[patch] update perf_event_open() for Linux 3.19

[patch] update perf_event_open() for Linux 3.19

[Vince Weaver]

This updates the perf_event_open support to match changes made with the 
upcoming 3.19 release.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

diff --git a/include/perf_event.h b/include/perf_event.h
index 51cd111..b331ae4 100644
--- a/include/perf_event.h
+++ b/include/perf_event.h
@@ -136,8 +136,9 @@ enum perf_event_sample_format {
 	PERF_SAMPLE_DATA_SRC			= 1U << 15,
 	PERF_SAMPLE_IDENTIFIER			= 1U << 16,
 	PERF_SAMPLE_TRANSACTION			= 1U << 17,
+	PERF_SAMPLE_REGS_INTR			= 1U << 18,
 
-	PERF_SAMPLE_MAX = 1U << 18,		/* non-ABI */
+	PERF_SAMPLE_MAX = 1U << 19,		/* non-ABI */
 };
 
 /*
@@ -237,6 +238,7 @@ enum perf_event_read_format {
 #define PERF_ATTR_SIZE_VER2	80	/* add: branch_sample_type */
 #define PERF_ATTR_SIZE_VER3	96	/* add: sample_regs_user */
 					/* add: sample_stack_user */
+#define PERF_ATTR_SIZE_VER4	104	/* add: sample_regs_intr */
 
 /*
  * Hardware event_id to monitor via a performance monitoring event:
@@ -333,6 +335,15 @@ struct perf_event_attr {
 
 	/* Align to u64. */
 	__u32	__reserved_2;
+	/*
+	 * Defines set of regs to dump for each sample
+	 * state captured on:
+	 *  - precise = 0: PMU interrupt
+	 *  - precise > 0: sampled instruction
+	 *
+	 * See asm/perf_regs.h for details.
+	 */
+	__u64	sample_regs_intr;
 };
 
 #define perf_flags(attr)	(*(&(attr)->read_format + 1))
@@ -363,7 +374,7 @@ struct perf_event_mmap_page {
 	/*
 	 * Bits needed to read the hw events in user-space.
 	 *
-	 *   u32 seq, time_mult, time_shift, idx, width;
+	 *   u32 seq, time_mult, time_shift, index, width;
 	 *   u64 count, enabled, running;
 	 *   u64 cyc, time_offset;
 	 *   s64 pmc = 0;
@@ -382,11 +393,11 @@ struct perf_event_mmap_page {
 	 *       time_shift  = pc->time_shift;
 	 *     }
 	 *
-	 *     idx = pc->index;
+	 *     index = pc->index;
 	 *     count = pc->offset;
-	 *     if (pc->cap_usr_rdpmc && idx) {
+	 *     if (pc->cap_user_rdpmc && index) {
 	 *       width = pc->pmc_width;
-	 *       pmc = rdpmc(idx - 1);
+	 *       pmc = rdpmc(index - 1);
 	 *     }
 	 *
 	 *     barrier();
@@ -414,7 +425,7 @@ struct perf_event_mmap_page {
 	};
 
 	/*
-	 * If cap_usr_rdpmc this field provides the bit-width of the value
+	 * If cap_user_rdpmc this field provides the bit-width of the value
 	 * read using the rdpmc() or equivalent instruction. This can be used
 	 * to sign extend the result like:
 	 *
@@ -438,10 +449,10 @@ struct perf_event_mmap_page {
 	 *
 	 * Where time_offset,time_mult,time_shift and cyc are read in the
 	 * seqcount loop described above. This delta can then be added to
-	 * enabled and possible running (if idx), improving the scaling:
+	 * enabled and possible running (if index), improving the scaling:
 	 *
 	 *   enabled += delta;
-	 *   if (idx)
+	 *   if (index)
 	 *     running += delta;
 	 *
 	 *   quot = count / running;
@@ -685,6 +696,8 @@ enum perf_event_type {
 	 *	{ u64			weight;   } && PERF_SAMPLE_WEIGHT
 	 *	{ u64			data_src; } && PERF_SAMPLE_DATA_SRC
 	 *	{ u64			transaction; } && PERF_SAMPLE_TRANSACTION
+	 *	{ u64			abi; # enum perf_sample_regs_abi
+	 *	  u64			regs[weight(mask)]; } && PERF_SAMPLE_REGS_INTR
 	 * };
 	 */
 	PERF_RECORD_SAMPLE			= 9,
diff --git a/syscalls/perf_event_open.c b/syscalls/perf_event_open.c
index 12bc04a..7f68375 100644
--- a/syscalls/perf_event_open.c
+++ b/syscalls/perf_event_open.c
@@ -870,6 +870,8 @@ static long long random_sample_type(void)
 		sample_type |= PERF_SAMPLE_IDENTIFIER;
 	if (rand_bool())
 		sample_type |= PERF_SAMPLE_TRANSACTION;
+	if (rand_bool())
+		sample_type |= PERF_SAMPLE_REGS_INTR;
 
 	return sample_type;
 }
@@ -898,7 +900,7 @@ static int random_attr_size(void) {
 
 	int size=0;
 
-	switch(rand() % 8) {
+	switch(rand() % 9) {
 	case 0:	size = PERF_ATTR_SIZE_VER0;
 		break;
 	case 1: size = PERF_ATTR_SIZE_VER1;
@@ -907,13 +909,15 @@ static int random_attr_size(void) {
 		break;
 	case 3: size = PERF_ATTR_SIZE_VER3;
 		break;
-	case 4: size = sizeof(struct perf_event_attr);
+	case 4: size = PERF_ATTR_SIZE_VER4;
+		break;
+	case 5: size = sizeof(struct perf_event_attr);
 		break;
-	case 5: size = rand32();
+	case 6: size = rand32();
 		break;
-	case 6:	size = get_len();
+	case 7:	size = get_len();
 		break;
-	case 7: size = 0;
+	case 8: size = 0;
 		break;
 	default:
 		break;

Re: [patch] update perf_event_open() for Linux 3.19

[Dave Jones]

On Tue, Feb 03, 2015 at 12:01:23PM -0500, Vince Weaver wrote:


 > @@ -237,6 +238,7 @@ enum perf_event_read_format {
 >  #define PERF_ATTR_SIZE_VER2	80	/* add: branch_sample_type */
 >  #define PERF_ATTR_SIZE_VER3	96	/* add: sample_regs_user */
 >  					/* add: sample_stack_user */
 > +#define PERF_ATTR_SIZE_VER4	104	/* add: sample_regs_intr */

I've not given this a lot of thought before, but I'm assuming these
are the 64-bit struct sizes.  It might be interesting to also
throw some 32-bit sizes in the mix.  Who knows what horrors
lie in wait for the compat syscalls.

	Dave

Re: [patch] update perf_event_open() for Linux 3.19

[Vince Weaver]

On Wed, 4 Feb 2015, Dave Jones wrote:

> On Tue, Feb 03, 2015 at 12:01:23PM -0500, Vince Weaver wrote:
> 
> 
>  > @@ -237,6 +238,7 @@ enum perf_event_read_format {
>  >  #define PERF_ATTR_SIZE_VER2	80	/* add: branch_sample_type */
>  >  #define PERF_ATTR_SIZE_VER3	96	/* add: sample_regs_user */
>  >  					/* add: sample_stack_user */
>  > +#define PERF_ATTR_SIZE_VER4	104	/* add: sample_regs_intr */
> 
> I've not given this a lot of thought before, but I'm assuming these
> are the 64-bit struct sizes.  It might be interesting to also
> throw some 32-bit sizes in the mix.  Who knows what horrors
> lie in wait for the compat syscalls.

I might be misunderstanding, but I think the attr structure is defined in 
a way that it has the same size on 32 and 64 bit.

Now, there are bitfields mixed into the interface so it causes some 
unspeakable horrors if you try to do cross-endian stuff (as some powerpc 
people have discovered), but I think as far as structure size goes the 
interface is clear.

I do have to admit though that at least the perf_fuzzer only does native 
calls to the system calls so I never stress the compat code at all.

Vince

Re: [patch] update perf_event_open() for Linux 3.19

[Dave Jones]

On Wed, Feb 04, 2015 at 03:41:17PM -0500, Vince Weaver wrote:
 > On Wed, 4 Feb 2015, Dave Jones wrote:
 > 
 > > On Tue, Feb 03, 2015 at 12:01:23PM -0500, Vince Weaver wrote:
 > > 
 > > 
 > >  > @@ -237,6 +238,7 @@ enum perf_event_read_format {
 > >  >  #define PERF_ATTR_SIZE_VER2	80	/* add: branch_sample_type */
 > >  >  #define PERF_ATTR_SIZE_VER3	96	/* add: sample_regs_user */
 > >  >  					/* add: sample_stack_user */
 > >  > +#define PERF_ATTR_SIZE_VER4	104	/* add: sample_regs_intr */
 > > 
 > > I've not given this a lot of thought before, but I'm assuming these
 > > are the 64-bit struct sizes.  It might be interesting to also
 > > throw some 32-bit sizes in the mix.  Who knows what horrors
 > > lie in wait for the compat syscalls.
 > 
 > I might be misunderstanding, but I think the attr structure is defined in 
 > a way that it has the same size on 32 and 64 bit.

ah, ok. Yeah, now that I look at the struct definition, it's all
u32/u64's, so this is the same size on both archs.

	Dave