On 08/22/2012 06:16 PM, Borislav Petkov wrote:
On Wed, Aug 22, 2012 at 06:00:54PM +0530, Naveen N. Rao wrote:
The ACPI spec doesn't provide for a way for the bios to pass down
recommended thresholds to the OS on a _per-bank_ basis. This patch adds
a new boot option, which if passed, allows bios to initialize the CMCI
threshold. In such a case, we simply skip programming any threshold
value.
As fail-safe, we initialize threshold to 1 if some banks have not been
initialized by the bios and warn the user.
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
Documentation/x86/x86_64/boot-options.txt | 5 ++++
arch/x86/include/asm/mce.h | 1 +
arch/x86/kernel/cpu/mcheck/mce.c | 4 +++
arch/x86/kernel/cpu/mcheck/mce_intel.c | 39 +++++++++++++++++++++++++++--
4 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/Documentation/x86/x86_64/boot-options.txt
b/Documentation/x86/x86_64/boot-options.txt
index c54b4f5..ec92540 100644
--- a/Documentation/x86/x86_64/boot-options.txt
+++ b/Documentation/x86/x86_64/boot-options.txt
@@ -50,6 +50,11 @@ Machine check
monarchtimeout:
Sets the time in us to wait for other CPUs on machine checks. 0
to disable.
+ mce=bios_cmci_threshold
+ Don't overwrite the bios-set CMCI threshold. This boot option
+ prevents Linux from overwriting the CMCI threshold set by the
+ bios. Without this option, Linux always sets the CMCI
+ threshold to 1.
nomce (for compatibility with i386): same as mce=off
diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index a3ac52b..8ad5078 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -171,6 +171,7 @@ DECLARE_PER_CPU(struct device *, mce_device);
#ifdef CONFIG_X86_MCE_INTEL
extern int mce_cmci_disabled;
extern int mce_ignore_ce;
+extern int mce_bios_cmci_threshold;
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..401359d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -82,6 +82,7 @@ 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_bios_cmci_threshold __read_mostly;
int mce_ser __read_mostly;
AFAICT, this is actually a single-bit flag but we're using a whole
integer for it and from looking at the other boot options a couple of
them are used as flags too.
Care to define a
struct boot_flags {
__u64 mce_bios_cmci_threshold : 1,
__reserved : 63;
};
and use
boot_flags.mce_bios_cmci_threshold
in the conditionals below instead?
Sure - that sounds like a good idea. Further, a #define can be used to
avoid the need to change other references, though I'm not sure it's
considered good practice:
#define mce_bios_cmci_threshold boot_flags.mce_bios_cmci_threshold
Thanks!
- Naveen
I'll try to convert the rest of them to that struct and thus save some
more space...
Thanks.
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