pinctrl: gpiochips section is only for pointers

The previous implementation of DECLARE_GPIO_CHIP was unintentionally
putting variable amounts of additional data in the "gpiochips" section,
which could lead to a crash. Restrict the section contents to pointers
to the actual structures.

Signed-off-by: Phil Elwell <[email protected]>

Author: pelwell

pinctrl/gpiochip.h

@@ -4,8 +4,8 @@
 #include "gpiolib.h"
 
 #define DECLARE_GPIO_CHIP(name, compatible, iface, size, data) \
-    const GPIO_CHIP_T name ## _chip __attribute__ ((section ("gpiochips"))) __attribute__ ((used)) = \
-    { #name, compatible, iface, size, data }
+    const GPIO_CHIP_T name ## _chip = { #name, compatible, iface, size, data }; \
+    const GPIO_CHIP_T *name ## _chip_ptr __attribute__ ((section ("gpiochips"))) __attribute__ ((used)) = &(name ## _chip)
 
 typedef struct GPIO_CHIP_INTERFACE_ GPIO_CHIP_INTERFACE_T;
 
@@ -36,7 +36,7 @@ struct GPIO_CHIP_INTERFACE_
     const char * (*gpio_get_fsel_name)(void *priv, uint32_t gpio, GPIO_FSEL_T fsel);
 };
 
-extern const GPIO_CHIP_T __start_gpiochips;
-extern const GPIO_CHIP_T __stop_gpiochips;
+extern const GPIO_CHIP_T *__start_gpiochips;
+extern const GPIO_CHIP_T *__stop_gpiochips;
 
 #endif

pinctrl/gpiolib.c

@@ -394,9 +394,10 @@ const char *gpio_get_drive_name(GPIO_DRIVE_T drive)
 
 static const GPIO_CHIP_T *gpio_find_chip(const char *name)
 {
-    const GPIO_CHIP_T *chip;
+    const GPIO_CHIP_T **chip_ptr;
 
-    for (chip = &__start_gpiochips; name && chip < &__stop_gpiochips; chip++) {
+    for (chip_ptr = &__start_gpiochips; name && chip_ptr < &__stop_gpiochips; chip_ptr++) {
+        const GPIO_CHIP_T *chip = *chip_ptr;
         if (!strcmp(name, chip->name) ||
             !strcmp(name, chip->compatible))
             return chip;