lkml.org 
[lkml]   [2017]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRE: [PATCH V5] perf: Add PERF_SAMPLE_PHYS_ADDR
Date
> On Thu, Aug 17, 2017 at 02:17:23PM -0400, kan.liang@intel.com wrote:
> > diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> > index a322fed..f0e8d9c 100644
> > --- a/arch/x86/events/intel/ds.c
> > +++ b/arch/x86/events/intel/ds.c
> > @@ -1065,6 +1065,35 @@ static inline u64 intel_hsw_transaction(struct
> pebs_record_skl *pebs)
> > return txn;
> > }
> >
> > +static u64 dla_to_phys(u64 dla)
> > +{
> > + u64 phys_addr = 0;
> > + struct page *p = NULL;
> > +
> > + if (dla >= TASK_SIZE) {
> > + /* If it's vmalloc()d memory, leave phys_addr as 0 */
> > + if (virt_addr_valid(dla) &&
> > + !(dla >= VMALLOC_START && dla < VMALLOC_END))
> > + phys_addr = (u64)virt_to_phys((void *)(uintptr_t)dla);
> > + } else {
> > + /*
> > + * Walking the pages tables for user address.
> > + * Interrupts are disabled, so it prevents any tear down
> > + * of the page tables.
> > + * Try IRQ-safe __get_user_pages_fast first.
> > + * If failed, leave phys_addr as 0.
> > + */
> > + if ((current->mm != NULL) &&
> > + (__get_user_pages_fast(dla, 1, 0, &p) == 1))
> > + phys_addr = page_to_phys(p) + dla % PAGE_SIZE;
> > +
> > + if (p)
> > + put_page(p);
> > + }
> > +
> > + return phys_addr;
> > +}
>
> Is this in any way x86 specific? AFAICT this should work in generic code as
> long as data->addr is provided.

No, it's not X86 specific. I think it can be used as generic code to convert
virtual address to physical address.

Thanks,
Kan
>
> > static void setup_pebs_sample_data(struct perf_event *event,
> > struct pt_regs *iregs, void *__pebs,
> > struct perf_sample_data *data, @@ -
> 1179,6 +1208,9 @@ static
> > void setup_pebs_sample_data(struct perf_event *event,
> > x86_pmu.intel_cap.pebs_format >= 1)
> > data->addr = pebs->dla;
> >
> > + if ((sample_type & PERF_SAMPLE_PHYS_ADDR) && (data->addr != 0))
> > + data->phys_addr = dla_to_phys(data->addr);
> > +
> > if (x86_pmu.intel_cap.pebs_format >= 2) {
> > /* Only set the TSX weight when no memory weight. */
> > if ((sample_type & PERF_SAMPLE_WEIGHT) && !fll)
>

\
 
 \ /
  Last update: 2017-08-22 19:18    [W:0.052 / U:1.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site