On Wed, Nov 6, 2019 at 12:14 PM Rick Chen rickchen36@gmail.com wrote:
Hi Anup
On Tue, Nov 5, 2019 at 7:19 AM Rick Chen rickchen36@gmail.com wrote:
Hi Anup
On Thu, Oct 31, 2019 at 1:42 PM Anup Patel anup@brainfault.org wrote:
On Thu, Oct 31, 2019 at 6:30 AM Alan Kao alankao@andestech.com wrote: > > Hi Bin, > > Thanks for the critics. Comments below. > On Wed, Oct 30, 2019 at 06:38:00PM +0800, Bin Meng wrote: > > Hi Rick, > > > > On Wed, Oct 30, 2019 at 10:50 AM Rick Chen rickchen36@gmail.com wrote: > > > > > > Hi Bin > > > > > > > > > > > Hi Rick, > > > > > > > > On Fri, Oct 25, 2019 at 2:18 PM Andes uboot@andestech.com wrote: > > > > > > > > > > From: Rick Chen rick@andestech.com > > > > > > > > > > It will work fine due to hart 0 always will be main > > > > > hart coincidentally. When develop SPL flow, I try to > > > > > force other harts to be main hart. And it will go > > > > > wrong in sending IPI flow. So fix it. > > > > > > > > Fix what? Does this commit contain 2 fixes, or just 1 fix? > > > > > > Yes, it include two fixs. But they will cause one negative result > > > that only hart 0 can send ipi to other harts. > > > > > > > > > > > > > > > > > Having this fix, any hart can be main hart in U-Boot SPL > > > > > theoretically, but it still fail somewhere. After dig in > > > > > and found there is an assumption that hart 0 shall be > > > > > main hart in OpenSbi. > > > > > > > > So does this mean there is a bug in OpenSBI too? > > > > > > I am not sure if it is a bug. Maybe it is a compatible issue. > > > There is a limitation that only hart 0 can be main hart in OpenSBI. > > > > I don't think OpenSBI has such limitation. > > > > Please check the source. > https://github.com/riscv/opensbi/blob/master/firmware/fw_base.S#L54 > > Apparently, the FIRST TWO LINEs of the initialization are the > 1. get hart ID. > 2. determine which route to take based on their ID respectively. > > So, I do think OpenSBI has this signature, if you are not willing to call it > a limitation.
This dependency on hart id #0 was not there until we added self-relocation in OpenSBI for FW_DYNAMIC.
I will try to fix this in OpenSBI but we might end-up having boot_lottery.
I have send a patch to fix this OpenSBI: "[PATCH] firmware: Introduce relocation lottery"
Can you try above patch and see if that helps ?
It will be great if you can provide Tested-by to my patch as well.
I can not find this patch in mailing list. Can you provide a hyperlink ?
You can try latest riscv/opensbi master.
I have tested the patch on SiFive Unleashed multiple times.
I have tried this patch, but it fail firmware: Introduce relocation lottery( 98f4a208995b027662a7b04a25e4fa5df5f3eefe)
The scenario was as below: There are 4 harts run in U-Boot SPL, hart 0 play as main hart. The hart 1 will receive ipi and come into OpenSBI(0x1000000) from U-Boot SPL(0x0), meanwhile hart 0,2,3 still run in U-Boot SPL. Then hart 1 will do _relocate_copy_to_lower which will copy data from 0x1000000 to 0x0. And it will corrupt U-Boot SPL.
The self-relocation in OpenSBI firmwares ensures that OpenSBI firmware are moved to the FW_TEXT_START before entering C code. This helps us load OpenSBI firmwares anywhere in RAM.
However, OpenSBI firmwares don't know where the U-Boot SPL is running.
In your case, both OpenSBI FW_DYNAMIC and U-Boot SPL are linked to address same address 0x0. This means secondary HARTs cannot safely wait while primary HART enters OpenSBI. You should hold secondary HARTs in U-Boot SPL only till OpenSBI FW_DYNAMIC and U-Boot proper are loaded in RAM by primary HART. All your HARTs should jump to OpenSBI at the same time after everything is loaded in RAM.
Regards, Anup