[U-Boot] [PATCH 1/2 v2] fit: Support compression for non-kernel components (e.g. FDT)
Julius Werner
jwerner at chromium.org
Tue Apr 30 22:34:39 UTC 2019
On Tue, Apr 30, 2019 at 11:25 AM Simon Goldschmidt
<simon.k.r.goldschmidt at gmail.com> wrote:
>
> Am 18.04.2019 um 23:08 schrieb Julius Werner:
> > This patch adds support for compressing non-kernel image nodes in a FIT
> > image (kernel nodes could already be compressed previously). This can
> > reduce the size of FIT images and therefore improve boot times
> > (especially when an image bundles many different kernel FDTs). The
> > images will automatically be decompressed on load.
> >
> > This patch does not support extracting compatible strings from
> > compressed FDTs, so it's not very helpful in conjunction with
> > CONFIG_FIT_BEST_MATCH yet, but it can already be used in environments
> > that select the configuration to load explicitly.
> >
> > Signed-off-by: Julius Werner <jwerner at chromium.org>
> > ---
> > common/image-fit.c | 83 +++++++++++++++++++++++++++-------------------
> > 1 file changed, 49 insertions(+), 34 deletions(-)
> >
> > diff --git a/common/image-fit.c b/common/image-fit.c
> > index ac901e131c..006e828b79 100644
> > --- a/common/image-fit.c
> > +++ b/common/image-fit.c
> > @@ -22,6 +22,7 @@
> > DECLARE_GLOBAL_DATA_PTR;
> > #endif /* !USE_HOSTCC*/
> >
> > +#include <bootm.h>
> > #include <image.h>
> > #include <bootstage.h>
> > #include <u-boot/crc.h>
> > @@ -1576,6 +1577,13 @@ int fit_conf_find_compat(const void *fit, const void *fdt)
> > kfdt_name);
> > continue;
> > }
> > +
> > + if (!fit_image_check_comp(fit, kfdt_noffset, IH_COMP_NONE)) {
> > + debug("Can't extract compat from \"%s\" (compressed)\n",
> > + kfdt_name);
> > + continue;
> > + }
> > +
>
> What's this block good for in this patch? Looks like it belongs to 2/2?
This is necessary because I'm removing the (image_type ==
IH_TYPE_FLATDT && !fit_image_check_comp(fit, noffset, IH_COMP_NONE))
check below. Previously, this function would just always hard fail
with compressed FDTs. With this patch, compressed FDTs can be loaded,
but they can't be used for compat string matching -- that's why I need
to add this check here to prevent it. You can still use compressed
FDTs when selecting a configuration explicitly (e.g. bootm
0x1000000#conf at 1). The next patch will then add another feature that
makes it possible to have compat string matching with compressed FDTs.
>
> > /*
> > * Get a pointer to this configuration's fdt.
> > */
> > @@ -1795,11 +1803,12 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> > const char *fit_uname_config;
> > const char *fit_base_uname_config;
> > const void *fit;
> > - const void *buf;
> > + void *buf;
> > + void *loadbuf;
> > size_t size;
> > int type_ok, os_ok;
> > - ulong load, data, len;
> > - uint8_t os;
> > + ulong load, load_end, data, len;
> > + uint8_t os, comp;
> > #ifndef USE_HOSTCC
> > uint8_t os_arch;
> > #endif
> > @@ -1895,12 +1904,6 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> > images->os.arch = os_arch;
> > #endif
> >
> > - if (image_type == IH_TYPE_FLATDT &&
> > - !fit_image_check_comp(fit, noffset, IH_COMP_NONE)) {
> > - puts("FDT image is compressed");
> > - return -EPROTONOSUPPORT;
> > - }
> > -
> > bootstage_mark(bootstage_id + BOOTSTAGE_SUB_CHECK_ALL);
> > type_ok = fit_image_check_type(fit, noffset, image_type) ||
> > fit_image_check_type(fit, noffset, IH_TYPE_FIRMWARE) ||
> > @@ -1931,7 +1934,8 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> > bootstage_mark(bootstage_id + BOOTSTAGE_SUB_CHECK_ALL_OK);
> >
> > /* get image data address and length */
> > - if (fit_image_get_data_and_size(fit, noffset, &buf, &size)) {
> > + if (fit_image_get_data_and_size(fit, noffset,
> > + (const void **)&buf, &size)) {
> > printf("Could not find %s subimage data!\n", prop_name);
> > bootstage_error(bootstage_id + BOOTSTAGE_SUB_GET_DATA);
> > return -ENOENT;
> > @@ -1939,30 +1943,15 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> >
> > #if !defined(USE_HOSTCC) && defined(CONFIG_FIT_IMAGE_POST_PROCESS)
> > /* perform any post-processing on the image data */
> > - board_fit_image_post_process((void **)&buf, &size);
> > + board_fit_image_post_process(&buf, &size);
> > #endif
> >
> > len = (ulong)size;
> >
> > - /* verify that image data is a proper FDT blob */
> > - if (image_type == IH_TYPE_FLATDT && fdt_check_header(buf)) {
> > - puts("Subimage data is not a FDT");
> > - return -ENOEXEC;
> > - }
> > -
> > bootstage_mark(bootstage_id + BOOTSTAGE_SUB_GET_DATA_OK);
> >
> > - /*
> > - * Work-around for eldk-4.2 which gives this warning if we try to
> > - * cast in the unmap_sysmem() call:
> > - * warning: initialization discards qualifiers from pointer target type
> > - */
> > - {
> > - void *vbuf = (void *)buf;
> > -
> > - data = map_to_sysmem(vbuf);
> > - }
> > -
> > + data = map_to_sysmem(buf);
> > + load = data;
> > if (load_op == FIT_LOAD_IGNORED) {
> > /* Don't load */
> > } else if (fit_image_get_load(fit, noffset, &load)) {
> > @@ -1974,8 +1963,6 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> > }
> > } else if (load_op != FIT_LOAD_OPTIONAL_NON_ZERO || load) {
> > ulong image_start, image_end;
> > - ulong load_end;
> > - void *dst;
> >
> > /*
> > * move image data to the load address,
> > @@ -1993,14 +1980,42 @@ int fit_image_load(bootm_headers_t *images, ulong addr,
> >
> > printf(" Loading %s from 0x%08lx to 0x%08lx\n",
> > prop_name, data, load);
> > + }
> >
> > - dst = map_sysmem(load, len);
> > - memmove(dst, buf, len);
> > - data = load;
> > + comp = IH_COMP_NONE;
> > + loadbuf = buf;
> > + /* Kernel images get decompressed later in bootm_host_load_image(). */
> > + if (!(image_type == IH_TYPE_KERNEL ||
> > + image_type == IH_TYPE_KERNEL_NOLOAD )&&
>
> Can we go without this special case for Kernel? Back last year in the
> discussion we had, we decided that it would be better to have things
> straightforward and let the FIT property "compression" decide about if
> the loader should uncompress things, not if the file behind is a
> compressed file (e.g. initrd can be passed compressed to the kernel, so
> use "compression=none" in the FIT).
>
> Leaving away the extra case in the FIT loader makes the code less hard
> to read.
>
> I had to add a patch to bootm.c, too (maybe because of leaving away the
> extra case for Kernel?):
> [1] https://patchwork.ozlabs.org/patch/984996/
Yes, I agree decompressing everything here would be better. But the
kernel compression is pretty ingrained in bootm, also for boot modes
that work without a FIT image, and I'm honestly not sure if I
understand all other possibilities of how code could end up in
bootm_load_os() well enough to be able to make and test changes that
will keep them all working. There's also the problem of the
decompression buffer... for FDTs and other minor components malloc()
should work well enough in most cases, but for the kernel there may
not be enough space, so we would still need a special case anyway (to
use CONFIG_SYS_BOOTM_LEN in that case). I feel all of this needs more
thought and would not be that trivial to get right. Can we please
defer this to future work (I think this patch already adds notable
benefit as is, and is self-contained enough that I can be confident it
shouldn't break any existing uses)?
> > + !fit_image_get_comp(fit, noffset, &comp) &&
> > + comp != IH_COMP_NONE) {
> > + ulong max_decomp_len = len * 20;
>
> Now that's a theoretical limit which I've kept at 0 to make
> 'bootm_decomp_image' use CONFIG_SYS_BOOTM_LEN as a maximum. See [1] above.
>
> To keep malloc/lmb_alloc block small, it would be best to know the size
> in advance, but we can work on that later.
>
> Given that and that CONFIG_SYS_BOOTM_LEN isn't available globally, let's
> start with your 'len * 20' and I'll supply the uncompressed size via
> mkimage as a follow-up (I've been working on that already last year, too).
Agreed, it would be great to have a better solution here eventually.
> > + if (load == data) {
> > + loadbuf = malloc(max_decomp_len);
>
> For decompressing FDT, using malloc should be OK, but for larger things
> (initrd/FPGA image), we should probably use lmb_alloc() (again, see
> discussion in [1]).
So... how should I change this? I don't really understand how lmb
works to be honest. Where do I get the struct lmb from that I have to
pass into lmb_alloc()?
It also seems like there's a CONFIG_LMB that needs to be enabled for
this to work... is that guaranteed to be available for all boards that
support FIT images?
Maybe this is also something we could leave for future work?
> > + load = map_to_sysmem(loadbuf);
> > + } else {
> > + loadbuf = map_sysmem(load, max_decomp_len);
> > + }
> > + if (bootm_decomp_image(comp, load, data, IH_TYPE_FLATDT,
>
> You should probably use 'image_type' here instead of IH_TYPE_FLATDT.
>
> > + loadbuf, buf, len, max_decomp_len, &load_end)) {
> > + printf("Error: Cannot decompress FDT image\n");
>
> Again, 'FDT' is wrong here now.
Right, those two were holdovers from the previous version, will fix.
> > + return -ENOEXEC;
> > + }
> > + len = load_end - load;
> > + } else if (load != data) {
> > + loadbuf = map_sysmem(load, len);
> > + memcpy(loadbuf, buf, len);
> > }
> > +
> > + /* verify that image data is a proper FDT blob */
> > + if (image_type == IH_TYPE_FLATDT && fdt_check_header(loadbuf)) {
> > + puts("Subimage data is not a FDT");
> > + return -ENOEXEC;
> > + }
> > +
> > bootstage_mark(bootstage_id + BOOTSTAGE_SUB_LOAD);
> >
> > - *datap = data;
> > + *datap = load;
> > *lenp = len;
> > if (fit_unamep)
> > *fit_unamep = (char *)fit_uname;
> >
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