Hi Marek,
Thank you for the patch.
On Sat, Mar 02, 2024 at 11:54:02PM +0100, Marek Vasut wrote:
> According to README CFG_SYS_BOOTMAPSZ section, in case both "bootm_low" and
> "bootm_size" variables are defined, "bootm_mapsize" variable is not defined
> and CFG_SYS_BOOTMAPSZ macro is not defined, all data for the Linux kernel
> must be between "bootm_low" and "bootm_low" + "bootm_size".
>
> Currently, for systems with DRAM between 0x4000_0000..0x7fff_ffff and with
> e.g. bootm_low=0x60000000 and bootm_size=0x10000000, the code will attempt
> to reserve memory from 0x4000_0000..0x4fff_ffff, which is incorrect. This
> is because "bootm_low" is not taken into consideration correctly.
>
> The last parameter of lmb_alloc_base() is the maximum physical address of
> the to be reserved LMB area. Currently this is the start of DRAM bank that
> is considered for LMB area reservation + min(DRAM bank size, bootm_size).
> In case bootm_low is set to non-zero, this maximum physical address has to
> be shifted upward, to min(DRAM bank start + size, bootm_low + bootm_size),
> otherwise the reserved memory may be below bootm_low address.
>
> In case of multiple DRAM banks, the current change reserves top part of
> the first bank, and reserves the rest of memory in the follow up banks.
>
> Signed-off-by: Marek Vasut <marek.vasut+rene...@mailbox.org>
> ---
> Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
> Cc: Hans Verkuil <hverkuil-ci...@xs4all.nl>
> Cc: Heinrich Schuchardt <xypron.g...@gmx.de>
> Cc: Kuninori Morimoto <kuninori.morimoto...@renesas.com>
> Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Cc: Niklas Söderlund <niklas.soderl...@ragnatech.se>
> Cc: Simon Glass <s...@chromium.org>
> Cc: Tom Rini <tr...@konsulko.com>
> Cc: Wolfram Sang <w...@kernel.org>
> ---
> boot/image-fdt.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/boot/image-fdt.c b/boot/image-fdt.c
> index 75bdd55f326..5e4aa9de0d2 100644
> --- a/boot/image-fdt.c
> +++ b/boot/image-fdt.c
> @@ -217,14 +217,14 @@ int boot_relocate_fdt(struct lmb *lmb, char
> **of_flat_tree, ulong *of_size)
> if (start + size < low)
> continue;
>
> - usable = min(size, (u64)mapsize);
> + usable = min(start + size, (u64)(low + mapsize));
low and mapsize are ulong, is there a risk this could overflow on 32-bit
platforms ?
I would rename usable to usable_end to make it clearer.
>
> /*
> * At least part of this DRAM bank is usable, try
> * using it for LMB allocation.
> */
> of_start = map_sysmem((ulong)lmb_alloc_base(lmb,
> - of_len, 0x1000, start + usable), of_len);
> + of_len, 0x1000, usable), of_len);
> /* Allocation succeeded, use this block. */
> if (of_start != NULL)
> break;
The code continue with
/*
* Reduce the mapping size in the next bank
* by the size of attempt in current bank.
*/
mapsize -= usable - max(start, (u64)low);
if (!mapsize)
break;
which seems to be correct now, but interestingly was not before :-)
--
Regards,
Laurent Pinchart
