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[PATCH v2] tools lib traceevent: str addresses in heterogeneous arch environments

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  [PATCH v2] tools lib traceevent: str addresses in heterogeneous arch environments Kapileshwar Singh <kapileshwar.singh@arm.com> - 2015-09-18 13:00 +0200
    Re: [PATCH v2] tools lib traceevent: str addresses in heterogeneous  arch environments Steven Rostedt <rostedt@goodmis.org> - 2015-09-18 15:50 +0200

#1227766 — [PATCH v2] tools lib traceevent: str addresses in heterogeneous arch environments

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 | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index cc25f059ab3d..bb554e2ae70d 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;
+	uint64_t addr;
 	char *str;
 	unsigned char *hex;
 	int print;
@@ -3754,7 +3754,24 @@ 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 the pointer must be 64-bit long
+			 */
+			addr = *(uint64_t *)(data + field->offset) &
+				((1ULL << pevent->long_size * 8) - 1);
+
 			/* Check if it matches a print format */
 			printk = find_printk(pevent, addr);
 			if (printk)
-- 
1.9.1

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#1227875 — Re: [PATCH v2] tools lib traceevent: str addresses in heterogeneous arch environments

On Fri, 18 Sep 2015 11:57:29 +0100
Kapileshwar Singh <kapileshwar.singh@arm.com> wrote:
\
> @@ -3754,7 +3754,24 @@ 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 the pointer must be 64-bit long
> +			 */
> +			addr = *(uint64_t *)(data + field->offset) &
> +				((1ULL << pevent->long_size * 8) - 1);

As I already replied. The above has two bugs in it.

-- Steve

> +
>  			/* Check if it matches a print format */
>  			printk = find_printk(pevent, addr);
>  			if (printk)

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