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-rw-r--r--src/arch/x86/lib/cpu.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/src/arch/x86/lib/cpu.c b/src/arch/x86/lib/cpu.c
index 3732ae296e..aaa0a16185 100644
--- a/src/arch/x86/lib/cpu.c
+++ b/src/arch/x86/lib/cpu.c
@@ -131,6 +131,26 @@ static const char *cpu_vendor_name(int vendor)
return name;
}
+static int cpu_cpuid_extended_level(void)
+{
+ return cpuid_eax(0x80000000);
+}
+
+#define CPUID_FEATURE_PAE (1 << 6)
+#define CPUID_FEATURE_PSE36 (1 << 17)
+
+int cpu_phys_address_size(void)
+{
+ if (!(have_cpuid_p()))
+ return 32;
+
+ if (cpu_cpuid_extended_level() > 0x80000008)
+ return cpuid_eax(0x80000008) & 0xff;
+
+ if (cpuid_eax(1) & (CPUID_FEATURE_PAE | CPUID_FEATURE_PSE36))
+ return 36;
+ return 32;
+}
static void identify_cpu(struct device *cpu)
{
char vendor_name[16];