Commit ff668a6b authored by Dawid Niedzwiecki's avatar Dawid Niedzwiecki Committed by Chris Friedt
Browse files

libc: newlib: add config to use custom sbrk 



Add a config to use the custom _sbrk function, defined by a user.

It is possible that an application doesn't want to use the entire
remaining RAM for the heap.

Signed-off-by: default avatarDawid Niedzwiecki <dawidn@google.com>
parent d6ed7503

include/zephyr/sys/libc-hooks.h

+1 −1
Original line number Diff line number Diff line
@@ -58,7 +58,7 @@ void __stdout_hook_install(int (*hook)(int)); 
#define Z_MALLOC_PARTITION_EXISTS 1

#endif



#elif defined(CONFIG_NEWLIB_LIBC)

#elif defined(CONFIG_NEWLIB_LIBC) && !defined(CONFIG_NEWLIB_LIBC_CUSTOM_SBRK)

/* If we are using newlib, the heap arena is in one of two areas:

 *  - If we have an MPU that requires power of two alignment, the heap bounds

 *    must be specified in Kconfig via CONFIG_NEWLIB_LIBC_ALIGNED_HEAP_SIZE.

lib/libc/newlib/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -64,4 +64,10 @@ config NEWLIB_LIBC_HEAP_LISTENER 
	  Notify registered heap listeners upon certain events related to the newlib

	  libc heap usage, such as the heap resize.



config NEWLIB_LIBC_CUSTOM_SBRK

	bool "Allow user to define _sbrk"

	help

	  Allow user to define custom version of the _sbrk function. Some application

	  may need to use the remaining RAM for also other purposes than heap.



endif # NEWLIB_LIBC

lib/libc/newlib/libc-hooks.c

+5 −0
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ int _lseek(int file, int ptr, int dir); 
int _kill(int pid, int sig);

int _getpid(void);



#ifndef CONFIG_NEWLIB_LIBC_CUSTOM_SBRK



#define LIBC_BSS	K_APP_BMEM(z_libc_partition)

#define LIBC_DATA	K_APP_DMEM(z_libc_partition)
@@ -146,6 +148,7 @@ SYS_INIT(malloc_prepare, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_LIBC); 


/* Current offset from HEAP_BASE of unused memory */

LIBC_BSS static size_t heap_sz;

#endif /* CONFIG_NEWLIB_LIBC_CUSTOM_SBRK */



static int _stdout_hook_default(int c)

{
@@ -297,6 +300,7 @@ __weak void _exit(int status) 
	}

}



#ifndef CONFIG_NEWLIB_LIBC_CUSTOM_SBRK

void *_sbrk(intptr_t count)

{

	void *ret, *ptr;
@@ -317,6 +321,7 @@ void *_sbrk(intptr_t count) 
	return ret;

}

__weak FUNC_ALIAS(_sbrk, sbrk, void *);

#endif /* CONFIG_NEWLIB_LIBC_CUSTOM_SBRK */



#ifdef CONFIG_MULTITHREADING

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