On 02.08.21 15:04, Tom Rini wrote: > On Mon, Aug 02, 2021 at 01:54:57PM +0200, Jan Kiszka wrote: >> On 02.08.21 13:38, Marek Vasut wrote: >>> On 8/2/21 1:36 PM, Jan Kiszka wrote: >>>> On 02.08.21 12:48, Marek Vasut wrote: >>>>> On 8/2/21 11:37 AM, Jan Kiszka wrote: >>>>>> On 02.08.21 02:54, Marek Vasut wrote: >>>>>>> On 7/29/21 6:58 PM, Tom Rini wrote: >>>>>>> >>>>>>> [...] >>>>>>> >>>>>>>>>> so when did rcar3 introduce something there that shouldn't be >>>>>>>>>> reserved? And you had phrased this to me on IRC as about reserving >>>>>>>>>> spot >>>>>>>>>> for ATAGS, and that not being needed of course on arm64. But >>>>>>>>>> that's >>>>>>>>>> not >>>>>>>>>> what's going on. Perhaps the answer is that rcar3 needs to >>>>>>>>>> introduce a >>>>>>>>>> board_lmb_reserve to free the normal arch one and provide whatever >>>>>>>>>> more >>>>>>>>>> narrow scope it needs. >>>>>>>>> >>>>>>>>> Based on the commit message 2359fa7a878 ("arm: bootm: Disable LMB >>>>>>>>> reservation for command line and board info on arm64") , this is >>>>>>>>> about ATAGS >>>>>>>>> and we really don't need to reserve those on arm64. >>>>>>>> >>>>>>>> Commit 2359fa7a878 disables the entire arch_lmb_reserve function on >>>>>>>> aarch64, yes. I assumed when we had talked that it was a small area >>>>>>>> being set aside and perhaps mis-recalled that ATAGS tended to live at >>>>>>>> DDR_BASE + 0x800 or so. >>>>>>> >>>>>>> That arch_lmb_reserve() is responsible for reserving architecture >>>>>>> specific memory. On arm32 it is ATAGS, on arm64 it is nothing as >>>>>>> far as >>>>>>> I can tell (and see below regarding the TLB). >>>>>>> >>>>>>>> This reservation is not at that spot, and a lot >>>>>>>> more than that. >>>>>>> >>>>>>> Can you please elaborate on this "lot more" part ? Because as much >>>>>>> as I >>>>>>> studied the reservation code, the "lot more" was ATAGS on arm32 and >>>>>>> nothing on arm64. >>>>>> >>>>>> See my commit log. >>>>> >>>>> This is not particularly useful answer, considering the commit log says: >>>>> "lot of crucial things", "Possibly more", "likely also on other boards" >>>>> and other opaque statements. But really, the problem so far happens on >>>>> one K3 board. >>>> >>>> "Such things are the page table (tlb_addr), >>>> relocated U-Boot and the active stack." >>> >>> Please read the rest of my answer, I don't believe the TLB should be >>> reserved at all. DTTO for the stack. If you think otherwise, please >>> explain why. >> >> Marek, I've provided you with three generic examples of active memory >> blocks that are relevant while U-Boot is allocating from and also >> filling that LMB. Please follow those cases and explain to us why they >> aren't active - or at least prove why they are specific the k3 (for >> which I found no traces). >> >> And stop following the TLB topic for now. That was only my first guess. >> The actual crash I'm seeing on my board come from plain code >> overwriting. It could have been TLB as well. It could also have been the >> stack. All those become unprotected via your reservation removal. > > Jan, one thing I didn't see before is, are you also using > include/configs/ti_armv7_common.h in the end, like the K3 reference > platforms, and if not are you setting bootm_size in your environment? I > have one more idea on why this fails on your board but not Marek's. > Thanks. >
We are including that header but we didn't use DEFAULT_LINUX_BOOT_ENV, in fact. That left bootm_size undefined. Can you explain the impact? Jan -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux