Re: [PATCH] x86 microcode: revert some work_on_cpu

From: Dmitry Adamushko
Date: Wed Apr 15 2009 - 06:12:46 EST

2009/4/15 Rusty Russell <rusty@xxxxxxxxxxxxxxx>:
> On Wed, 15 Apr 2009 03:55:42 am Hugh Dickins wrote:
>> Revert part of af5c820a3169e81af869c113e18ec7588836cd50
>> x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c
>>
>> That change is causing only one Intel CPU's microcode to be updated e.g.
>> microcode: CPU3 updated from revision 0x9 to 0x17, date = 2005-04-22
>> where before it announced that also for CPU0 and CPU1 and CPU2.
>>
>> We cannot use work_on_cpu() in the CONFIG_MICROCODE_OLD_INTERFACE code,
>> because Intel's request_microcode_user() involves a copy_from_user() from
>> /sbin/microcode_ctl, which therefore needs to be on that CPU at the time.
>
> Erk. Ack the reversion, but this needs to be fixed properly.
>
> We can't just mug a process's affinity. I'll look at this code again and
> see what I can do.

Rusty,


what's about something like below?

Disclaimer: it's not even compilation-tested, consider it merely as an
illustration of an approach. I'll be able to test it later.

- run collect_cpu_info() and apply_microcode() on a target cpu, the
rest of callbacks are just fine to run on any cpu;

- some synchronization changes (based on
http://lkml.indiana.edu/hypermail/linux/kernel/0903.1/00525.html)
See the "Synchronization" note in microcode_core.c

- removed sysfs_remove_group() from mc_sysdev_add() to avoid warnings
being triggered in some cases (there were a few reports on lkml) --
perhaps, to be reworked.

- some things perhaps need to be changed, e.g. add a return code to
apply_microcode(), ...

(the non-white-space damaged version is enclosed)

diff -upr linux-2.6.git/arch/x86/include/asm/microcode.h
linux-2.6.git.my/arch/x86/include/asm/microcode.h
--- linux-2.6.git/arch/x86/include/asm/microcode.h 2009-04-14
22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/include/asm/microcode.h 2009-04-15
11:49:47.000000000 +0200
@@ -13,10 +13,16 @@ struct microcode_ops {
int (*request_microcode_user) (int cpu, const void __user
*buf, size_t size);
int (*request_microcode_fw) (int cpu, struct device *device);

- void (*apply_microcode) (int cpu);
+ void (*microcode_fini_cpu) (int cpu);

+ /*
+ * The generic 'microcode_core' part guarantees that
+ * the callbacks below run on a target cpu when they
+ * are being called.
+ * See also the "Synchronization" section in microcode_core.c.
+ */
+ void (*apply_microcode) (int cpu);
int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);
- void (*microcode_fini_cpu) (int cpu);
};

struct ucode_cpu_info {
diff -upr linux-2.6.git/arch/x86/kernel/microcode_amd.c
linux-2.6.git.my/arch/x86/kernel/microcode_amd.c
--- linux-2.6.git/arch/x86/kernel/microcode_amd.c 2009-04-14
22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_amd.c 2009-04-15
11:46:38.000000000 +0200
@@ -17,7 +17,6 @@
#include <linux/capability.h>
#include <linux/miscdevice.h>
#include <linux/firmware.h>
-#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/pci_ids.h>
#include <linux/uaccess.h>
@@ -79,9 +78,6 @@ struct microcode_amd {
#define UCODE_CONTAINER_SECTION_HDR 8
#define UCODE_CONTAINER_HEADER_SIZE 12

-/* serialize access to the physical write */
-static DEFINE_SPINLOCK(microcode_update_lock);
-
static struct equiv_cpu_entry *equiv_cpu_table;

static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
@@ -158,11 +154,9 @@ static void apply_microcode_amd(int cpu)
if (mc_amd == NULL)
return;

- spin_lock_irqsave(&microcode_update_lock, flags);
wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code);
/* get patch id after patching */
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
- spin_unlock_irqrestore(&microcode_update_lock, flags);

/* check current patch id and patch's id for match */
if (rev != mc_amd->hdr.patch_id) {
@@ -327,9 +321,6 @@ static int request_microcode_fw(int cpu,
const struct firmware *firmware;
int ret;

- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
-
ret = request_firmware(&firmware, fw_name, device);
if (ret) {
printk(KERN_ERR "microcode: failed to load file %s\n", fw_name);
diff -upr linux-2.6.git/arch/x86/kernel/microcode_core.c
linux-2.6.git.my/arch/x86/kernel/microcode_core.c
--- linux-2.6.git/arch/x86/kernel/microcode_core.c 2009-04-14
22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_core.c 2009-04-15
11:45:48.000000000 +0200
@@ -101,36 +101,89 @@ MODULE_LICENSE("GPL");

static struct microcode_ops *microcode_ops;

-/* no concurrent ->write()s are allowed on /dev/cpu/microcode */
+/*
+ * Synchronization.
+ *
+ * All non cpu-hotplug-callback call sites use:
+ *
+ * - microcode_mutex to synchronize with each other;
+ * - get/put_online_cpus() to synchronize with
+ * the cpu-hotplug-callback call sites.
+ *
+ * We guarantee that only a single cpu is being
+ * updated at any particular moment of time.
+ */
static DEFINE_MUTEX(microcode_mutex);

struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
EXPORT_SYMBOL_GPL(ucode_cpu_info);

+/*
+ * Operations that are run on a target cpu:
+ */
+
+struct collect_for_cpu {
+ struct cpu_signature cpu_sig;
+ int cpu;
+};
+
+static long collect_cpu_info_local(void *arg)
+{
+ struct collect_for_cpu *cfc = arg;
+
+ BUG_ON(cfc->cpu != smp_processor_id());
+
+ return microcode_ops->collect_cpu_info(cfc->cpu, &cfc->cpu_sig);
+}
+
+static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
+{
+ return work_on_cpu(cpu, collect_cpu_info_local, cpu_sig);
+}
+
+static void collect_cpu_info(int cpu)
+{
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+ memset(uci, 0, sizeof(*uci));
+ if (!collect_cpu_info_on_target(cpu, &uci->cpu_sig))
+ uci->valid = 1;
+}
+
+static long apply_microcode_local(void *arg)
+{
+ int cpu = (int)arg;
+
+ BUG_ON(cpu != smp_processor_id());
+ microcode_ops->apply_microcode(cpu);
+
+ return 0;
+}
+
+static int apply_microcode_on_target(int cpu)
+{
+ return work_on_cpu(cpu, apply_microcode_local, (void *)cpu);
+}
+
#ifdef CONFIG_MICROCODE_OLD_INTERFACE
static int do_microcode_update(const void __user *buf, size_t size)
{
- cpumask_t old;
int error = 0;
int cpu;

- old = current->cpus_allowed;
-
for_each_online_cpu(cpu) {
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

if (!uci->valid)
continue;

- set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
error = microcode_ops->request_microcode_user(cpu, buf, size);
if (error < 0)
- goto out;
+ break;
if (!error)
- microcode_ops->apply_microcode(cpu);
+ apply_microcode_on_target(cpu);
}
-out:
- set_cpus_allowed_ptr(current, &old);
+
return error;
}

@@ -205,17 +258,16 @@ MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
/* fake device for request_firmware */
static struct platform_device *microcode_pdev;

-static long reload_for_cpu(void *unused)
+static int reload_for_cpu(int cpu)
{
- struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
int err = 0;

mutex_lock(&microcode_mutex);
if (uci->valid) {
- err = microcode_ops->request_microcode_fw(smp_processor_id(),
- &microcode_pdev->dev);
+ err = microcode_ops->request_microcode_fw(cpu,
&microcode_pdev->dev);
if (!err)
- microcode_ops->apply_microcode(smp_processor_id());
+ apply_microcode_on_target(cpu);
}
mutex_unlock(&microcode_mutex);
return err;
@@ -235,7 +287,7 @@ static ssize_t reload_store(struct sys_d
if (val == 1) {
get_online_cpus();
if (cpu_online(cpu))
- err = work_on_cpu(cpu, reload_for_cpu, NULL);
+ err = reload_for_cpu(cpu);
put_online_cpus();
}
if (err)
@@ -275,7 +327,7 @@ static struct attribute_group mc_attr_gr
.name = "microcode",
};

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

@@ -283,22 +335,6 @@ static void __microcode_fini_cpu(int cpu
uci->valid = 0;
}

-static void microcode_fini_cpu(int cpu)
-{
- mutex_lock(&microcode_mutex);
- __microcode_fini_cpu(cpu);
- mutex_unlock(&microcode_mutex);
-}
-
-static void collect_cpu_info(int cpu)
-{
- struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-
- memset(uci, 0, sizeof(*uci));
- if (!microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig))
- uci->valid = 1;
-}
-
static int microcode_resume_cpu(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -313,15 +349,15 @@ static int microcode_resume_cpu(int cpu)
* Let's verify that the 'cached' ucode does belong
* to this cpu (a bit of paranoia):
*/
- if (microcode_ops->collect_cpu_info(cpu, &nsig)) {
- __microcode_fini_cpu(cpu);
+ if (collect_cpu_info_on_target(cpu, &nsig)) {
+ microcode_fini_cpu(cpu);
printk(KERN_ERR "failed to collect_cpu_info for
resuming cpu #%d\n",
cpu);
return -1;
}

if ((nsig.sig != uci->cpu_sig.sig) || (nsig.pf != uci->cpu_sig.pf)) {
- __microcode_fini_cpu(cpu);
+ microcode_fini_cpu(cpu);
printk(KERN_ERR "cached ucode doesn't match the
resuming cpu #%d\n",
cpu);
/* Should we look for a new ucode here? */
@@ -331,9 +367,9 @@ static int microcode_resume_cpu(int cpu)
return 0;
}

-static long microcode_update_cpu(void *unused)
+static int microcode_init_cpu(int cpu)
{
- struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
int err = 0;

/*
@@ -341,25 +377,16 @@ static long microcode_update_cpu(void *u
* otherwise just request a firmware:
*/
if (uci->valid) {
- err = microcode_resume_cpu(smp_processor_id());
+ err = microcode_resume_cpu(cpu);
} else {
- collect_cpu_info(smp_processor_id());
+ collect_cpu_info(cpu);
if (uci->valid && system_state == SYSTEM_RUNNING)
err = microcode_ops->request_microcode_fw(
- smp_processor_id(),
+ cpu,
&microcode_pdev->dev);
}
if (!err)
- microcode_ops->apply_microcode(smp_processor_id());
- return err;
-}
-
-static int microcode_init_cpu(int cpu)
-{
- int err;
- mutex_lock(&microcode_mutex);
- err = work_on_cpu(cpu, microcode_update_cpu, NULL);
- mutex_unlock(&microcode_mutex);
+ apply_microcode_on_target(cpu);

return err;
}
@@ -380,8 +407,6 @@ static int mc_sysdev_add(struct sys_devi
return err;

err = microcode_init_cpu(cpu);
- if (err)
- sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);

return err;
}
@@ -406,8 +431,17 @@ static int mc_sysdev_resume(struct sys_d
if (!cpu_online(cpu))
return 0;

- /* only CPU 0 will apply ucode here */
- microcode_update_cpu(NULL);
+ /*
+ * All non-bootup cpus are still disabled,
+ * so only CPU 0 will apply ucode here.
+ *
+ * Moreover, there can be no concurrent
+ * updates from any other places at this point.
+ */
+ WARN_ON(cpu != 0);
+
+ microcode_init_cpu(cpu);
+
return 0;
}

@@ -471,9 +505,6 @@ static int __init microcode_init(void)
return -ENODEV;
}

- error = microcode_dev_init();
- if (error)
- return error;
microcode_pdev = platform_device_register_simple("microcode", -1,
NULL, 0);
if (IS_ERR(microcode_pdev)) {
@@ -482,14 +513,26 @@ static int __init microcode_init(void)
}

get_online_cpus();
+ /*
+ * --dimm. Hmm, we can avoid it if we perhaps first
+ * try to apply ucode in mc_sysdev_add() and only
+ * then create a sysfs group.
+ */
+ mutex_lock(&microcode_mutex);
error = sysdev_driver_register(&cpu_sysdev_class, &mc_sysdev_driver);
+ mutex_unlock(&microcode_mutex);
+
put_online_cpus();
+
if (error) {
- microcode_dev_exit();
platform_device_unregister(microcode_pdev);
return error;
}

+ error = microcode_dev_init();
+ if (error)
+ return error;
+
register_hotcpu_notifier(&mc_cpu_notifier);

printk(KERN_INFO
@@ -507,7 +550,9 @@ static void __exit microcode_exit(void)
unregister_hotcpu_notifier(&mc_cpu_notifier);

get_online_cpus();
+ mutex_lock(&microcode_mutex);
sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
+ mutex_unlock(&microcode_mutex);
put_online_cpus();

platform_device_unregister(microcode_pdev);
diff -upr linux-2.6.git/arch/x86/kernel/microcode_intel.c
linux-2.6.git.my/arch/x86/kernel/microcode_intel.c
--- linux-2.6.git/arch/x86/kernel/microcode_intel.c 2009-04-14
22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_intel.c 2009-04-15
11:47:21.000000000 +0200
@@ -75,7 +75,6 @@
#include <linux/miscdevice.h>
#include <linux/firmware.h>
#include <linux/smp_lock.h>
-#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
@@ -150,9 +149,6 @@ struct extended_sigtable {

#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);
-
static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
{
struct cpuinfo_x86 *c = &cpu_data(cpu_num);
@@ -176,15 +172,11 @@ static int collect_cpu_info(int cpu_num,
csig->pf = 1 << ((val[1] >> 18) & 7);
}

- /* serialize access to the physical write to MSR 0x79 */
- spin_lock_irqsave(&microcode_update_lock, flags);
-
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], csig->rev);
- spin_unlock_irqrestore(&microcode_update_lock, flags);

pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
csig->sig, csig->pf, csig->rev);
@@ -336,9 +328,6 @@ static void apply_microcode(int cpu)
if (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) mc_intel->bits,
@@ -351,7 +340,6 @@ static void apply_microcode(int cpu)
/* 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] != mc_intel->hdr.rev) {
printk(KERN_ERR "microcode: CPU%d update from revision "
"0x%x to 0x%x failed\n",
@@ -445,8 +433,6 @@ static int request_microcode_fw(int cpu,
const struct firmware *firmware;
int ret;

- /* 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);
ret = request_firmware(&firmware, name, device);
@@ -470,9 +456,6 @@ static int get_ucode_user(void *to, cons

static int request_microcode_user(int cpu, const void __user *buf, size_t size)
{
- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
-
return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
}



---





--
Best regards,
Dmitry Adamushko
diff -upr linux-2.6.git/arch/x86/include/asm/microcode.h linux-2.6.git.my/arch/x86/include/asm/microcode.h
--- linux-2.6.git/arch/x86/include/asm/microcode.h 2009-04-14 22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/include/asm/microcode.h 2009-04-15 11:49:47.000000000 +0200
@@ -13,10 +13,16 @@ struct microcode_ops {
int (*request_microcode_user) (int cpu, const void __user *buf, size_t size);
int (*request_microcode_fw) (int cpu, struct device *device);

- void (*apply_microcode) (int cpu);
+ void (*microcode_fini_cpu) (int cpu);

+ /*
+ * The generic 'microcode_core' part guarantees that
+ * the callbacks below run on a target cpu when they
+ * are being called.
+ * See also the "Synchronization" section in microcode_core.c.
+ */
+ void (*apply_microcode) (int cpu);
int (*collect_cpu_info) (int cpu, struct cpu_signature *csig);
- void (*microcode_fini_cpu) (int cpu);
};

struct ucode_cpu_info {
diff -upr linux-2.6.git/arch/x86/kernel/microcode_amd.c linux-2.6.git.my/arch/x86/kernel/microcode_amd.c
--- linux-2.6.git/arch/x86/kernel/microcode_amd.c 2009-04-14 22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_amd.c 2009-04-15 11:46:38.000000000 +0200
@@ -17,7 +17,6 @@
#include <linux/capability.h>
#include <linux/miscdevice.h>
#include <linux/firmware.h>
-#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/pci_ids.h>
#include <linux/uaccess.h>
@@ -79,9 +78,6 @@ struct microcode_amd {
#define UCODE_CONTAINER_SECTION_HDR 8
#define UCODE_CONTAINER_HEADER_SIZE 12

-/* serialize access to the physical write */
-static DEFINE_SPINLOCK(microcode_update_lock);
-
static struct equiv_cpu_entry *equiv_cpu_table;

static int collect_cpu_info_amd(int cpu, struct cpu_signature *csig)
@@ -158,11 +154,9 @@ static void apply_microcode_amd(int cpu)
if (mc_amd == NULL)
return;

- spin_lock_irqsave(&microcode_update_lock, flags);
wrmsrl(MSR_AMD64_PATCH_LOADER, (u64)(long)&mc_amd->hdr.data_code);
/* get patch id after patching */
rdmsr(MSR_AMD64_PATCH_LEVEL, rev, dummy);
- spin_unlock_irqrestore(&microcode_update_lock, flags);

/* check current patch id and patch's id for match */
if (rev != mc_amd->hdr.patch_id) {
@@ -327,9 +321,6 @@ static int request_microcode_fw(int cpu,
const struct firmware *firmware;
int ret;

- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
-
ret = request_firmware(&firmware, fw_name, device);
if (ret) {
printk(KERN_ERR "microcode: failed to load file %s\n", fw_name);
diff -upr linux-2.6.git/arch/x86/kernel/microcode_core.c linux-2.6.git.my/arch/x86/kernel/microcode_core.c
--- linux-2.6.git/arch/x86/kernel/microcode_core.c 2009-04-14 22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_core.c 2009-04-15 11:45:48.000000000 +0200
@@ -101,36 +101,89 @@ MODULE_LICENSE("GPL");

static struct microcode_ops *microcode_ops;

-/* no concurrent ->write()s are allowed on /dev/cpu/microcode */
+/*
+ * Synchronization.
+ *
+ * All non cpu-hotplug-callback call sites use:
+ *
+ * - microcode_mutex to synchronize with each other;
+ * - get/put_online_cpus() to synchronize with
+ * the cpu-hotplug-callback call sites.
+ *
+ * We guarantee that only a single cpu is being
+ * updated at any particular moment of time.
+ */
static DEFINE_MUTEX(microcode_mutex);

struct ucode_cpu_info ucode_cpu_info[NR_CPUS];
EXPORT_SYMBOL_GPL(ucode_cpu_info);

+/*
+ * Operations that are run on a target cpu:
+ */
+
+struct collect_for_cpu {
+ struct cpu_signature cpu_sig;
+ int cpu;
+};
+
+static long collect_cpu_info_local(void *arg)
+{
+ struct collect_for_cpu *cfc = arg;
+
+ BUG_ON(cfc->cpu != smp_processor_id());
+
+ return microcode_ops->collect_cpu_info(cfc->cpu, &cfc->cpu_sig);
+}
+
+static int collect_cpu_info_on_target(int cpu, struct cpu_signature *cpu_sig)
+{
+ return work_on_cpu(cpu, collect_cpu_info_local, cpu_sig);
+}
+
+static void collect_cpu_info(int cpu)
+{
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
+
+ memset(uci, 0, sizeof(*uci));
+ if (!collect_cpu_info_on_target(cpu, &uci->cpu_sig))
+ uci->valid = 1;
+}
+
+static long apply_microcode_local(void *arg)
+{
+ int cpu = (int)arg;
+
+ BUG_ON(cpu != smp_processor_id());
+ microcode_ops->apply_microcode(cpu);
+
+ return 0;
+}
+
+static int apply_microcode_on_target(int cpu)
+{
+ return work_on_cpu(cpu, apply_microcode_local, (void *)cpu);
+}
+
#ifdef CONFIG_MICROCODE_OLD_INTERFACE
static int do_microcode_update(const void __user *buf, size_t size)
{
- cpumask_t old;
int error = 0;
int cpu;

- old = current->cpus_allowed;
-
for_each_online_cpu(cpu) {
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;

if (!uci->valid)
continue;

- set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
error = microcode_ops->request_microcode_user(cpu, buf, size);
if (error < 0)
- goto out;
+ break;
if (!error)
- microcode_ops->apply_microcode(cpu);
+ apply_microcode_on_target(cpu);
}
-out:
- set_cpus_allowed_ptr(current, &old);
+
return error;
}

@@ -205,17 +258,16 @@ MODULE_ALIAS_MISCDEV(MICROCODE_MINOR);
/* fake device for request_firmware */
static struct platform_device *microcode_pdev;

-static long reload_for_cpu(void *unused)
+static int reload_for_cpu(int cpu)
{
- struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
int err = 0;

mutex_lock(&microcode_mutex);
if (uci->valid) {
- err = microcode_ops->request_microcode_fw(smp_processor_id(),
- &microcode_pdev->dev);
+ err = microcode_ops->request_microcode_fw(cpu, &microcode_pdev->dev);
if (!err)
- microcode_ops->apply_microcode(smp_processor_id());
+ apply_microcode_on_target(cpu);
}
mutex_unlock(&microcode_mutex);
return err;
@@ -235,7 +287,7 @@ static ssize_t reload_store(struct sys_d
if (val == 1) {
get_online_cpus();
if (cpu_online(cpu))
- err = work_on_cpu(cpu, reload_for_cpu, NULL);
+ err = reload_for_cpu(cpu);
put_online_cpus();
}
if (err)
@@ -275,7 +327,7 @@ static struct attribute_group mc_attr_gr
.name = "microcode",
};

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

@@ -283,22 +335,6 @@ static void __microcode_fini_cpu(int cpu
uci->valid = 0;
}

-static void microcode_fini_cpu(int cpu)
-{
- mutex_lock(&microcode_mutex);
- __microcode_fini_cpu(cpu);
- mutex_unlock(&microcode_mutex);
-}
-
-static void collect_cpu_info(int cpu)
-{
- struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
-
- memset(uci, 0, sizeof(*uci));
- if (!microcode_ops->collect_cpu_info(cpu, &uci->cpu_sig))
- uci->valid = 1;
-}
-
static int microcode_resume_cpu(int cpu)
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@@ -313,15 +349,15 @@ static int microcode_resume_cpu(int cpu)
* Let's verify that the 'cached' ucode does belong
* to this cpu (a bit of paranoia):
*/
- if (microcode_ops->collect_cpu_info(cpu, &nsig)) {
- __microcode_fini_cpu(cpu);
+ if (collect_cpu_info_on_target(cpu, &nsig)) {
+ microcode_fini_cpu(cpu);
printk(KERN_ERR "failed to collect_cpu_info for resuming cpu #%d\n",
cpu);
return -1;
}

if ((nsig.sig != uci->cpu_sig.sig) || (nsig.pf != uci->cpu_sig.pf)) {
- __microcode_fini_cpu(cpu);
+ microcode_fini_cpu(cpu);
printk(KERN_ERR "cached ucode doesn't match the resuming cpu #%d\n",
cpu);
/* Should we look for a new ucode here? */
@@ -331,9 +367,9 @@ static int microcode_resume_cpu(int cpu)
return 0;
}

-static long microcode_update_cpu(void *unused)
+static int microcode_init_cpu(int cpu)
{
- struct ucode_cpu_info *uci = ucode_cpu_info + smp_processor_id();
+ struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
int err = 0;

/*
@@ -341,25 +377,16 @@ static long microcode_update_cpu(void *u
* otherwise just request a firmware:
*/
if (uci->valid) {
- err = microcode_resume_cpu(smp_processor_id());
+ err = microcode_resume_cpu(cpu);
} else {
- collect_cpu_info(smp_processor_id());
+ collect_cpu_info(cpu);
if (uci->valid && system_state == SYSTEM_RUNNING)
err = microcode_ops->request_microcode_fw(
- smp_processor_id(),
+ cpu,
&microcode_pdev->dev);
}
if (!err)
- microcode_ops->apply_microcode(smp_processor_id());
- return err;
-}
-
-static int microcode_init_cpu(int cpu)
-{
- int err;
- mutex_lock(&microcode_mutex);
- err = work_on_cpu(cpu, microcode_update_cpu, NULL);
- mutex_unlock(&microcode_mutex);
+ apply_microcode_on_target(cpu);

return err;
}
@@ -380,8 +407,6 @@ static int mc_sysdev_add(struct sys_devi
return err;

err = microcode_init_cpu(cpu);
- if (err)
- sysfs_remove_group(&sys_dev->kobj, &mc_attr_group);

return err;
}
@@ -406,8 +431,17 @@ static int mc_sysdev_resume(struct sys_d
if (!cpu_online(cpu))
return 0;

- /* only CPU 0 will apply ucode here */
- microcode_update_cpu(NULL);
+ /*
+ * All non-bootup cpus are still disabled,
+ * so only CPU 0 will apply ucode here.
+ *
+ * Moreover, there can be no concurrent
+ * updates from any other places at this point.
+ */
+ WARN_ON(cpu != 0);
+
+ microcode_init_cpu(cpu);
+
return 0;
}

@@ -471,9 +505,6 @@ static int __init microcode_init(void)
return -ENODEV;
}

- error = microcode_dev_init();
- if (error)
- return error;
microcode_pdev = platform_device_register_simple("microcode", -1,
NULL, 0);
if (IS_ERR(microcode_pdev)) {
@@ -482,14 +513,26 @@ static int __init microcode_init(void)
}

get_online_cpus();
+ /*
+ * --dimm. Hmm, we can avoid it if we perhaps first
+ * try to apply ucode in mc_sysdev_add() and only
+ * then create a sysfs group.
+ */
+ mutex_lock(&microcode_mutex);
error = sysdev_driver_register(&cpu_sysdev_class, &mc_sysdev_driver);
+ mutex_unlock(&microcode_mutex);
+
put_online_cpus();
+
if (error) {
- microcode_dev_exit();
platform_device_unregister(microcode_pdev);
return error;
}

+ error = microcode_dev_init();
+ if (error)
+ return error;
+
register_hotcpu_notifier(&mc_cpu_notifier);

printk(KERN_INFO
@@ -507,7 +550,9 @@ static void __exit microcode_exit(void)
unregister_hotcpu_notifier(&mc_cpu_notifier);

get_online_cpus();
+ mutex_lock(&microcode_mutex);
sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver);
+ mutex_unlock(&microcode_mutex);
put_online_cpus();

platform_device_unregister(microcode_pdev);
diff -upr linux-2.6.git/arch/x86/kernel/microcode_intel.c linux-2.6.git.my/arch/x86/kernel/microcode_intel.c
--- linux-2.6.git/arch/x86/kernel/microcode_intel.c 2009-04-14 22:51:48.000000000 +0200
+++ linux-2.6.git.my/arch/x86/kernel/microcode_intel.c 2009-04-15 11:47:21.000000000 +0200
@@ -75,7 +75,6 @@
#include <linux/miscdevice.h>
#include <linux/firmware.h>
#include <linux/smp_lock.h>
-#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
@@ -150,9 +149,6 @@ struct extended_sigtable {

#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);
-
static int collect_cpu_info(int cpu_num, struct cpu_signature *csig)
{
struct cpuinfo_x86 *c = &cpu_data(cpu_num);
@@ -176,15 +172,11 @@ static int collect_cpu_info(int cpu_num,
csig->pf = 1 << ((val[1] >> 18) & 7);
}

- /* serialize access to the physical write to MSR 0x79 */
- spin_lock_irqsave(&microcode_update_lock, flags);
-
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], csig->rev);
- spin_unlock_irqrestore(&microcode_update_lock, flags);

pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
csig->sig, csig->pf, csig->rev);
@@ -336,9 +328,6 @@ static void apply_microcode(int cpu)
if (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) mc_intel->bits,
@@ -351,7 +340,6 @@ static void apply_microcode(int cpu)
/* 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] != mc_intel->hdr.rev) {
printk(KERN_ERR "microcode: CPU%d update from revision "
"0x%x to 0x%x failed\n",
@@ -445,8 +433,6 @@ static int request_microcode_fw(int cpu,
const struct firmware *firmware;
int ret;

- /* 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);
ret = request_firmware(&firmware, name, device);
@@ -470,9 +456,6 @@ static int get_ucode_user(void *to, cons

static int request_microcode_user(int cpu, const void __user *buf, size_t size)
{
- /* We should bind the task to the CPU */
- BUG_ON(cpu != raw_smp_processor_id());
-
return generic_load_microcode(cpu, (void *)buf, size, &get_ucode_user);
}