> On Jun 2, 2019, at 9:22 PM, Rick Chen <rickche...@gmail.com> wrote: > > Hi Troy > >>> From: Troy Benjegerdes [mailto:troy.benjeger...@sifive.com] >>> Sent: Saturday, June 01, 2019 12:24 AM >>> To: Auer, Lukas >>> Cc: Rick Jian-Zhi Chen(陳建志); bmeng...@gmail.com; pal...@sifive.com >>> Subject: Re: Hart lottery and CONFIG_XIP >>> >>> >>> >>>> On May 31, 2019, at 9:13 AM, Auer, Lukas <lukas.a...@aisec.fraunhofer.de> >>> wrote: >>>> >>>> Hi Troy, >>>> >>>> On Fri, 2019-05-31 at 08:18 -0500, Troy Benjegerdes wrote: >>>>> Wouldn't the following line in head.S fail when running from flash >>>>> (although maybe not in a way that prevents booting) >>>>> >>>>> /* save the boot hart id to global_data */ >>>>> SREG tp, GD_BOOT_HART(gp) >>>>> >>>>> Shouldn’t this be protected by CONFIG_XIP? >>>> >>>> The boot hart ID is stored in global data, which is allocated from the >>>> stack (in board_init_f_alloc_reserve() ). It is therefore writable and >>>> won't cause any issues when running from flash. >>> >>> Sorry about the confusion, I was reading it wrong earlier. >>> >>> I’m hoping to have a couple of patches ready later today to change the >>> CONFIG_XIP patch to ‘CONFIG_HART_LOTTERY’ since it is also useful to >>> remove the potential indeterminism of which hart wins the lottery when doing >>> board bringup and debugging. > > I am OK with that. > Actually my preliminary patch about > [PATCH 0/4] AE350 support SMP boot from flash > did as your wish. > > You can refer it : > [PATCH 1/4] riscv: hart_lottery and available harts feature can be seletable > https://www.mail-archive.com/u-boot@lists.denx.de/msg323419.html > > Rick
To follow up on https://www.mail-archive.com/u-boot@lists.denx.de/msg323526.html It is confusing and misleading to mix CONFIG_XIP and CONFIG_HART_LOTTERY. From an system testing and validation point of view, I would find it much better (especially at very early boot stages, where U-boot might be the first non-ROM code running) to have a deterministic process to determine what core runs U-boot. This necessarily seems as it will require a CONFIG_BOOT_HART option, as we are not in a position to parse a device tree in head.S _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
