lkml.org 
[lkml]   [2011]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/6] x86, mce: Add mechanism to safely save information in MCE handler

* Tony Luck <tony.luck@intel.com> wrote:

> Machine checks on Intel cpus interrupt execution on all cpus, regardless
> of interrupt masking. We have a need to save some data about the cause
> of the machine check (physical address) in the machine check handler that
> can be retrieved later to attempt recovery in a more flexible execution
> state.
>
> Signed-off-by: Tony Luck <tony.luck@intel.com>
> ---
> arch/x86/kernel/cpu/mcheck/mce.c | 51 ++++++++++++++++++++++++++++++++++++++
> 1 files changed, 51 insertions(+), 0 deletions(-)

Just some cleanliness nits:

> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index 43f22c8..9b83b7d 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -887,6 +887,57 @@ static void mce_clear_state(unsigned long *toclear)
> }
>
> /*
> + * Need to save faulting physical address associated with a process
> + * in the machine check handler some place where we can grab it back
> + * later in mce_notify_process()
> + */
> +#define MAX_MCE_INFO 16
> +struct mce_info {

please separate non-bulk definitons by newlines.

> + atomic_t inuse;
> + struct task_struct *t;
> + __u64 paddr;
> +} mce_info[MAX_MCE_INFO];
> +
> +static void mce_save_info(__u64 addr)
> +{
> + int i;

that tab looks weird. [there's repeat occurances further below
as well]

> +
> + for (i = 0; i < MAX_MCE_INFO; i++)
> + if (atomic_cmpxchg(&mce_info[i].inuse, 0, 1) == 0) {
> + mce_info[i].t = current;
> + mce_info[i].paddr = addr;
> + return;
> + }

We typically use curly braces for all multi-line statements - so
two would be needed above.

> +
> + mce_panic("Too many concurrent recoverable errors", NULL, NULL);
> +}
> +
> +static int mce_find_info(__u64 *paddr)
> +{
> + int i;
> +
> + for (i = 0; i < MAX_MCE_INFO; i++)
> + if (atomic_read(&mce_info[i].inuse) &&
> + mce_info[i].t == current) {
> + *paddr = mce_info[i].paddr;
> + return 1;
> + }
> + return 0;
> +}
> +
> +static void mce_clear_info(void)
> +{
> + int i;
> +
> + for (i = 0; i < MAX_MCE_INFO; i++)
> + if (atomic_read(&mce_info[i].inuse) &&
> + mce_info[i].t == current) {

the line-break shows that the code has complexit troubles. Doing
this in the loop iterator:

struct mce_info *mi = mce_info + i;

would help make it shorter and more readable.

Thanks,

Ingo


\
 
 \ /
  Last update: 2011-12-14 08:57    [W:0.108 / U:6.864 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site