("cpu%u:%s", cpu->id, features);
+            ptr = features;
+            size = sizeof(features);
+            i--;
+            continue;
+        }
+
+        ptr += bytes;
+        size -= bytes;
+    }
+
+    log_info("cpu%u:%s", cpu->id, features);
 }
 
 void __init
diff --git a/arch/x86/machine/cpu.h b/arch/x86/machine/cpu.h
index 94291acc..033c17dc 100644
--- a/arch/x86/machine/cpu.h
+++ b/arch/x86/machine/cpu.h
@@ -138,26 +138,46 @@
 #define CPU_EFER_LME                            0x00000100
 
 /*
- * Feature2 flags.
- *
- * TODO Better names.
+ * Bit used to make extended CPUID requests.
+ */
+#define CPU_CPUID_EXT_BIT                       0x80000000
+
+/*
+ * CPU feature flags as returned by CPUID.
  */
-#define CPU_FEATURE2_FPU                        0x00000001
-#define CPU_FEATURE2_PSE                        0x00000008
-#define CPU_FEATURE2_PAE                        0x00000040
-#define CPU_FEATURE2_MSR                        0x00000020
-#define CPU_FEATURE2_CX8                        0x00000100
-#define CPU_FEATURE2_APIC                       0x00000200
-#define CPU_FEATURE2_PGE                        0x00002000
+#define CPU_CPUID_BASIC1_EDX_FPU                0x00000001
+#define CPU_CPUID_BASIC1_EDX_PSE                0x00000008
+#define CPU_CPUID_BASIC1_EDX_PAE                0x00000040
+#define CPU_CPUID_BASIC1_EDX_MSR                0x00000020
+#define CPU_CPUID_BASIC1_EDX_CX8                0x00000100
+#define CPU_CPUID_BASIC1_EDX_APIC               0x00000200
+#define CPU_CPUID_BASIC1_EDX_PGE                0x00002000
+#define CPU_CPUID_EXT1_EDX_1GP                  0x04000000
+#define CPU_CPUID_EXT1_EDX_LM                   0x20000000
+
+#ifndef __ASSEMBLER__
 
-#define CPU_FEATURE4_1GP                        0x04000000
-#define CPU_FEATURE4_LM                         0x20000000
+enum cpu_feature {
+    CPU_FEATURE_FPU,
+    CPU_FEATURE_PSE,
+    CPU_FEATURE_PAE,
+    CPU_FEATURE_MSR,
+    CPU_FEATURE_CX8,
+    CPU_FEATURE_APIC,
+    CPU_FEATURE_PGE,
+    CPU_FEATURE_1GP,
+    CPU_FEATURE_LM,
+    CPU_NR_FEATURES
+};
+
+#endif /* __ASSEMBLER__ */
 
 #include <machine/cpu_i.h>
 
 #ifndef __ASSEMBLER__
 
 #include <stdalign.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdnoreturn.h>
 
@@ -429,6 +449,12 @@ cpu_from_id(unsigned int cpu)
     return percpu_ptr(cpu_desc, cpu);
 }
 
+static inline bool
+cpu_has_feature(const struct cpu *cpu, enum cpu_feature feature)
+{
+    return cpu_feature_map_test(&cpu->feature_map, feature);
+}
+
 static __always_inline void
 cpu_enable_pse(void)
 {
@@ -444,7 +470,7 @@ cpu_enable_pae(void)
 static inline int
 cpu_has_global_pages(void)
 {
-    return cpu_current()->features2 & CPU_FEATURE2_PGE;
+    return cpu_has_feature(cpu_current(), CPU_FEATURE_PGE);
 }
 
 /*
diff --git a/arch/x86/machine/cpu_i.h b/arch/x86/machine/cpu_i.h
index 66fe5f51..d3cc4a38 100644
--- a/arch/x86/machine/cpu_i.h
+++ b/arch/x86/machine/cpu_i.h
@@ -47,8 +47,11 @@
 #ifndef __ASSEMBLER__
 
 #include <stdalign.h>
+#include <stdbool.h>
 #include <stdint.h>
 
+#include <kern/bitmap.h>
+
 struct cpu_tss {
 #ifdef __LP64__
     uint32_t reserved0;
@@ -108,6 +111,10 @@ struct cpu_gdt {
 #define CPU_VENDOR_ID_SIZE  13
 #define CPU_MODEL_NAME_SIZE 49
 
+struct cpu_feature_map {
+    BITMAP_DECLARE(flags, CPU_NR_FEATURES);
+};
+
 struct cpu {
     unsigned int id;
     unsigned int apic_id;
@@ -122,10 +129,7 @@ struct cpu {
     unsigned int stepping;
     unsigned int clflush_size;
     unsigned int initial_apic_id;
-    unsigned int features1; // TODO Use a struct bitmap
-    unsigned int features2;
-    unsigned int features3;
-    unsigned int features4;
+    struct cpu_feature_map feature_map;
     unsigned short phys_addr_width;
     unsigned short virt_addr_width;
 
@@ -163,6 +167,13 @@ struct cpu {
  */
 extern void *cpu_local_area;
 
+static inline bool
+cpu_feature_map_test(const struct cpu_feature_map *map,
+                     enum cpu_feature feature)
+{
+    return bitmap_test(map->flags, feature);
+}
+
 /*
  * Return the content of the EFLAGS register.
  *
diff --git a/arch/x86/machine/pmap.c b/arch/x86/machine/pmap.c
index 73c31ca4..f77c6aa5 100644
--- a/arch/x86/machine/pmap.c
+++ b/arch/x86/machine/pmap.c
@@ -342,17 +342,17 @@ pmap_boot_get_pgsize(void)
     unsigned int eax, ebx, ecx, edx;
 
 #ifdef __LP64__
-    eax = 0x80000000;
+    eax = CPU_CPUID_EXT_BIT;
     cpu_cpuid(&eax, &ebx, &ecx, &edx);
 
-    if (eax <= 0x80000000) {
+    if (eax <= CPU_CPUID_EXT_BIT) {
         goto out;
     }
 
-    eax = 0x80000001;
+    eax = (CPU_CPUID_EXT_BIT | 1);
     cpu_cpuid(&eax, &ebx, &ecx, &edx);
 
-    if (edx & CPU_FEATURE4_1GP) {
+    if (edx & CPU_CPUID_EXT1_EDX_1GP) {
         return (1 << PMAP_L2_SKIP);
     }
 
@@ -370,13 +370,13 @@ out:
     cpu_cpuid(&eax, &ebx, &ecx, &edx);
 
 #ifdef CONFIG_X86_PAE
-    if (!(edx & CPU_FEATURE2_PAE)) {
+    if (!(edx & CPU_CPUID_BASIC1_EDX_PAE)) {
         boot_panic(pmap_panic_no_pae);
     }
 
     return (1 << PMAP_L1_SKIP);
 #else /* CONFIG_X86_PAE */
-    if (edx & CPU_FEATURE2_PSE) {
+    if (edx & CPU_CPUID_BASIC1_EDX_PSE) {
         return (1 << PMAP_L1_SKIP);
     }
 #endif /* CONFIG_X86_PAE */