On Fri, 19 Apr 2024 at 16:04, Chintan Vankar <c-van...@ti.com> wrote: > > > > On 18/04/24 17:30, Sughosh Ganu wrote: > > On Thu, 18 Apr 2024 at 16:08, Chintan Vankar <c-van...@ti.com> wrote: > >> > >> > >> > >> On 17/04/24 21:34, Tom Rini wrote: > >>> On Wed, Apr 17, 2024 at 05:48:31PM +0530, Sughosh Ganu wrote: > >>>> hi Chintan, > >>>> > >>>> On Wed, 17 Apr 2024 at 13:21, Chintan Vankar <c-van...@ti.com> wrote: > >>>>> > >>>>> > >>>>> > >>>>> On 16/04/24 22:30, Tom Rini wrote: > >>>>>> On Tue, Apr 16, 2024 at 05:52:58PM +0530, Chintan Vankar wrote: > >>>>>>> > >>>>>>> > >>>>>>> On 12/04/24 03:37, Tom Rini wrote: > >>>>>>>> On Wed, Apr 03, 2024 at 06:18:01PM +0530, Chintan Vankar wrote: > >>>>>>>>> > >>>>>>>>> > >>>>>>>>> On 22/01/24 10:11, Siddharth Vadapalli wrote: > >>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> On 20/01/24 22:11, Tom Rini wrote: > >>>>>>>>>>> On Mon, Jan 15, 2024 at 01:42:51PM +0530, Siddharth Vadapalli > >>>>>>>>>>> wrote: > >>>>>>>>>>>> Hello Tom, > >>>>>>>>>>>> > >>>>>>>>>>>> On 12/01/24 18:56, Tom Rini wrote: > >>>>>>>>>> > >>>>>>>>>> ... > >>>>>>>>>> > >>>>>>>>>>>>> The list of conditionals in common/spl/spl.c::board_init_r() > >>>>>>>>>>>>> should be > >>>>>>>>>>>>> updated and probably use SPL_NET as the option to check for. > >>>>>>>>>>>> > >>>>>>>>>>>> Thank you for reviewing the patch and pointing this out. I > >>>>>>>>>>>> wasn't aware of it. I > >>>>>>>>>>>> assume that you are referring to the following change: > >>>>>>>>>>>> > >>>>>>>>>>>> if (IS_ENABLED(CONFIG_SPL_OS_BOOT) || > >>>>>>>>>>>> CONFIG_IS_ENABLED(HANDOFF) || > >>>>>>>>>>>> - IS_ENABLED(CONFIG_SPL_ATF)) > >>>>>>>>>>>> + IS_ENABLED(CONFIG_SPL_ATF) || > >>>>>>>>>>>> IS_ENABLED(CONFIG_SPL_NET)) > >>>>>>>>>>>> dram_init_banksize(); > >>>>>>>>>>>> > >>>>>>>>>>>> I shall replace the current patch with the above change in the > >>>>>>>>>>>> v2 series. Since > >>>>>>>>>>>> this is in the common section, is there a generic reason I could > >>>>>>>>>>>> provide in the > >>>>>>>>>>>> commit message rather than the existing commit message which > >>>>>>>>>>>> seems to be board > >>>>>>>>>>>> specific? Also, I hope that the above change will not cause > >>>>>>>>>>>> regressions for > >>>>>>>>>>>> other non-TI devices. Please let me know. > >>>>>>>>>>> > >>>>>>>>>>> Yes, that's the area, and just note that networking also requires > >>>>>>>>>>> the > >>>>>>>>>>> DDR to be initialized. > >>>>>>>>>>> > >>>>>>>>>> > >>>>>>>>>> Thank you for confirming and providing your suggestion for the > >>>>>>>>>> contents of the > >>>>>>>>>> commit message. > >>>>>>>>>> > >>>>>>>>> Following Tom's Suggestion of adding CONFIG_SPL_NET in > >>>>>>>>> common/spl/spl.c > >>>>>>>>> "dram_init_banksize()", the issue of fetching a file at SPL stage > >>>>>>>>> seemed > >>>>>>>>> to be fixed. However the commit "ba20b2443c29", which sets > >>>>>>>>> gd->ram_top > >>>>>>>>> for the very first time in "spl_enable_cache()" results in > >>>>>>>>> "arch_lmb_reserve()" function reserving memory region from Stack > >>>>>>>>> pointer > >>>>>>>>> at "0x81FFB820" to gd->ram_top pointing to "0x100000000". Previously > >>>>>>>>> when gd->ram_top was zero "arch_lmb_reserve()" was noop. Now using > >>>>>>>>> TFTP > >>>>>>>>> to fetch U-Boot image at SPL stage results in > >>>>>>>>> "tftp_init_load_addr()" > >>>>>>>>> function call that invokes "arch_lmb_reserve()" function, which > >>>>>>>>> reserves > >>>>>>>>> entire memory starting from Stack Pointer to gd->ram_top leaving no > >>>>>>>>> space to load U-Boot image via TFTP since TFTP loads files at pre > >>>>>>>>> configured memory address at "0x82000000". > >>>>>>>>> > >>>>>>>>> As a workaround for this issue, one solution we can propose is to > >>>>>>>>> disable the checks "lmb_get_free_size()" at SPL and U-Boot stage. > >>>>>>>>> For > >>>>>>>>> that we can define a new config option for LMB reserve checks as > >>>>>>>>> "SPL_LMB". This config will be enable by default for the backword > >>>>>>>>> compatibility and disable for our use case at SPL and U-Boot stage. > >>>>>>>> > >>>>>>>> The problem here is that we need LMB for booting an OS, which is > >>>>>>>> something we'll want in SPL in non-cortex-R cases too, which means > >>>>>>>> this > >>>>>>>> platform, so that's a no-go. I think you need to dig harder and see > >>>>>>>> if > >>>>>>>> you can correct the logic somewhere so that we don't over reserve? > >>>>>>>> > >>>>>>> Since this issue is due to function call "lmb_init_and_reserve()" > >>>>>>> function invoked from "tftp_init_load_addr()" function. This function > >>>>>>> is defined by Simon in commit "a156c47e39ad", which fixes > >>>>>>> "CVE-2018-18439" to prevent overwriting reserved memory. Simon, can > >>>>>>> you > >>>>>>> explain why do we need to call "lmb_init_and_reserve()" function here > >>>>>>> ? > >>>>>> > >>>>>> This is indeed a tricky area which is why Sughosh is looking in to > >>>>>> trying to re-work the LMB mechanic and we've had a few long threads > >>>>>> about it as well. > >>>>>> > >>>>>> I've honestly forgotten the use case you have here, can you please > >>>>>> remind us? > >>>>>> > >>>>> We are trying to boot AM62x using Ethernet for which we need to load > >>>>> binary files at SPL and U-Boot stage using TFTP. To store the file we > >>>>> need a free memory in RAM, specifically we are storing these files at > >>>>> 0x82000000. But we are facing an issue while loading the file since > >>>>> the memory area having an address 0x82000000 is reserved due to > >>>>> "lmb_init_and_reserve()" function call. This function is called in > >>>>> "tftp_init_load_addr()" function which is getting called exactly before > >>>>> we are trying to get the free memory area by calling > >>>>> "lmb_get_free_size()". > >>>> > >>>> I have no idea about your platform but I was wondering if there is any > >>>> particular importance of the load address of 0x82000000? It looks as > >>>> though the current location of the SP when arch_lmb_reserve() gets > >>>> called means that the load address is getting reserved for the U-Boot > >>>> image. Do you not have the option of loading the image at a lower > >>>> address instead? > >>> > >> > >> Sughosh, > >> > >> I think my explanation was not clear at: > >> "We are trying to boot AM62x using Ethernet for which we need to load > >> binary files at SPL and U-Boot stage using TFTP." > >> - In Ethernet Booting we are fetching U-Boot image at SPL stage via > >> TFTP at specified address 0x82000000. While loading U-Boot image we are > >> getting TFTP error, since address from stack pointer till gd->ram_top is > >> reserved due to "lmb_init_and_reserve()" function call. I want to know > >> for which purpose this address range is reserved. > > > > On relocation, the U-Boot image is located typically at the top of the > > DRAM memory used by U-Boot(ram_top). That region of memory is reserved > > to ensure that the memory occupied by the U-Boot image does not get > > overwritten by a LMB reservation. > > > > Yes, you are correct about U-Boot relocation but we are facing an issue > at the time of fetching U-Boot proper at SPL stage.
The arch_lmb_reserve_generic() function would reserve the memory region from the ram_top to the current SP. Btw, you mentioned in an earlier reply that you are trying to load the U-Boot image at 0x82000000. From the config file it looks like that is the address of your SPL stack in RAM. So you might be overwriting your SPL stack. I think you can try a couple of things. One, move the SPL image above the SPL stack, like it is with U-Boot -- I think the way things stand, the SPL image is at a lower address than the SP. And then use a lower address to load the U-Boot image with tftp. -sughosh > > > Btw, are you facing this issue in SPL, or U-Boot proper? I built the > > images for the am62x_evm_a53 config, and I don't see the > > We are getting "TFTP error" at runtime while fetching U-Boot proper at > SPL stage while booting via "Ethernet", and we are using > "am62x_evm_a53_ethboot_defconfig" instead of "am62x_evm_a53_defconfig". > > These are the extra configs we are using on top of > "am62x_evm_a53_defconfig": > > CONFIG_SPL_DRIVERS_MISC=y > CONFIG_SPL_BOARD_INIT=y > CONFIG_SPL_DMA=y > CONFIG_SPL_ENV_SUPPORT=y > CONFIG_SPL_ETH=y > CONFIG_SPL_NET=y > CONFIG_SPL_NET_VCI_STRING="AM62X U-Boot A53 SPL" > CONFIG_SPL_SYSCON=y > > > arch_lmb_reserve() function getting included in the SPL image -- both > > the .text.arch_lmb_reserve and .text.arch_lmb_reserve_generic are part > > of discarded sections. So I am wondering how you are observing this > > behaviour in SPL. > > > > -sughosh > > > >> > >>> Or using a higher address for SPL stack? You might be able to solve this > >>> just by re-examining which addresses (and RAM size limitations) need to > >>> be considered here. > >>> > >> > >> Tom, > >> > >> We tried this approach of assigning a higher address for SPL stack, but > >> it is not working as expected.