On Wed, 18 Nov 2020 11:22:49 -0500 Steven Rostedt <[email protected]> wrote:
> On Thu, 19 Nov 2020 00:35:44 +0900 > Masami Hiramatsu <[email protected]> wrote: > > > + > > + /* To align up the total size to BOOTCONFIG_ALIGN, get padding size */ > > + total_size = stat.st_size + size + sizeof(u32) * 2 + > > BOOTCONFIG_MAGIC_LEN; > > + pad = BOOTCONFIG_ALIGN - total_size % BOOTCONFIG_ALIGN; > > + if (pad == BOOTCONFIG_ALIGN) > > + pad = 0; > > If alignment is always a power of two, you could simply do: > > pad = (total_size + BOOTCONFIG_ALIGN - 1) & ~(BOOTCONFIG_ALIGN - 1)) - > total_size; > > Which will give you the proper padding, without the if. Thanks, and in that case, I would like to introduce BOOTCONFIG_ALINE_BITS and BOOTCONFIG_ALINE_MASK so that we make sure the alignment is power of two. > > + size += pad; > > + > > + /* Add a footer */ > > + *(u32 *)(data + size) = size; > > + *(u32 *)(data + size + sizeof(u32)) = csum; > > + memcpy(data + size + sizeof(u32) * 2, BOOTCONFIG_MAGIC, > > BOOTCONFIG_MAGIC_LEN); > > + total_size = size + sizeof(u32) * 2 + BOOTCONFIG_MAGIC_LEN; > > I wonder if it would be cleaner to just have a void pointer index for the > above: > > void *p; > > p = data + size; > *(u32 *)p = size; > p += sizeof(u32); > > *(u32 *)p = csum; > p += sizeof(u32); > > memcpy(p, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN); > p += BOOTCONFIG_MAGIC_LEN; > > total_size = p - (void *)data; OK. > Also, how does this work if we run this on a little endian box for a big > endian crossbuild? Hmm, good point. I expected that the bootconfig command will be used natively. Hmm, there are 2 options. - Add endian option to the bootconfig (-le/-be) for cross build. - Update the footer format to use "ascii" size and checksum. To generalize the format, latter one is better. But it also involves the kernel side update too. Thank you, > > -- Steve > > > > + > > + ret = write(fd, data, total_size); > > + if (ret < total_size) { > > if (ret < 0) > > ret = -errno; > > pr_err("Failed to apply a boot config: %d\n", ret); > > - if (ret < 0) > > - goto out; > > - goto out_rollback; > > - } > > - /* Write a magic word of the bootconfig */ > > - ret = write(fd, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN); > > - if (ret < BOOTCONFIG_MAGIC_LEN) { > > - if (ret < 0) > > - ret = -errno; > > - pr_err("Failed to apply a boot config magic: %d\n", ret); > > - goto out_rollback; > > - } > > - ret = 0; > > + if (ret > 0) > > + goto out_rollback; > > + } else > > + ret = 0; > > + > > out: > > close(fd); > > free(data); -- Masami Hiramatsu <[email protected]>
