[M] Change in coreboot[main]: drivers/intel/usb4: Guard usage of RFMU with a null check

[Sean Rhodes (Code Review)]

Sean Rhodes has submitted this change. ( https://review.coreboot.org/c/coreboot/+/84615?usp=email )

(

3 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.
 )Change subject: drivers/intel/usb4: Guard usage of RFMU with a null check
......................................................................

drivers/intel/usb4: Guard usage of RFMU with a null check

Add a null check around the usage of the RFWU (Retimer Firmware
Update path) in the `usb4_retimer_execute_ec_cmd` function. This
ensures that any interaction with RFWU is only performed when the
path is valid, preventing potential null pointer dereferences.

This fixes are large amount of errors when `ec_retimer_fw_update_path`
isn't declared, such as comparisons like `If ((Local0 == Break))`.

Change-Id: I5a219345440f91332f680885b51e2cc09f14f7a7
Signed-off-by: Sean Rhodes 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/84615
Tested-by: build bot (Jenkins) 
Reviewed-by: coreboot org 
---
M src/drivers/intel/usb4/retimer/retimer.c
1 file changed, 39 insertions(+), 34 deletions(-)

Approvals:
  coreboot org: Looks good to me, approved
  build bot (Jenkins): Verified

diff --git a/src/drivers/intel/usb4/retimer/retimer.c b/src/drivers/intel/usb4/retimer/retimer.c
index 3769fc9..40dd4c1 100644
--- a/src/drivers/intel/usb4/retimer/retimer.c
+++ b/src/drivers/intel/usb4/retimer/retimer.c
@@ -36,10 +36,12 @@
    /* Invoke EC Retimer firmware update command execution */
    ec_retimer_fw_update(data);
    /* If RFWU has return value 0xfe, return error -1 */
-	acpigen_write_if_lequal_namestr_int(RFWU, USB_RETIMER_FW_UPDATE_ERROR);
-	acpigen_disable_tx_gpio(power_gpio);
-	acpigen_write_return_integer(-1);
-	acpigen_pop_len(); /* If */
+	if (RFWU) {
+		acpigen_write_if_lequal_namestr_int(RFWU, USB_RETIMER_FW_UPDATE_ERROR);
+		acpigen_disable_tx_gpio(power_gpio);
+		acpigen_write_return_integer(-1);
+		acpigen_pop_len(); /* If */
+	}

acpigen_write_store_int_to_op(USB4_RETIMER_ITERATION_NUM, LOCAL2_OP);
    acpigen_emit_byte(WHILE_OP);
@@ -47,39 +49,42 @@
    acpigen_emit_byte(LGREATER_OP);
    acpigen_emit_byte(LOCAL2_OP);
    acpigen_emit_byte(ZERO_OP);
-	acpigen_write_if_lequal_namestr_int(RFWU, expected_value);
-	acpigen_emit_byte(BREAK_OP);
-	acpigen_pop_len(); /* If */

-	if (cmd == USB_RETIMER_FW_UPDATE_GET_MUX) {
-		acpigen_write_if_lequal_namestr_int(RFWU, USB_RETIMER_FW_UPDATE_INVALID_MUX);
-		acpigen_write_sleep(USB4_RETIMER_POLL_CYCLE_MS);
-		acpigen_emit_byte(DECREMENT_OP);
-		acpigen_emit_byte(LOCAL2_OP);
-		acpigen_emit_byte(CONTINUE_OP);
-		acpigen_pop_len(); /* If */
-
-		acpigen_emit_byte(AND_OP);
-		acpigen_emit_namestring(RFWU);
-		acpigen_write_integer(USB_RETIMER_FW_UPDATE_MUX_MASK);
-		acpigen_emit_byte(LOCAL3_OP);
-		acpigen_write_if();
-		acpigen_emit_byte(LNOT_OP);
-		acpigen_emit_byte(LEQUAL_OP);
-		acpigen_emit_byte(LOCAL3_OP);
-		acpigen_emit_byte(0);
-		acpigen_disable_tx_gpio(power_gpio);
-		acpigen_write_return_integer(-1);
-		acpigen_pop_len(); /* If */
-	} else if (cmd == USB_RETIMER_FW_UPDATE_SET_TBT) {
-		/*
-		 * EC return either USB_PD_MUX_USB4_ENABLED or USB_PD_MUX_TBT_COMPAT_ENABLED
-		 * to RFWU after the USB_RETIMER_FW_UPDATE_SET_TBT command execution. It is
-		 * needed to add additional check for USB_PD_MUX_TBT_COMPAT_ENABLED.
-		 */
-		acpigen_write_if_lequal_namestr_int(RFWU, USB_PD_MUX_TBT_COMPAT_ENABLED);
+	if (RFWU) {
+		acpigen_write_if_lequal_namestr_int(RFWU, expected_value);
    	acpigen_emit_byte(BREAK_OP);
    	acpigen_pop_len(); /* If */
+
+		if (cmd == USB_RETIMER_FW_UPDATE_GET_MUX) {
+			acpigen_write_if_lequal_namestr_int(RFWU, USB_RETIMER_FW_UPDATE_INVALID_MUX);
+			acpigen_write_sleep(USB4_RETIMER_POLL_CYCLE_MS);
+			acpigen_emit_byte(DECREMENT_OP);
+			acpigen_emit_byte(LOCAL2_OP);
+			acpigen_emit_byte(CONTINUE_OP);
+			acpigen_pop_len(); /* If */
+
+			acpigen_emit_byte(AND_OP);
+			acpigen_emit_namestring(RFWU);
+			acpigen_write_integer(USB_RETIMER_FW_UPDATE_MUX_MASK);
+			acpigen_emit_byte(LOCAL3_OP);
+			acpigen_write_if();
+			acpigen_emit_byte(LNOT_OP);
+			acpigen_emit_byte(LEQUAL_OP);
+			acpigen_emit_byte(LOCAL3_OP);
+			acpigen_emit_byte(0);
+			acpigen_disable_tx_gpio(power_gpio);
+			acpigen_write_return_integer(-1);
+			acpigen_pop_len(); /* If */
+		} else if (cmd == USB_RETIMER_FW_UPDATE_SET_TBT) {
+			/*
+			 * EC return either USB_PD_MUX_USB4_ENABLED or USB_PD_MUX_TBT_COMPAT_ENABLED
+			 * to RFWU after the USB_RETIMER_FW_UPDATE_SET_TBT command execution. It is
+			 * needed to add additional check for USB_PD_MUX_TBT_COMPAT_ENABLED.
+			 */
+			acpigen_write_if_lequal_namestr_int(RFWU, USB_PD_MUX_TBT_COMPAT_ENABLED);
+			acpigen_emit_byte(BREAK_OP);
+			acpigen_pop_len(); /* If */
+		}
    }

acpigen_write_sleep(USB4_RETIMER_POLL_CYCLE_MS);