x86-microcode: fix unbalanced use of get_cpu()

[mirror_ubuntu-bionic-kernel.git] / arch / x86 / kernel / microcode_intel.c

/*
 *	Intel CPU Microcode Update Driver for Linux
 *
 *	Copyright (C) 2000-2006 Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
 *		      2006	Shaohua Li <shaohua.li@intel.com>
 *
 *	This driver allows to upgrade microcode on Intel processors
 *	belonging to IA-32 family - PentiumPro, Pentium II,
 *	Pentium III, Xeon, Pentium 4, etc.
 *
 *	Reference: Section 8.11 of Volume 3a, IA-32 Intel? Architecture
 *	Software Developer's Manual
 *	Order Number 253668 or free download from:
 *
 *	http://developer.intel.com/design/pentium4/manuals/253668.htm
 *
 *	For more information, go to http://www.urbanmyth.org/microcode
 *
 *	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.
 *
 *	1.0	16 Feb 2000, Tigran Aivazian <tigran@sco.com>
 *		Initial release.
 *	1.01	18 Feb 2000, Tigran Aivazian <tigran@sco.com>
 *		Added read() support + cleanups.
 *	1.02	21 Feb 2000, Tigran Aivazian <tigran@sco.com>
 *		Added 'device trimming' support. open(O_WRONLY) zeroes
 *		and frees the saved copy of applied microcode.
 *	1.03	29 Feb 2000, Tigran Aivazian <tigran@sco.com>
 *		Made to use devfs (/dev/cpu/microcode) + cleanups.
 *	1.04	06 Jun 2000, Simon Trimmer <simon@veritas.com>
 *		Added misc device support (now uses both devfs and misc).
 *		Added MICROCODE_IOCFREE ioctl to clear memory.
 *	1.05	09 Jun 2000, Simon Trimmer <simon@veritas.com>
 *		Messages for error cases (non Intel & no suitable microcode).
 *	1.06	03 Aug 2000, Tigran Aivazian <tigran@veritas.com>
 *		Removed ->release(). Removed exclusive open and status bitmap.
 *		Added microcode_rwsem to serialize read()/write()/ioctl().
 *		Removed global kernel lock usage.
 *	1.07	07 Sep 2000, Tigran Aivazian <tigran@veritas.com>
 *		Write 0 to 0x8B msr and then cpuid before reading revision,
 *		so that it works even if there were no update done by the
 *		BIOS. Otherwise, reading from 0x8B gives junk (which happened
 *		to be 0 on my machine which is why it worked even when I
 *		disabled update by the BIOS)
 *		Thanks to Eric W. Biederman <ebiederman@lnxi.com> for the fix.
 *	1.08	11 Dec 2000, Richard Schaal <richard.schaal@intel.com> and
 *			     Tigran Aivazian <tigran@veritas.com>
 *		Intel Pentium 4 processor support and bugfixes.
 *	1.09	30 Oct 2001, Tigran Aivazian <tigran@veritas.com>
 *		Bugfix for HT (Hyper-Threading) enabled processors
 *		whereby processor resources are shared by all logical processors
 *		in a single CPU package.
 *	1.10	28 Feb 2002 Asit K Mallick <asit.k.mallick@intel.com> and
 *		Tigran Aivazian <tigran@veritas.com>,
 *		Serialize updates as required on HT processors due to
 *		speculative nature of implementation.
 *	1.11	22 Mar 2002 Tigran Aivazian <tigran@veritas.com>
 *		Fix the panic when writing zero-length microcode chunk.
 *	1.12	29 Sep 2003 Nitin Kamble <nitin.a.kamble@intel.com>,
 *		Jun Nakajima <jun.nakajima@intel.com>
 *		Support for the microcode updates in the new format.
 *	1.13	10 Oct 2003 Tigran Aivazian <tigran@veritas.com>
 *		Removed ->read() method and obsoleted MICROCODE_IOCFREE ioctl
 *		because we no longer hold a copy of applied microcode
 *		in kernel memory.
 *	1.14	25 Jun 2004 Tigran Aivazian <tigran@veritas.com>
 *		Fix sigmatch() macro to handle old CPUs with pf == 0.
 *		Thanks to Stuart Swales for pointing out this bug.
 */

/* #define DEBUG */ /* pr_debug */
#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/smp_lock.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/cpu.h>
#include <linux/firmware.h>
#include <linux/platform_device.h>

#include <asm/msr.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/microcode.h>

MODULE_DESCRIPTION("Microcode Update Driver");
MODULE_AUTHOR("Tigran Aivazian <tigran@aivazian.fsnet.co.uk>");
MODULE_LICENSE("GPL");

#define DEFAULT_UCODE_DATASIZE 	(2000)
#define MC_HEADER_SIZE		(sizeof(struct microcode_header_intel))
#define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
#define EXT_HEADER_SIZE		(sizeof(struct extended_sigtable))
#define EXT_SIGNATURE_SIZE	(sizeof(struct extended_signature))
#define DWSIZE			(sizeof(u32))
#define get_totalsize(mc) \
	(((struct microcode_intel *)mc)->hdr.totalsize ? \
	 ((struct microcode_intel *)mc)->hdr.totalsize : \
	 DEFAULT_UCODE_TOTALSIZE)

#define get_datasize(mc) \
	(((struct microcode_intel *)mc)->hdr.datasize ? \
	 ((struct microcode_intel *)mc)->hdr.datasize : DEFAULT_UCODE_DATASIZE)

#define sigmatch(s1, s2, p1, p2) \
	(((s1) == (s2)) && (((p1) & (p2)) || (((p1) == 0) && ((p2) == 0))))

#define exttable_size(et) ((et)->count * EXT_SIGNATURE_SIZE + EXT_HEADER_SIZE)

/* serialize access to the physical write to MSR 0x79 */
static DEFINE_SPINLOCK(microcode_update_lock);

/* no concurrent ->write()s are allowed on /dev/cpu/microcode */
extern struct mutex microcode_mutex;

extern struct ucode_cpu_info ucode_cpu_info[NR_CPUS];

static void collect_cpu_info(int cpu_num)
{
	struct cpuinfo_x86 *c = &cpu_data(cpu_num);
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;
	unsigned int val[2];

	/* We should bind the task to the CPU */
	BUG_ON(raw_smp_processor_id() != cpu_num);
	uci->pf = uci->rev = 0;
	uci->mc.mc_intel = NULL;
	uci->valid = 1;

	if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
	    cpu_has(c, X86_FEATURE_IA64)) {
		printk(KERN_ERR "microcode: CPU%d not a capable Intel "
			"processor\n", cpu_num);
		uci->valid = 0;
		return;
	}

	uci->sig = cpuid_eax(0x00000001);

	if ((c->x86_model >= 5) || (c->x86 > 6)) {
		/* get processor flags from MSR 0x17 */
		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
		uci->pf = 1 << ((val[1] >> 18) & 7);
	}

	wrmsr(MSR_IA32_UCODE_REV, 0, 0);
	/* see notes above for revision 1.07.  Apparent chip bug */
	sync_core();
	/* get the current revision from MSR 0x8B */
	rdmsr(MSR_IA32_UCODE_REV, val[0], uci->rev);
	pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
			uci->sig, uci->pf, uci->rev);
}

static inline int microcode_update_match(int cpu_num,
	struct microcode_header_intel *mc_header, int sig, int pf)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;

	if (!sigmatch(sig, uci->sig, pf, uci->pf)
		|| mc_header->rev <= uci->rev)
		return 0;
	return 1;
}

static int microcode_sanity_check(void *mc)
{
	struct microcode_header_intel *mc_header = mc;
	struct extended_sigtable *ext_header = NULL;
	struct extended_signature *ext_sig;
	unsigned long total_size, data_size, ext_table_size;
	int sum, orig_sum, ext_sigcount = 0, i;

	total_size = get_totalsize(mc_header);
	data_size = get_datasize(mc_header);
	if (data_size + MC_HEADER_SIZE > total_size) {
		printk(KERN_ERR "microcode: error! "
			"Bad data size in microcode data file\n");
		return -EINVAL;
	}

	if (mc_header->ldrver != 1 || mc_header->hdrver != 1) {
		printk(KERN_ERR "microcode: error! "
			"Unknown microcode update format\n");
		return -EINVAL;
	}
	ext_table_size = total_size - (MC_HEADER_SIZE + data_size);
	if (ext_table_size) {
		if ((ext_table_size < EXT_HEADER_SIZE)
		 || ((ext_table_size - EXT_HEADER_SIZE) % EXT_SIGNATURE_SIZE)) {
			printk(KERN_ERR "microcode: error! "
				"Small exttable size in microcode data file\n");
			return -EINVAL;
		}
		ext_header = mc + MC_HEADER_SIZE + data_size;
		if (ext_table_size != exttable_size(ext_header)) {
			printk(KERN_ERR "microcode: error! "
				"Bad exttable size in microcode data file\n");
			return -EFAULT;
		}
		ext_sigcount = ext_header->count;
	}

	/* check extended table checksum */
	if (ext_table_size) {
		int ext_table_sum = 0;
		int *ext_tablep = (int *)ext_header;

		i = ext_table_size / DWSIZE;
		while (i--)
			ext_table_sum += ext_tablep[i];
		if (ext_table_sum) {
			printk(KERN_WARNING "microcode: aborting, "
				"bad extended signature table checksum\n");
			return -EINVAL;
		}
	}

	/* calculate the checksum */
	orig_sum = 0;
	i = (MC_HEADER_SIZE + data_size) / DWSIZE;
	while (i--)
		orig_sum += ((int *)mc)[i];
	if (orig_sum) {
		printk(KERN_ERR "microcode: aborting, bad checksum\n");
		return -EINVAL;
	}
	if (!ext_table_size)
		return 0;
	/* check extended signature checksum */
	for (i = 0; i < ext_sigcount; i++) {
		ext_sig = (void *)ext_header + EXT_HEADER_SIZE +
			  EXT_SIGNATURE_SIZE * i;
		sum = orig_sum
			- (mc_header->sig + mc_header->pf + mc_header->cksum)
			+ (ext_sig->sig + ext_sig->pf + ext_sig->cksum);
		if (sum) {
			printk(KERN_ERR "microcode: aborting, bad checksum\n");
			return -EINVAL;
		}
	}
	return 0;
}

/*
 * return 0 - no update found
 * return 1 - found update
 * return < 0 - error
 */
static int get_matching_microcode(void *mc, int cpu)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	struct microcode_header_intel *mc_header = mc;
	struct extended_sigtable *ext_header;
	unsigned long total_size = get_totalsize(mc_header);
	int ext_sigcount, i;
	struct extended_signature *ext_sig;
	void *new_mc;

	if (microcode_update_match(cpu, mc_header,
			mc_header->sig, mc_header->pf))
		goto find;

	if (total_size <= get_datasize(mc_header) + MC_HEADER_SIZE)
		return 0;

	ext_header = mc + get_datasize(mc_header) + MC_HEADER_SIZE;
	ext_sigcount = ext_header->count;
	ext_sig = (void *)ext_header + EXT_HEADER_SIZE;
	for (i = 0; i < ext_sigcount; i++) {
		if (microcode_update_match(cpu, mc_header,
				ext_sig->sig, ext_sig->pf))
			goto find;
		ext_sig++;
	}
	return 0;
find:
	pr_debug("microcode: CPU%d found a matching microcode update with"
		 " version 0x%x (current=0x%x)\n",
		 cpu, mc_header->rev, uci->rev);
	new_mc = vmalloc(total_size);
	if (!new_mc) {
		printk(KERN_ERR "microcode: error! Can not allocate memory\n");
		return -ENOMEM;
	}

	/* free previous update file */
	vfree(uci->mc.mc_intel);

	memcpy(new_mc, mc, total_size);
	uci->mc.mc_intel = new_mc;
	return 1;
}

static void apply_microcode(int cpu)
{
	unsigned long flags;
	unsigned int val[2];
	int cpu_num = raw_smp_processor_id();
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu_num;

	/* We should bind the task to the CPU */
	BUG_ON(cpu_num != cpu);

	if (uci->mc.mc_intel == NULL)
		return;

	/* serialize access to the physical write to MSR 0x79 */
	spin_lock_irqsave(&microcode_update_lock, flags);

	/* write microcode via MSR 0x79 */
	wrmsr(MSR_IA32_UCODE_WRITE,
	      (unsigned long) uci->mc.mc_intel->bits,
	      (unsigned long) uci->mc.mc_intel->bits >> 16 >> 16);
	wrmsr(MSR_IA32_UCODE_REV, 0, 0);

	/* see notes above for revision 1.07.  Apparent chip bug */
	sync_core();

	/* get the current revision from MSR 0x8B */
	rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);

	spin_unlock_irqrestore(&microcode_update_lock, flags);
	if (val[1] != uci->mc.mc_intel->hdr.rev) {
		printk(KERN_ERR "microcode: CPU%d update from revision "
			"0x%x to 0x%x failed\n", cpu_num, uci->rev, val[1]);
		return;
	}
	printk(KERN_INFO "microcode: CPU%d updated from revision "
	       "0x%x to 0x%x, date = %04x-%02x-%02x \n",
		cpu_num, uci->rev, val[1],
		uci->mc.mc_intel->hdr.date & 0xffff,
		uci->mc.mc_intel->hdr.date >> 24,
		(uci->mc.mc_intel->hdr.date >> 16) & 0xff);
	uci->rev = val[1];
}

#ifdef CONFIG_MICROCODE_OLD_INTERFACE
extern void __user *user_buffer;        /* user area microcode data buffer */
extern unsigned int user_buffer_size;   /* it's size */

static long get_next_ucode(void **mc, long offset)
{
	struct microcode_header_intel mc_header;
	unsigned long total_size;

	/* No more data */
	if (offset >= user_buffer_size)
		return 0;
	if (copy_from_user(&mc_header, user_buffer + offset, MC_HEADER_SIZE)) {
		printk(KERN_ERR "microcode: error! Can not read user data\n");
		return -EFAULT;
	}
	total_size = get_totalsize(&mc_header);
	if (offset + total_size > user_buffer_size) {
		printk(KERN_ERR "microcode: error! Bad total size in microcode "
				"data file\n");
		return -EINVAL;
	}
	*mc = vmalloc(total_size);
	if (!*mc)
		return -ENOMEM;
	if (copy_from_user(*mc, user_buffer + offset, total_size)) {
		printk(KERN_ERR "microcode: error! Can not read user data\n");
		vfree(*mc);
		return -EFAULT;
	}
	return offset + total_size;
}
#endif

static long get_next_ucode_from_buffer(void **mc, const u8 *buf,
	unsigned long size, long offset)
{
	struct microcode_header_intel *mc_header;
	unsigned long total_size;

	/* No more data */
	if (offset >= size)
		return 0;
	mc_header = (struct microcode_header_intel *)(buf + offset);
	total_size = get_totalsize(mc_header);

	if (offset + total_size > size) {
		printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
		return -EINVAL;
	}

	*mc = vmalloc(total_size);
	if (!*mc) {
		printk(KERN_ERR "microcode: error! Can not allocate memory\n");
		return -ENOMEM;
	}
	memcpy(*mc, buf + offset, total_size);
	return offset + total_size;
}

/* fake device for request_firmware */
extern struct platform_device *microcode_pdev;

static int cpu_request_microcode(int cpu)
{
	char name[30];
	struct cpuinfo_x86 *c = &cpu_data(cpu);
	const struct firmware *firmware;
	const u8 *buf;
	unsigned long size;
	long offset = 0;
	int error;
	void *mc;

	/* We should bind the task to the CPU */
	BUG_ON(cpu != raw_smp_processor_id());
	sprintf(name, "intel-ucode/%02x-%02x-%02x",
		c->x86, c->x86_model, c->x86_mask);
	error = request_firmware(&firmware, name, &microcode_pdev->dev);
	if (error) {
		pr_debug("microcode: data file %s load failed\n", name);
		return error;
	}
	buf = firmware->data;
	size = firmware->size;
	while ((offset = get_next_ucode_from_buffer(&mc, buf, size, offset))
			> 0) {
		error = microcode_sanity_check(mc);
		if (error)
			break;
		error = get_matching_microcode(mc, cpu);
		if (error < 0)
			break;
		/*
		 * It's possible the data file has multiple matching ucode,
		 * lets keep searching till the latest version
		 */
		if (error == 1) {
			apply_microcode(cpu);
			error = 0;
		}
		vfree(mc);
	}
	if (offset > 0)
		vfree(mc);
	if (offset < 0)
		error = offset;
	release_firmware(firmware);

	return error;
}

static int apply_microcode_check_cpu(int cpu)
{
	struct cpuinfo_x86 *c = &cpu_data(cpu);
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
	cpumask_t old;
	unsigned int val[2];
	int err = 0;

	/* Check if the microcode is available */
	if (!uci->mc.mc_intel)
		return 0;

	old = current->cpus_allowed;
	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	/* Check if the microcode we have in memory matches the CPU */
	if (c->x86_vendor != X86_VENDOR_INTEL || c->x86 < 6 ||
	    cpu_has(c, X86_FEATURE_IA64) || uci->sig != cpuid_eax(0x00000001))
		err = -EINVAL;

	if (!err && ((c->x86_model >= 5) || (c->x86 > 6))) {
		/* get processor flags from MSR 0x17 */
		rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
		if (uci->pf != (1 << ((val[1] >> 18) & 7)))
			err = -EINVAL;
	}

	if (!err) {
		wrmsr(MSR_IA32_UCODE_REV, 0, 0);
		/* see notes above for revision 1.07.  Apparent chip bug */
		sync_core();
		/* get the current revision from MSR 0x8B */
		rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
		if (uci->rev != val[1])
			err = -EINVAL;
	}

	if (!err)
		apply_microcode(cpu);
	else
		printk(KERN_ERR "microcode: Could not apply microcode to CPU%d:"
			" sig=0x%x, pf=0x%x, rev=0x%x\n",
			cpu, uci->sig, uci->pf, uci->rev);

	set_cpus_allowed_ptr(current, &old);
	return err;
}

static void microcode_fini_cpu(int cpu)
{
	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

	mutex_lock(&microcode_mutex);
	uci->valid = 0;
	vfree(uci->mc.mc_intel);
	uci->mc.mc_intel = NULL;
	mutex_unlock(&microcode_mutex);
}

static struct microcode_ops microcode_intel_ops = {
	.get_next_ucode                   = get_next_ucode,
	.get_matching_microcode           = get_matching_microcode,
	.microcode_sanity_check           = microcode_sanity_check,
	.apply_microcode_check_cpu        = apply_microcode_check_cpu,
	.cpu_request_microcode            = cpu_request_microcode,
	.collect_cpu_info                 = collect_cpu_info,
	.apply_microcode                  = apply_microcode,
	.microcode_fini_cpu               = microcode_fini_cpu,
};

static int __init microcode_intel_module_init(void)
{
	struct cpuinfo_x86 *c = &cpu_data(0);

	if (c->x86_vendor != X86_VENDOR_INTEL) {
                printk(KERN_ERR "microcode: CPU platform is not Intel-capable\n");
		return -ENODEV;
	}

	return microcode_init(&microcode_intel_ops, THIS_MODULE);
}

static void __exit microcode_intel_module_exit(void)
{
	microcode_exit();
}

module_init(microcode_intel_module_init)
module_exit(microcode_intel_module_exit)