Currently number of error reporting register banks is hardcoded to
6 on AMD processors. This may break in virtualized scenarios when
a hypervisor prefers to report fewer banks that the physical HW
provides.
Since number of supported banks is reported in MSR_IA32_MCG_CAP[7:0]
that's what we should use.
Signed-off-by: Boris Ostrovsky <[email protected]>
---
arch/x86/kernel/cpu/mcheck/mce_amd.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
index 1ac581f..cb7c739 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
@@ -33,7 +33,6 @@
#include <asm/mce.h>
#include <asm/msr.h>
-#define NR_BANKS 6
#define NR_BLOCKS 9
#define THRESHOLD_MAX 0xFFF
#define INT_TYPE_APIC 0x00020000
@@ -57,9 +56,9 @@ static const char * const th_names[] = {
"execution_unit",
};
-static DEFINE_PER_CPU(struct threshold_bank * [NR_BANKS], threshold_banks);
+static DEFINE_PER_CPU(struct threshold_bank **, threshold_banks);
-static unsigned char shared_bank[NR_BANKS] = {
+static unsigned char shared_bank[MAX_NR_BANKS] = {
0, 0, 0, 0, 1
};
@@ -214,7 +213,7 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c)
unsigned int bank, block;
int offset = -1;
- for (bank = 0; bank < NR_BANKS; ++bank) {
+ for (bank = 0; bank < mca_cfg.banks; ++bank) {
for (block = 0; block < NR_BLOCKS; ++block) {
if (block == 0)
address = MSR_IA32_MC0_MISC + bank * 4;
@@ -276,7 +275,7 @@ static void amd_threshold_interrupt(void)
mce_setup(&m);
/* assume first bank caused it */
- for (bank = 0; bank < NR_BANKS; ++bank) {
+ for (bank = 0; bank < mca_cfg.banks; ++bank) {
if (!(per_cpu(bank_map, m.cpu) & (1 << bank)))
continue;
for (block = 0; block < NR_BLOCKS; ++block) {
@@ -467,7 +466,7 @@ static __cpuinit int allocate_threshold_blocks(unsigned int cpu,
u32 low, high;
int err;
- if ((bank >= NR_BANKS) || (block >= NR_BLOCKS))
+ if ((bank >= mca_cfg.banks) || (block >= NR_BLOCKS))
return 0;
if (rdmsr_safe_on_cpu(cpu, address, &low, &high))
@@ -637,7 +636,12 @@ static __cpuinit int threshold_create_device(unsigned int cpu)
unsigned int bank;
int err = 0;
- for (bank = 0; bank < NR_BANKS; ++bank) {
+ per_cpu(threshold_banks, cpu) = kzalloc(sizeof(struct threshold_bank *)
+ * mca_cfg.banks, GFP_KERNEL);
+ if (per_cpu(threshold_banks, cpu) == NULL)
+ return -ENOMEM;
+
+ for (bank = 0; bank < mca_cfg.banks; ++bank) {
if (!(per_cpu(bank_map, cpu) & (1 << bank)))
continue;
err = threshold_create_bank(cpu, bank);
@@ -719,11 +723,12 @@ static void threshold_remove_device(unsigned int cpu)
{
unsigned int bank;
- for (bank = 0; bank < NR_BANKS; ++bank) {
+ for (bank = 0; bank < mca_cfg.banks; ++bank) {
if (!(per_cpu(bank_map, cpu) & (1 << bank)))
continue;
threshold_remove_bank(cpu, bank);
}
+ kfree(per_cpu(threshold_banks, cpu));
}
/* get notified when a cpu comes on/off */
--
1.8.1.2
On Thu, Mar 14, 2013 at 12:11:18PM -0400, Boris Ostrovsky wrote:
> Currently number of error reporting register banks is hardcoded to
> 6 on AMD processors. This may break in virtualized scenarios when
> a hypervisor prefers to report fewer banks that the physical HW
> provides.
>
> Since number of supported banks is reported in MSR_IA32_MCG_CAP[7:0]
> that's what we should use.
Yes, I definitely like it.
A couple of suggestions below :
>
> Signed-off-by: Boris Ostrovsky <[email protected]>
> ---
> arch/x86/kernel/cpu/mcheck/mce_amd.c | 21 +++++++++++++--------
> 1 file changed, 13 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce_amd.c b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> index 1ac581f..cb7c739 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce_amd.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce_amd.c
> @@ -33,7 +33,6 @@
> #include <asm/mce.h>
> #include <asm/msr.h>
>
> -#define NR_BANKS 6
> #define NR_BLOCKS 9
> #define THRESHOLD_MAX 0xFFF
> #define INT_TYPE_APIC 0x00020000
> @@ -57,9 +56,9 @@ static const char * const th_names[] = {
> "execution_unit",
> };
>
> -static DEFINE_PER_CPU(struct threshold_bank * [NR_BANKS], threshold_banks);
> +static DEFINE_PER_CPU(struct threshold_bank **, threshold_banks);
>
> -static unsigned char shared_bank[NR_BANKS] = {
> +static unsigned char shared_bank[MAX_NR_BANKS] = {
This shared_bank thing is a kinda clumsy way of saying that bank 4 is
shared. Great, with this change we're allocating a static array of 32
unsigned chars just to ask whether bank 4 is shared. :-)
I know, I know, this was there before but maybe we could clean it up
properly while at it.
IOW, we probably want to kill that in a pre-patch and replace the test
with:
/* is this a shared bank */
if (bank == 4)
The comment should explain why we're testing this way.
For the future, if we get more shared banks, we could introduce a
is_shared_bank() helper but no need to do it just yet.
> 0, 0, 0, 0, 1
> };
>
> @@ -214,7 +213,7 @@ void mce_amd_feature_init(struct cpuinfo_x86 *c)
> unsigned int bank, block;
> int offset = -1;
>
> - for (bank = 0; bank < NR_BANKS; ++bank) {
> + for (bank = 0; bank < mca_cfg.banks; ++bank) {
> for (block = 0; block < NR_BLOCKS; ++block) {
> if (block == 0)
> address = MSR_IA32_MC0_MISC + bank * 4;
> @@ -276,7 +275,7 @@ static void amd_threshold_interrupt(void)
> mce_setup(&m);
>
> /* assume first bank caused it */
> - for (bank = 0; bank < NR_BANKS; ++bank) {
> + for (bank = 0; bank < mca_cfg.banks; ++bank) {
> if (!(per_cpu(bank_map, m.cpu) & (1 << bank)))
> continue;
> for (block = 0; block < NR_BLOCKS; ++block) {
> @@ -467,7 +466,7 @@ static __cpuinit int allocate_threshold_blocks(unsigned int cpu,
> u32 low, high;
> int err;
>
> - if ((bank >= NR_BANKS) || (block >= NR_BLOCKS))
> + if ((bank >= mca_cfg.banks) || (block >= NR_BLOCKS))
> return 0;
>
> if (rdmsr_safe_on_cpu(cpu, address, &low, &high))
> @@ -637,7 +636,12 @@ static __cpuinit int threshold_create_device(unsigned int cpu)
> unsigned int bank;
> int err = 0;
>
> - for (bank = 0; bank < NR_BANKS; ++bank) {
> + per_cpu(threshold_banks, cpu) = kzalloc(sizeof(struct threshold_bank *)
> + * mca_cfg.banks, GFP_KERNEL);
per_cpu accesses are not cheap. You should define a local pointer here
and use it instead in all the calls and do the per_cpu assignment only
at the end:
per_cpu(threshold_banks, cpu) = local_ptr;
> + if (per_cpu(threshold_banks, cpu) == NULL)
> + return -ENOMEM;
Which makes this test much more readable too:
if (!local_ptr)
return -ENOMEM;
Btw, those threshold_{create,remove}_device are the hotplug callbacks
and the alloc/dealloc looks right but you might want to stress them a
bit by taking cores on- and offline while testing, just in case.
Thanks.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--