cregit-Linux how code gets into the kernel

Release 4.14 arch/powerpc/boot/simple_alloc.c

/*
 * Implement primitive realloc(3) functionality.
 *
 * Author: Mark A. Greer <mgreer@mvista.com>
 *
 * 2006 (c) MontaVista, Software, Inc.  This file is licensed under
 * the terms of the GNU General Public License version 2.  This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */

#include <stddef.h>
#include "types.h"
#include "page.h"
#include "string.h"
#include "ops.h"


#define	ENTRY_BEEN_USED	0x01

#define	ENTRY_IN_USE	0x02


static struct alloc_info {
	
unsigned long	flags;
	
unsigned long	base;
	
unsigned long	size;

} *alloc_tbl;


static unsigned long tbl_entries;

static unsigned long alloc_min;

static unsigned long next_base;

static unsigned long space_left;

/*
 * First time an entry is used, its base and size are set.
 * An entry can be freed and re-malloc'd but its base & size don't change.
 * Should be smart enough for needs of bootwrapper.
 */

static void *simple_malloc(unsigned long size) { unsigned long i; struct alloc_info *p = alloc_tbl; if (size == 0) goto err_out; size = _ALIGN_UP(size, alloc_min); for (i=0; i<tbl_entries; i++, p++) if (!(p->flags & ENTRY_BEEN_USED)) { /* never been used */ if (size <= space_left) { p->base = next_base; p->size = size; p->flags = ENTRY_BEEN_USED | ENTRY_IN_USE; next_base += size; space_left -= size; return (void *)p->base; } goto err_out; /* not enough space left */ } /* reuse an entry keeping same base & size */ else if (!(p->flags & ENTRY_IN_USE) && (size <= p->size)) { p->flags |= ENTRY_IN_USE; return (void *)p->base; } err_out: return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer15897.53%150.00%
Geert Uytterhoeven42.47%150.00%
Total162100.00%2100.00%


static struct alloc_info *simple_find_entry(void *ptr) { unsigned long i; struct alloc_info *p = alloc_tbl; for (i=0; i<tbl_entries; i++,p++) { if (!(p->flags & ENTRY_BEEN_USED)) break; if ((p->flags & ENTRY_IN_USE) && (p->base == (unsigned long)ptr)) return p; } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer7795.06%150.00%
Geert Uytterhoeven44.94%150.00%
Total81100.00%2100.00%


static void simple_free(void *ptr) { struct alloc_info *p = simple_find_entry(ptr); if (p != NULL) p->flags &= ~ENTRY_IN_USE; }

Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer33100.00%1100.00%
Total33100.00%1100.00%

/* * Change size of area pointed to by 'ptr' to 'size'. * If 'ptr' is NULL, then its a malloc(). If 'size' is 0, then its a free(). * 'ptr' must be NULL or a pointer to a non-freed area previously returned by * simple_realloc() or simple_malloc(). */
static void *simple_realloc(void *ptr, unsigned long size) { struct alloc_info *p; void *new; if (size == 0) { simple_free(ptr); return NULL; } if (ptr == NULL) return simple_malloc(size); p = simple_find_entry(ptr); if (p == NULL) /* ptr not from simple_malloc/simple_realloc */ return NULL; if (size <= p->size) /* fits in current block */ return ptr; new = simple_malloc(size); memcpy(new, ptr, p->size); simple_free(ptr); return new; }

Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer107100.00%1100.00%
Total107100.00%1100.00%

/* * Returns addr of first byte after heap so caller can see if it took * too much space. If so, change args & try again. */
void *simple_alloc_init(char *base, unsigned long heap_size, unsigned long granularity, unsigned long max_allocs) { unsigned long heap_base, tbl_size; heap_size = _ALIGN_UP(heap_size, granularity); alloc_min = granularity; tbl_entries = max_allocs; tbl_size = tbl_entries * sizeof(struct alloc_info); alloc_tbl = (struct alloc_info *)_ALIGN_UP((unsigned long)base, 8); memset(alloc_tbl, 0, tbl_size); heap_base = _ALIGN_UP((unsigned long)alloc_tbl + tbl_size, alloc_min); next_base = heap_base; space_left = heap_size; platform_ops.malloc = simple_malloc; platform_ops.free = simple_free; platform_ops.realloc = simple_realloc; return (void *)(heap_base + heap_size); }

Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer12492.54%150.00%
Geert Uytterhoeven107.46%150.00%
Total134100.00%2100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Mark A. Greer55294.52%150.00%
Geert Uytterhoeven325.48%150.00%
Total584100.00%2100.00%
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