> Subject: Re: [PATCH] cpu: imx8_cpu: Avoid revision to corrupt device > tree > > On Thu, Oct 17, 2024 at 01:10:02AM +0000, Peng Fan wrote: > > > Subject: Re: [PATCH] cpu: imx8_cpu: Avoid revision to corrupt > device > > > tree > > > > > > On Sat, Oct 12, 2024 at 12:16:14AM +0000, Peng Fan wrote: > > > > > Subject: Re: [PATCH] cpu: imx8_cpu: Avoid revision to corrupt > > > device > > > > > tree > > > > > > > > > > > Why isn't this padding and alignment with the BSS being > taken > > > care > > > > > of > > > > > > in either the linker script or the binman dts? > > > > > > > > Sorry, I am not sure what you mean. > > > > > > I mean, why are things placed in this position to start with? Why is > > > the device tree not already in a place where we aren't smashing it > > > at run time? Is this a problem of the alignment / placement of items > in a blob? > > > A runtime placement problem? What? > > > > Whether binman or not. I think u-boot.dtb is padded just end of > > u-boot-nodtb.bin. Not alignment or else. > > > > This is a common issue, bss should not be written before reloc_fdt. > > It's possible I'm missing the examples in my quick grep right now but, > yes, why are you needing to make this device tree change so early? We > should not be using the "put this in the data section" kludge unless > strictly necessary. Why is this necessary and cannot wait until, well, > further along in the boot? This is supposed to be for pre-DRAM- > initialization stuff.
You may misunderstand. It is imx8_cpu driver probe at pre reloc stage before reloc_fdt, so the written to bss area in imx8_cpu driver will corrupt device tree which padded after u-boot-nodtb.bin. Then after reloc_fdt, the new dtb is actually a broken one. Regards, Peng. > > -- > Tom
