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-rw-r--r--arch/x86/boot/cpucheck.c227
1 files changed, 227 insertions, 0 deletions
diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
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+++ b/arch/x86/boot/cpucheck.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * 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/intel-family.h>
+#include <asm/processor-flags.h>
+#include <asm/required-features.h>
+#include <asm/msr-index.h>
+#include "string.h"
+#include "msr.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 */
+ 0, /* REQUIRED_MASK8 not implemented in this file */
+ 0, /* REQUIRED_MASK9 not implemented in this file */
+ 0, /* REQUIRED_MASK10 not implemented in this file */
+ 0, /* REQUIRED_MASK11 not implemented in this file */
+ 0, /* REQUIRED_MASK12 not implemented in this file */
+ 0, /* REQUIRED_MASK13 not implemented in this file */
+ 0, /* REQUIRED_MASK14 not implemented in this file */
+ 0, /* REQUIRED_MASK15 not implemented in this file */
+ REQUIRED_MASK16,
+};
+
+#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 */
+
+ struct msr m;
+
+ boot_rdmsr(MSR_K7_HWCR, &m);
+ m.l &= ~(1 << 15);
+ boot_wrmsr(MSR_K7_HWCR, &m);
+
+ 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 */
+
+ struct msr m;
+
+ boot_rdmsr(MSR_VIA_FCR, &m);
+ m.l |= (1 << 1) | (1 << 7);
+ boot_wrmsr(MSR_VIA_FCR, &m);
+
+ 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 */
+
+ struct msr m, m_tmp;
+ u32 level = 1;
+
+ boot_rdmsr(0x80860004, &m);
+ m_tmp = m;
+ m_tmp.l = ~0;
+ boot_wrmsr(0x80860004, &m_tmp);
+ asm("cpuid"
+ : "+a" (level), "=d" (cpu.flags[0])
+ : : "ecx", "ebx");
+ boot_wrmsr(0x80860004, &m);
+
+ 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)
+ err = check_knl_erratum();
+
+ 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;
+}
+
+int check_knl_erratum(void)
+{
+ /*
+ * First check for the affected model/family:
+ */
+ if (!is_intel() ||
+ cpu.family != 6 ||
+ cpu.model != INTEL_FAM6_XEON_PHI_KNL)
+ return 0;
+
+ /*
+ * This erratum affects the Accessed/Dirty bits, and can
+ * cause stray bits to be set in !Present PTEs. We have
+ * enough bits in our 64-bit PTEs (which we have on real
+ * 64-bit mode or PAE) to avoid using these troublesome
+ * bits. But, we do not have enough space in our 32-bit
+ * PTEs. So, refuse to run on 32-bit non-PAE kernels.
+ */
+ if (IS_ENABLED(CONFIG_X86_64) || IS_ENABLED(CONFIG_X86_PAE))
+ return 0;
+
+ puts("This 32-bit kernel can not run on this Xeon Phi x200\n"
+ "processor due to a processor erratum. Use a 64-bit\n"
+ "kernel, or enable PAE in this 32-bit kernel.\n\n");
+
+ return -1;
+}
+
+