[cpuid] Provide cpuid_supported() to test for supported functions

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/arch/x86/core/cpuid.c b/src/arch/x86/core/cpuid.c
index bc5a6c68c21842855891364b04e81565e6951921..864c1035d824fc2c632f7fa26ab7954db6491d2b 100644 (file)
--- a/src/arch/x86/core/cpuid.c
+++ b/src/arch/x86/core/cpuid.c
@@ -24,6 +24,7 @@
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 #include <string.h>
+#include <errno.h>
 #include <ipxe/cpuid.h>
 
 /** @file
@@ -32,15 +33,19 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  */
 
+/** Colour for debug messages */
+#define colour 0x861d
+
 /**
  * Check whether or not CPUID instruction is supported
  *
- * @ret is_supported   CPUID instruction is supported
+ * @ret rc             Return status code
  */
-int cpuid_is_supported ( void ) {
+static int cpuid_instruction_supported ( void ) {
        unsigned long original;
        unsigned long inverted;
 
+       /* Check for instruction existence via flag modifiability */
        __asm__ ( "pushf\n\t"
                  "pushf\n\t"
                  "pop %0\n\t"
@@ -53,7 +58,54 @@ int cpuid_is_supported ( void ) {
                  "popf\n\t"
                  : "=&r" ( original ), "=&r" ( inverted )
                  : "ir" ( CPUID_FLAG ) );
-       return ( ( original ^ inverted ) & CPUID_FLAG );
+       if ( ! ( ( original ^ inverted ) & CPUID_FLAG ) ) {
+               DBGC ( colour, "CPUID instruction is not supported\n" );
+               return -ENOTSUP;
+       }
+
+       return 0;
+}
+
+/**
+ * Check whether or not CPUID function is supported
+ *
+ * @v function         CPUID function
+ * @ret rc             Return status code
+ */
+int cpuid_supported ( uint32_t function ) {
+       uint32_t max_function;
+       uint32_t discard_b;
+       uint32_t discard_c;
+       uint32_t discard_d;
+       int rc;
+
+       /* Check that CPUID instruction is available */
+       if ( ( rc = cpuid_instruction_supported() ) != 0 )
+               return rc;
+
+       /* Find highest supported function number within this family */
+       cpuid ( ( function & CPUID_EXTENDED ), &max_function, &discard_b,
+               &discard_c, &discard_d );
+
+       /* Fail if maximum function number is meaningless (e.g. if we
+        * are attempting to call an extended function on a CPU which
+        * does not support them).
+        */
+       if ( ( max_function & CPUID_AMD_CHECK_MASK ) !=
+            ( function & CPUID_AMD_CHECK_MASK ) ) {
+               DBGC ( colour, "CPUID invalid maximum function %#08x\n",
+                      max_function );
+               return -EINVAL;
+       }
+
+       /* Fail if this function is not supported */
+       if ( function > max_function ) {
+               DBGC ( colour, "CPUID function %#08x not supported\n",
+                      function );
+               return -ENOTTY;
+       }
+
+       return 0;
 }
 
 /**
@@ -62,18 +114,13 @@ int cpuid_is_supported ( void ) {
  * @v features         x86 CPU features to fill in
  */
 static void x86_intel_features ( struct x86_features *features ) {
-       uint32_t max_level;
        uint32_t discard_a;
        uint32_t discard_b;
-       uint32_t discard_c;
-       uint32_t discard_d;
+       int rc;
 
        /* Check that features are available via CPUID */
-       cpuid ( CPUID_VENDOR_ID, &max_level, &discard_b, &discard_c,
-               &discard_d );
-       if ( max_level < CPUID_FEATURES ) {
-               DBGC ( features, "CPUID has no Intel-defined features (max "
-                      "level %08x)\n", max_level );
+       if ( ( rc = cpuid_supported ( CPUID_FEATURES ) ) != 0 ) {
+               DBGC ( features, "CPUID has no Intel-defined features\n" );
                return;
        }
 
@@ -91,22 +138,13 @@ static void x86_intel_features ( struct x86_features *features ) {
  * @v features         x86 CPU features to fill in
  */
 static void x86_amd_features ( struct x86_features *features ) {
-       uint32_t max_level;
        uint32_t discard_a;
        uint32_t discard_b;
-       uint32_t discard_c;
-       uint32_t discard_d;
+       int rc;
 
        /* Check that features are available via CPUID */
-       cpuid ( CPUID_AMD_MAX_FN, &max_level, &discard_b, &discard_c,
-               &discard_d );
-       if ( ( max_level & CPUID_AMD_CHECK_MASK ) != CPUID_AMD_CHECK ) {
-               DBGC ( features, "CPUID has no extended functions\n" );
-               return;
-       }
-       if ( max_level < CPUID_AMD_FEATURES ) {
-               DBGC ( features, "CPUID has no AMD-defined features (max "
-                      "level %08x)\n", max_level );
+       if ( ( rc = cpuid_supported ( CPUID_AMD_FEATURES ) ) != 0 ) {
+               DBGC ( features, "CPUID has no AMD-defined features\n" );
                return;
        }
 
@@ -127,12 +165,6 @@ void x86_features ( struct x86_features *features ) {
        /* Clear all features */
        memset ( features, 0, sizeof ( *features ) );
 
-       /* Check that CPUID instruction is available */
-       if ( ! cpuid_is_supported() ) {
-               DBGC ( features, "CPUID instruction is not supported\n" );
-               return;
-       }
-
        /* Get Intel-defined features */
        x86_intel_features ( features );
 

diff --git a/src/arch/x86/core/cpuid_settings.c b/src/arch/x86/core/cpuid_settings.c
index 08bd3918a454fff29c2792e7f40f46a82c3c3bf6..306dbefb86d1fcfebcc80316ce7633d76ba52025 100644 (file)
--- a/src/arch/x86/core/cpuid_settings.c
+++ b/src/arch/x86/core/cpuid_settings.c
@@ -149,48 +149,25 @@ static int cpuid_settings_fetch ( struct settings *settings,
                                  struct setting *setting,
                                  void *data, size_t len ) {
        uint32_t function;
-       uint32_t max_function;
        uint32_t num_functions;
        uint32_t registers;
        uint32_t num_registers;
        uint32_t buf[4];
        uint32_t output;
-       uint32_t discard_b;
-       uint32_t discard_c;
-       uint32_t discard_d;
        size_t frag_len;
        size_t result_len = 0;
-
-       /* Fail unless CPUID is supported */
-       if ( ! cpuid_is_supported() ) {
-               DBGC ( settings, "CPUID not supported\n" );
-               return -ENOTSUP;
-       }
-
-       /* Find highest supported function number within this set */
-       function = CPUID_FUNCTION ( setting->tag );
-       cpuid ( function & CPUID_EXTENDED, &max_function, &discard_b,
-               &discard_c, &discard_d );
-
-       /* Fail if maximum function number is meaningless (e.g. if we
-        * are attempting to call an extended function on a CPU which
-        * does not support them).
-        */
-       if ( ( max_function & CPUID_AMD_CHECK_MASK ) !=
-            ( function & CPUID_AMD_CHECK_MASK ) ) {
-               DBGC ( settings, "CPUID invalid maximum function\n" );
-               return -ENOTSUP;
-       }
+       int rc;
 
        /* Call each function in turn */
+       function = CPUID_FUNCTION ( setting->tag );
        num_functions = CPUID_NUM_FUNCTIONS ( setting->tag );
        for ( ; num_functions-- ; function++ ) {
 
                /* Fail if this function is not supported */
-               if ( function > max_function ) {
-                       DBGC ( settings, "CPUID function %#08x not supported\n",
-                              function );
-                       return -ENOTSUP;
+               if ( ( rc = cpuid_supported ( function ) ) != 0 ) {
+                       DBGC ( settings, "CPUID function %#08x not supported: "
+                              "%s\n", function, strerror ( rc ) );
+                       return rc;
                }
 
                /* Issue CPUID */

diff --git a/src/arch/x86/include/bits/errfile.h b/src/arch/x86/include/bits/errfile.h
index f4816e62a2c4c8037ee7b3b6684d305130305eaf..105cdf5d29d83a6ac7e77ab962374bde9b31c16f 100644 (file)
--- a/src/arch/x86/include/bits/errfile.h
+++ b/src/arch/x86/include/bits/errfile.h
@@ -25,6 +25,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #define ERRFILE_gdbmach                ( ERRFILE_ARCH | ERRFILE_CORE | 0x000e0000 )
 #define ERRFILE_rtc_entropy    ( ERRFILE_ARCH | ERRFILE_CORE | 0x000f0000 )
 #define ERRFILE_acpipwr                ( ERRFILE_ARCH | ERRFILE_CORE | 0x00100000 )
+#define ERRFILE_cpuid          ( ERRFILE_ARCH | ERRFILE_CORE | 0x00110000 )
 
 #define ERRFILE_bootsector     ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00000000 )
 #define ERRFILE_bzimage               ( ERRFILE_ARCH | ERRFILE_IMAGE | 0x00010000 )

diff --git a/src/arch/x86/include/ipxe/cpuid.h b/src/arch/x86/include/ipxe/cpuid.h
index da85d0b882253dab2863f04eb4a4621f4e4b0114..2e2cc7c1ae713ae96a097e65fb75291783635e28 100644 (file)
--- a/src/arch/x86/include/ipxe/cpuid.h
+++ b/src/arch/x86/include/ipxe/cpuid.h
@@ -60,22 +60,22 @@ struct x86_features {
 /**
  * Issue CPUID instruction
  *
- * @v operation                CPUID operation
+ * @v function         CPUID function
  * @v eax              Output via %eax
  * @v ebx              Output via %ebx
  * @v ecx              Output via %ecx
  * @v edx              Output via %edx
  */
 static inline __attribute__ (( always_inline )) void
-cpuid ( uint32_t operation, uint32_t *eax, uint32_t *ebx, uint32_t *ecx,
+cpuid ( uint32_t function, uint32_t *eax, uint32_t *ebx, uint32_t *ecx,
        uint32_t *edx ) {
 
        __asm__ ( "cpuid"
                  : "=a" ( *eax ), "=b" ( *ebx ), "=c" ( *ecx ), "=d" ( *edx )
-                 : "0" ( operation ) );
+                 : "0" ( function ) );
 }
 
-extern int cpuid_is_supported ( void );
+extern int cpuid_supported ( uint32_t function );
 extern void x86_features ( struct x86_features *features );
 
 #endif /* _IPXE_CPUID_H */