Messages in this thread Patch in this message | | | From | Tony Luck <> | Date | Mon, 12 Dec 2011 13:06:02 -0800 | Subject | [PATCH 4/6] x86, mce: Add mechanism to safely save information in MCE handler |
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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(-)
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 { + atomic_t inuse; + struct task_struct *t; + __u64 paddr; +} mce_info[MAX_MCE_INFO]; + +static void mce_save_info(__u64 addr) +{ + int i; + + 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; + } + + 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) { + atomic_set(&mce_info[i].inuse, 0); + return; + } +} + +/* * The actual machine check handler. This only handles real * exceptions when something got corrupted coming in through int 18. * -- 1.7.3.1
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