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Message-ID: <503B93D2.7090702@linux.vnet.ibm.com>
Date: Mon, 27 Aug 2012 21:05:46 +0530
From: "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
To: Borislav Petkov <bp@...64.org>
CC: tony.luck@...el.com, andi@...stfloor.org,
gong.chen@...ux.intel.com, ananth@...ibm.com,
masbock@...ux.vnet.ibm.com, x86@...nel.org,
linux-kernel@...r.kernel.org, lcm@...ibm.com, mingo@...hat.com,
tglx@...utronix.de, linux-edac@...r.kernel.org
Subject: Re: [PATCH 1/2] x86/mce: Pack boolean MCE boot flags into a structure
On 08/27/2012 08:06 PM, Borislav Petkov wrote:
> On Mon, Aug 27, 2012 at 04:55:03PM +0530, Naveen N. Rao wrote:
>> Many MCE boot flags are boolean in nature, but are declared as integers
>> currently. We can pack these into a bitfield to save some space.
>>
>> Signed-off-by: Naveen N. Rao <naveen.n.rao@...ux.vnet.ibm.com>
>
> Ok,
>
> looks good.
>
> A couple of issues though:
>
> You need to prepare your patches against tip/master (which contains
> tip/x86/mce) because there are MCE changes in tip and they conflict with
> your changes.
Sure, will do so for my next iteration.
>
>> ---
>> arch/x86/include/asm/mce.h | 11 +++-
>> arch/x86/kernel/cpu/mcheck/mce.c | 86 +++++++++++++++++++++-----------
>> arch/x86/kernel/cpu/mcheck/mce_intel.c | 2 -
>> 3 files changed, 66 insertions(+), 33 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
>> index a3ac52b..78caeb2 100644
>> --- a/arch/x86/include/asm/mce.h
>> +++ b/arch/x86/include/asm/mce.h
>> @@ -129,6 +129,15 @@ struct mce_log {
>>
>> #ifdef __KERNEL__
>>
>> +struct mce_boot_flags {
>> + __u32 cmci_disabled : 1,
>> + ignore_ce : 1,
>> + dont_log_ce : 1,
>> + __pad : 29;
>> +};
>
> This looks ok but I think it would be even better if it went into
> mce-internal.h where all the mce-only stuff can be collected in a
> private struct so that we don't pollute the global MCE namespace.
>
> Then you can call the struct simply
>
> struct boot_flags
>
> since it is private to mce code.
Good idea - will do.
>
>> +
>> +extern struct mce_boot_flags mce_boot_flags;
>
> Why do we need that extern thing?
So that this is visible across mce.c and mce_intel.c?
>
>> +
>> extern void mce_register_decode_chain(struct notifier_block *nb);
>> extern void mce_unregister_decode_chain(struct notifier_block *nb);
>>
>> @@ -169,8 +178,6 @@ DECLARE_PER_CPU(struct device *, mce_device);
>> #define MAX_NR_BANKS 32
>>
>> #ifdef CONFIG_X86_MCE_INTEL
>> -extern int mce_cmci_disabled;
>> -extern int mce_ignore_ce;
>> void mce_intel_feature_init(struct cpuinfo_x86 *c);
>> void cmci_clear(void);
>> void cmci_reenable(void);
>> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
>> index 292d025..5a0d399 100644
>> --- a/arch/x86/kernel/cpu/mcheck/mce.c
>> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
>> @@ -79,11 +79,10 @@ static int rip_msr __read_mostly;
>> static int mce_bootlog __read_mostly = -1;
>> static int monarch_timeout __read_mostly = -1;
>> static int mce_panic_timeout __read_mostly;
>> -static int mce_dont_log_ce __read_mostly;
>> -int mce_cmci_disabled __read_mostly;
>> -int mce_ignore_ce __read_mostly;
>> int mce_ser __read_mostly;
>>
>> +struct mce_boot_flags mce_boot_flags __read_mostly;
>> +
>> struct mce_bank *mce_banks __read_mostly;
>>
>> /* User mode helper program triggered by machine check event */
>> @@ -630,7 +629,7 @@ void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
>> * Don't get the IP here because it's unlikely to
>> * have anything to do with the actual error location.
>> */
>> - if (!(flags & MCP_DONTLOG) && !mce_dont_log_ce)
>> + if (!(flags & MCP_DONTLOG) && !mce_boot_flags.dont_log_ce)
>> mce_log(&m);
>>
>> /*
>> @@ -1601,7 +1600,7 @@ static void __mcheck_cpu_init_timer(void)
>>
>> setup_timer(t, mce_timer_fn, smp_processor_id());
>>
>> - if (mce_ignore_ce)
>> + if (mce_boot_flags.ignore_ce)
>> return;
>>
>> __this_cpu_write(mce_next_interval, iv);
>> @@ -1919,11 +1918,11 @@ static int __init mcheck_enable(char *str)
>> if (!strcmp(str, "off"))
>> mce_disabled = 1;
>> else if (!strcmp(str, "no_cmci"))
>> - mce_cmci_disabled = 1;
>> + mce_boot_flags.cmci_disabled = 1;
>> else if (!strcmp(str, "dont_log_ce"))
>> - mce_dont_log_ce = 1;
>> + mce_boot_flags.dont_log_ce = 1;
>> else if (!strcmp(str, "ignore_ce"))
>> - mce_ignore_ce = 1;
>> + mce_boot_flags.ignore_ce = 1;
>> else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog"))
>> mce_bootlog = (str[0] == 'b');
>> else if (isdigit(str[0])) {
>> @@ -2076,7 +2075,7 @@ show_trigger(struct device *s, struct device_attribute *attr, char *buf)
>> }
>>
>> static ssize_t set_trigger(struct device *s, struct device_attribute *attr,
>> - const char *buf, size_t siz)
>> + const char *buf, size_t size)
>> {
>> char *p;
>>
>
> This is an unrelated change, pls drop it.
Ok.
>
>> @@ -2090,6 +2089,34 @@ static ssize_t set_trigger(struct device *s, struct device_attribute *attr,
>> return strlen(mce_helper) + !!p;
>> }
>>
>> +static ssize_t get_dont_log_ce(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + return snprintf(buf, PAGE_SIZE, "%d\n", mce_boot_flags.dont_log_ce);
>> +}
>> +
>> +static ssize_t set_dont_log_ce(struct device *s,
>> + struct device_attribute *attr,
>> + const char *buf, size_t size)
>> +{
>> + u64 new;
>> +
>> + if (strict_strtoull(buf, 0, &new) < 0)
>> + return -EINVAL;
>> +
>> + mce_boot_flags.dont_log_ce = !!new;
>> +
>> + return size;
>> +}
>> +
>> +static ssize_t get_ignore_ce(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + return snprintf(buf, PAGE_SIZE, "%d\n", mce_boot_flags.ignore_ce);
>> +}
>> +
>
> Those could be combined into a function similar to device_show/store_int
> pairs but working on a bitfield.
>
> Maybe later.
Yes, this looks like it needs some work and I wasn't sure it would be
helpful at this time. So, yeah, maybe later.
Thanks!
- Naveen
>
>> static ssize_t set_ignore_ce(struct device *s,
>> struct device_attribute *attr,
>> const char *buf, size_t size)
>> @@ -2099,21 +2126,28 @@ static ssize_t set_ignore_ce(struct device *s,
>> if (strict_strtoull(buf, 0, &new) < 0)
>> return -EINVAL;
>>
>> - if (mce_ignore_ce ^ !!new) {
>> + if (mce_boot_flags.ignore_ce ^ !!new) {
>> if (new) {
>> /* disable ce features */
>> mce_timer_delete_all();
>> on_each_cpu(mce_disable_cmci, NULL, 1);
>> - mce_ignore_ce = 1;
>> + mce_boot_flags.ignore_ce = 1;
>> } else {
>> /* enable ce features */
>> - mce_ignore_ce = 0;
>> + mce_boot_flags.ignore_ce = 0;
>> on_each_cpu(mce_enable_ce, (void *)1, 1);
>> }
>> }
>> return size;
>> }
>>
>> +static ssize_t get_cmci_disabled(struct device *dev,
>> + struct device_attribute *attr,
>> + char *buf)
>> +{
>> + return snprintf(buf, PAGE_SIZE, "%d\n", mce_boot_flags.cmci_disabled);
>> +}
>> +
>> static ssize_t set_cmci_disabled(struct device *s,
>> struct device_attribute *attr,
>> const char *buf, size_t size)
>> @@ -2123,14 +2157,14 @@ static ssize_t set_cmci_disabled(struct device *s,
>> if (strict_strtoull(buf, 0, &new) < 0)
>> return -EINVAL;
>>
>> - if (mce_cmci_disabled ^ !!new) {
>> + if (mce_boot_flags.cmci_disabled ^ !!new) {
>> if (new) {
>> /* disable cmci */
>> on_each_cpu(mce_disable_cmci, NULL, 1);
>> - mce_cmci_disabled = 1;
>> + mce_boot_flags.cmci_disabled = 1;
>> } else {
>> /* enable cmci */
>> - mce_cmci_disabled = 0;
>> + mce_boot_flags.cmci_disabled = 0;
>> on_each_cpu(mce_enable_ce, NULL, 1);
>> }
>> }
>> @@ -2149,31 +2183,23 @@ static ssize_t store_int_with_restart(struct device *s,
>> static DEVICE_ATTR(trigger, 0644, show_trigger, set_trigger);
>> static DEVICE_INT_ATTR(tolerant, 0644, tolerant);
>> static DEVICE_INT_ATTR(monarch_timeout, 0644, monarch_timeout);
>> -static DEVICE_INT_ATTR(dont_log_ce, 0644, mce_dont_log_ce);
>> +static DEVICE_ATTR(dont_log_ce, 0644, get_dont_log_ce, set_dont_log_ce);
>> +static DEVICE_ATTR(ignore_ce, 0644, get_ignore_ce, set_ignore_ce);
>> +static DEVICE_ATTR(cmci_disabled, 0644, get_cmci_disabled, set_cmci_disabled);
>>
>> static struct dev_ext_attribute dev_attr_check_interval = {
>> __ATTR(check_interval, 0644, device_show_int, store_int_with_restart),
>> &check_interval
>> };
>>
>> -static struct dev_ext_attribute dev_attr_ignore_ce = {
>> - __ATTR(ignore_ce, 0644, device_show_int, set_ignore_ce),
>> - &mce_ignore_ce
>> -};
>> -
>> -static struct dev_ext_attribute dev_attr_cmci_disabled = {
>> - __ATTR(cmci_disabled, 0644, device_show_int, set_cmci_disabled),
>> - &mce_cmci_disabled
>> -};
>> -
>> static struct device_attribute *mce_device_attrs[] = {
>> &dev_attr_tolerant.attr,
>> &dev_attr_check_interval.attr,
>> &dev_attr_trigger,
>> &dev_attr_monarch_timeout.attr,
>> - &dev_attr_dont_log_ce.attr,
>> - &dev_attr_ignore_ce.attr,
>> - &dev_attr_cmci_disabled.attr,
>> + &dev_attr_dont_log_ce,
>> + &dev_attr_ignore_ce,
>> + &dev_attr_cmci_disabled,
>> NULL
>> };
>>
>> @@ -2314,7 +2340,7 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
>> break;
>> case CPU_DOWN_FAILED:
>> case CPU_DOWN_FAILED_FROZEN:
>> - if (!mce_ignore_ce && check_interval) {
>> + if (!mce_boot_flags.ignore_ce && check_interval) {
>> t->expires = round_jiffies(jiffies +
>> per_cpu(mce_next_interval, cpu));
>> add_timer_on(t, cpu);
>> diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c
>> index 38e49bc..aaf5c51 100644
>> --- a/arch/x86/kernel/cpu/mcheck/mce_intel.c
>> +++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c
>> @@ -36,7 +36,7 @@ static int cmci_supported(int *banks)
>> {
>> u64 cap;
>>
>> - if (mce_cmci_disabled || mce_ignore_ce)
>> + if (mce_boot_flags.cmci_disabled || mce_boot_flags.ignore_ce)
>> return 0;
>
> Thanks.
>
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