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 :/ Will
