1 files changed, 210 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpuid/api.h b/arch/x86/include/asm/cpuid/api.h
new file mode 100644
index 000000000000..9c180c9cc58e
--- /dev/null
+++ b/arch/x86/include/asm/cpuid/api.h
@@ -0,0 +1,210 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_CPUID_API_H
+#define _ASM_X86_CPUID_API_H
+
+#include <asm/cpuid/types.h>
+
+#include <linux/build_bug.h>
+#include <linux/types.h>
+
+#include <asm/string.h>
+
+/*
+ * Raw CPUID accessors:
+ */
+
+#ifdef CONFIG_X86_32
+bool have_cpuid_p(void);
+#else
+static inline bool have_cpuid_p(void)
+{
+	return true;
+}
+#endif
+
+static inline void native_cpuid(u32 *eax, u32 *ebx,
+				u32 *ecx, u32 *edx)
+{
+	/* ecx is often an input as well as an output. */
+	asm volatile("cpuid"
+	    : "=a" (*eax),
+	      "=b" (*ebx),
+	      "=c" (*ecx),
+	      "=d" (*edx)
+	    : "0" (*eax), "2" (*ecx)
+	    : "memory");
+}
+
+#define NATIVE_CPUID_REG(reg)					\
+static inline u32 native_cpuid_##reg(u32 op)	\
+{								\
+	u32 eax = op, ebx, ecx = 0, edx;		\
+								\
+	native_cpuid(&eax, &ebx, &ecx, &edx);			\
+								\
+	return reg;						\
+}
+
+/*
+ * Native CPUID functions returning a single datum:
+ */
+NATIVE_CPUID_REG(eax)
+NATIVE_CPUID_REG(ebx)
+NATIVE_CPUID_REG(ecx)
+NATIVE_CPUID_REG(edx)
+
+#ifdef CONFIG_PARAVIRT_XXL
+# include <asm/paravirt.h>
+#else
+# define __cpuid native_cpuid
+#endif
+
+/*
+ * Generic CPUID function
+ *
+ * Clear ECX since some CPUs (Cyrix MII) do not set or clear ECX
+ * resulting in stale register contents being returned.
+ */
+static inline void cpuid(u32 op,
+			 u32 *eax, u32 *ebx,
+			 u32 *ecx, u32 *edx)
+{
+	*eax = op;
+	*ecx = 0;
+	__cpuid(eax, ebx, ecx, edx);
+}
+
+/* Some CPUID calls want 'count' to be placed in ECX */
+static inline void cpuid_count(u32 op, int count,
+			       u32 *eax, u32 *ebx,
+			       u32 *ecx, u32 *edx)
+{
+	*eax = op;
+	*ecx = count;
+	__cpuid(eax, ebx, ecx, edx);
+}
+
+/*
+ * CPUID functions returning a single datum:
+ */
+
+static inline u32 cpuid_eax(u32 op)
+{
+	u32 eax, ebx, ecx, edx;
+
+	cpuid(op, &eax, &ebx, &ecx, &edx);
+
+	return eax;
+}
+
+static inline u32 cpuid_ebx(u32 op)
+{
+	u32 eax, ebx, ecx, edx;
+
+	cpuid(op, &eax, &ebx, &ecx, &edx);
+
+	return ebx;
+}
+
+static inline u32 cpuid_ecx(u32 op)
+{
+	u32 eax, ebx, ecx, edx;
+
+	cpuid(op, &eax, &ebx, &ecx, &edx);
+
+	return ecx;
+}
+
+static inline u32 cpuid_edx(u32 op)
+{
+	u32 eax, ebx, ecx, edx;
+
+	cpuid(op, &eax, &ebx, &ecx, &edx);
+
+	return edx;
+}
+
+static inline void __cpuid_read(u32 leaf, u32 subleaf, u32 *regs)
+{
+	regs[CPUID_EAX] = leaf;
+	regs[CPUID_ECX] = subleaf;
+	__cpuid(regs + CPUID_EAX, regs + CPUID_EBX, regs + CPUID_ECX, regs + CPUID_EDX);
+}
+
+#define cpuid_subleaf(leaf, subleaf, regs) {		\
+	static_assert(sizeof(*(regs)) == 16);		\
+	__cpuid_read(leaf, subleaf, (u32 *)(regs));	\
+}
+
+#define cpuid_leaf(leaf, regs) {			\
+	static_assert(sizeof(*(regs)) == 16);		\
+	__cpuid_read(leaf, 0, (u32 *)(regs));		\
+}
+
+static inline void __cpuid_read_reg(u32 leaf, u32 subleaf,
+				    enum cpuid_regs_idx regidx, u32 *reg)
+{
+	u32 regs[4];
+
+	__cpuid_read(leaf, subleaf, regs);
+	*reg = regs[regidx];
+}
+
+#define cpuid_subleaf_reg(leaf, subleaf, regidx, reg) {		\
+	static_assert(sizeof(*(reg)) == 4);			\
+	__cpuid_read_reg(leaf, subleaf, regidx, (u32 *)(reg));	\
+}
+
+#define cpuid_leaf_reg(leaf, regidx, reg) {			\
+	static_assert(sizeof(*(reg)) == 4);			\
+	__cpuid_read_reg(leaf, 0, regidx, (u32 *)(reg));	\
+}
+
+static __always_inline bool cpuid_function_is_indexed(u32 function)
+{
+	switch (function) {
+	case 4:
+	case 7:
+	case 0xb:
+	case 0xd:
+	case 0xf:
+	case 0x10:
+	case 0x12:
+	case 0x14:
+	case 0x17:
+	case 0x18:
+	case 0x1d:
+	case 0x1e:
+	case 0x1f:
+	case 0x24:
+	case 0x8000001d:
+		return true;
+	}
+
+	return false;
+}
+
+#define for_each_possible_hypervisor_cpuid_base(function) \
+	for (function = 0x40000000; function < 0x40010000; function += 0x100)
+
+static inline u32 hypervisor_cpuid_base(const char *sig, u32 leaves)
+{
+	u32 base, eax, signature[3];
+
+	for_each_possible_hypervisor_cpuid_base(base) {
+		cpuid(base, &eax, &signature[0], &signature[1], &signature[2]);
+
+		/*
+		 * This must not compile to "call memcmp" because it's called
+		 * from PVH early boot code before instrumentation is set up
+		 * and memcmp() itself may be instrumented.
+		 */
+		if (!__builtin_memcmp(sig, signature, 12) &&
+		    (leaves == 0 || ((eax - base) >= leaves)))
+			return base;
+	}
+
+	return 0;
+}
+
+#endif /* _ASM_X86_CPUID_API_H */