[U-Boot] [PATCH v3 0/2] sunxi: Fix boot of Cubietruk and al.

[U-Boot] [PATCH v3 0/2] sunxi: Fix boot of Cubietruk and al.

[Maxime Ripard]

Hi

Most featureful boards, such as the Cubietruck, have been broken since
the release 2017.09 (the two variants of the Olinuxino-Lime2 and the
cubietruck at least, possibly more since then).

This is due to a size increase of the binary that will trip us across
the size we've been using in our default configuration since forever,
and widely distributed through the u-boot-sunxi-with-spl.bin file.

We would have several ways to work around it. The first one would be
to just increase the offset of the environment. However, since it
would break all the environments of our users and possibly the custom
partition scheme that they would have created, it doesn't really seem
like a smart move.

The second one would be to move the environment to a filesystem file,
which would also break all the existing users. This can be envisionned
as a long term fix though.

Another one would be to start trimming down a bit our enabled options
in order to reduce the size and to gain some extra space for users
customisations. However, this will always result in pointless and
endless discussions, so let's move away from that.

The final one that has been implemented would be to just build U-Boot
using thumb2 to push back the issue until hopefully I'm no longer
maintainer or the switch to the env filesystem would have been done.

I've also added a patch to make sure that the compilation breaks and
that we can notice.

Maxime

Changes from v2:
  - Reorder the patches
  - Changed the wording of U-boot to U-Boot
  - Changed the hardcoded value for CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR


Maxime Ripard (2):
  sunxi: Enable THUMB build for the U-Boot binary
  sunxi: binman: Add U-Boot binary size check

 arch/arm/Kconfig               |  1 +
 arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
 2 files changed, 13 insertions(+)

-- 
2.14.2

[U-Boot] [PATCH v3 1/2] sunxi: Enable THUMB build for the U-Boot binary

[Maxime Ripard]

We start to get to the limit of our main U-Boot binary size (with some
boards even crossing it). Enable its build using thumb2 to get some extra
room.

Suggested-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 arch/arm/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 64e0ee43f112..83b7aa51dc2c 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -698,6 +698,7 @@ config ARCH_SUNXI
 	select SPL_SYS_MALLOC_SIMPLE if SPL
 	select SYS_NS16550
 	select SPL_SYS_THUMB_BUILD if !ARM64
+	select SYS_THUMB_BUILD if !ARM64
 	select USB if DISTRO_DEFAULTS
 	select USB_STORAGE if DISTRO_DEFAULTS
 	select USB_KEYBOARD if DISTRO_DEFAULTS
-- 
2.14.2

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Maxime Ripard]

The U-Boot binary may trip over its actual allocated size in the storage.
In such a case, the environment will not be readable anymore (because
corrupted when the new image was flashed), and any attempt at using saveenv
to reconstruct the environment will result in a corrupted U-Boot binary.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
index 5adfd9bca2ec..72e95afd780e 100644
--- a/arch/arm/dts/sunxi-u-boot.dtsi
+++ b/arch/arm/dts/sunxi-u-boot.dtsi
@@ -1,5 +1,14 @@
 #include <config.h>
 
+/*
+ * This is the maximum size the U-Boot binary can be, which is basically
+ * the start of the environment, minus the start of the U-Boot binary in
+ * the MMC. This makes the assumption that the MMC is using 512-bytes
+ * blocks, but devices using something other than that remains to be
+ * seen.
+ */
+#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
+
 / {
 	binman {
 		filename = "u-boot-sunxi-with-spl.bin";
@@ -8,6 +17,9 @@
 			filename = "spl/sunxi-spl.bin";
 		};
 		u-boot-img {
+#ifdef CONFIG_MMC
+			size = <UBOOT_MMC_MAX_SIZE>;
+#endif
 			pos = <CONFIG_SPL_PAD_TO>;
 		};
 	};
-- 
2.14.2

[U-Boot] [PATCH v3 1/2] sunxi: Enable THUMB build for the U-Boot binary

[André Przywara]

On 20/10/17 13:16, Maxime Ripard wrote:
> We start to get to the limit of our main U-Boot binary size (with some
> boards even crossing it). Enable its build using thumb2 to get some extra
> room.
> 
> Suggested-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

I quickly boot tested this on an OrangePi Zero and a BananaPi-M1, also
Pine64 (fwiw).
Also buildman was happy (with the whole series) on all 123 sunxi boards
(ignoring the warnings a new dtc pops up on the 64-bit boards).

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>

Thanks!
Andre

> ---
>  arch/arm/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 64e0ee43f112..83b7aa51dc2c 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -698,6 +698,7 @@ config ARCH_SUNXI
>  	select SPL_SYS_MALLOC_SIMPLE if SPL
>  	select SYS_NS16550
>  	select SPL_SYS_THUMB_BUILD if !ARM64
> +	select SYS_THUMB_BUILD if !ARM64
>  	select USB if DISTRO_DEFAULTS
>  	select USB_STORAGE if DISTRO_DEFAULTS
>  	select USB_KEYBOARD if DISTRO_DEFAULTS
> 

[U-Boot] [PATCH v3 0/2] sunxi: Fix boot of Cubietruk and al.

[Maxime Ripard]

On Fri, Oct 20, 2017 at 02:16:12PM +0200, Maxime Ripard wrote:
> Hi
> 
> Most featureful boards, such as the Cubietruck, have been broken since
> the release 2017.09 (the two variants of the Olinuxino-Lime2 and the
> cubietruck at least, possibly more since then).
> 
> This is due to a size increase of the binary that will trip us across
> the size we've been using in our default configuration since forever,
> and widely distributed through the u-boot-sunxi-with-spl.bin file.
> 
> We would have several ways to work around it. The first one would be
> to just increase the offset of the environment. However, since it
> would break all the environments of our users and possibly the custom
> partition scheme that they would have created, it doesn't really seem
> like a smart move.
> 
> The second one would be to move the environment to a filesystem file,
> which would also break all the existing users. This can be envisionned
> as a long term fix though.
> 
> Another one would be to start trimming down a bit our enabled options
> in order to reduce the size and to gain some extra space for users
> customisations. However, this will always result in pointless and
> endless discussions, so let's move away from that.
> 
> The final one that has been implemented would be to just build U-Boot
> using thumb2 to push back the issue until hopefully I'm no longer
> maintainer or the switch to the env filesystem would have been done.
> 
> I've also added a patch to make sure that the compilation breaks and
> that we can notice.

Applied both, thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Måns Rullgård]

Maxime Ripard <maxime.ripard@free-electrons.com> writes:

> The U-Boot binary may trip over its actual allocated size in the storage.
> In such a case, the environment will not be readable anymore (because
> corrupted when the new image was flashed), and any attempt at using saveenv
> to reconstruct the environment will result in a corrupted U-Boot binary.
>
> Reviewed-by: Andre Przywara <andre.przywara@arm.com>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
> index 5adfd9bca2ec..72e95afd780e 100644
> --- a/arch/arm/dts/sunxi-u-boot.dtsi
> +++ b/arch/arm/dts/sunxi-u-boot.dtsi
> @@ -1,5 +1,14 @@
>  #include <config.h>
>
> +/*
> + * This is the maximum size the U-Boot binary can be, which is basically
> + * the start of the environment, minus the start of the U-Boot binary in
> + * the MMC. This makes the assumption that the MMC is using 512-bytes
> + * blocks, but devices using something other than that remains to be
> + * seen.
> + */
> +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
> +
>  / {
>  	binman {
>  		filename = "u-boot-sunxi-with-spl.bin";
> @@ -8,6 +17,9 @@
>  			filename = "spl/sunxi-spl.bin";
>  		};
>  		u-boot-img {
> +#ifdef CONFIG_MMC
> +			size = <UBOOT_MMC_MAX_SIZE>;
> +#endif
>  			pos = <CONFIG_SPL_PAD_TO>;
>  		};
>  	};
> -- 

This is broken in (at least) two ways:

1. It is simply nonsensical if u-boot and env are on different devices
   or not on mmc even if mmc support is enabled.

2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
   At best, this is useless.  If the env doesn't immediately follow
   u-boot, it really breaks things.

Please fix or revert, I don't really care which.

-- 
Måns Rullgård

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Siarhei Siamashka]

On Tue, 01 May 2018 18:25:06 +0100
Måns Rullgård <mans@mansr.com> wrote:

> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
> 
> > The U-Boot binary may trip over its actual allocated size in the storage.
> > In such a case, the environment will not be readable anymore (because
> > corrupted when the new image was flashed), and any attempt at using saveenv
> > to reconstruct the environment will result in a corrupted U-Boot binary.
> >
> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > ---
> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >
> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
> > index 5adfd9bca2ec..72e95afd780e 100644
> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
> > @@ -1,5 +1,14 @@
> >  #include <config.h>
> >
> > +/*
> > + * This is the maximum size the U-Boot binary can be, which is basically
> > + * the start of the environment, minus the start of the U-Boot binary in
> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
> > + * blocks, but devices using something other than that remains to be
> > + * seen.
> > + */
> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
> > +
> >  / {
> >  	binman {
> >  		filename = "u-boot-sunxi-with-spl.bin";
> > @@ -8,6 +17,9 @@
> >  			filename = "spl/sunxi-spl.bin";
> >  		};
> >  		u-boot-img {
> > +#ifdef CONFIG_MMC
> > +			size = <UBOOT_MMC_MAX_SIZE>;
> > +#endif
> >  			pos = <CONFIG_SPL_PAD_TO>;
> >  		};
> >  	};
> > --   
> 
> This is broken in (at least) two ways:
> 
> 1. It is simply nonsensical if u-boot and env are on different devices
>    or not on mmc even if mmc support is enabled.
> 
> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
>    At best, this is useless.  If the env doesn't immediately follow
>    u-boot, it really breaks things.
> 
> Please fix or revert, I don't really care which.

The padding is not useless. It reserves space for future size expansions
and makes it harder for the users to hurt themselves.

For example, if the padded U-Boot size is 1024K while the actual size
is only ~800K, then adventurous users might be tempted to fit some of
their data into this gap. Yay, ~200K of storage space for free! Except
that the next U-Boot release may grow up to 900K without any warning
and if the users are not careful enough, then their data would be
corrupted during upgrade.

Could you please tell us what is your problem and why reverting this
patch would fix it?

-- 
Best regards,
Siarhei Siamashka

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Måns Rullgård]

Siarhei Siamashka <siarhei.siamashka@gmail.com> writes:

> On Tue, 01 May 2018 18:25:06 +0100
> M책ns Rullg책rd <mans@mansr.com> wrote:
>
>> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
>> 
>> > The U-Boot binary may trip over its actual allocated size in the storage.
>> > In such a case, the environment will not be readable anymore (because
>> > corrupted when the new image was flashed), and any attempt at using saveenv
>> > to reconstruct the environment will result in a corrupted U-Boot binary.
>> >
>> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
>> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> > ---
>> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
>> >  1 file changed, 12 insertions(+)
>> >
>> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
>> > index 5adfd9bca2ec..72e95afd780e 100644
>> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
>> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
>> > @@ -1,5 +1,14 @@
>> >  #include <config.h>
>> >
>> > +/*
>> > + * This is the maximum size the U-Boot binary can be, which is basically
>> > + * the start of the environment, minus the start of the U-Boot binary in
>> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
>> > + * blocks, but devices using something other than that remains to be
>> > + * seen.
>> > + */
>> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
>> > +
>> >  / {
>> >  	binman {
>> >  		filename = "u-boot-sunxi-with-spl.bin";
>> > @@ -8,6 +17,9 @@
>> >  			filename = "spl/sunxi-spl.bin";
>> >  		};
>> >  		u-boot-img {
>> > +#ifdef CONFIG_MMC
>> > +			size = <UBOOT_MMC_MAX_SIZE>;
>> > +#endif
>> >  			pos = <CONFIG_SPL_PAD_TO>;
>> >  		};
>> >  	};
>> > --   
>> 
>> This is broken in (at least) two ways:
>> 
>> 1. It is simply nonsensical if u-boot and env are on different devices
>>    or not on mmc even if mmc support is enabled.
>> 
>> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
>>    At best, this is useless.  If the env doesn't immediately follow
>>    u-boot, it really breaks things.
>> 
>> Please fix or revert, I don't really care which.
>
> The padding is not useless. It reserves space for future size expansions
> and makes it harder for the users to hurt themselves.
>
> For example, if the padded U-Boot size is 1024K while the actual size
> is only ~800K, then adventurous users might be tempted to fit some of
> their data into this gap. Yay, ~200K of storage space for free! Except
> that the next U-Boot release may grow up to 900K without any warning
> and if the users are not careful enough, then their data would be
> corrupted during upgrade.

Do U-Boot users really need that level of hand-holding?

> Could you please tell us what is your problem and why reverting this
> patch would fix it?

See above.  Best case, it just wastes space in the created file.  If the
configuration is anything other than U-Boot immediately followed by env
on the same device, it _will_ break things horribly.  A few examples:

1.  U-Boot and env are on different devices, e.g. U-Boot on mmc and env
    in SPI NOR flash.  In this case, padding the file to the env offset
    makes no sense.  Writing the image will corrupt anything stored
    after U-Boot at a smaller (but still safe) offset.

2.  U-Boot at a non-zero offset, followed by env, but _not_ on mmc.  If
    CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, probably at its default
    value, is smaller than the offset of U-Boot in its actual device,
    the padding will be too large.  Writing the image file will then
    corrupt a stored env.

3.  U-Boot at start of device, env at end as indicated by a negative
    CONFIG_ENV_OFFSET.  With this configuration, binman tries to pad the
    image to (nearly) 2^64 bytes and promptly fills up your storage
    device.

I keep running into variants of these, and I'm weary of it.

-- 
M책ns Rullg책rd

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Maxime Ripard]

1;5201;0c
On Wed, May 02, 2018 at 10:34:49AM +0100, M책ns Rullg책rd wrote:
> Siarhei Siamashka <siarhei.siamashka@gmail.com> writes:
> 
> > On Tue, 01 May 2018 18:25:06 +0100
> > M책ns Rullg책rd <mans@mansr.com> wrote:
> >
> >> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
> >> 
> >> > The U-Boot binary may trip over its actual allocated size in the storage.
> >> > In such a case, the environment will not be readable anymore (because
> >> > corrupted when the new image was flashed), and any attempt at using saveenv
> >> > to reconstruct the environment will result in a corrupted U-Boot binary.
> >> >
> >> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
> >> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> >> > ---
> >> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
> >> >  1 file changed, 12 insertions(+)
> >> >
> >> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
> >> > index 5adfd9bca2ec..72e95afd780e 100644
> >> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
> >> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
> >> > @@ -1,5 +1,14 @@
> >> >  #include <config.h>
> >> >
> >> > +/*
> >> > + * This is the maximum size the U-Boot binary can be, which is basically
> >> > + * the start of the environment, minus the start of the U-Boot binary in
> >> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
> >> > + * blocks, but devices using something other than that remains to be
> >> > + * seen.
> >> > + */
> >> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
> >> > +
> >> >  / {
> >> >  	binman {
> >> >  		filename = "u-boot-sunxi-with-spl.bin";
> >> > @@ -8,6 +17,9 @@
> >> >  			filename = "spl/sunxi-spl.bin";
> >> >  		};
> >> >  		u-boot-img {
> >> > +#ifdef CONFIG_MMC
> >> > +			size = <UBOOT_MMC_MAX_SIZE>;
> >> > +#endif
> >> >  			pos = <CONFIG_SPL_PAD_TO>;
> >> >  		};
> >> >  	};
> >> > --   
> >> 
> >> This is broken in (at least) two ways:
> >> 
> >> 1. It is simply nonsensical if u-boot and env are on different devices
> >>    or not on mmc even if mmc support is enabled.
> >> 
> >> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
> >>    At best, this is useless.  If the env doesn't immediately follow
> >>    u-boot, it really breaks things.
> >> 
> >> Please fix or revert, I don't really care which.
> >
> > The padding is not useless. It reserves space for future size expansions
> > and makes it harder for the users to hurt themselves.
> >
> > For example, if the padded U-Boot size is 1024K while the actual size
> > is only ~800K, then adventurous users might be tempted to fit some of
> > their data into this gap. Yay, ~200K of storage space for free! Except
> > that the next U-Boot release may grow up to 900K without any warning
> > and if the users are not careful enough, then their data would be
> > corrupted during upgrade.
> 
> Do U-Boot users really need that level of hand-holding?

Yes, and that's never a good argument to make, because...

> > Could you please tell us what is your problem and why reverting this
> > patch would fix it?
> 
> See above.  Best case, it just wastes space in the created file.  If the
> configuration is anything other than U-Boot immediately followed by env
> on the same device, it _will_ break things horribly.  A few examples:
> 
> 1.  U-Boot and env are on different devices, e.g. U-Boot on mmc and env
>     in SPI NOR flash.  In this case, padding the file to the env offset
>     makes no sense.  Writing the image will corrupt anything stored
>     after U-Boot at a smaller (but still safe) offset.

.. I could make pretty much the same one for all your cases, which
would be completely useless, and wouldn't fix anything.

I guess this one could be solved using an ifdef guard with
ENV_IS_IN_MMC.

> 2.  U-Boot at a non-zero offset, followed by env, but _not_ on mmc.  If
>     CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, probably at its default
>     value, is smaller than the offset of U-Boot in its actual device,
>     the padding will be too large.  Writing the image file will then
>     corrupt a stored env.

This one would be covered too.

> 3.  U-Boot at start of device, env at end as indicated by a negative
>     CONFIG_ENV_OFFSET.  With this configuration, binman tries to pad the
>     image to (nearly) 2^64 bytes and promptly fills up your storage
>     device.

I'm not too sure about how to fix this one though. Any suggestion?

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Måns Rullgård]

Maxime Ripard <maxime.ripard@bootlin.com> writes:

> 1;5201;0c
> On Wed, May 02, 2018 at 10:34:49AM +0100, Måns Rullgård wrote:
>> Siarhei Siamashka <siarhei.siamashka@gmail.com> writes:
>> 
>> > On Tue, 01 May 2018 18:25:06 +0100
>> > Måns Rullgård <mans@mansr.com> wrote:
>> >
>> >> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
>> >> 
>> >> > The U-Boot binary may trip over its actual allocated size in the storage.
>> >> > In such a case, the environment will not be readable anymore (because
>> >> > corrupted when the new image was flashed), and any attempt at using saveenv
>> >> > to reconstruct the environment will result in a corrupted U-Boot binary.
>> >> >
>> >> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
>> >> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> >> > ---
>> >> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
>> >> >  1 file changed, 12 insertions(+)
>> >> >
>> >> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
>> >> > index 5adfd9bca2ec..72e95afd780e 100644
>> >> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
>> >> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
>> >> > @@ -1,5 +1,14 @@
>> >> >  #include <config.h>
>> >> >
>> >> > +/*
>> >> > + * This is the maximum size the U-Boot binary can be, which is basically
>> >> > + * the start of the environment, minus the start of the U-Boot binary in
>> >> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
>> >> > + * blocks, but devices using something other than that remains to be
>> >> > + * seen.
>> >> > + */
>> >> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
>> >> > +
>> >> >  / {
>> >> >  	binman {
>> >> >  		filename = "u-boot-sunxi-with-spl.bin";
>> >> > @@ -8,6 +17,9 @@
>> >> >  			filename = "spl/sunxi-spl.bin";
>> >> >  		};
>> >> >  		u-boot-img {
>> >> > +#ifdef CONFIG_MMC
>> >> > +			size = <UBOOT_MMC_MAX_SIZE>;
>> >> > +#endif
>> >> >  			pos = <CONFIG_SPL_PAD_TO>;
>> >> >  		};
>> >> >  	};
>> >> > --   
>> >> 
>> >> This is broken in (at least) two ways:
>> >> 
>> >> 1. It is simply nonsensical if u-boot and env are on different devices
>> >>    or not on mmc even if mmc support is enabled.
>> >> 
>> >> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
>> >>    At best, this is useless.  If the env doesn't immediately follow
>> >>    u-boot, it really breaks things.
>> >> 
>> >> Please fix or revert, I don't really care which.
>> >
>> > The padding is not useless. It reserves space for future size expansions
>> > and makes it harder for the users to hurt themselves.
>> >
>> > For example, if the padded U-Boot size is 1024K while the actual size
>> > is only ~800K, then adventurous users might be tempted to fit some of
>> > their data into this gap. Yay, ~200K of storage space for free! Except
>> > that the next U-Boot release may grow up to 900K without any warning
>> > and if the users are not careful enough, then their data would be
>> > corrupted during upgrade.
>> 
>> Do U-Boot users really need that level of hand-holding?
>
> Yes, and that's never a good argument to make, because...
>
>> > Could you please tell us what is your problem and why reverting this
>> > patch would fix it?
>> 
>> See above.  Best case, it just wastes space in the created file.  If the
>> configuration is anything other than U-Boot immediately followed by env
>> on the same device, it _will_ break things horribly.  A few examples:
>> 
>> 1.  U-Boot and env are on different devices, e.g. U-Boot on mmc and env
>>     in SPI NOR flash.  In this case, padding the file to the env offset
>>     makes no sense.  Writing the image will corrupt anything stored
>>     after U-Boot at a smaller (but still safe) offset.
>
> .. I could make pretty much the same one for all your cases, which
> would be completely useless, and wouldn't fix anything.

Huh?  I'm saying we shouldn't "helpfully" do things that actually break
perfectly valid setups.  U-Boot users are expected to know what they are
doing, and shouldn't need that kind of help.  In my opinion.

> I guess this one could be solved using an ifdef guard with
> ENV_IS_IN_MMC.

Not if env is on a different mmc device.

>> 2.  U-Boot at a non-zero offset, followed by env, but _not_ on mmc.  If
>>     CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, probably at its default
>>     value, is smaller than the offset of U-Boot in its actual device,
>>     the padding will be too large.  Writing the image file will then
>>     corrupt a stored env.
>
> This one would be covered too.
>
>> 3.  U-Boot at start of device, env at end as indicated by a negative
>>     CONFIG_ENV_OFFSET.  With this configuration, binman tries to pad the
>>     image to (nearly) 2^64 bytes and promptly fills up your storage
>>     device.
>
> I'm not too sure about how to fix this one though. Any suggestion?

I just don't see the point in trying to pin down the very specific case
of U-Boot and env being on the same device with only a (small) amount of
padding between them.  There are a million other ways for users to screw
up, so why should we be making a half-hearted effort to prevent this
one?

-- 
Måns Rullgård

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Maxime Ripard]

On Wed, May 02, 2018 at 03:24:50PM +0100, Måns Rullgård wrote:
> Maxime Ripard <maxime.ripard@bootlin.com> writes:
> 
> > 1;5201;0c
> > On Wed, May 02, 2018 at 10:34:49AM +0100, Måns Rullgård wrote:
> >> Siarhei Siamashka <siarhei.siamashka@gmail.com> writes:
> >> 
> >> > On Tue, 01 May 2018 18:25:06 +0100
> >> > Måns Rullgård <mans@mansr.com> wrote:
> >> >
> >> >> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
> >> >> 
> >> >> > The U-Boot binary may trip over its actual allocated size in the storage.
> >> >> > In such a case, the environment will not be readable anymore (because
> >> >> > corrupted when the new image was flashed), and any attempt at using saveenv
> >> >> > to reconstruct the environment will result in a corrupted U-Boot binary.
> >> >> >
> >> >> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
> >> >> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> >> >> > ---
> >> >> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
> >> >> >  1 file changed, 12 insertions(+)
> >> >> >
> >> >> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
> >> >> > index 5adfd9bca2ec..72e95afd780e 100644
> >> >> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
> >> >> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
> >> >> > @@ -1,5 +1,14 @@
> >> >> >  #include <config.h>
> >> >> >
> >> >> > +/*
> >> >> > + * This is the maximum size the U-Boot binary can be, which is basically
> >> >> > + * the start of the environment, minus the start of the U-Boot binary in
> >> >> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
> >> >> > + * blocks, but devices using something other than that remains to be
> >> >> > + * seen.
> >> >> > + */
> >> >> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
> >> >> > +
> >> >> >  / {
> >> >> >  	binman {
> >> >> >  		filename = "u-boot-sunxi-with-spl.bin";
> >> >> > @@ -8,6 +17,9 @@
> >> >> >  			filename = "spl/sunxi-spl.bin";
> >> >> >  		};
> >> >> >  		u-boot-img {
> >> >> > +#ifdef CONFIG_MMC
> >> >> > +			size = <UBOOT_MMC_MAX_SIZE>;
> >> >> > +#endif
> >> >> >  			pos = <CONFIG_SPL_PAD_TO>;
> >> >> >  		};
> >> >> >  	};
> >> >> > --   
> >> >> 
> >> >> This is broken in (at least) two ways:
> >> >> 
> >> >> 1. It is simply nonsensical if u-boot and env are on different devices
> >> >>    or not on mmc even if mmc support is enabled.
> >> >> 
> >> >> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
> >> >>    At best, this is useless.  If the env doesn't immediately follow
> >> >>    u-boot, it really breaks things.
> >> >> 
> >> >> Please fix or revert, I don't really care which.
> >> >
> >> > The padding is not useless. It reserves space for future size expansions
> >> > and makes it harder for the users to hurt themselves.
> >> >
> >> > For example, if the padded U-Boot size is 1024K while the actual size
> >> > is only ~800K, then adventurous users might be tempted to fit some of
> >> > their data into this gap. Yay, ~200K of storage space for free! Except
> >> > that the next U-Boot release may grow up to 900K without any warning
> >> > and if the users are not careful enough, then their data would be
> >> > corrupted during upgrade.
> >> 
> >> Do U-Boot users really need that level of hand-holding?
> >
> > Yes, and that's never a good argument to make, because...
> >
> >> > Could you please tell us what is your problem and why reverting this
> >> > patch would fix it?
> >> 
> >> See above.  Best case, it just wastes space in the created file.  If the
> >> configuration is anything other than U-Boot immediately followed by env
> >> on the same device, it _will_ break things horribly.  A few examples:
> >> 
> >> 1.  U-Boot and env are on different devices, e.g. U-Boot on mmc and env
> >>     in SPI NOR flash.  In this case, padding the file to the env offset
> >>     makes no sense.  Writing the image will corrupt anything stored
> >>     after U-Boot at a smaller (but still safe) offset.
> >
> > .. I could make pretty much the same one for all your cases, which
> > would be completely useless, and wouldn't fix anything.
> 
> Huh?  I'm saying we shouldn't "helpfully" do things that actually break
> perfectly valid setups.  U-Boot users are expected to know what they are
> doing, and shouldn't need that kind of help.  In my opinion.

My point is that this is a slippery slope. Anyway..

> > I guess this one could be solved using an ifdef guard with
> > ENV_IS_IN_MMC.
> 
> Not if env is on a different mmc device.

Ah, right...

> >> 2.  U-Boot at a non-zero offset, followed by env, but _not_ on mmc.  If
> >>     CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, probably at its default
> >>     value, is smaller than the offset of U-Boot in its actual device,
> >>     the padding will be too large.  Writing the image file will then
> >>     corrupt a stored env.
> >
> > This one would be covered too.
> >
> >> 3.  U-Boot at start of device, env at end as indicated by a negative
> >>     CONFIG_ENV_OFFSET.  With this configuration, binman tries to pad the
> >>     image to (nearly) 2^64 bytes and promptly fills up your storage
> >>     device.
> >
> > I'm not too sure about how to fix this one though. Any suggestion?
> 
> I just don't see the point in trying to pin down the very specific case
> of U-Boot and env being on the same device with only a (small) amount of
> padding between them.  There are a million other ways for users to screw
> up, so why should we be making a half-hearted effort to prevent this
> one?

Unfortunately, this isn't a very specific case this is the default we
shipped for years. And we have people relying on it in the wild.

This is why we added that check in the first place, because the size
of uboot increased so much that it was now overlapping with the
environment.

I guess now that we transitioned with the release of 2018.05, we can
remove that check entirely, since the default is the first partition,
wherever that is.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

[U-Boot] [PATCH v3 2/2] sunxi: binman: Add U-Boot binary size check

[Måns Rullgård]

Maxime Ripard <maxime.ripard@bootlin.com> writes:

> On Wed, May 02, 2018 at 03:24:50PM +0100, Måns Rullgård wrote:
>> Maxime Ripard <maxime.ripard@bootlin.com> writes:
>> 
>> > 1;5201;0c
>> > On Wed, May 02, 2018 at 10:34:49AM +0100, Måns Rullgård wrote:
>> >> Siarhei Siamashka <siarhei.siamashka@gmail.com> writes:
>> >> 
>> >> > On Tue, 01 May 2018 18:25:06 +0100
>> >> > Måns Rullgård <mans@mansr.com> wrote:
>> >> >
>> >> >> Maxime Ripard <maxime.ripard@free-electrons.com> writes:
>> >> >> 
>> >> >> > The U-Boot binary may trip over its actual allocated size in the storage.
>> >> >> > In such a case, the environment will not be readable anymore (because
>> >> >> > corrupted when the new image was flashed), and any attempt at using saveenv
>> >> >> > to reconstruct the environment will result in a corrupted U-Boot binary.
>> >> >> >
>> >> >> > Reviewed-by: Andre Przywara <andre.przywara@arm.com>
>> >> >> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> >> >> > ---
>> >> >> >  arch/arm/dts/sunxi-u-boot.dtsi | 12 ++++++++++++
>> >> >> >  1 file changed, 12 insertions(+)
>> >> >> >
>> >> >> > diff --git a/arch/arm/dts/sunxi-u-boot.dtsi b/arch/arm/dts/sunxi-u-boot.dtsi
>> >> >> > index 5adfd9bca2ec..72e95afd780e 100644
>> >> >> > --- a/arch/arm/dts/sunxi-u-boot.dtsi
>> >> >> > +++ b/arch/arm/dts/sunxi-u-boot.dtsi
>> >> >> > @@ -1,5 +1,14 @@
>> >> >> >  #include <config.h>
>> >> >> >
>> >> >> > +/*
>> >> >> > + * This is the maximum size the U-Boot binary can be, which is basically
>> >> >> > + * the start of the environment, minus the start of the U-Boot binary in
>> >> >> > + * the MMC. This makes the assumption that the MMC is using 512-bytes
>> >> >> > + * blocks, but devices using something other than that remains to be
>> >> >> > + * seen.
>> >> >> > + */
>> >> >> > +#define UBOOT_MMC_MAX_SIZE	(CONFIG_ENV_OFFSET - (CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR * 512))
>> >> >> > +
>> >> >> >  / {
>> >> >> >  	binman {
>> >> >> >  		filename = "u-boot-sunxi-with-spl.bin";
>> >> >> > @@ -8,6 +17,9 @@
>> >> >> >  			filename = "spl/sunxi-spl.bin";
>> >> >> >  		};
>> >> >> >  		u-boot-img {
>> >> >> > +#ifdef CONFIG_MMC
>> >> >> > +			size = <UBOOT_MMC_MAX_SIZE>;
>> >> >> > +#endif
>> >> >> >  			pos = <CONFIG_SPL_PAD_TO>;
>> >> >> >  		};
>> >> >> >  	};
>> >> >> > --   
>> >> >> 
>> >> >> This is broken in (at least) two ways:
>> >> >> 
>> >> >> 1. It is simply nonsensical if u-boot and env are on different devices
>> >> >>    or not on mmc even if mmc support is enabled.
>> >> >> 
>> >> >> 2. It causes u-boot-sunxi-with-spl.bin to be padded to the env offset.
>> >> >>    At best, this is useless.  If the env doesn't immediately follow
>> >> >>    u-boot, it really breaks things.
>> >> >> 
>> >> >> Please fix or revert, I don't really care which.
>> >> >
>> >> > The padding is not useless. It reserves space for future size expansions
>> >> > and makes it harder for the users to hurt themselves.
>> >> >
>> >> > For example, if the padded U-Boot size is 1024K while the actual size
>> >> > is only ~800K, then adventurous users might be tempted to fit some of
>> >> > their data into this gap. Yay, ~200K of storage space for free! Except
>> >> > that the next U-Boot release may grow up to 900K without any warning
>> >> > and if the users are not careful enough, then their data would be
>> >> > corrupted during upgrade.
>> >> 
>> >> Do U-Boot users really need that level of hand-holding?
>> >
>> > Yes, and that's never a good argument to make, because...
>> >
>> >> > Could you please tell us what is your problem and why reverting this
>> >> > patch would fix it?
>> >> 
>> >> See above.  Best case, it just wastes space in the created file.  If the
>> >> configuration is anything other than U-Boot immediately followed by env
>> >> on the same device, it _will_ break things horribly.  A few examples:
>> >> 
>> >> 1.  U-Boot and env are on different devices, e.g. U-Boot on mmc and env
>> >>     in SPI NOR flash.  In this case, padding the file to the env offset
>> >>     makes no sense.  Writing the image will corrupt anything stored
>> >>     after U-Boot at a smaller (but still safe) offset.
>> >
>> > .. I could make pretty much the same one for all your cases, which
>> > would be completely useless, and wouldn't fix anything.
>> 
>> Huh?  I'm saying we shouldn't "helpfully" do things that actually break
>> perfectly valid setups.  U-Boot users are expected to know what they are
>> doing, and shouldn't need that kind of help.  In my opinion.
>
> My point is that this is a slippery slope. Anyway..

Yes, trying to be overly helpful is indeed a slippery slope.

>> > I guess this one could be solved using an ifdef guard with
>> > ENV_IS_IN_MMC.
>> 
>> Not if env is on a different mmc device.
>
> Ah, right...
>
>> >> 2.  U-Boot at a non-zero offset, followed by env, but _not_ on mmc.  If
>> >>     CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR, probably at its default
>> >>     value, is smaller than the offset of U-Boot in its actual device,
>> >>     the padding will be too large.  Writing the image file will then
>> >>     corrupt a stored env.
>> >
>> > This one would be covered too.
>> >
>> >> 3.  U-Boot at start of device, env at end as indicated by a negative
>> >>     CONFIG_ENV_OFFSET.  With this configuration, binman tries to pad the
>> >>     image to (nearly) 2^64 bytes and promptly fills up your storage
>> >>     device.
>> >
>> > I'm not too sure about how to fix this one though. Any suggestion?
>> 
>> I just don't see the point in trying to pin down the very specific case
>> of U-Boot and env being on the same device with only a (small) amount of
>> padding between them.  There are a million other ways for users to screw
>> up, so why should we be making a half-hearted effort to prevent this
>> one?
>
> Unfortunately, this isn't a very specific case this is the default we
> shipped for years.

Your default is still just one specific case of nearly infinite
possibilities.

> And we have people relying on it in the wild.

How can anyone *rely* on that padding being there?

> This is why we added that check in the first place, because the size
> of uboot increased so much that it was now overlapping with the
> environment.

I get that.  Unfortunately, the check was flawed for all but your
default use case.

> I guess now that we transitioned with the release of 2018.05, we can
> remove that check entirely, since the default is the first partition,
> wherever that is.

I don't care how you justify it as long as you get rid of the broken code.

-- 
Måns Rullgård