On Fri, Nov 29, 2024 at 12:19 AM Conor Dooley <conor@xxxxxxxxxx> wrote: > > On Thu, Nov 28, 2024 at 03:50:09PM +0100, Alexandre Ghiti wrote: > > On 28/11/2024 15:14, Conor Dooley wrote: > > > On Thu, Nov 28, 2024 at 01:41:36PM +0000, Will Deacon wrote: > > > > On Thu, Nov 28, 2024 at 12:56:55PM +0000, Conor Dooley wrote: > > > > > On Sun, Nov 03, 2024 at 03:51:53PM +0100, Alexandre Ghiti wrote: > > > > > > In order to produce a generic kernel, a user can select > > > > > > CONFIG_COMBO_SPINLOCKS which will fallback at runtime to the ticket > > > > > > spinlock implementation if Zabha or Ziccrse are not present. > > > > > > > > > > > > Note that we can't use alternatives here because the discovery of > > > > > > extensions is done too late and we need to start with the qspinlock > > > > > > implementation because the ticket spinlock implementation would pollute > > > > > > the spinlock value, so let's use static keys. > > > > > > > > > > > > This is largely based on Guo's work and Leonardo reviews at [1]. > > > > > > > > > > > > Link: https://lore.kernel.org/linux-riscv/20231225125847.2778638-1-guoren@xxxxxxxxxx/ [1] > > > > > > Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> > > > > > > Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx> > > > > > This patch (now commit ab83647fadae2 ("riscv: Add qspinlock support")) > > > > > breaks boot on polarfire soc. It dies before outputting anything to the > > > > > console. My .config has: > > > > > > > > > > # CONFIG_RISCV_TICKET_SPINLOCKS is not set > > > > > # CONFIG_RISCV_QUEUED_SPINLOCKS is not set > > > > > CONFIG_RISCV_COMBO_SPINLOCKS=y > > > > I pointed out some of the fragility during review: > > > > > > > > https://lore.kernel.org/all/20241111164259.GA20042@willie-the-truck/ > > > > > > > > so I'm kinda surprised it got merged tbh :/ > > > Maybe it could be reverted rather than having a broken boot with the > > > default settings in -rc1. > > > > > > No need to rush before we know what's happening,I guess you bisected to this > > commit right? > > The symptom is a failure to boot, without any console output, of course > I bisected it before blaming something specific. But I don't think it is > "rushing" as having -rc1 broken with an option's default is a massive pain > in the arse when it comes to testing. > > > I don't have this soc, so can you provide $stval/$sepc/$scause, a config, a > > kernel, anything? > > I don't have the former cos it died immediately on boot. config is > attached. It reproduces in QEMU so you don't need any hardware. If QEMU could reproduce, could you provide a dmesg by the below method? Qemu cmd append: -s -S ref: https://qemu-project.gitlab.io/qemu/system/gdb.html Connect gdb and in console: 1. file vmlinux 2. source ./Documentation/admin-guide/kdump/gdbmacros.txt 3. dmesg Then, we could get the kernel's early boot logs from memory. > > > Does the polarfire soc provide Ziccrse? > > I don't think that is relevant because ziccrse is not listed in the dts, > so the kernel should not be assuming that LR/SC has a forward progress > guarantee. It's not even getting as far as riscv_spinlock_init() given > several things before that should be emitting logs, so it doesn't even > get to make any decisions about Ziccrse. -- Best Regards Guo Ren
