Hi Tom,
Further update.
I asked this question to linux maintainer, and he pointed out that load address
that I am using is not correct.
The linux load address should be (2 MB aligned + text_offset).
The text_offset can be obtained from first 64 bytes in linux Image.
For our use case it comes out to be 0x81080000.
One thing that I wonder though is, that I did not receive any warning or error
from uboot about load address.
Can such warning/error be added in uboot ?
Regards,
Pankaj Bansal
> -----Original Message-----
> From: Pankaj Bansal
> Sent: Tuesday, 7 May, 2019 03:48 PM
> To: 'Tom Rini' <[email protected]>
> Cc: '[email protected]' <[email protected]>; Prabhakar Kushwaha
> <[email protected]>; Varun Sethi <[email protected]>
> Subject: RE: [EXT] Re: [ARMv8] kernel entry point
>
> On further testing I tried to boot the linux from ATF (https://github.com/ARM-
> software/arm-trusted-firmware)
> Without using u-boot
> Even with ATF, the linux is not able to boot from 0x81000000, but is able to
> boot
> from 0x80080000 Seems like linux issue and not u-boot issue.
> I will ask this question in linux community.
>
> Regards,
> Pankaj Bansal
>
> > -----Original Message-----
> > From: Pankaj Bansal
> > Sent: Tuesday, 7 May, 2019 08:30 AM
> > To: 'Tom Rini' <[email protected]>
> > Cc: '[email protected]' <[email protected]>; Prabhakar Kushwaha
> > <[email protected]>; Varun Sethi <[email protected]>
> > Subject: RE: [EXT] Re: [ARMv8] kernel entry point
> >
> > Hi Tom,
> >
> > In order to determine whether linux entry point has been called or
> > not, I put a loop in kernel:
> >
> > diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index
> > 261f3f88364c..dea6cb8baa6a 100644
> > --- a/arch/arm64/kernel/head.S
> > +++ b/arch/arm64/kernel/head.S
> > @@ -80,6 +80,7 @@ _head:
> > * its opcode forms the magic "MZ" signature required by UEFI.
> > */
> > add x13, x18, #0x16
> > + b .
> > b stext
> > #else
> > b stext // branch to kernel start,
> > magic
> >
> > This loop is being executed when I boot the kernel, but after I jump
> > over this loop there is no log.
> > Does it mean that bootloader is working fine, it's the linux that is
> > not able to boot from 0x81000000 (0x80000000 being the RAM starting
> address) ?
> >
> > Regards,
> > Pankaj Bansal
> >
> > > -----Original Message-----
> > > From: Pankaj Bansal
> > > Sent: Monday, 6 May, 2019 07:04 PM
> > > To: Tom Rini <[email protected]>
> > > Cc: [email protected]; Prabhakar Kushwaha
> > > <[email protected]>; Varun Sethi <[email protected]>
> > > Subject: RE: [EXT] Re: [ARMv8] kernel entry point
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Tom Rini <[email protected]>
> > > > Sent: Monday, 6 May, 2019 06:59 PM
> > > > To: Pankaj Bansal <[email protected]>
> > > > Cc: [email protected]; Prabhakar Kushwaha
> > > > <[email protected]>; Varun Sethi <[email protected]>
> > > > Subject: [EXT] Re: [ARMv8] kernel entry point
> > > >
> > > > On Mon, May 06, 2019 at 01:06:45PM +0000, Pankaj Bansal wrote:
> > > >
> > > > > Hi Tom et. Al,
> > > > >
> > > > > I am facing an issue while booting linux on our ARMv8 based platform.
> > > > > In our platform DDR address starts from 0x80000000.
> > > > > If I make the linux kernel entry point 0x80080000 in mkimage,
> > > > > then linux boots
> > > > fine.
> > > > > BUT, if I make the linux image entry point as 0x81000000 in
> > > > > mkimage, the
> > > > kernel doesn't boot.
> > > > >
> > > > > => bootm 0xa0000000 - 0xa1000000 ## Current stack ends at
> > > > > 0xfbb24400 ## Booting kernel from Legacy Image at
> > > > a0000000 ...
> > > > > Image Name: linux
> > > > > Image Type: AArch64 Linux Kernel Image (gzip compressed)
> > > > > Data Size: 9110442 Bytes = 8.7 MiB
> > > > > Load Address: 81000000
> > > > > Entry Point: 81000000
> > > > > Verifying Checksum ... OK
> > > > > ## Flattened Device Tree blob at a1000000
> > > > > Booting using the fdt blob at 0xa1000000
> > > > > Uncompressing Kernel Image ... OK
> > > > > using: FDT
> > > > > reserving fdt memory region: addr=80000000 size=10000
> > > > > Loading Device Tree to 000000009fff6000, end 000000009ffff2f8 ...
> > > > > OK ## Transferring control to Linux (at address 81000000)...
> > > > >
> > > > > Starting kernel ...
> > > > >
> > > > > I get no kernel logs after this. I am failing to understand why.
> > > > > Can you please help me in debugging this issue?
> > > >
> > > > Why are you using a legacy image on AArch64 at all? You should be
> > > > using either the kernel Image (and booti) or a FIT image.
> > >
> > > This issue is coming even if I use FIT image.
> > >
> > > => bootm 0xa0000000#lx2160ardb
> > > ## Current stack ends at 0xfbb24400 ## Loading kernel from FIT Image
> > > at
> > > a0000000 ...
> > > Using 'lx2160ardb' configuration
> > > Trying 'kernel' kernel subimage
> > > Description: ARM64 Kernel
> > > Type: Kernel Image
> > > Compression: gzip compressed
> > > Data Start: 0xa00000d0
> > > Data Size: 9110442 Bytes = 8.7 MiB
> > > Architecture: AArch64
> > > OS: Linux
> > > Load Address: 0x81000000
> > > Entry Point: 0x81000000
> > > Hash algo: crc32
> > > Hash value: 39f59891
> > > Verifying Hash Integrity ... crc32+ OK ## Loading ramdisk from
> > > FIT Image at
> > > a0000000 ...
> > > Using 'lx2160ardb' configuration
> > > Trying 'initrd' ramdisk subimage
> > > Description: initrd for arm64
> > > Type: RAMDisk Image
> > > Compression: uncompressed
> > > Data Start: 0xa08b055c
> > > Data Size: 29171975 Bytes = 27.8 MiB
> > > Architecture: AArch64
> > > OS: Linux
> > > Load Address: 0x00000000
> > > Entry Point: 0x00000000
> > > Hash algo: crc32
> > > Hash value: 23038325
> > > Verifying Hash Integrity ... crc32+ OK ## Loading fdt from FIT
> > > Image at
> > > a0000000 ...
> > > Using 'lx2160ardb' configuration
> > > Trying 'lx2160ardb-dtb' fdt subimage
> > > Description: lx2160ardb-dtb
> > > Type: Flat Device Tree
> > > Compression: uncompressed
> > > Data Start: 0xa249071c
> > > Data Size: 25337 Bytes = 24.7 KiB
> > > Architecture: AArch64
> > > Load Address: 0x90000000
> > > Hash algo: crc32
> > > Hash value: 8e4d595f
> > > Verifying Hash Integrity ... crc32+ OK
> > > Loading fdt from 0xa249071c to 0x90000000
> > > Booting using the fdt blob at 0x90000000
> > > Uncompressing Kernel Image ... OK
> > > using: FDT
> > > reserving fdt memory region: addr=80000000 size=10000
> > > Loading Device Tree to 000000009fff6000, end 000000009ffff2f8 ...
> > > OK ## Transferring control to Linux (at address 81000000)...
> > >
> > > Starting kernel ...
> > >
> > >
> > > >
> > > > --
> > > > Tom
--- Begin Message ---
Hi Mark,
> -----Original Message-----
> From: Mark Rutland <[email protected]>
> Sent: Friday, 10 May, 2019 07:11 PM
> To: Pankaj Bansal <[email protected]>
> Cc: Catalin Marinas <[email protected]>; Will Deacon
> <[email protected]>; Ard Biesheuvel <[email protected]>; Wasim
> Khan <[email protected]>; Varun Sethi <[email protected]>; linux-arm-
> [email protected]
> Subject: Re: [ARMv8] kernel entry point
>
> Hi Pankaj,
>
> On Fri, May 10, 2019 at 01:24:55PM +0000, Pankaj Bansal wrote:
> > + Ard,
> > Hi Ard,
> >
> > Can you please check below mail? We are not able to boot linux loading
> > Image at 16MB offset (0x81000000) from DDR start address (0x80000000)
> > I have tested with both u-boot as well as atf.
> >
> > This issue is occurring with latest kernel (5.1) Image. If I revert
> > kernel code to commit a7f8de168ace ("arm64: allow kernel Image to be
> > loaded anywhere in physical memory "), then this issue doesn't occur.
>
> That commit allows the 2MiB base to be arbitrary, but the text_offset must
> still
> be taken into account. That's all documented in:
>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel
> .org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Ftree%
> 2FDocumentation%2Farm64%2Fbooting.txt%3Fh%3Dv5.1%23n125&data=
> 02%7C01%7Cpankaj.bansal%40nxp.com%7C045f77d8202040db896108d6d54d1
> 5f2%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636930924443311
> 148&sdata=nOHlA67bfSc21hS0kTnHGJ%2BqxSa2KvAGnRPq7%2FEQgmg%3
> D&reserved=0
>
> .. where we say:
>
> | The Image must be placed text_offset bytes from a 2MB aligned base
> | address anywhere in usable system RAM and called there. The region
> | between the 2 MB aligned base address and the start of the image has
> | no special significance to the kernel, and may be used for other purposes.
> | At least image_size bytes from the start of the image must be free for
> | use by the kernel.
>
> ... and where text_offset is defined in the Image header:
>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel
> .org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Ftree%
> 2FDocumentation%2Farm64%2Fbooting.txt%3Fh%3Dv5.1%23n73&data=0
> 2%7C01%7Cpankaj.bansal%40nxp.com%7C045f77d8202040db896108d6d54d15
> f2%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6369309244433111
> 48&sdata=Zw2JQ176V6cFXz%2BFcS1uJuYkCZUISjHI%2Bb3HNnkf30k%3D&a
> mp;reserved=0
>
> On a contemporary defconfig kernel, text_offset is 0x80000, so
> 0x81000000 is not a valid address to load the kernel at.
>
> I suspect that things will work if you load your kernel at 0x81080000.
Thank you for this tip. It worked.
>
> I would strongly recommend you use a bootloader that parses the kernel Image
> header, and respects text_offset automatically.
I am using u-boot. I don't know if uboot takes into account text_offset in
kernel Image header.
I don't think it's there, otherwise uboot would have given an error to respect
the load address requirements.
I will ask uboot maintainer if such checks (load address = 2MB aligned +
text_offset) can be added in uboot.
Thanks again for your help.
>
> Thanks,
> Mark.
>
> >
> > Do you know why the support of "loading kernel Image anywhere in
> > memory" has been removed in latest kernel ?
> >
> > Regards,
> > Pankaj Bansal
> >
> > > -----Original Message-----
> > > From: Pankaj Bansal
> > > Sent: Tuesday, 7 May, 2019 04:03 PM
> > > To: 'Catalin Marinas' <[email protected]>; 'Will Deacon'
> > > <[email protected]>
> > > Cc: '[email protected]' <linux-arm-
> > > [email protected]>; Varun Sethi <[email protected]>
> > > Subject: [ARMv8] kernel entry point
> > >
> > > Hi Catalin/Will et. Al,
> > >
> > > I am s/w engineer from NXP India Pvt. Ltd.
> > > I am facing an issue while booting linux on our ARMv8 based platform.
> > > In our platform DDR address starts from 0x80000000.
> > > If I load kernel image @ address 0x80080000 and then try to boot
> > > linux image from this address, then linux is booting fine.
> > > BUT if I load kernel image @ address 0x81000000 and then try to boot
> > > linux image from this address, then linux is not booting.
> > > I have tried to boot linux using u-boot as well as arm trusted firmware.
> > > Linux is not booting with either of these if the linux load address is
> 0x81000000.
> > >
> > > I get no kernel logs like "[ 0.000000] Booting Linux on physical CPU
> > > 0x0"
> > >
> > > The linux version that I am using is 4.14.53 Can you please help me
> > > in debugging this issue?
> > >
> > > Regards,
> > > Pankaj Bansal
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > [email protected]
> > https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists
> > .infradead.org%2Fmailman%2Flistinfo%2Flinux-arm-
> kernel&data=02%7C0
> >
> 1%7Cpankaj.bansal%40nxp.com%7C045f77d8202040db896108d6d54d15f2%7C
> 686ea
> >
> 1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636930924443311148&sda
> ta=Ykm
> > rBwDOYYLdrOtWFDeBxY2on3xwBP%2F8O1seKm9aiio%3D&reserved=0
--- End Message ---
_______________________________________________
U-Boot mailing list
[email protected]
https://lists.denx.de/listinfo/u-boot
