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Groups > linux.kernel > #1574273 > unrolled thread
| Started by | Alban <albeu@free.fr> |
|---|---|
| First post | 2017-02-05 21:30 +0100 |
| Last post | 2017-02-13 12:00 +0100 |
| Articles | 5 — 3 participants |
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[PATCH] MIPS: Allow compressed images to be loaded at the usual address Alban <albeu@free.fr> - 2017-02-05 21:30 +0100
Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2017-02-06 10:00 +0100
Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address Jonas Gorski <jonas.gorski@gmail.com> - 2017-02-09 13:30 +0100
Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address Alban <albeu@free.fr> - 2017-02-13 09:40 +0100
Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address Jonas Gorski <jonas.gorski@gmail.com> - 2017-02-13 12:00 +0100
| From | Alban <albeu@free.fr> |
|---|---|
| Date | 2017-02-05 21:30 +0100 |
| Subject | [PATCH] MIPS: Allow compressed images to be loaded at the usual address |
| Message-ID | <t7BBG-3FO-81@gated-at.bofh.it> |
From: Alban Bedel <albeu@free.fr> Normally compressed images have to be loaded at a different address to allow the decompressor to run. This add an option to let vmlinuz copy itself to the correct address from the normal vmlinux address. Signed-off-by: Alban Bedel <albeu@free.fr> --- arch/mips/Kconfig | 8 ++++++++ arch/mips/boot/compressed/head.S | 13 +++++++++++++ 2 files changed, 21 insertions(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index b3c5bde..8074fc5 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -2961,6 +2961,14 @@ choice bool "Extend builtin kernel arguments with bootloader arguments" endchoice +config ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS + bool "Load compressed images at the same address as uncompressed" + depends on SYS_SUPPORTS_ZBOOT + help + vmlinux and vmlinuz normally have different load addresses, with + this option vmlinuz expect to be loaded at the same address as + vmlinux. + endmenu config LOCKDEP_SUPPORT diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S index 409cb48..a215171 100644 --- a/arch/mips/boot/compressed/head.S +++ b/arch/mips/boot/compressed/head.S @@ -25,6 +25,19 @@ start: move s2, a2 move s3, a3 +#ifdef CONFIG_ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS + /* Move the text, data section and DTB to the correct address */ + PTR_LA a0, .text + PTR_LI a1, VMLINUX_LOAD_ADDRESS + PTR_LA a2, _edata +0: + lw a3, 0(a1) + sw a3, 0(a0) + addiu a1, a1, 4 + bne a2, a0, 0b + addiu a0, a0, 4 +#endif + /* Clear BSS */ PTR_LA a0, _edata PTR_LA a2, _end -- 2.7.4
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| From | Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> |
|---|---|
| Date | 2017-02-06 10:00 +0100 |
| Subject | Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address |
| Message-ID | <t7Nju-2A1-45@gated-at.bofh.it> |
| In reply to | #1574273 |
Hello!
On 2/5/2017 11:21 PM, Alban wrote:
> From: Alban Bedel <albeu@free.fr>
>
> Normally compressed images have to be loaded at a different address to
> allow the decompressor to run. This add an option to let vmlinuz copy
> itself to the correct address from the normal vmlinux address.
>
> Signed-off-by: Alban Bedel <albeu@free.fr>
[...]
Just some grammar nitpicking...
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index b3c5bde..8074fc5 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -2961,6 +2961,14 @@ choice
> bool "Extend builtin kernel arguments with bootloader arguments"
> endchoice
>
> +config ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS
> + bool "Load compressed images at the same address as uncompressed"
> + depends on SYS_SUPPORTS_ZBOOT
> + help
> + vmlinux and vmlinuz normally have different load addresses, with
> + this option vmlinuz expect to be loaded at the same address as
Expects.
[...]
MBR, Sergei
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| From | Jonas Gorski <jonas.gorski@gmail.com> |
|---|---|
| Date | 2017-02-09 13:30 +0100 |
| Message-ID | <t8W1k-66e-11@gated-at.bofh.it> |
| In reply to | #1574273 |
Hi, On 5 February 2017 at 21:21, Alban <albeu@free.fr> wrote: > From: Alban Bedel <albeu@free.fr> > > Normally compressed images have to be loaded at a different address to > allow the decompressor to run. This add an option to let vmlinuz copy > itself to the correct address from the normal vmlinux address. > > Signed-off-by: Alban Bedel <albeu@free.fr> > --- > arch/mips/Kconfig | 8 ++++++++ > arch/mips/boot/compressed/head.S | 13 +++++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig > index b3c5bde..8074fc5 100644 > --- a/arch/mips/Kconfig > +++ b/arch/mips/Kconfig > @@ -2961,6 +2961,14 @@ choice > bool "Extend builtin kernel arguments with bootloader arguments" > endchoice > > +config ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS > + bool "Load compressed images at the same address as uncompressed" > + depends on SYS_SUPPORTS_ZBOOT > + help > + vmlinux and vmlinuz normally have different load addresses, with > + this option vmlinuz expect to be loaded at the same address as > + vmlinux. > + > endmenu Okay, it took me a while to understand the intention of this change. I thought it was for supporting the case that VMLINUZ_LOAD_ADDRESS == VMLINUX_LOAD_ADDRESS, but it is indented for VMLINUZ_LOAD_ADDRESS != VMLINUX_LOAD_ADDRESS, but still being loaded at VMLINUX_LOAD_ADDRESS. So I guess that this can only happen with vmlinuz.bin, as vmlinux's ELF header will cause it to be loaded at the expected address (for sane bootloaders at least). > config LOCKDEP_SUPPORT > diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S > index 409cb48..a215171 100644 > --- a/arch/mips/boot/compressed/head.S > +++ b/arch/mips/boot/compressed/head.S > @@ -25,6 +25,19 @@ start: > move s2, a2 > move s3, a3 > > +#ifdef CONFIG_ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS With a bit of BAL trickery you could easily detect this at runtime and then conditionally copy without requiring any additional config symbols. Then you aren't limited to being executed from VMLINUX_LOAD_ADDRESS. > + /* Move the text, data section and DTB to the correct address */ > + PTR_LA a0, .text > + PTR_LI a1, VMLINUX_LOAD_ADDRESS > + PTR_LA a2, _edata > +0: > + lw a3, 0(a1) > + sw a3, 0(a0) > + addiu a1, a1, 4 > + bne a2, a0, 0b > + addiu a0, a0, 4 > +#endif > + > /* Clear BSS */ > PTR_LA a0, _edata > PTR_LA a2, _end Regards Jonas
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| From | Alban <albeu@free.fr> |
|---|---|
| Date | 2017-02-13 09:40 +0100 |
| Subject | Re: [PATCH] MIPS: Allow compressed images to be loaded at the usual address |
| Message-ID | <takkW-1fk-3@gated-at.bofh.it> |
| In reply to | #1577527 |
[Multipart message — attachments visible in raw view] — view raw
On Thu, 9 Feb 2017 13:22:37 +0100 Jonas Gorski <jonas.gorski@gmail.com> wrote: > Hi, > > On 5 February 2017 at 21:21, Alban <albeu@free.fr> wrote: > > From: Alban Bedel <albeu@free.fr> > > > > Normally compressed images have to be loaded at a different address to > > allow the decompressor to run. This add an option to let vmlinuz copy > > itself to the correct address from the normal vmlinux address. > > > > Signed-off-by: Alban Bedel <albeu@free.fr> > > --- > > arch/mips/Kconfig | 8 ++++++++ > > arch/mips/boot/compressed/head.S | 13 +++++++++++++ > > 2 files changed, 21 insertions(+) > > > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig > > index b3c5bde..8074fc5 100644 > > --- a/arch/mips/Kconfig > > +++ b/arch/mips/Kconfig > > @@ -2961,6 +2961,14 @@ choice > > bool "Extend builtin kernel arguments with bootloader arguments" > > endchoice > > > > +config ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS > > + bool "Load compressed images at the same address as uncompressed" > > + depends on SYS_SUPPORTS_ZBOOT > > + help > > + vmlinux and vmlinuz normally have different load addresses, with > > + this option vmlinuz expect to be loaded at the same address as > > + vmlinux. > > + > > endmenu > > Okay, it took me a while to understand the intention of this change. I > thought it was for supporting the case that VMLINUZ_LOAD_ADDRESS == > VMLINUX_LOAD_ADDRESS, but it is indented for VMLINUZ_LOAD_ADDRESS != > VMLINUX_LOAD_ADDRESS, but still being loaded at VMLINUX_LOAD_ADDRESS. > > So I guess that this can only happen with vmlinuz.bin, as vmlinux's > ELF header will cause it to be loaded at the expected address (for > sane bootloaders at least). Yes, this is for bootloaders that use raw images. Having to configure different load addresses for compressed and uncompressed images was just too annoying. > > config LOCKDEP_SUPPORT > > diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S > > index 409cb48..a215171 100644 > > --- a/arch/mips/boot/compressed/head.S > > +++ b/arch/mips/boot/compressed/head.S > > @@ -25,6 +25,19 @@ start: > > move s2, a2 > > move s3, a3 > > > > +#ifdef CONFIG_ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS > > With a bit of BAL trickery you could easily detect this at runtime and > then conditionally copy without requiring any additional config > symbols. Then you aren't limited to being executed from > VMLINUX_LOAD_ADDRESS. Could you expand a bit on what you mean with "BAL trickery"? I hoped that it would be possible to auto detect the current running address, but as I know very little about MIPS assembly I didn't found how that could be done. Alban
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| From | Jonas Gorski <jonas.gorski@gmail.com> |
|---|---|
| Date | 2017-02-13 12:00 +0100 |
| Message-ID | <tamwp-2Cb-3@gated-at.bofh.it> |
| In reply to | #1579525 |
Hi,
On 13 February 2017 at 09:37, Alban <albeu@free.fr> wrote:
> On Thu, 9 Feb 2017 13:22:37 +0100
> Jonas Gorski <jonas.gorski@gmail.com> wrote:
>
>> Hi,
>>
>> On 5 February 2017 at 21:21, Alban <albeu@free.fr> wrote:
>> > From: Alban Bedel <albeu@free.fr>
>> >
>> > Normally compressed images have to be loaded at a different address to
>> > allow the decompressor to run. This add an option to let vmlinuz copy
>> > itself to the correct address from the normal vmlinux address.
>> >
>> > Signed-off-by: Alban Bedel <albeu@free.fr>
>> > ---
>> > arch/mips/Kconfig | 8 ++++++++
>> > arch/mips/boot/compressed/head.S | 13 +++++++++++++
>> > 2 files changed, 21 insertions(+)
>> >
>> > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
>> > index b3c5bde..8074fc5 100644
>> > --- a/arch/mips/Kconfig
>> > +++ b/arch/mips/Kconfig
>> > @@ -2961,6 +2961,14 @@ choice
>> > bool "Extend builtin kernel arguments with bootloader arguments"
>> > endchoice
>> >
>> > +config ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS
>> > + bool "Load compressed images at the same address as uncompressed"
>> > + depends on SYS_SUPPORTS_ZBOOT
>> > + help
>> > + vmlinux and vmlinuz normally have different load addresses, with
>> > + this option vmlinuz expect to be loaded at the same address as
>> > + vmlinux.
>> > +
>> > endmenu
>>
>> Okay, it took me a while to understand the intention of this change. I
>> thought it was for supporting the case that VMLINUZ_LOAD_ADDRESS ==
>> VMLINUX_LOAD_ADDRESS, but it is indented for VMLINUZ_LOAD_ADDRESS !=
>> VMLINUX_LOAD_ADDRESS, but still being loaded at VMLINUX_LOAD_ADDRESS.
>>
>> So I guess that this can only happen with vmlinuz.bin, as vmlinux's
>> ELF header will cause it to be loaded at the expected address (for
>> sane bootloaders at least).
>
> Yes, this is for bootloaders that use raw images. Having to configure
> different load addresses for compressed and uncompressed images was just
> too annoying.
>
>> > config LOCKDEP_SUPPORT
>> > diff --git a/arch/mips/boot/compressed/head.S b/arch/mips/boot/compressed/head.S
>> > index 409cb48..a215171 100644
>> > --- a/arch/mips/boot/compressed/head.S
>> > +++ b/arch/mips/boot/compressed/head.S
>> > @@ -25,6 +25,19 @@ start:
>> > move s2, a2
>> > move s3, a3
>> >
>> > +#ifdef CONFIG_ZBOOT_VMLINUZ_AT_VMLINUX_LOAD_ADDRESS
>>
>> With a bit of BAL trickery you could easily detect this at runtime and
>> then conditionally copy without requiring any additional config
>> symbols. Then you aren't limited to being executed from
>> VMLINUX_LOAD_ADDRESS.
>
> Could you expand a bit on what you mean with "BAL trickery"? I hoped
> that it would be possible to auto detect the current running address,
> but as I know very little about MIPS assembly I didn't found how that
> could be done.
With BAL (branch and link) you can do a pc-relative jump, and the
current address will be stored in $ra. comparing it with the expected
address will give you the offset by which you were loaded. To quote
the lzma-loader from OpenWrt/Lede[1]:
la t0, __reloc_label # get linked address of label
bal __reloc_label # branch and link to label to
nop # get actual address
__reloc_label:
subu t0, ra, t0 # get reloc_delta
beqz t0, __reloc_done # if delta is 0 we are in the
right place
nop
/* Copy our code to the right place */
la t1, _code_start # get linked address of _code_start
la t2, _code_end # get linked address of _code_end
addu t0, t0, t1 # calculate actual address of
_code_start
__reloc_copy:
...
__reloc_done:
...
Regards
Jonas
[1] https://git.lede-project.org/?p=source.git;a=blob;f=target/linux/ar71xx/image/lzma-loader/src/head.S;h=47a7c9bd6300ad92e6a0d426c5f44bc0f3e7e85f;hb=HEAD#l49
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