tree: Remove non-standard "%ph" printf format

The non-standard "%ph" format is replaced with snprintf_hex_buffer and
then using "%s" to print the resulting buffer.

Using standard format specifiers makes it easier to switch between the
"builtin" EC standard library and the C standard library provided by the
toolchain (or Zephyr).

BRANCH=none
BUG=b:238433667, b:234181908
TEST=Enable CONFIG_CMD_RAND in nocturne_fp/board.h
     On icetower v0.1 with servo_micro and J-Trace:

     Before change:
     > rand
     rand 8ab8b15090ca5ae83bdad671c906d51a5f2b98a359a4106054ee6b54a4087190

     After change:
     > rand
     rand 2a8645235a31936a28b8d1b9c4948f46d39662e7fcb10a185ddb14c6a998e2eb

Signed-off-by: Tom Hughes <tomhughes@chromium.org>
Change-Id: I3bff928d32579440d7cdb27a75899e45159accfb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3759123
Reviewed-by: Denis Brockus <dbrockus@chromium.org>

15 files changed, 151 insertions, 78 deletions

diff --git a/chip/it83xx/i2c_peripheral.c b/chip/it83xx/i2c_peripheral.c
index c5455327a0..e12173c690 100644
--- a/chip/it83xx/i2c_peripheral.c
+++ b/chip/it83xx/i2c_peripheral.c
@@ -10,6 +10,7 @@
 #include "gpio.h"
 #include "hooks.h"
 #include "i2c_peripheral.h"
+#include "printf.h"
 #include "registers.h"
 #include <stddef.h>
 #include <string.h>
@@ -178,13 +179,17 @@ void i2c_peripheral_read_write_data(int port)
 			/* Peripheral finish */
 			if (periph_status & IT83XX_I2C_P_CLR) {
 				if (wr_done[idx]) {
+					char str_buf[hex_str_buf_size(
+						I2C_MAX_BUFFER_SIZE)];
 					/*
 					 * TODO(b:129360157): Handle controller
 					 * write data by "in_data" array.
 					 */
-					CPRINTS("WData: %ph",
+					snprintf_hex_buffer(
+						str_buf, sizeof(str_buf),
 						HEX_BUF(in_data[idx],
 							I2C_MAX_BUFFER_SIZE));
+					CPRINTS("WData: %s", str_buf);
 					wr_done[idx] = 0;
 				}
 			}
diff --git a/chip/stm32/trng.c b/chip/stm32/trng.c
index 6538263add..a975c4c584 100644
--- a/chip/stm32/trng.c
+++ b/chip/stm32/trng.c
@@ -9,6 +9,7 @@
 #include "console.h"
 #include "host_command.h"
 #include "panic.h"
+#include "printf.h"
 #include "registers.h"
 #include "system.h"
 #include "task.h"
@@ -106,12 +107,15 @@ test_mockable void trng_exit(void)
 static int command_rand(int argc, char **argv)
 {
 	uint8_t data[32];
+	char str_buf[hex_str_buf_size(sizeof(data))];
 
 	trng_init();
 	trng_rand_bytes(data, sizeof(data));
 	trng_exit();
 
-	ccprintf("rand %ph\n", HEX_BUF(data, sizeof(data)));
+	snprintf_hex_buffer(str_buf, sizeof(str_buf),
+			    HEX_BUF(data, sizeof(data)));
+	ccprintf("rand %s\n", str_buf);
 
 	return EC_SUCCESS;
 }
diff --git a/common/host_command.c b/common/host_command.c
index 417a2f3465..a2d8defbef 100644
--- a/common/host_command.c
+++ b/common/host_command.c
@@ -655,10 +655,14 @@ static void host_command_debug_request(struct host_cmd_handler_args *args)
 		hc_prev_cmd = args->command;
 	}
 
-	if (hcdebug >= HCDEBUG_PARAMS && args->params_size)
-		CPRINTS("HC 0x%04x.%d:%ph", args->command, args->version,
-			HEX_BUF(args->params, args->params_size));
-	else
+	if (hcdebug >= HCDEBUG_PARAMS && args->params_size) {
+		char str_buf[hex_str_buf_size(args->params_size)];
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(args->params, args->params_size));
+		CPRINTS("HC 0x%04x.%d:%s", args->command, args->version,
+			str_buf);
+	} else
 		CPRINTS("HC 0x%04x", args->command);
 }
 
@@ -714,9 +718,14 @@ uint16_t host_command_process(struct host_cmd_handler_args *args)
 	if (rv != EC_RES_SUCCESS)
 		CPRINTS("HC 0x%04x err %d", args->command, rv);
 
-	if (hcdebug >= HCDEBUG_PARAMS && args->response_size)
-		CPRINTS("HC resp:%ph",
-			HEX_BUF(args->response, args->response_size));
+	if (hcdebug >= HCDEBUG_PARAMS && args->response_size) {
+		char str_buf[hex_str_buf_size(args->response_size)];
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(args->response,
+					    args->response_size));
+		CPRINTS("HC resp:%s", str_buf);
+	}
 
 	return rv;
 }
@@ -878,10 +887,13 @@ static int command_host_command(int argc, char **argv)
 
 	if (res != EC_RES_SUCCESS)
 		ccprintf("Command returned %d\n", res);
-	else if (args.response_size)
-		ccprintf("Response: %ph\n",
-			 HEX_BUF(cmd_params, args.response_size));
-	else
+	else if (args.response_size) {
+		char str_buf[hex_str_buf_size(args.response_size)];
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(cmd_params, args.response_size));
+		ccprintf("Response: %s\n", str_buf);
+	} else
 		ccprintf("Command succeeded; no response.\n");
 
 	shared_mem_release(cmd_params);
diff --git a/common/i2c_controller.c b/common/i2c_controller.c
index ea85f80a14..cc7dad9bed 100644
--- a/common/i2c_controller.c
+++ b/common/i2c_controller.c
@@ -15,6 +15,7 @@
 #include "i2c.h"
 #include "i2c_bitbang.h"
 #include "i2c_private.h"
+#include "printf.h"
 #include "system.h"
 #include "task.h"
 #include "usb_pd.h"
@@ -1710,8 +1711,13 @@ static int command_i2cxfer(int argc, char **argv)
 
 		rv = i2c_xfer(port, addr_flags, (uint8_t *)&offset, 1, data, v);
 
-		if (!rv)
-			ccprintf("Data: %ph\n", HEX_BUF(data, v));
+		if (!rv) {
+			char str_buf[hex_str_buf_size(v)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(data, v));
+			ccprintf("Data: %s\n", str_buf);
+		}
 
 	} else if (strcasecmp(argv[1], "w") == 0) {
 		/* 8-bit write */
@@ -1780,9 +1786,13 @@ static int command_i2cxfer(int argc, char **argv)
 					       read_count,
 					       I2C_XFER_START | I2C_XFER_STOP);
 			i2c_lock(port, 0);
-			if (!rv)
-				ccprintf("Data: %ph\n",
-					 HEX_BUF(data, read_count));
+			if (!rv) {
+				char str_buf[hex_str_buf_size(read_count)];
+
+				snprintf_hex_buffer(str_buf, sizeof(str_buf),
+						    HEX_BUF(data, read_count));
+				ccprintf("Data: %s\n", str_buf);
+			}
 		}
 #endif /* CONFIG_CMD_I2C_XFER_RAW */
 	} else {
diff --git a/common/peci.c b/common/peci.c
index dc17f86a56..5acc49dfd2 100644
--- a/common/peci.c
+++ b/common/peci.c
@@ -8,6 +8,7 @@
 #include "chipset.h"
 #include "console.h"
 #include "peci.h"
+#include "printf.h"
 #include "util.h"
 
 static int peci_get_cpu_temp(int *cpu_temp)
@@ -139,9 +140,15 @@ static int peci_cmd(int argc, char **argv)
 	if (peci_transaction(&peci)) {
 		ccprintf("PECI transaction error\n");
 		return EC_ERROR_UNKNOWN;
+	} else {
+		char str_buf[hex_str_buf_size(peci.r_len)];
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(r_buf, sizeof(str_buf)));
+		ccprintf("PECI read data: %s\n", str_buf);
+
+		return EC_SUCCESS;
 	}
-	ccprintf("PECI read data: %ph\n", HEX_BUF(r_buf, peci.r_len));
-	return EC_SUCCESS;
 }
 DECLARE_CONSOLE_COMMAND(peci, peci_cmd, "addr wlen rlen cmd timeout(us)",
 			"PECI command");
diff --git a/common/printf.c b/common/printf.c
index b3e9d45109..f25a5ac0b2 100644
--- a/common/printf.c
+++ b/common/printf.c
@@ -393,28 +393,9 @@ int vfnprintf(int (*addchar)(void *context, int c), void *context,
 				ptrspec = *format++;
 				ptrval = va_arg(args, void *);
 				/*
-				 * Avoid null pointer dereference for %ph.
 				 * %pP can accept null.
 				 */
-				if (ptrval == NULL && ptrspec != 'P')
-					continue;
-				else if (ptrspec == 'h') {
-					/* %ph - Print a hex byte buffer. */
-					struct hex_buffer_params *hexbuf =
-						ptrval;
-					int rc;
-
-					rc = print_hex_buffer(addchar, context,
-							      hexbuf->buffer,
-							      hexbuf->size, 0,
-							      0);
-
-					if (rc != EC_SUCCESS)
-						return rc;
-
-					continue;
-
-				} else if (ptrspec == 'P') {
+				if (ptrspec == 'P') {
 					/* %pP - Print a raw pointer. */
 					v = (unsigned long)ptrval;
 					base = 16;
diff --git a/common/spi_commands.c b/common/spi_commands.c
index 45c2f3ce70..b51609d257 100644
--- a/common/spi_commands.c
+++ b/common/spi_commands.c
@@ -8,6 +8,7 @@
 
 #include "common.h"
 #include "console.h"
+#include "printf.h"
 #include "spi.h"
 #include "timer.h"
 #include "util.h"
@@ -45,8 +46,13 @@ static int command_spixfer(int argc, char **argv)
 
 		rv = spi_transaction(&spi_devices[dev_id], &cmd, 1, data, v);
 
-		if (!rv)
-			ccprintf("Data: %ph\n", HEX_BUF(data, v));
+		if (!rv) {
+			char str_buf[hex_str_buf_size(v)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(data, v));
+			ccprintf("Data: %s\n", str_buf);
+		}
 
 	} else if (strcasecmp(argv[1], "w") == 0) {
 		/* 8-bit write */
diff --git a/common/usb_host_command.c b/common/usb_host_command.c
index e4872750dd..697885a1f7 100644
--- a/common/usb_host_command.c
+++ b/common/usb_host_command.c
@@ -9,6 +9,7 @@
 #include "ec_commands.h"
 #include "queue_policies.h"
 #include "host_command.h"
+#include "printf.h"
 #include "system.h"
 #include "usb_api.h"
 #include "usb_hw.h"
@@ -161,8 +162,13 @@ static void usbhc_written(struct consumer const *consumer, size_t count)
 		block_index = 0;
 		/* Only version 3 is supported. Using in_msg as a courtesy. */
 		QUEUE_REMOVE_UNITS(consumer->queue, in_msg, count);
-		if (IS_ENABLED(DEBUG))
-			CPRINTS("%ph", HEX_BUF(in_msg, count));
+		if (IS_ENABLED(DEBUG)) {
+			char str_buf[hex_str_buf_size(count)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(in_msg, count));
+			CPRINTS("%s", str_buf);
+		}
 		if (in_msg[0] != EC_HOST_REQUEST_VERSION) {
 			CPRINTS("Unsupported version: %u", in_msg[0]);
 			return;
diff --git a/common/vboot_hash.c b/common/vboot_hash.c
index fe32f774eb..bb51858374 100644
--- a/common/vboot_hash.c
+++ b/common/vboot_hash.c
@@ -11,6 +11,7 @@
 #include "flash.h"
 #include "hooks.h"
 #include "host_command.h"
+#include "printf.h"
 #include "sha256.h"
 #include "shared_mem.h"
 #include "stdbool.h"
@@ -130,6 +131,8 @@ static void hash_next_chunk(size_t size)
 
 static void vboot_hash_all_chunks(void)
 {
+	char str_buf[hex_str_buf_size(SHA256_PRINT_SIZE)];
+
 	do {
 		size_t size = MIN(CHUNK_SIZE, data_size - curr_pos);
 		hash_next_chunk(size);
@@ -137,7 +140,9 @@ static void vboot_hash_all_chunks(void)
 	} while (curr_pos < data_size);
 
 	hash = SHA256_final(&ctx);
-	CPRINTS("hash done %ph", HEX_BUF(hash, SHA256_PRINT_SIZE));
+	snprintf_hex_buffer(str_buf, sizeof(str_buf),
+			    HEX_BUF(hash, SHA256_PRINT_SIZE));
+	CPRINTS("hash done %s", str_buf);
 	in_progress = 0;
 	clock_enable_module(MODULE_FAST_CPU, 0);
 
@@ -165,9 +170,14 @@ static void vboot_hash_next_chunk(void)
 
 	curr_pos += size;
 	if (curr_pos >= data_size) {
+		char str_buf[hex_str_buf_size(SHA256_PRINT_SIZE)];
+
 		/* Store the final hash */
 		hash = SHA256_final(&ctx);
-		CPRINTS("hash done %ph", HEX_BUF(hash, SHA256_PRINT_SIZE));
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(hash, SHA256_PRINT_SIZE));
+		CPRINTS("hash done %s", str_buf);
 
 		in_progress = 0;
 
@@ -343,9 +353,13 @@ static int command_hash(int argc, char **argv)
 			ccprintf("(aborting)\n");
 		else if (in_progress)
 			ccprintf("(in progress)\n");
-		else if (hash)
-			ccprintf("%ph\n", HEX_BUF(hash, SHA256_DIGEST_SIZE));
-		else
+		else if (hash) {
+			char str_buf[hex_str_buf_size(SHA256_DIGEST_SIZE)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(hash, SHA256_DIGEST_SIZE));
+			ccprintf("%s\n", str_buf);
+		} else
 			ccprintf("(invalid)\n");
 
 		return EC_SUCCESS;
diff --git a/driver/nfc/ctn730.c b/driver/nfc/ctn730.c
index 16ab40d025..ea7eeb29df 100644
--- a/driver/nfc/ctn730.c
+++ b/driver/nfc/ctn730.c
@@ -10,6 +10,7 @@
 #include "gpio.h"
 #include "i2c.h"
 #include "peripheral_charger.h"
+#include "printf.h"
 #include "timer.h"
 #include "util.h"
 #include "watchdog.h"
@@ -256,8 +257,13 @@ static int _process_payload_response(struct pchg *ctx, struct ctn730_msg *res)
 		int rv = _i2c_read(ctx->cfg->i2c_port, buf, len);
 		if (rv)
 			return rv;
-		if (IS_ENABLED(CTN730_DEBUG))
-			CPRINTS("Payload: %ph", HEX_BUF(buf, len));
+		if (IS_ENABLED(CTN730_DEBUG)) {
+			char str_buf[hex_str_buf_size(len)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(buf, len));
+			CPRINTS("Payload: %s", str_buf);
+		}
 	}
 
 	ctx->event = PCHG_EVENT_NONE;
@@ -357,8 +363,13 @@ static int _process_payload_event(struct pchg *ctx, struct ctn730_msg *res)
 		int rv = _i2c_read(ctx->cfg->i2c_port, buf, len);
 		if (rv)
 			return rv;
-		if (IS_ENABLED(CTN730_DEBUG))
-			CPRINTS("Payload: %ph", HEX_BUF(buf, len));
+		if (IS_ENABLED(CTN730_DEBUG)) {
+			char str_buf[hex_str_buf_size(len)];
+
+			snprintf_hex_buffer(str_buf, sizeof(str_buf),
+					    HEX_BUF(buf, len));
+			CPRINTS("Payload: %s", str_buf);
+		}
 	}
 
 	ctx->event = PCHG_EVENT_NONE;
diff --git a/driver/touchpad_st.c b/driver/touchpad_st.c
index db45b951c6..e5fab5ef7d 100644
--- a/driver/touchpad_st.c
+++ b/driver/touchpad_st.c
@@ -11,6 +11,7 @@
 #include "hwtimer.h"
 #include "hooks.h"
 #include "i2c.h"
+#include "printf.h"
 #include "registers.h"
 #include "spi.h"
 #include "task.h"
@@ -578,7 +579,7 @@ static void dump_error(void)
 static void dump_memory(void)
 {
 	uint32_t size = 0x10000, rx_len = 512 + ST_TP_EXTRA_BYTE;
-	uint32_t offset, i;
+	uint32_t offset, i, j;
 	uint8_t cmd[] = { 0xFB, 0x00, 0x10, 0x00, 0x00 };
 
 	if (!dump_memory_on_error)
@@ -591,16 +592,16 @@ static void dump_memory(void)
 				rx_len);
 
 		for (i = 0; i < rx_len - ST_TP_EXTRA_BYTE; i += 32) {
-			CPRINTF("%ph %ph %ph %ph "
-				"%ph %ph %ph %ph\n",
-				HEX_BUF(rx_buf.bytes + i + 4 * 0, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 1, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 2, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 3, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 4, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 5, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 6, 4),
-				HEX_BUF(rx_buf.bytes + i + 4 * 7, 4));
+			for (j = 0; j < 8; j++) {
+				char str_buf[hex_str_buf_size(4)];
+
+				snprintf_hex_buffer(
+					str_buf, sizeof(str_buf),
+					HEX_BUF(rx_buf.bytes + i + 4 * j, 4));
+
+				CPRINTF("%s ", str_buf);
+			}
+			CPRINTF("\n");
 			msleep(8);
 		}
 	}
@@ -1235,13 +1236,17 @@ int touchpad_debug(const uint8_t *param, unsigned int param_size,
 		*data_size = 0;
 		st_tp_stop_scan();
 		return EC_SUCCESS;
-	case ST_TP_DEBUG_CMD_READ_BUF_HEADER:
+	case ST_TP_DEBUG_CMD_READ_BUF_HEADER: {
+		char str_buf[hex_str_buf_size(8)];
 		*data = buf;
 		*data_size = 8;
 		st_tp_read_host_buffer_header();
 		memcpy(buf, rx_buf.bytes, *data_size);
-		CPRINTS("header: %ph", HEX_BUF(buf, *data_size));
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(buf, *data_size));
+		CPRINTS("header: %s", str_buf);
 		return EC_SUCCESS;
+	}
 	case ST_TP_DEBUG_CMD_READ_EVENTS:
 		num_events = st_tp_read_all_events(0);
 		if (num_events) {
diff --git a/fuzz/host_command_fuzz.c b/fuzz/host_command_fuzz.c
index 856310db2b..b6c4c4685f 100644
--- a/fuzz/host_command_fuzz.c
+++ b/fuzz/host_command_fuzz.c
@@ -12,6 +12,7 @@
 #include "console.h"
 #include "host_command.h"
 #include "host_test.h"
+#include "printf.h"
 #include "task.h"
 #include "test_util.h"
 #include "timer.h"
@@ -112,8 +113,11 @@ static int hostcmd_fill(const uint8_t *data, size_t size)
 	 * issues.
 	 */
 	if (first) {
-		ccprintf("Request: cmd=%04x data=%ph\n", req->command,
-			 HEX_BUF(req_buf, req_size));
+		char str_buf[hex_str_buf_size(req_size)];
+
+		snprintf_hex_buffer(str_buf, sizeof(str_buf),
+				    HEX_BUF(req_buf, req_size));
+		ccprintf("Request: cmd=%04x data=%s\n", req->command, str_buf);
 		first = 0;
 	}
 
diff --git a/include/printf.h b/include/printf.h
index e5afb7f2d1..48117042f9 100644
--- a/include/printf.h
+++ b/include/printf.h
@@ -65,8 +65,6 @@
  *   - 'b' - unsigned integer, print as binary
  *
  * Special format codes:
- *   - '%ph' - binary data, print as hex; Use HEX_BUF(buffer, size) to encode
- *             parameters.
  *   - '%pP' - raw pointer.
  */
 
diff --git a/test/host_command.c b/test/host_command.c
index 5c13e2b4cf..17637b52de 100644
--- a/test/host_command.c
+++ b/test/host_command.c
@@ -8,6 +8,7 @@
 #include "common.h"
 #include "console.h"
 #include "host_command.h"
+#include "printf.h"
 #include "task.h"
 #include "test_util.h"
 #include "timer.h"
@@ -177,6 +178,7 @@ static int test_hostcmd_reuse_response_buffer(void)
 	struct ec_host_request *h = (struct ec_host_request *)resp_buf;
 	struct ec_params_hello *d =
 		(struct ec_params_hello *)(resp_buf + sizeof(*h));
+	char str_buf[hex_str_buf_size(BUFFER_SIZE)];
 
 	h->struct_version = 3;
 	h->checksum = 0;
@@ -201,13 +203,15 @@ static int test_hostcmd_reuse_response_buffer(void)
 
 	h->checksum = calculate_checksum(resp_buf, pkt.request_size);
 
-	ccprintf("\nBuffer contents before process 0x%ph\n",
-		 HEX_BUF(resp_buf, BUFFER_SIZE));
+	snprintf_hex_buffer(str_buf, sizeof(str_buf),
+			    HEX_BUF(resp_buf, BUFFER_SIZE));
+	ccprintf("\nBuffer contents before process 0x%s\n", str_buf);
 	host_packet_receive(&pkt);
 	task_wait_event(-1);
 
-	ccprintf("\nBuffer contents after process 0x%ph\n",
-		 HEX_BUF(resp_buf, BUFFER_SIZE));
+	snprintf_hex_buffer(str_buf, sizeof(str_buf),
+			    HEX_BUF(resp_buf, BUFFER_SIZE));
+	ccprintf("\nBuffer contents after process 0x%s\n", str_buf);
 
 	TEST_EQ(calculate_checksum(resp_buf, sizeof(*resp) + resp->data_len), 0,
 		"%d");
@@ -239,6 +243,7 @@ static void hostcmd_fill_chip_info(void)
 static int test_hostcmd_clears_unused_data(void)
 {
 	int i, found_null;
+	char str_buf[hex_str_buf_size(BUFFER_SIZE)];
 
 	/* Set the buffer to junk and ensure that is gets cleared */
 	memset(resp_buf, 0xAA, BUFFER_SIZE);
@@ -246,7 +251,9 @@ static int test_hostcmd_clears_unused_data(void)
 
 	hostcmd_send();
 
-	ccprintf("\nBuffer contents 0x%ph\n", HEX_BUF(resp_buf, BUFFER_SIZE));
+	snprintf_hex_buffer(str_buf, sizeof(str_buf),
+			    HEX_BUF(resp_buf, BUFFER_SIZE));
+	ccprintf("\nBuffer contents 0x%s\n", str_buf);
 
 	TEST_EQ(calculate_checksum(resp_buf, sizeof(*resp) + resp->data_len), 0,
 		"%d");
diff --git a/test/printf.c b/test/printf.c
index 0ef24d1acd..5b7f3de99e 100644
--- a/test/printf.c
+++ b/test/printf.c
@@ -416,9 +416,12 @@ test_static int test_vsnprintf_hexdump(void)
 {
 	const char bytes[] = { 0x00, 0x5E };
 
-	T(expect_success("005e", "%ph", HEX_BUF(bytes, 2)));
-	T(expect_success("", "%ph", HEX_BUF(bytes, 0)));
-	T(expect_success("00", "%ph", HEX_BUF(bytes, 1)));
+	/*
+	 * Test %ph, which used to print buffers as hex, but is non-standard
+	 * and no longer supported.
+	 */
+	T(expect(EC_ERROR_INVAL, "", false, sizeof(output), "%ph",
+		 HEX_BUF(bytes, 2)));
 	return EC_SUCCESS;
 }