diff mbox

[v2] ARM: shmobile: uImage load address rework

Message ID 76205076.EsFJngGrIh@avalon (mailing list archive)
State Accepted
Commit 12dca809ef785e451263351325d4806198040b40
Headers show

Commit Message

Laurent Pinchart June 19, 2013, 1:16 p.m. UTC 
Hi Magnus,

On Wednesday 12 June 2013 04:31:26 Laurent Pinchart wrote:
> On Wednesday 12 June 2013 11:21:34 Magnus Damm wrote:
> > On Wed, Jun 12, 2013 at 6:50 AM, Laurent Pinchart wrote:
> > > On Monday 10 June 2013 18:28:57 Magnus Damm wrote:
> > >> From: Magnus Damm <damm@opensource.se>
> > >> 
> > >> This is V2 of the mach-shmobile uImage load address rework patch.
> > >> 
> > >> Rework the mach-shmobile uImage load address calculation by storing
> > >> the per-board load addresses in Makefile.boot. This removes the
> > >> CONFIG_MEMORY_START dependency from Makefile.boot, and it also makes
> > >> it possible to create safe kernel images that boot on multiple boards.
> > >> 
> > >> This is one of several series of code that reworks code not to rely on
> > >> CONFIG_MEMORY_START/SIZE which in turn is needed for
> > >> ARCH_MULTIPLATFORM.
> > >> 
> > >> Signed-off-by: Magnus Damm <damm@opensource.se>
> > >> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > >> Reviewed-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> > > 
> > > I've noticed today that KZM9G doesn't boot v3.10-rc2 with
> > > CONFIG_AUTO_ZRELADDR=y. While not caused by this patch, that's something
> > > that will need to be fixed to support multi-arch kernels. I'm not too
> > > familiar with early boot code, would you be able to have a look at this
> > > ?
> > 
> > I will have a look. I suspect that issue is not related to this patch, is
> > it?
> 
> No, it isn't, the issue is present in v3.10-rc2. I don't know if it has ever
> worked.

The following patch fixes the issue, caused by physical RAM being present at 
0x41000000 on KZM9G. I'm not sure if it would be acceptable as a generic 
solution though.

Comments

Magnus Damm June 25, 2013, 2 p.m. UTC | #1 
Hi Laurent,

On Wed, Jun 19, 2013 at 10:16 PM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Wednesday 12 June 2013 04:31:26 Laurent Pinchart wrote:
>> On Wednesday 12 June 2013 11:21:34 Magnus Damm wrote:
>> > On Wed, Jun 12, 2013 at 6:50 AM, Laurent Pinchart wrote:
>> > > I've noticed today that KZM9G doesn't boot v3.10-rc2 with
>> > > CONFIG_AUTO_ZRELADDR=y. While not caused by this patch, that's something
>> > > that will need to be fixed to support multi-arch kernels. I'm not too
>> > > familiar with early boot code, would you be able to have a look at this
>> > > ?
>> >
>> > I will have a look. I suspect that issue is not related to this patch, is
>> > it?
>>
>> No, it isn't, the issue is present in v3.10-rc2. I don't know if it has ever
>> worked.
>
> The following patch fixes the issue, caused by physical RAM being present at
> 0x41000000 on KZM9G. I'm not sure if it would be acceptable as a generic
> solution though.
>
> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> index fe4d9c3..ea2f112 100644
> --- a/arch/arm/boot/compressed/head.S
> +++ b/arch/arm/boot/compressed/head.S
> @@ -176,7 +176,7 @@ not_angel:
>  #ifdef CONFIG_AUTO_ZRELADDR
>                 @ determine final kernel image address
>                 mov     r4, pc
> -               and     r4, r4, #0xf8000000
> +               and     r4, r4, #0xff000000
>                 add     r4, r4, #TEXT_OFFSET
>  #else
>                 ldr     r4, =zreladdr

Thanks for tracking this down. I've now been looking into this a bit,
and I think we should try to get KZM9G working without modifying the
generic code. I am afraid that I have not been able to find the proper
fix for this though, see below for a dump of the current state.

To be able to get some more details from the kernel I've cooked up
some debug patches. It turns out that it's not really the code in
boot/compressed/ that is problematic - more the kernel itself. Also,
before trying to enable relocatable support via AUTO_ZRELADDR=y I
think we should try to get the regular AUTO_ZRELADDR=n case going with
an address that is compatible with the generic code that you pointed
out above. Then when that is fine it should be relatively easy to
support the relocatable case as well.

The attached patch
"linux-3.11-pre-arm-shmobile-kzm9g-zreladdr-48000000-20130625.patch"
makes sure the uImage gets loaded at 0x48008000 which from the
boot/compressed code is compatible with either AUTO_ZRELADDR=n or =y.

I've used the following patches on top of renesas git
renesas-next-20130620 to enable output together with DEBUG_LL=y and
EARLY_PRINTK=y:

linux-3.11-pre-arm-shmobile-kzm9g-putc-20130625b.patch
linux-3.11-pre-arm-shmobile-kzm9g-debug-macro-20130625.patch
linux-3.11-pre-arm-mem-add-printout-20130625.patch
linux-3.11-pre-arm-shmobile-kzm9g-zreladdr-48000000-20130625.patch

With the patches applied I get this serial output:

- - -

Filename 'kzm9g/uImage'.
Load address: 0x43000000
Loading: #################################################################
         ##########################
done
Bytes transferred = 1335151 (145f6f hex)
## Booting kernel from Legacy Image at 43000000 ...
   Image Name:   'Linux-3.10.0-rc2'
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    1335087 Bytes = 1.3 MiB
   Load Address: 48008000
   Entry Point:  48008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK
OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Linux version 3.10.0-rc2 (damm@w520) (gcc version 4.5.1 (Sourcery G++
Lite 2010.09-50) ) #1 SMP Tue Jun 25 22:25:10 JST 2013
CPU: ARMv7 Processor [412fc098] revision 8 (ARMv7), cr=10c5347d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine: kzm9g, model: KZM-A9-GT
Adding RAM at 41000000-5f7fffff.
bootconsole [earlycon0] enabled
debug: ignoring loglevel setting.
Ignoring RAM at 41000000-5f7fffff (vmalloc region overlap).
cma: CMA: failed to reserve 16 MiB
Memory policy: ECC disabled, Data cache writealloc
Kernel panic - not syncing: ERROR: Failed to allocate 0x1000 bytes below 0x0.

- - -

The fatal memory allocation most likely fails because all system
memory is ignored, see "(vmalloc region overlap)" above. This seems to
be the case regardless of HIGHMEM=y or =n.

It is possible to work around this issue by changing the memory bank
start address in the DTS:

--- 0001/arch/arm/boot/dts/sh73a0-kzm9g.dts
+++ work/arch/arm/boot/dts/sh73a0-kzm9g.dts     2013-06-25
22:17:19.000000000 +0900
@@ -19,8 +19,14 @@
                bootargs = "console=tty0 console=ttySC4,115200
root=/dev/nfs ip=dhcp ignore_loglevel earlyprintk=sh-sci.4,115200";
        };

-       memory {
+       memory@48000000 {
                device_type = "memory";
-               reg = <0x41000000 0x1e800000>;
+               reg = <0x48000000 0x10000000>;
        };

With the above hunk the kernel boots just fine. Unfortunately we
cannot enable all memory which is kind of limiting. =)

So my current conclusion is that it looks like the kernel doesn't like
to have the memory start address not aligned to 128 MByte somehow..

Cheers,

/ magnus
Laurent Pinchart July 3, 2013, 11:53 p.m. UTC | #2 
Hi Magnus,

On Tuesday 25 June 2013 23:00:49 Magnus Damm wrote:
> On Wed, Jun 19, 2013 at 10:16 PM, Laurent Pinchart wrote:
> > On Wednesday 12 June 2013 04:31:26 Laurent Pinchart wrote:
> >> On Wednesday 12 June 2013 11:21:34 Magnus Damm wrote:
> >> > On Wed, Jun 12, 2013 at 6:50 AM, Laurent Pinchart wrote:
> >> > > I've noticed today that KZM9G doesn't boot v3.10-rc2 with
> >> > > CONFIG_AUTO_ZRELADDR=y. While not caused by this patch, that's
> >> > > something that will need to be fixed to support multi-arch kernels.
> >> > > I'm not too familiar with early boot code, would you be able to have
> >> > > a look at this ?
> >> > 
> >> > I will have a look. I suspect that issue is not related to this patch,
> >> > is it?
> >> 
> >> No, it isn't, the issue is present in v3.10-rc2. I don't know if it has
> >> ever worked.
> > 
> > The following patch fixes the issue, caused by physical RAM being present
> > at 0x41000000 on KZM9G. I'm not sure if it would be acceptable as a
> > generic solution though.
> > 
> > diff --git a/arch/arm/boot/compressed/head.S
> > b/arch/arm/boot/compressed/head.S index fe4d9c3..ea2f112 100644
> > --- a/arch/arm/boot/compressed/head.S
> > +++ b/arch/arm/boot/compressed/head.S
> > @@ -176,7 +176,7 @@ not_angel:
> >  #ifdef CONFIG_AUTO_ZRELADDR
> >                 @ determine final kernel image address
> >                 mov     r4, pc
> > -               and     r4, r4, #0xf8000000
> > +               and     r4, r4, #0xff000000
> >                 add     r4, r4, #TEXT_OFFSET
> >  #else
> >                 ldr     r4, =zreladdr
> 
> Thanks for tracking this down. I've now been looking into this a bit, and I
> think we should try to get KZM9G working without modifying the generic code.
> I am afraid that I have not been able to find the proper fix for this
> though, see below for a dump of the current state.
> 
> To be able to get some more details from the kernel I've cooked up some
> debug patches. It turns out that it's not really the code in
> boot/compressed/ that is problematic - more the kernel itself. Also, before
> trying to enable relocatable support via AUTO_ZRELADDR=y I think we should
> try to get the regular AUTO_ZRELADDR=n case going with an address that is
> compatible with the generic code that you pointed out above. Then when that
> is fine it should be relatively easy to support the relocatable case as
> well.
> 
> The attached patch
> "linux-3.11-pre-arm-shmobile-kzm9g-zreladdr-48000000-20130625.patch"
> makes sure the uImage gets loaded at 0x48008000 which from the
> boot/compressed code is compatible with either AUTO_ZRELADDR=n or =y.
> 
> I've used the following patches on top of renesas git
> renesas-next-20130620 to enable output together with DEBUG_LL=y and
> EARLY_PRINTK=y:
> 
> linux-3.11-pre-arm-shmobile-kzm9g-putc-20130625b.patch
> linux-3.11-pre-arm-shmobile-kzm9g-debug-macro-20130625.patch
> linux-3.11-pre-arm-mem-add-printout-20130625.patch
> linux-3.11-pre-arm-shmobile-kzm9g-zreladdr-48000000-20130625.patch
> 
> With the patches applied I get this serial output:
> 
> - - -
> 
> Filename 'kzm9g/uImage'.
> Load address: 0x43000000
> Loading: #################################################################
>          ##########################
> done
> Bytes transferred = 1335151 (145f6f hex)
> ## Booting kernel from Legacy Image at 43000000 ...
>    Image Name:   'Linux-3.10.0-rc2'
>    Image Type:   ARM Linux Kernel Image (uncompressed)
>    Data Size:    1335087 Bytes = 1.3 MiB
>    Load Address: 48008000
>    Entry Point:  48008000
>    Verifying Checksum ... OK
>    Loading Kernel Image ... OK
> OK
> 
> Starting kernel ...
> 
> Uncompressing Linux... done, booting the kernel.
> Booting Linux on physical CPU 0x0
> Linux version 3.10.0-rc2 (damm@w520) (gcc version 4.5.1 (Sourcery G++
> Lite 2010.09-50) ) #1 SMP Tue Jun 25 22:25:10 JST 2013
> CPU: ARMv7 Processor [412fc098] revision 8 (ARMv7), cr=10c5347d
> CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
> Machine: kzm9g, model: KZM-A9-GT
> Adding RAM at 41000000-5f7fffff.
> bootconsole [earlycon0] enabled
> debug: ignoring loglevel setting.
> Ignoring RAM at 41000000-5f7fffff (vmalloc region overlap).
> cma: CMA: failed to reserve 16 MiB
> Memory policy: ECC disabled, Data cache writealloc
> Kernel panic - not syncing: ERROR: Failed to allocate 0x1000 bytes below
> 0x0.
> 
> - - -
> 
> The fatal memory allocation most likely fails because all system memory is
> ignored, see "(vmalloc region overlap)" above. This seems to be the case
> regardless of HIGHMEM=y or =n.
> 
> It is possible to work around this issue by changing the memory bank start
> address in the DTS:
> 
> --- 0001/arch/arm/boot/dts/sh73a0-kzm9g.dts
> +++ work/arch/arm/boot/dts/sh73a0-kzm9g.dts     2013-06-25
> 22:17:19.000000000 +0900
> @@ -19,8 +19,14 @@
>                 bootargs = "console=tty0 console=ttySC4,115200
> root=/dev/nfs ip=dhcp ignore_loglevel earlyprintk=sh-sci.4,115200";
>         };
> 
> -       memory {
> +       memory@48000000 {
>                 device_type = "memory";
> -               reg = <0x41000000 0x1e800000>;
> +               reg = <0x48000000 0x10000000>;
>         };
> 
> With the above hunk the kernel boots just fine. Unfortunately we cannot
> enable all memory which is kind of limiting. =)
> 
> So my current conclusion is that it looks like the kernel doesn't like to
> have the memory start address not aligned to 128 MByte somehow..

The vmalloc overlap range check will be gone in v3.11-rc1, but that 
unfortunately won't fix our issue. The kernel now fails to boot with

Uncompressing Linux... done, booting the kernel.
Booting Linux on physical CPU 0x0
Linux version 3.10.0-ag5+ (laurent@avalon) (gcc version 4.7.3 20130205 
(prerelease) (crosstool-NG linaro-1.13.1-4.7-2013.02-01-20130221 - Linaro GCC 
2013.02) ) #450 SMP Thu Jul 4 01:16:013
CPU: ARMv7 Processor [412fc098] revision 8 (ARMv7), cr=10c5387d
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
Machine: kzm9g, model: KZM-A9-GT
Adding RAM at 41000000-5f7fffff.
debug: ignoring loglevel setting.
bootconsole [earlycon0] enabled
cma: dma_contiguous_reserve(limit 5f800000)
cma: dma_contiguous_reserve: reserving 16 MiB for global area
cma: dma_declare_contiguous(size 1000000, base 00000000, limit 5f800000)
cma: CMA: reserved 16 MiB at 5e800000
Memory policy: ECC disabled, Data cache writealloc
BUG: not creating mapping for 0x41000000 at 0xb9000000 in user region

Further investigation showed that the problem lies in a wrong dynamic 
PHYS_OFFSET computation, in __fixup_pv_table (arch/arm/kernel/head.S). The 
code assumes that the kernel is loaded at the beginning of the physical memory 
and thus computes a PHYS_OFFSET of 0x48000000. The value is stored in 
__pv_phys_offset, later used in the __phys_to_virt() implementation.

When adding low memory the base physical address 0x41000000 is erroneously 
converted to a virtual address of 0xb9000000 instead of 0xc0000000, which 
leads to the bug.

I'm pretty new to early boot code, so don't really see a way to compute the 
PHYS_OFFSET without assuming that the kernel is loaded at the beginning of the 
physical memory.
diff mbox

Patch

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index fe4d9c3..ea2f112 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -176,7 +176,7 @@  not_angel:
 #ifdef CONFIG_AUTO_ZRELADDR
 		@ determine final kernel image address
 		mov	r4, pc
-		and	r4, r4, #0xf8000000
+		and	r4, r4, #0xff000000
 		add	r4, r4, #TEXT_OFFSET
 #else
 		ldr	r4, =zreladdr