From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Tue, 29 Aug 2017 09:15:30 +0100 Subject: ARM64 kernel Image size limitations? In-Reply-To: References: <02d56481-bba0-fd32-17d8-9f3760d09148@gmail.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 28 August 2017 at 22:24, Florian Fainelli wrote: > (fixed Will's address, apologies) > > On 08/28/2017 01:01 PM, Ard Biesheuvel wrote: >> Hi, >> >> On 28 August 2017 at 20:55, Florian Fainelli wrote: >>> Hi, >>> >>> I have been fighting with a reasonably large kernel Image: 46MB and >>> found unable to boot it. This is on v4.13-rc6, but I could go back as >>> far as v4.9~ish. It is so big, because it's got some debugging enabled, >>> and the initramfs compression is disabled, but still that ought to be >>> possible. >>> >>> After some experimentation I found that the breaking size is somewhere >>> around 33MB total for arch/arm64/boot/Image and when that happens, I get >>> the following backtrace which suggests that there is some memory >>> corruption of some kind (or so it seems to me), other experiments >>> indicated that the backtrace may point back to where the bootloader had >>> set up its exception vector. I am fairly confident that the bootloader >>> is not responsible for corrupting the Image that is loaded. >>> >>> Is there such a size limitation or am I possibly tripping over something >>> else? >>> >> >> What boot environment are you using? Is it possible the DTB is copied >> on top of the kernel by the boot loader? > > Bootloader is BOLT (Broadcom's own implementation, has PSCI and is > capable of doing FDT live patching), and yes the DTB is provided by the > bootloader at an address higher than the kernel. > > Physical offset of the RAM on this platform is 0, so the load is going > to be at PA 0x80000, 0x80000 + size (35MB) = 0x2280000, DTB is placed at > 0x771f000 and is 0x90ef bytes. > Could you try to dump __log_buf from gdb?