libc: newlib: fix virtual memory arena size

#define HEAP_BASE	USED_RAM_END_ADDR

#endif /* Z_MALLOC_PARTITION_EXISTS */

#ifdef CONFIG_XTENSA

#ifdef CONFIG_MMU

/* Currently a placeholder, we're just setting up all unused RAM pages

 * past the end of the kernel as the heap arena. SRAM_BASE_ADDRESS is

 * a physical address so we can't use that.

 *

 * Later, we should do this much more like other VM-enabled operating systems:

 * - Set up a core kernel ontology of free physical pages

 * - Allow anonymous memoory mappings drawing from the pool of free physical

 *   pages

 * - Have _sbrk() map anonymous pages into the heap arena as needed

 * - See: https://github.com/zephyrproject-rtos/zephyr/issues/29526

 */

#define MAX_HEAP_SIZE	(CONFIG_KERNEL_RAM_SIZE - (HEAP_BASE - \

						   CONFIG_KERNEL_VM_BASE))

#elif defined(CONFIG_XTENSA)

extern void *_heap_sentry;

#define MAX_HEAP_SIZE	(POINTER_TO_UINT(&_heap_sentry) - HEAP_BASE)

#else

#define MAX_HEAP_SIZE	(KB(CONFIG_SRAM_SIZE) - \

			 (HEAP_BASE - CONFIG_SRAM_BASE_ADDRESS))

#endif

#define MAX_HEAP_SIZE	(KB(CONFIG_SRAM_SIZE) - (HEAP_BASE - \

						 CONFIG_SRAM_BASE_ADDRESS))

#endif /* CONFIG_MMU */

#if Z_MALLOC_PARTITION_EXISTS

struct k_mem_partition z_malloc_partition;