[PATCH v3] tools lib traceevent: str addresses in heterogeneous arch environments

[PATCH v3] tools lib traceevent: str addresses in heterogeneous arch environments

[Kapileshwar Singh]

When a trace recorded on a 32-bit device is processed with a 64-bit
binary, the higher 32-bits of the address need to ignored

The lack of this results in the output of the 64-bit pointer
value to the trace as the 32-bit address lookup fails in find_printk.

Before:
burn-1778  [003]   548.600305: bputs:   0xc0046db2s: 2cec5c058d98c

After:
burn-1778  [003]   548.600305: bputs:   0xc0046db2s: RT throttling activated

The problem occurs in PRINT_FEILD when the field is recognized as a pointer
to a string (of the type const char *)

Heterogeneous architectures cases below can arise and should be handled:

* Traces recorded using 32-bit addresses processed on a 64-bit machine
* Traces recorded using 64-bit addresses processed on a 32-bit machine

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Javi Merino <javi.merino@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Reported-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Kapileshwar Singh <kapileshwar.singh@arm.com>
---
 tools/lib/traceevent/event-parse.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index cc25f059ab3d..9916e84e12a5 100644
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -3721,7 +3721,7 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 	struct format_field *field;
 	struct printk_map *printk;
 	long long val, fval;
-	unsigned long addr;
+	unsigned long long addr;
 	char *str;
 	unsigned char *hex;
 	int print;
@@ -3754,13 +3754,31 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
 		 */
 		if (!(field->flags & FIELD_IS_ARRAY) &&
 		    field->size == pevent->long_size) {
-			addr = *(unsigned long *)(data + field->offset);
+
+			/* Handle heterogeneous recording and processing
+			 * architectures
+			 *
+			 * CASE I:
+			 * Traces recorded on 32-bit devices (32-bit
+			 * addressing) and processed on 64-bit devices:
+			 * In this case, the higher 32-bits of the address
+			 * need to be ignored.
+			 *
+			 * CASE II:
+			 * Traces recorded on 64 bit devices and processed
+			 * on 32-bit devices. In this case 64 bits must be
+			 * read.
+			 */
+			addr = (pevent->long_size == 8) ?
+			*(unsigned long long *)(data + field->offset) :
+			(unsigned long long)*(unsigned int *)(data + field->offset);
+
 			/* Check if it matches a print format */
 			printk = find_printk(pevent, addr);
 			if (printk)
 				trace_seq_puts(s, printk->printk);
 			else
-				trace_seq_printf(s, "%lx", addr);
+				trace_seq_printf(s, "%llx", addr);
 			break;
 		}
 		str = malloc(len + 1);
-- 
1.9.1

Re: [PATCH v3] tools lib traceevent: str addresses in heterogeneous arch environments

[Steven Rostedt]

On Mon, 21 Sep 2015 14:24:13 +0100
Kapileshwar Singh <kapileshwar.singh@arm.com> wrote:

Thanks, this is better but one nit (below).

> @@ -3754,13 +3754,31 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
>  		 */
>  		if (!(field->flags & FIELD_IS_ARRAY) &&
>  		    field->size == pevent->long_size) {
> -			addr = *(unsigned long *)(data + field->offset);
> +
> +			/* Handle heterogeneous recording and processing
> +			 * architectures
> +			 *
> +			 * CASE I:
> +			 * Traces recorded on 32-bit devices (32-bit
> +			 * addressing) and processed on 64-bit devices:
> +			 * In this case, the higher 32-bits of the address
> +			 * need to be ignored.
> +			 *
> +			 * CASE II:
> +			 * Traces recorded on 64 bit devices and processed
> +			 * on 32-bit devices. In this case 64 bits must be
> +			 * read.
> +			 */
> +			addr = (pevent->long_size == 8) ?
> +			*(unsigned long long *)(data + field->offset) :
> +			(unsigned long long)*(unsigned int *)(data + field->offset);

Please indent the above lines such that it's not at the same level as
the start. It is a single C command, and needs to be reflected as such.
If it goes more than 80 characters, so be it. The above is worse than a
line a little longer than 80.

-- Steve

> +
>  			/* Check if it matches a print format */
>  			printk = find_printk(pevent, addr);
>  			if (printk)
>  				trace_seq_puts(s, printk->printk);
>  			else
> -				trace_seq_printf(s, "%lx", addr);
> +				trace_seq_printf(s, "%llx", addr);
>  			break;
>  		}
>  		str = malloc(len + 1);

Re: [PATCH v3] tools lib traceevent: str addresses in heterogeneous arch environments

[Kapileshwar Singh]

Hi Steve!

Thanks again for reviewing.

On 21/09/15 14:56, Steven Rostedt wrote:
> On Mon, 21 Sep 2015 14:24:13 +0100
> Kapileshwar Singh <kapileshwar.singh@arm.com> wrote:
> 
> Thanks, this is better but one nit (below).
> 
>> @@ -3754,13 +3754,31 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
>>  		 */
>>  		if (!(field->flags & FIELD_IS_ARRAY) &&
>>  		    field->size == pevent->long_size) {
>> -			addr = *(unsigned long *)(data + field->offset);
>> +
>> +			/* Handle heterogeneous recording and processing
>> +			 * architectures
>> +			 *
>> +			 * CASE I:
>> +			 * Traces recorded on 32-bit devices (32-bit
>> +			 * addressing) and processed on 64-bit devices:
>> +			 * In this case, the higher 32-bits of the address
>> +			 * need to be ignored.
>> +			 *
>> +			 * CASE II:
>> +			 * Traces recorded on 64 bit devices and processed
>> +			 * on 32-bit devices. In this case 64 bits must be
>> +			 * read.
>> +			 */
>> +			addr = (pevent->long_size == 8) ?
>> +			*(unsigned long long *)(data + field->offset) :
>> +			(unsigned long long)*(unsigned int *)(data + field->offset);
> 
> Please indent the above lines such that it's not at the same level as
> the start. It is a single C command, and needs to be reflected as such.
> If it goes more than 80 characters, so be it. The above is worse than a
> line a little longer than 80.
> 

Makes sense. Will send an updated version.

Regards, 
KP

> -- Steve
> 
>> +
>>  			/* Check if it matches a print format */
>>  			printk = find_printk(pevent, addr);
>>  			if (printk)
>>  				trace_seq_puts(s, printk->printk);
>>  			else
>> -				trace_seq_printf(s, "%lx", addr);
>> +				trace_seq_printf(s, "%llx", addr);
>>  			break;
>>  		}
>>  		str = malloc(len + 1);
>