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?
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
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