From: Andrew Jones <ajones@ventanamicro.com>
To: Anup Patel <apatel@ventanamicro.com>
Cc: Atish Patra <atishp@rivosinc.com>,
Anup Patel <anup@brainfault.org>,
opensbi@lists.infradead.org
Subject: Re: [PATCH] platform: generic: Keep some empty space in FDT passed to next stage
Date: Wed, 5 Nov 2025 10:14:49 -0600 [thread overview]
Message-ID: <20251105-c4154b1f28934a0798a712a0@orel> (raw)
In-Reply-To: <20251105160146.271156-1-apatel@ventanamicro.com>
On Wed, Nov 05, 2025 at 09:31:45PM +0530, Anup Patel wrote:
> Leaving no empty space in the FDT passed to the next booting stage
> causes the following U-Boot crash on Ventana internal platforms:
>
> Unhandled exception: Load access fault
> EPC: 00000000fffa6372 RA: 00000000fffa7418 TVAL: 0001746174730068
> EPC: 0000000080245372 RA: 0000000080246418 reloc adjusted
>
> SP: 00000000fef38440 GP: 00000000fef40e60 TP: 0000000000000000
> T0: 00000000fef40a70 T1: 000000000000ff00 T2: 0000000000000000
> S0: 00000000fffc17a8 S1: 00000000fef38d40 A0: 7375746174730068
> A1: 00000000fffc17a8 A2: 0000000000000010 A3: 0000000000000010
> A4: 0000000000000000 A5: 00000000fffc17b8 A6: 0000000000ff0000
> A7: 000000000000b100 S2: 0000000000000000 S3: 0000000000000001
> S4: 00000000fef38d40 S5: 7375746174730068 S6: 0000000000000000
> S7: 00000000fef4eef0 S8: 00000000fef4ef90 S9: 0000000000000000
> S10: 0000000000000000 S11: 00000000fef4efc0 T3: 00000000fef40ea8
> T4: 0000000000ff0000 T5: 00000000fef40a60 T6: 00000000fef40a6c
>
> To address the above issue, keep some minimal empty space in the
> FDT instead of no empty space.
>
> Fixes: bbe9a23060e9 ("platform: generic: Pack the FDT after applying fixups")
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> ---
> platform/generic/platform.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/platform/generic/platform.c b/platform/generic/platform.c
> index e66f99fa..ea44676b 100644
> --- a/platform/generic/platform.c
> +++ b/platform/generic/platform.c
> @@ -245,7 +245,9 @@ int generic_final_init(bool cold_boot)
> fdt_fixups(fdt);
> fdt_domain_fixup(fdt);
>
> + /* Minimize the empty space in FDT to 4KB */
> fdt_pack(fdt);
> + fdt_open_into(fdt, fdt, fdt_totalsize(fdt) + 4096);
>
> return 0;
> }
> --
> 2.43.0
>
I agree opensbi needs to workaround uboot issues in order to ensure it
doesn't break current configurations, but maybe we should make the
extra space added be a Kconfig managed define, rather than a hard 4096.
The main reason would be to enable setting it to zero so issues with
second stage loaders like this one can be flushed out and fixed.
Thanks,
drew
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next prev parent reply other threads:[~2025-11-05 16:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-05 16:01 [PATCH] platform: generic: Keep some empty space in FDT passed to next stage Anup Patel
2025-11-05 16:14 ` Andrew Jones [this message]
2025-12-01 4:59 ` Anup Patel
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