On Mon, Nov 16, 2015 at 01:56:54PM +0100, Andreas Fenkart wrote:
> From: Andreas Fenkart <afenkart at gmail.com>
>
> booting a non-devicetree kernel from a devicetree kernel failed,
> since the memory layout wasn't passed.
Nice catch.
> Signed-off-by: Andreas Fenkart <andreas.fenkart at dev.digitalstrom.org>
> ---
> kexec/arch/arm/kexec-zImage-arm.c | 43 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/kexec/arch/arm/kexec-zImage-arm.c b/kexec/arch/arm/kexec-zImage-arm.c
> index ff4e38d..f460ba7 100644
> --- a/kexec/arch/arm/kexec-zImage-arm.c
> +++ b/kexec/arch/arm/kexec-zImage-arm.c
> @@ -4,6 +4,7 @@
> */
> #define _GNU_SOURCE
> #define _XOPEN_SOURCE
> +#include <assert.h>
> #include <stdio.h>
> #include <string.h>
> #include <stdlib.h>
> @@ -139,6 +140,42 @@ struct tag * atag_read_tags(void)
> return (struct tag *) buf;
> }
>
> +static
> +int create_mem32_tag(struct tag_mem32 *tag_mem32)
> +{
> + const char fn[]= "/proc/device-tree/memory/reg";
> + FILE *fp;
> + uint32_t tmp[2];
> + int ret = 0;
> +
> + assert(tag_mem32);
I think the assertion here is unnecessary. Could you remove it?
> + fp = fopen(fn, "r");
> + if (!fp) {
> + ret = errno;
> + fprintf(stderr, "Cannot open %s: %m\n", fn);
> + return ret;
I think that returning -1 for error and 0 for success would
be both consistent with the rest of the source in the same file
and result in slightly simpler code.
> + }
> +
> + if (!fread(tmp, sizeof(tmp[0]), 2, fp)) {
> + ret = ENOENT;
> + fprintf(stderr, "Short read %s\n", fn);
> + goto out;
> + }
> +
> + if (ferror(fp)) {
> + ret = errno;
> + fprintf(stderr, "Cannot read %s: %m\n", fn);
> + goto out;
> + }
> +
> + /* atags_mem32 has base/size fields reversed! */
> + tag_mem32->size = be32_to_cpu(tmp[1]);
> + tag_mem32->start = be32_to_cpu(tmp[0]);
> +
> +out:
> + fclose(fp);
> + return ret;
> +}
>
> static
> int atag_arm_load(struct kexec_info *info, unsigned long base,
> @@ -182,6 +219,12 @@ int atag_arm_load(struct kexec_info *info, unsigned long base,
> params->hdr.size = 2;
> params->hdr.tag = ATAG_CORE;
> params = tag_next(params);
> +
> + if (!create_mem32_tag(¶ms->u.mem)) {
> + params->hdr.size = 4;
> + params->hdr.tag = ATAG_MEM;
> + params = tag_next(params);
> + }
> }
>
> if (initrd) {
