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authorSimon Glass <sjg@chromium.org>2013-11-10 10:26:57 -0700
committerSimon Glass <sjg@chromium.org>2014-01-08 17:24:19 -0700
commit77595c6d9e2c1af9c3b143f496c4c47d0e95a458 (patch)
treefd18c5f9e08c1a556ad703eb1e9b1086164cf8f6
parentf4d8de48f5a2aa1885daa0d425b8c0568a2ccb69 (diff)
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sandbox: Improve/augment memory allocation functions
Implement realloc() and free() for sandbox, by adding a header to each block which contains the block size. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Che-Liang Chiou <clchiou@chromium.org> Reviewed-by: Hung-ying Tyan <tyanh@chromium.org>
-rw-r--r--arch/sandbox/cpu/os.c45
-rw-r--r--include/os.h29
2 files changed, 72 insertions, 2 deletions
diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index 26f44cb..88dd371 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -27,6 +27,10 @@
/* Operating System Interface */
+struct os_mem_hdr {
+ size_t length; /* number of bytes in the block */
+};
+
ssize_t os_read(int fd, void *buf, size_t count)
{
return read(fd, buf, count);
@@ -128,8 +132,45 @@ void os_tty_raw(int fd)
void *os_malloc(size_t length)
{
- return mmap(NULL, length, PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ struct os_mem_hdr *hdr;
+
+ hdr = mmap(NULL, length + sizeof(*hdr), PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if (hdr == MAP_FAILED)
+ return NULL;
+ hdr->length = length;
+
+ return hdr + 1;
+}
+
+void *os_free(void *ptr)
+{
+ struct os_mem_hdr *hdr = ptr;
+
+ hdr--;
+ if (ptr)
+ munmap(hdr, hdr->length + sizeof(*hdr));
+}
+
+void *os_realloc(void *ptr, size_t length)
+{
+ struct os_mem_hdr *hdr = ptr;
+ void *buf = NULL;
+
+ hdr--;
+ if (length != 0) {
+ buf = os_malloc(length);
+ if (!buf)
+ return buf;
+ if (ptr) {
+ if (length > hdr->length)
+ length = hdr->length;
+ memcpy(buf, ptr, length);
+ }
+ }
+ os_free(ptr);
+
+ return buf;
}
void os_usleep(unsigned long usec)
diff --git a/include/os.h b/include/os.h
index 950433d..1575a96 100644
--- a/include/os.h
+++ b/include/os.h
@@ -107,6 +107,35 @@ void os_tty_raw(int fd);
void *os_malloc(size_t length);
/**
+ * Free memory previous allocated with os_malloc()/os_realloc()
+ *
+ * This returns the memory to the OS.
+ *
+ * \param ptr Pointer to memory block to free
+ */
+void *os_free(void *ptr);
+
+/**
+ * Reallocate previously-allocated memory to increase/decrease space
+ *
+ * This works in a similar way to the C library realloc() function. If
+ * length is 0, then ptr is freed. Otherwise the space used by ptr is
+ * expanded or reduced depending on whether length is larger or smaller
+ * than before.
+ *
+ * If ptr is NULL, then this is similar to calling os_malloc().
+ *
+ * This function may need to move the memory block to make room for any
+ * extra space, in which case the new pointer is returned.
+ *
+ * \param ptr Pointer to memory block to reallocate
+ * \param length New length for memory block
+ * \return pointer to new memory block, or NULL on failure or if length
+ * is 0.
+ */
+void *os_realloc(void *ptr, size_t length);
+
+/**
* Access to the usleep function of the os
*
* \param usec Time to sleep in micro seconds