* [PATCH] platform: generic: Keep some empty space in FDT passed to next stage
@ 2025-11-05 16:01 Anup Patel
2025-11-05 16:14 ` Andrew Jones
0 siblings, 1 reply; 3+ messages in thread
From: Anup Patel @ 2025-11-05 16:01 UTC (permalink / raw)
To: Atish Patra; +Cc: Andrew Jones, Anup Patel, opensbi, Anup Patel
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
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] platform: generic: Keep some empty space in FDT passed to next stage
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
2025-12-01 4:59 ` Anup Patel
0 siblings, 1 reply; 3+ messages in thread
From: Andrew Jones @ 2025-11-05 16:14 UTC (permalink / raw)
To: Anup Patel; +Cc: Atish Patra, Anup Patel, opensbi
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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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] platform: generic: Keep some empty space in FDT passed to next stage
2025-11-05 16:14 ` Andrew Jones
@ 2025-12-01 4:59 ` Anup Patel
0 siblings, 0 replies; 3+ messages in thread
From: Anup Patel @ 2025-12-01 4:59 UTC (permalink / raw)
To: Andrew Jones; +Cc: Atish Patra, Anup Patel, opensbi
On Wed, Nov 5, 2025 at 9:44 PM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> 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.
>
Adding a Kconfig option for the amount of extra space should be fine,
I will update and send v2.
Thanks,
Anup
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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
2025-12-01 4:59 ` Anup Patel
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