perf test: test_intel_pt.sh: Add jitdump test

Add a test for decoding self-modifying code using a jitdump file.

The test creates a workload that uses self-modifying code and generates its
own jitdump file.  The result is processed with perf inject --jit and
checked for decoding errors.

Note the test will fail without patch "perf inject: Fix GEN_ELF_TEXT_OFFSET
for jit" applied.

Signed-off-by: Adrian Hunter <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: ahunter6

tools/perf/tests/shell/test_intel_pt.sh

@@ -22,6 +22,7 @@ outfile="${temp_dir}/test-out.txt"
 errfile="${temp_dir}/test-err.txt"
 workload="${temp_dir}/workload"
 awkscript="${temp_dir}/awkscript"
+jitdump_workload="${temp_dir}/jitdump_workload"
 
 cleanup()
 {
@@ -50,6 +51,13 @@ perf_record_no_decode()
 	perf record -B -N --no-bpf-event "$@"
 }
 
+# perf record for testing should not need BPF events
+perf_record_no_bpf()
+{
+	# Options for no BPF events
+	perf record --no-bpf-event "$@"
+}
+
 have_workload=false
 cat << _end_of_file_ | /usr/bin/cc -o "${workload}" -xc - -pthread && have_workload=true
 #include <time.h>
@@ -269,6 +277,159 @@ test_per_thread()
 	return 0
 }
 
+test_jitdump()
+{
+	echo "--- Test tracing self-modifying code that uses jitdump ---"
+
+	script_path=$(realpath "$0")
+	script_dir=$(dirname "$script_path")
+	jitdump_incl_dir="${script_dir}/../../util"
+	jitdump_h="${jitdump_incl_dir}/jitdump.h"
+
+	if [ ! -e "${jitdump_h}" ] ; then
+		echo "SKIP: Include file jitdump.h not found"
+		return 2
+	fi
+
+	if [ -z "${have_jitdump_workload}" ] ; then
+		have_jitdump_workload=false
+		# Create a workload that uses self-modifying code and generates its own jitdump file
+		cat <<- "_end_of_file_" | /usr/bin/cc -o "${jitdump_workload}" -I "${jitdump_incl_dir}" -xc - -pthread && have_jitdump_workload=true
+		#define _GNU_SOURCE
+		#include <sys/mman.h>
+		#include <sys/types.h>
+		#include <stddef.h>
+		#include <stdio.h>
+		#include <stdint.h>
+		#include <unistd.h>
+		#include <string.h>
+
+		#include "jitdump.h"
+
+		#define CHK_BYTE 0x5a
+
+		static inline uint64_t rdtsc(void)
+		{
+			unsigned int low, high;
+
+			asm volatile("rdtsc" : "=a" (low), "=d" (high));
+
+			return low | ((uint64_t)high) << 32;
+		}
+
+		static FILE *open_jitdump(void)
+		{
+			struct jitheader header = {
+				.magic      = JITHEADER_MAGIC,
+				.version    = JITHEADER_VERSION,
+				.total_size = sizeof(header),
+				.pid        = getpid(),
+				.timestamp  = rdtsc(),
+				.flags      = JITDUMP_FLAGS_ARCH_TIMESTAMP,
+			};
+			char filename[256];
+			FILE *f;
+			void *m;
+
+			snprintf(filename, sizeof(filename), "jit-%d.dump", getpid());
+			f = fopen(filename, "w+");
+			if (!f)
+				goto err;
+			/* Create an MMAP event for the jitdump file. That is how perf tool finds it. */
+			m = mmap(0, 4096, PROT_READ | PROT_EXEC, MAP_PRIVATE, fileno(f), 0);
+			if (m == MAP_FAILED)
+				goto err_close;
+			munmap(m, 4096);
+			if (fwrite(&header,sizeof(header),1,f) != 1)
+				goto err_close;
+			return f;
+
+		err_close:
+			fclose(f);
+		err:
+			return NULL;
+		}
+
+		static int write_jitdump(FILE *f, void *addr, const uint8_t *dat, size_t sz, uint64_t *idx)
+		{
+			struct jr_code_load rec = {
+				.p.id          = JIT_CODE_LOAD,
+				.p.total_size  = sizeof(rec) + sz,
+				.p.timestamp   = rdtsc(),
+				.pid	       = getpid(),
+				.tid	       = gettid(),
+				.vma           = (unsigned long)addr,
+				.code_addr     = (unsigned long)addr,
+				.code_size     = sz,
+				.code_index    = ++*idx,
+			};
+
+			if (fwrite(&rec,sizeof(rec),1,f) != 1 ||
+			fwrite(dat, sz, 1, f) != 1)
+				return -1;
+			return 0;
+		}
+
+		static void close_jitdump(FILE *f)
+		{
+			fclose(f);
+		}
+
+		int main()
+		{
+			/* Get a memory page to store executable code */
+			void *addr = mmap(0, 4096, PROT_WRITE | PROT_EXEC, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+			/* Code to execute: mov CHK_BYTE, %eax ; ret */
+			uint8_t dat[] = {0xb8, CHK_BYTE, 0x00, 0x00, 0x00, 0xc3};
+			FILE *f = open_jitdump();
+			uint64_t idx = 0;
+			int ret = 1;
+
+			if (!f)
+				return 1;
+			/* Copy executable code to executable memory page */
+			memcpy(addr, dat, sizeof(dat));
+			/* Record it in the jitdump file */
+			if (write_jitdump(f, addr, dat, sizeof(dat), &idx))
+				goto out_close;
+			/* Call it */
+			ret = ((int (*)(void))addr)() - CHK_BYTE;
+		out_close:
+			close_jitdump(f);
+			return ret;
+		}
+		_end_of_file_
+	fi
+
+	if ! $have_jitdump_workload ; then
+		echo "SKIP: No jitdump workload"
+		return 2
+	fi
+
+	# Change to temp_dir so jitdump collateral files go there
+	cd "${temp_dir}"
+	perf_record_no_bpf -o "${tmpfile}" -e intel_pt//u "${jitdump_workload}"
+	perf inject -i "${tmpfile}" -o "${perfdatafile}" --jit
+	decode_br_cnt=$(perf script -i "${perfdatafile}" --itrace=b | wc -l)
+	# Note that overflow and lost errors are suppressed for the error count
+	decode_err_cnt=$(perf script -i "${perfdatafile}" --itrace=e-o-l | grep -ci error)
+	cd -
+	# Should be thousands of branches
+	if [ "${decode_br_cnt}" -lt 1000 ] ; then
+		echo "Decode failed, only ${decode_br_cnt} branches"
+		return 1
+	fi
+	# Should be no errors
+	if [ "${decode_err_cnt}" -ne 0 ] ; then
+		echo "Decode failed, ${decode_err_cnt} errors"
+		perf script -i "${perfdatafile}" --itrace=e-o-l
+		return 1
+	fi
+
+	echo OK
+	return 0
+}
+
 count_result()
 {
 	if [ "$1" -eq 2 ] ; then
@@ -286,6 +447,7 @@ ret=0
 test_system_wide_side_band		|| ret=$? ; count_result $ret ; ret=0
 test_per_thread "" ""			|| ret=$? ; count_result $ret ; ret=0
 test_per_thread "k" "(incl. kernel) "	|| ret=$? ; count_result $ret ; ret=0
+test_jitdump				|| ret=$? ; count_result $ret ; ret=0
 
 cleanup