lib: Add obvious definition for `calloc`

The calloc() function is useful in addition to malloc and friends, so
add the obvious definition.

Change-Id: I57a568e323344a97b35014b7b8bec16adc2fd720
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51949
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/stdlib.h

@@ -5,6 +5,7 @@
 
 void *memalign(size_t boundary, size_t size);
 void *malloc(size_t size);
+void *calloc(size_t nitems, size_t size);
 void free(void *ptr);
 
 #endif /* STDLIB_H */

src/lib/malloc.c

@@ -1,5 +1,6 @@
-#include <stdlib.h>
 #include <console/console.h>
+#include <stdlib.h>
+#include <string.h>
 
 #if CONFIG(DEBUG_MALLOC)
 #define MALLOCDBG(x...) printk(BIOS_SPEW, x)
@@ -54,6 +55,15 @@ void *malloc(size_t size)
 	return memalign(sizeof(u64), size);
 }
 
+void *calloc(size_t nitems, size_t size)
+{
+	void *p = malloc(nitems * size);
+	if (p)
+		memset(p, 0, nitems * size);
+
+	return p;
+}
+
 void free(void *ptr)
 {
 	if (ptr == NULL)

tests/lib/malloc-test.c

@@ -2,6 +2,7 @@
 
 /* Include malloc() and memalign() source code and alter its name to indicate the functions
    source origin. */
+#define calloc cb_calloc
 #define malloc cb_malloc
 #define free cb_free
 #define memalign cb_memalign
@@ -10,6 +11,7 @@
 
 #include "../lib/malloc.c"
 
+#undef calloc
 #undef malloc
 #undef free
 #undef memalign
@@ -46,6 +48,12 @@ static int setup_test(void **state)
 	return 0;
 }
 
+static int setup_calloc_test(void **state)
+{
+	memset(&_heap, 0xFF, TEST_HEAP_SZ);
+	return setup_test(state);
+}
+
 static void test_malloc_out_of_memory(void **state)
 {
 	/* Expect die() call if out of memory */
@@ -130,6 +138,19 @@ static void test_memalign_multiple_small_allocations(void **state)
 	}
 }
 
+static void test_calloc_memory_is_zeroed(void **state)
+{
+	const size_t nitems = 42;
+	const size_t size = sizeof(uint32_t);
+	void *ptr = cb_calloc(nitems, size);
+	assert_non_null(ptr);
+
+	for (size_t i = 0; i < nitems; i++) {
+		const uint32_t *p = (const uint32_t *)ptr + i;
+		assert_int_equal(*p, 0);
+	}
+}
+
 int main(void)
 {
 	const struct CMUnitTest tests[] = {
@@ -140,6 +161,7 @@ int main(void)
 		cmocka_unit_test_setup(test_memalign_out_of_memory, setup_test),
 		cmocka_unit_test_setup(test_memalign_zero, setup_test),
 		cmocka_unit_test_setup(test_memalign_multiple_small_allocations, setup_test),
+		cmocka_unit_test_setup(test_calloc_memory_is_zeroed, setup_calloc_test),
 	};
 
 	return cmocka_run_group_tests(tests, NULL, NULL);