mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-17 01:34:00 +08:00
1d9e13e8ef
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Compact binary representation of ihex records. Some devices need their
|
|
* firmware loaded in strange orders rather than a single big blob, but
|
|
* actually parsing ihex-as-text within the kernel seems silly. Thus,...
|
|
*/
|
|
|
|
#ifndef __LINUX_IHEX_H__
|
|
#define __LINUX_IHEX_H__
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/firmware.h>
|
|
#include <linux/device.h>
|
|
|
|
/* Intel HEX files actually limit the length to 256 bytes, but we have
|
|
drivers which would benefit from using separate records which are
|
|
longer than that, so we extend to 16 bits of length */
|
|
struct ihex_binrec {
|
|
__be32 addr;
|
|
__be16 len;
|
|
uint8_t data[];
|
|
} __attribute__((packed));
|
|
|
|
static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p)
|
|
{
|
|
return be16_to_cpu(p->len) + sizeof(*p);
|
|
}
|
|
|
|
/* Find the next record, taking into account the 4-byte alignment */
|
|
static inline const struct ihex_binrec *
|
|
__ihex_next_binrec(const struct ihex_binrec *rec)
|
|
{
|
|
const void *p = rec;
|
|
|
|
return p + ALIGN(ihex_binrec_size(rec), 4);
|
|
}
|
|
|
|
static inline const struct ihex_binrec *
|
|
ihex_next_binrec(const struct ihex_binrec *rec)
|
|
{
|
|
rec = __ihex_next_binrec(rec);
|
|
|
|
return be16_to_cpu(rec->len) ? rec : NULL;
|
|
}
|
|
|
|
/* Check that ihex_next_binrec() won't take us off the end of the image... */
|
|
static inline int ihex_validate_fw(const struct firmware *fw)
|
|
{
|
|
const struct ihex_binrec *end, *rec;
|
|
|
|
rec = (const void *)fw->data;
|
|
end = (const void *)&fw->data[fw->size - sizeof(*end)];
|
|
|
|
for (; rec <= end; rec = __ihex_next_binrec(rec)) {
|
|
/* Zero length marks end of records */
|
|
if (rec == end && !be16_to_cpu(rec->len))
|
|
return 0;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Request firmware and validate it so that we can trust we won't
|
|
* run off the end while reading records... */
|
|
static inline int request_ihex_firmware(const struct firmware **fw,
|
|
const char *fw_name,
|
|
struct device *dev)
|
|
{
|
|
const struct firmware *lfw;
|
|
int ret;
|
|
|
|
ret = request_firmware(&lfw, fw_name, dev);
|
|
if (ret)
|
|
return ret;
|
|
ret = ihex_validate_fw(lfw);
|
|
if (ret) {
|
|
dev_err(dev, "Firmware \"%s\" not valid IHEX records\n",
|
|
fw_name);
|
|
release_firmware(lfw);
|
|
return ret;
|
|
}
|
|
*fw = lfw;
|
|
return 0;
|
|
}
|
|
#endif /* __LINUX_IHEX_H__ */
|