linux/arch/x86/kernel/microcode_core_early.c
H. Peter Anvin 74c3e3fcf3 x86, microcode: Verify the family before dispatching microcode patching
For each CPU vendor that implements CPU microcode patching, there will
be a minimum family for which this is implemented.  Verify this
minimum level of support.

This can be done in the dispatch function or early in the application
functions.  Doing the latter turned out to be somewhat awkward because
of the ineviable split between the BSP and the AP paths, and rather
than pushing deep into the application functions, do this in
the dispatch function.

Reported-by: "Bryan O'Donoghue" <bryan.odonoghue.lkml@nexus-software.ie>
Suggested-by: Borislav Petkov <bp@alien8.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1366392183-4149-1-git-send-email-bryan.odonoghue.lkml@nexus-software.ie
2013-04-19 16:36:03 -07:00

101 lines
2.5 KiB
C

/*
* X86 CPU microcode early update for Linux
*
* Copyright (C) 2012 Fenghua Yu <fenghua.yu@intel.com>
* H Peter Anvin" <hpa@zytor.com>
*
* This driver allows to early upgrade microcode on Intel processors
* belonging to IA-32 family - PentiumPro, Pentium II,
* Pentium III, Xeon, Pentium 4, etc.
*
* Reference: Section 9.11 of Volume 3, IA-32 Intel Architecture
* Software Developer's Manual.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <asm/microcode_intel.h>
#include <asm/processor.h>
#define QCHAR(a, b, c, d) ((a) + ((b) << 8) + ((c) << 16) + ((d) << 24))
#define CPUID_INTEL1 QCHAR('G', 'e', 'n', 'u')
#define CPUID_INTEL2 QCHAR('i', 'n', 'e', 'I')
#define CPUID_INTEL3 QCHAR('n', 't', 'e', 'l')
#define CPUID_AMD1 QCHAR('A', 'u', 't', 'h')
#define CPUID_AMD2 QCHAR('e', 'n', 't', 'i')
#define CPUID_AMD3 QCHAR('c', 'A', 'M', 'D')
#define CPUID_IS(a, b, c, ebx, ecx, edx) \
(!((ebx ^ (a))|(edx ^ (b))|(ecx ^ (c))))
/*
* In early loading microcode phase on BSP, boot_cpu_data is not set up yet.
* x86_vendor() gets vendor id for BSP.
*
* In 32 bit AP case, accessing boot_cpu_data needs linear address. To simplify
* coding, we still use x86_vendor() to get vendor id for AP.
*
* x86_vendor() gets vendor information directly through cpuid.
*/
static int __cpuinit x86_vendor(void)
{
u32 eax = 0x00000000;
u32 ebx, ecx = 0, edx;
native_cpuid(&eax, &ebx, &ecx, &edx);
if (CPUID_IS(CPUID_INTEL1, CPUID_INTEL2, CPUID_INTEL3, ebx, ecx, edx))
return X86_VENDOR_INTEL;
if (CPUID_IS(CPUID_AMD1, CPUID_AMD2, CPUID_AMD3, ebx, ecx, edx))
return X86_VENDOR_AMD;
return X86_VENDOR_UNKNOWN;
}
static int __cpuinit x86_family(void)
{
u32 eax = 0x00000001;
u32 ebx, ecx = 0, edx;
int x86;
native_cpuid(&eax, &ebx, &ecx, &edx);
x86 = (eax >> 8) & 0xf;
if (x86 == 15)
x86 += (eax >> 20) & 0xff;
return x86;
}
void __init load_ucode_bsp(void)
{
int vendor, x86;
if (!have_cpuid_p())
return;
vendor = x86_vendor();
x86 = x86_family();
if (vendor == X86_VENDOR_INTEL && x86 >= 6)
load_ucode_intel_bsp();
}
void __cpuinit load_ucode_ap(void)
{
int vendor, x86;
if (!have_cpuid_p())
return;
vendor = x86_vendor();
x86 = x86_family();
if (vendor == X86_VENDOR_INTEL && x86 >= 6)
load_ucode_intel_ap();
}