Initial import

1 files changed, 187 insertions, 0 deletions

diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
new file mode 100644
index 000000000..1fd7d5750
--- /dev/null
+++ b/arch/x86/boot/cpucheck.c
@@ -0,0 +1,187 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Check for obligatory CPU features and abort if the features are not
+ * present.  This code should be compilable as 16-, 32- or 64-bit
+ * code, so be very careful with types and inline assembly.
+ *
+ * This code should not contain any messages; that requires an
+ * additional wrapper.
+ *
+ * As written, this code is not safe for inclusion into the kernel
+ * proper (after FPU initialization, in particular).
+ */
+
+#ifdef _SETUP
+# include "boot.h"
+#endif
+#include <linux/types.h>
+#include <asm/processor-flags.h>
+#include <asm/required-features.h>
+#include <asm/msr-index.h>
+#include "string.h"
+
+static u32 err_flags[NCAPINTS];
+
+static const int req_level = CONFIG_X86_MINIMUM_CPU_FAMILY;
+
+static const u32 req_flags[NCAPINTS] =
+{
+	REQUIRED_MASK0,
+	REQUIRED_MASK1,
+	0, /* REQUIRED_MASK2 not implemented in this file */
+	0, /* REQUIRED_MASK3 not implemented in this file */
+	REQUIRED_MASK4,
+	0, /* REQUIRED_MASK5 not implemented in this file */
+	REQUIRED_MASK6,
+	0, /* REQUIRED_MASK7 not implemented in this file */
+};
+
+#define A32(a, b, c, d) (((d) << 24)+((c) << 16)+((b) << 8)+(a))
+
+static int is_amd(void)
+{
+	return cpu_vendor[0] == A32('A', 'u', 't', 'h') &&
+	       cpu_vendor[1] == A32('e', 'n', 't', 'i') &&
+	       cpu_vendor[2] == A32('c', 'A', 'M', 'D');
+}
+
+static int is_centaur(void)
+{
+	return cpu_vendor[0] == A32('C', 'e', 'n', 't') &&
+	       cpu_vendor[1] == A32('a', 'u', 'r', 'H') &&
+	       cpu_vendor[2] == A32('a', 'u', 'l', 's');
+}
+
+static int is_transmeta(void)
+{
+	return cpu_vendor[0] == A32('G', 'e', 'n', 'u') &&
+	       cpu_vendor[1] == A32('i', 'n', 'e', 'T') &&
+	       cpu_vendor[2] == A32('M', 'x', '8', '6');
+}
+
+static int is_intel(void)
+{
+	return cpu_vendor[0] == A32('G', 'e', 'n', 'u') &&
+	       cpu_vendor[1] == A32('i', 'n', 'e', 'I') &&
+	       cpu_vendor[2] == A32('n', 't', 'e', 'l');
+}
+
+/* Returns a bitmask of which words we have error bits in */
+static int check_cpuflags(void)
+{
+	u32 err;
+	int i;
+
+	err = 0;
+	for (i = 0; i < NCAPINTS; i++) {
+		err_flags[i] = req_flags[i] & ~cpu.flags[i];
+		if (err_flags[i])
+			err |= 1 << i;
+	}
+
+	return err;
+}
+
+/*
+ * Returns -1 on error.
+ *
+ * *cpu_level is set to the current CPU level; *req_level to the required
+ * level.  x86-64 is considered level 64 for this purpose.
+ *
+ * *err_flags_ptr is set to the flags error array if there are flags missing.
+ */
+int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr)
+{
+	int err;
+
+	memset(&cpu.flags, 0, sizeof cpu.flags);
+	cpu.level = 3;
+
+	if (has_eflag(X86_EFLAGS_AC))
+		cpu.level = 4;
+
+	get_cpuflags();
+	err = check_cpuflags();
+
+	if (test_bit(X86_FEATURE_LM, cpu.flags))
+		cpu.level = 64;
+
+	if (err == 0x01 &&
+	    !(err_flags[0] &
+	      ~((1 << X86_FEATURE_XMM)|(1 << X86_FEATURE_XMM2))) &&
+	    is_amd()) {
+		/* If this is an AMD and we're only missing SSE+SSE2, try to
+		   turn them on */
+
+		u32 ecx = MSR_K7_HWCR;
+		u32 eax, edx;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		eax &= ~(1 << 15);
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		get_cpuflags();	/* Make sure it really did something */
+		err = check_cpuflags();
+	} else if (err == 0x01 &&
+		   !(err_flags[0] & ~(1 << X86_FEATURE_CX8)) &&
+		   is_centaur() && cpu.model >= 6) {
+		/* If this is a VIA C3, we might have to enable CX8
+		   explicitly */
+
+		u32 ecx = MSR_VIA_FCR;
+		u32 eax, edx;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		eax |= (1<<1)|(1<<7);
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		set_bit(X86_FEATURE_CX8, cpu.flags);
+		err = check_cpuflags();
+	} else if (err == 0x01 && is_transmeta()) {
+		/* Transmeta might have masked feature bits in word 0 */
+
+		u32 ecx = 0x80860004;
+		u32 eax, edx;
+		u32 level = 1;
+
+		asm("rdmsr" : "=a" (eax), "=d" (edx) : "c" (ecx));
+		asm("wrmsr" : : "a" (~0), "d" (edx), "c" (ecx));
+		asm("cpuid"
+		    : "+a" (level), "=d" (cpu.flags[0])
+		    : : "ecx", "ebx");
+		asm("wrmsr" : : "a" (eax), "d" (edx), "c" (ecx));
+
+		err = check_cpuflags();
+	} else if (err == 0x01 &&
+		   !(err_flags[0] & ~(1 << X86_FEATURE_PAE)) &&
+		   is_intel() && cpu.level == 6 &&
+		   (cpu.model == 9 || cpu.model == 13)) {
+		/* PAE is disabled on this Pentium M but can be forced */
+		if (cmdline_find_option_bool("forcepae")) {
+			puts("WARNING: Forcing PAE in CPU flags\n");
+			set_bit(X86_FEATURE_PAE, cpu.flags);
+			err = check_cpuflags();
+		}
+		else {
+			puts("WARNING: PAE disabled. Use parameter 'forcepae' to enable at your own risk!\n");
+		}
+	}
+
+	if (err_flags_ptr)
+		*err_flags_ptr = err ? err_flags : NULL;
+	if (cpu_level_ptr)
+		*cpu_level_ptr = cpu.level;
+	if (req_level_ptr)
+		*req_level_ptr = req_level;
+
+	return (cpu.level < req_level || err) ? -1 : 0;
+}