On Thu, 9 Feb 2017 13:22:37 +0100 Jonas Gorski <jonas.gorski@xxxxxxxxx> wrote: > Hi, > > On 5 February 2017 at 21:21, Alban <albeu@xxxxxxx> wrote: > > From: Alban Bedel <albeu@xxxxxxx> > > > > 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@xxxxxxx> > > --- > > 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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